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1
Pires, Lucas Alves Sarmento, Graciele de Caro Reis Machado, Rodrigo Mota Pacheco Fernandes, Jorge Henrique Martins Manaia, João Francisco Silva Champs, and Marcio Antonio Babinski. "Notes on the Accessory Flexor Carpi Ulnaris Muscle: A Rare Supernumerary Variation." Journal of Morphological Sciences 36, no. 02 (February 28, 2019): 138–40. http://dx.doi.org/10.1055/s-0039-1681108.
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AbstractVariations of the forearm muscles are well described in the literature. In spite of that, reports regarding the accessory flexor carpi ulnaris muscle are scarce due to its rarity. This muscle usually originates from the medial epicondyle of the humerus with the flexor muscle mass and inserts itself into the palmar aponeurosis or the pisiform bone together with the flexor carpi ulnaris muscle. Supernumerary and anomalous muscles of the anterior compartment of the forearm have been associated with ulnar nerve and artery compression. Furthermore, they may also mimic neuromas and soft tissue tumors. The study of supernumerary muscles is necessary, as they may be an option to tendon grafts and muscle flaps. The aim of this paper is to describe the presence of the accessory flexor carpi ulnaris muscle on the left forearm of a cadaver fixated in a phenol solution and discuss its clinical and anthropological significance.
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Teo, Wendy Z. W., Reshvinder Kaur, and Sandeep Sebastin. "Traumatic Rupture of the Flexor Carpi Ulnaris Muscle Belly in a Circus Rigger." Journal of Hand Surgery (Asian-Pacific Volume) 26, no. 02 (January 11, 2021): 274–79. http://dx.doi.org/10.1142/s2424835521720073.
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Closed traumatic rupture of forearm flexor muscles has been reported rarely. Previous reports have included ruptures of the flexor digitorum profundus, flexor digitorum superficialis, flexor pollicis longus, flexor carpi radialis, pronator quadratus and the palmaris longus. We report a patient with a closed traumatic rupture through the muscle belly of the flexor carpi ulnaris and summarise the published literature on ruptures involving the forearm flexor muscles. Overall, conservative treatment can result in excellent outcomes. Early surgical intervention is recommended in patients with nerve involvement and compartment syndrome and delayed reconstruction may be considered for patients with functional deficits.
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Nayak, Soubhagya R., Suranjali Sharma, Hasi Dasgupta, and Kalyan Bhattacharya. "PRESENCE OF TRIPLE GANTZER'S MUSCLE - A RARE ANATOMICAL VARIATION." Journal of Health and Allied Sciences NU 03, no. 01 (March 2013): 69–71. http://dx.doi.org/10.1055/s-0040-1703638.
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AbstractAnomalous muscles usually do not result in adverse symptoms but are of academic interest. However, these muscles can create neurovascular compression at times. Muscle anomalies of the upper extremity are recognized causes of peripheral nerve disorder. Koloh-Nevin Syndrome (Anterior Interosseous Nerve Syndrome) caused by the compression neuropathy of the anterior interosseous nerve in the forearm is believed to occur because of its compression by the accessory heads of flexor pollics longus (FPLah) and flexor digitorum profundus (FDPah). The above two accessory muscles are also called Gantzer's muscle. During routine cadaveric dissection, we encountered multiple Gantzer's muscles in a 60 year-old- formalin embalmed male cadaver. Along with the usual FPLah and FDPah described by Gantzer, we too observed an accessory muscle in relation to the flexor digitorum superficialis (FDS). All the three anomalous muscles had a common origin from the under cover of the FDS fibers and by fibrous band above the insertion of brachialis. The presence of multiple additional muscles in the forearm flexor compartment is rare and clinically significant.
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Couzens, Greg, and Graham Kerr. "Anticipatory and Reactive Response to Falls: Muscle Synergy Activation of Forearm Muscles." Hand Surgery 20, no. 03 (September 21, 2015): 343–51. http://dx.doi.org/10.1142/s0218810415400067.
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We investigated the surface electromyogram response of six forearm muscles to falls onto the outstretched hand. The extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris, abductor pollicis longus, flexor carpi radialis and flexor carpi ulnaris muscles were sampled from eight volunteers who underwent ten self-initiated falls. All muscles initiated prior to impact. Co-contraction is the most obvious surface electromyogram feature. The predominant response is in the radial deviators. The surface electromyogram timing we recorded would appear to be a complex anticipatory response to falling modified by the effect on the forearm muscles following impact. The mitigation of the force of impact is probably more importantly through shoulder abduction and extension and elbow flexion rather than action of the forearm muscles.
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Dai, Chenyun, and Xiaogang Hu. "Extracting and Classifying Spatial Muscle Activation Patterns in Forearm Flexor Muscles Using High-Density Electromyogram Recordings." International Journal of Neural Systems 29, no. 01 (January 10, 2019): 1850025. http://dx.doi.org/10.1142/s0129065718500259.
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The human hand is capable of producing versatile yet precise movements largely owing to the complex neuromuscular systems that control our finger movement. This study seeks to quantify the spatial activation patterns of the forearm flexor muscles during individualized finger flexions. High-density (HD) surface electromyogram (sEMG) signals of forearm flexor muscles were obtained, and individual motor units were decomposed from the sEMG. Both macro-level spatial patterns of EMG activity and micro-level motor unit distributions were used to systematically characterize the forearm flexor activation patterns. Different features capturing the spatial patterns were extracted, and the unique patterns of forearm flexor activation were then quantified using pattern recognition approaches. We found that the forearm flexor spatial activation during the ring finger flexion was mostly distinct from other fingers, whereas the activation patterns of the middle finger were least distinguishable. However, all the different activation patterns can still be classified in high accuracy (94–100%) using pattern recognition. Our findings indicate that the partial overlapping of neural activation can limit accurate identification of specific finger movement based on limited recordings and sEMG features, and that HD sEMG recordings capturing detailed spatial activation patterns at both macro- and micro-levels are needed.
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Mewes, K., and P. D. Cheney. "Facilitation and suppression of wrist and digit muscles from single rubromotoneuronal cells in the awake monkey." Journal of Neurophysiology 66, no. 6 (December 1, 1991): 1965–77. http://dx.doi.org/10.1152/jn.1991.66.6.1965.
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1. The output effects of 214 cells in the magnocellular red nuclei of two rhesus monkeys (Macaca mulatta) were tested with spike-triggered averaging of electromyogram (EMG) activity from six forearm extensor and six flexor muscles. The monkeys performed an alternating wrist movement task (auxotonic paradigm) or generated wrist torque trajectories alternating between flexion and extension (isometric paradigm). 2. Sixty-five cells (30%) were identified as rubromotoneuronal (RM) cells on the basis of their postpike effects on forearm flexor and extensor muscles. Three major types of RM cell output organization were identified: 1) pure facilitation (28 cells), 2) reciprocal (18 cells), and 3) cofacilitation (16 cells). 3. RM cell output showed a strong preference for facilitation of extensor forearm muscles. This preference was reflected in the fact that 69% (43 of 62) of RM cells facilitated extensors exclusively or most strongly; 27% facilitated flexors exclusively or most strongly; and 5% facilitated flexors and extensors equally. Postspike facilitation (PSpF) was observed in 45% of the extensor muscles and 20% of the flexors tested. In contrast, postpike suppression (PSpS) was observed in 3% of the extensors and 7% of the flexors. 4. The mean number of extensors facilitated per RM cell was 3.1 (53% of tested) compared with 2.8 (51% of tested) flexors facilitated per cell. The extensor and flexor PSpS muscle field sizes were both 2.0 (35% of extensors and 36% of flexors tested). The mean number of muscles facilitated by cofacilitation cells was 5.8 (48%) per cell. No clear preference was found for facilitation of particular combinations of synergist muscles. 5. PSpF magnitude was assessed by measuring both the percent change of facilitation or suppression from baseline and the signal-to-noise ratio of effects. The overall average magnitudes of RM PSpF and PSpS were 4.1 +/- 2.0 and 4.0 +/- 2.3% change from baseline, respectively. The average magnitude of PSpF in flexors was not significantly different from that of extensors; neither was there a difference in the average magnitude of PSpS in flexors and extensors. 6. The mean onset latency of RM cell PSpS was greater than PSpF (9.2 +/- 3.0 vs. 5.7 +/- 1.8 ms; P less than or equal to 0.05). This can be attributed to an underlying minimal disynaptic linkage to motoneurons for suppression effects, whereas most PSpFs are probably mediated by underlying monosynaptic connections. The mean onset latency of flexor PSpFs was greater than that of extensors (6.4 +/- 2.3 vs. 5.4 +/- 1.5 ms; P less than or equal to 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)
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Vallence, Ann-Maree, Geoffrey R. Hammond, and Karen T. Reilly. "Increase in flexor but not extensor corticospinal motor outputs following ischemic nerve block." Journal of Neurophysiology 107, no. 12 (June 15, 2012): 3417–27. http://dx.doi.org/10.1152/jn.01118.2010.
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Human motor cortex is capable of rapid and long-lasting reorganization, evident globally, as shifts in body part representations, and at the level of individual muscles as changes in corticospinal excitability. Representational shifts provide an overview of how various body parts reorganize relative to each other but do not tell us whether all muscles in a given body part reorganize in the same manner and to the same extent. Transcranial magnetic stimulation (TMS) provides information about individual muscles and can therefore inform us about the uniformity of plastic changes within a body part. We used TMS to investigate changes in corticospinal excitability of forearm flexors and extensors after inflation of a tourniquet around the wrist. Motor evoked potential (MEP) amplitudes and input/output (I/O) curves were obtained from wrist flexors and extensors simultaneously before and during block. TMS was delivered to the optimal site for eliciting MEPs in flexors in experiment 1, extensors in experiment 2, and both flexors and extensors in experiment 3. In all experiments flexor MEP amplitude increased during block while extensor MEP amplitude showed no systematic change, and the slope of flexor but not extensor I/O curves increased. Flexor H-reflex amplitude normalized to maximal M wave showed negligible changes during block, suggesting that the increase in corticospinal excitability in the flexors cannot be completely explained by increased excitability at the spinal cord level. These findings show that forearm flexors and extensors differ in their potential for plastic changes, highlight the importance of investigating how experimentally induced plasticity affects anatomically close, but functionally distinct, muscle groups, and suggest that rehabilitation interventions aiming to alter cortical organization should consider the differential sensitivity of various muscle groups to plasticity processes.
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Hafez, S. "A report on the accessory head of Flexor Pollicis Longus and Variations of Forearm Musculature." Journal of Morphological Sciences 34, no. 02 (April 2017): 098–106. http://dx.doi.org/10.4322/jms.103616.
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Abstract Introduction: Gantzer's muscle has drawn attention from several authors owing to the possibility of interosseous nerve compression. This is a report of an accessory head of flexor pollicis longus (FPL, a variant of Gantzer's muscle) and a review of the variations of all muscles of the forearm. Materials and Methods: An accessory head of FPL was discovered in both the right and left antebrachial regions during a cadaver dissection. The muscle was dissected and photographed. Results: The anatomical variation I report is a slender conical muscle joining the FPL. Its origin merged with fibers of the flexor digitorum superficialis. It inserted into the upper part of the middle third of the forearm by joining the medial tendinous part of the FPL; this join was by means of a short cylindrical tendon. The reported muscle was innervated by the anterior interosseous nerve, which was seen to be present posterolateral to the muscle in both forearms. Conclusion: The described muscle might cause pressure problems to the underlying structures especially the anterior interosseous nerve. Variations must be considered during surgical intervention to avoid unintentional damage to healthy tendons. In addition, accessory tendons can potentially be useful in the repair or replacement of damaged tendons through surgical transfer or transplantation. Variations of muscles, especially accessory muscles, may mimic the behavior of soft tissue tumors and can result in nerve compressions. This collection of variations of the forearm musculature will be useful to surgeons in practice as well as students in dissection labs.
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Mustafa, Amal Yousif Ahmed Elhag, Abdullah Glil Alkushi, Wardah Abdullah Mohammed Alasmari, Ashraf Mohamed Elsayed Ali Sakran, and Asma Mohammed Elamin. "ANATOMICAL STUDY OF THE ACCESSORY HEADS OF THE DEEP FLEXOR MUSCLES OF THE FOREARM (GANTZER MUSCLES)." International Journal of Anatomy and Research 4, no. 4.1 (October 31, 2016): 2984–87. http://dx.doi.org/10.16965/ijar.2016.389.
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Rubin, G., R. Palti, S. Gurevitz, and B. Yaffe. "Free myocutaneous flap transfer to treat congenital Volkmann’s contracture of the forearm." Journal of Hand Surgery (European Volume) 40, no. 6 (March 24, 2014): 614–19. http://dx.doi.org/10.1177/1753193414528850.
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The purpose of this study is to report our experience with free functional muscle transfer procedures for the late sequelae of the rare condition of congenital Volkmann’s ischaemic contracture of the forearm. Four children, with an average age of 9.5 years (range 1.5–17), were treated and were followed for a mean of 6 years (range 1–14). Two patients had dorsal forearm contractures, and two had both flexor and extensor forearm contractures. We carried out free functional muscle transfers to replace the flexor or extensor muscles. The functional result was assessed according to the classification system of Hovius and Ultee. All patients had wrist contractures and skeletal involvement with limb length discrepancy that influenced the outcome. All five transferred muscles survived and improved the function of the hand in three of the four patients. Level of evidence: 4
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Pressney, Ian, Bhavin Upadhyay, Sherine Dewlett, Michael Khoo, Anastasia Fotiadou, and Asif Saifuddin. "Accessory flexor carpi ulnaris: case report and review of the literature." BJR|case reports 6, no. 3 (September 2020): 20200010. http://dx.doi.org/10.1259/bjrcr.20200010.
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Most of the accessory muscles of the forearm described in the radiology literature are located either in the radial aspect of the forearm or towards the hypothenar eminence. We present an unusual case of an ulnar-sided distal forearm accessory flexor carpi ulnaris muscle presenting as a “pseudotumour“ demonstrated with both ultrasound and MRI, rarely reported in the current surgical and anatomical literature. Given the location and relation to the ulnar nerve towards Guyon’s canal, the accessory muscle may also predispose to distal ulnar nerve entrapment.
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Belhaj-Saïf, Abderraouf, and Paul D. Cheney. "Plasticity in the Distribution of the Red Nucleus Output to Forearm Muscles After Unilateral Lesions of the Pyramidal Tract." Journal of Neurophysiology 83, no. 5 (May 1, 2000): 3147–53. http://dx.doi.org/10.1152/jn.2000.83.5.3147.
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It has been hypothesized that the magnocellular red nucleus (RNm) contributes to compensation for motor impairments associated with lesions of the pyramidal tract. To test this hypothesis, we used stimulus triggered averaging (StTA) of electromyographic (EMG) activity to characterize changes in motor output from the red nucleus after lesions of the pyramidal tract. Three monkeys were trained to perform a reach and prehension task. EMG activity was recorded from 11 forearm muscles including one elbow, five wrist, and five digit muscles. Microstimulation (20 μA at 20 Hz) was delivered throughout the movement task to compute StTAs. Two monkeys served as controls. In a third monkey, 65% of the left pyramidal tract had been destroyed by an electrolytic lesion method five years before recording. The results demonstrate a clear pattern of postlesion reorganization in red nucleus–mediated output effects on forearm muscles. The normally prominent extensor preference in excitatory output from the RNm (92% in extensors) was greatly diminished in the lesioned monkey (59%). Similarly, suppression effects, which are normally much more prominent in flexor than in extensor muscles (90% in flexors), were also more evenly distributed after recovery from pyramidal tract lesions. Because of the limited excitatory output from the RNm to flexor muscles that normally exists, loss of corticospinal output would leave control of flexors particularly weak. The changes in RNm organization reported in this study would help restore function to flexor muscles. These results support the hypothesis that the RNm is capable of reorganization that contributes to the recovery of forelimb motor function after pyramidal tract lesions.
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Malar, D. "Bilateral Variation of Forearm Flexor Muscles - A Case Report and Clinical Significance." National Journal of Clinical Anatomy 01, no. 01 (January 2012): 040–43. http://dx.doi.org/10.1055/s-0039-3401657.
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AbstractDuring routine dissection, bilateral multiple variations of forearm flexor muscles were observed in a male cadaver. The variations were a) an additional belly arising from the coronoid process of ulna, distal to the origin of ulnar head of flexor digitorum superficialis, passing deep to flexor digitorum superficialis and joining the tendon of flexor digitorum profundus to the middle finger; b) an additional belly arising from the distal part of flexor carpi ulnaris and passing superficial to ulnar nerve and ulnar vessels in the Guyon's canal and c) the origin of second lumbricals from the profundus tendon in the carpal tunnel. An aberrant muscle may stimulate a ganglion or a soft tissue tumor or if in close proximity to a nerve, it may cause pressure neuritis. Identification of these variations is important in defining the anatomical features for clinical diagnosis and surgical procedures.
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Joo Oh, Hyun, Yee Kyoung Ko, Sa Sun Cho, and Sang Pil Yoon. "A Cadaveric Study of Needle Insertion at Pc6 in Eight Wrists of Four Subjects and An Understanding of the Anatomy." Acupuncture in Medicine 30, no. 1 (March 2012): 44–46. http://dx.doi.org/10.1136/acupmed-2011-010092.
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The anatomical structures vulnerable to acupuncture around the PC6 acupuncture point were investigated. Needles were inserted in PC6 of eight wrists from four cadavers to a depth of 2 cm, the forearms were dissected and the adjacent structures around the path of the needles were observed. The needles passed between the tendons of the palmaris longus and flexor carpi radialis muscles and then penetrated the flexor digitorum superficialis, flexor digitorum profundus and pronator quadratus muscles. The inserted needles were located adjacent to the median nerve. To minimise the risk of unintended injury by acupuncture, it is recommended that needles should not be inserted deeply at the PC6 acupuncture point. An understanding of the anatomical variations of the median nerve and the persistent median artery in the forearm is of clinical importance when performing acupuncture procedures.
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Alam, Mohd Mukhtar, Abid Ali Khan, and Mohd Farooq. "Effects of vibratory massage therapy on grip strength, endurance time and forearm muscle performance." Work 68, no. 3 (March 26, 2021): 619–32. http://dx.doi.org/10.3233/wor-203397.
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BACKGROUND: Vibration therapy (VT) causes an increase in motor unit activation tendency, an involuntary recruitment of earlier sedentary motor units, which increases the muscle fiber force generating capacity and muscle performance. OBJECTIVE: To evaluate the effect of vibratory massage therapy at 23 Hz and 35 Hz on grip strength, endurance, and forearm muscle performance (in terms of EMG activity). METHODS: Ten healthy and right-handed men participated voluntarily in this study. The experiment was characterized by the measurement of MVC (maximal voluntary contraction) grip strength and grip endurance time at 50%MVC, accompanied by the corresponding measurement of the EMG signals of the muscles viz., flexor digitorum superficialis (FDS); flexor carpi ulnaris (FCU); extensor carpi radialis brevis (ECRB); and extensor carpi ulnaris (ECU) in supine posture. RESULTS: MANCOVA results showed significant effects of VT frequency on endurance time (p < 0.001); but no significant effect on the grip strength (p = 0.161) and muscle performance (in terms of EMG activities of the forearm muscles). However, VT improves the MVC grip strength and grip endurance time (better at 35 Hz). The Pearson correlation was significant between: weight, palm length, palm circumference, and forearm length with MVC grip strength; and the palm length with the endurance time. In addition, the palm length, palm circumference, and forearm circumference generally serve to better predict MVC grip strength and grip endurance time. CONCLUSIONS: Vibration therapy at 35 Hz for 10 minutes on the forearms had a significant positive effect on the neuromuscular performance to enhance muscle performance of upper extermitites and can be used as the optimal range to study the effect of VT. Findings may be used to prepare guidelines for VT in rehabilitation, healthcare, sports, and medical for therapists.
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Silva, Daniel Barbosa da, Paulo Cesar Moreira, Viviane Souza Cruz, Eduarda Pereira Santana, Alberto Corrêa Mendonça, and Júlio Roquete Cardoso. "Anatomical aspects of the forearm muscles of Myrmecophaga tridactyla." Acta Veterinaria Brasilica 15, no. 1 (March 31, 2021): 60–65. http://dx.doi.org/10.21708/avb.2021.15.1.9615.
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The giant anteater is one of the species classified as vulnerable to extinction. Burning and being run over are among important causes in the decrease of individuals of this species and a better knowledge of the anatomy of these animals can contribute to the treatment of injured animals and their restoration to the environment. Thus, the objective of this work was to describe aspects of the anatomy of the muscles of the forearm of M. tridactyla. For this purpose, six adult specimens were used, three females and three males. The corpses were fixed with a 10% formaldehyde solution and preserved in vats contai-ning the same solution. The thoracic limbs were dissected by routine dissection techniques. The forearm muscles of M. tridac-tyla were: brachioradialis; radial carpal extensor; common finger extensor; lateral finger extensor, ulnar carpal extensor; finger extensor I and II; long abductor of finger I; supinator, radial carpal flexor; ulnar flexor of the carpus, superficial flexor of the fingers, deep flexor of the fingers, pronator teres and square pronator, which were innervated by the radial, ulnar and median nerves. These muscles give a large volume to the forearm, are robust and have highly developed tendons, especially those invol-ved with the flexion of the carpus, digits and elbow, actions that are fundamental to your defense habits and search for food.
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Golubev, I. O., and S. A. Zhuravlyov. "Applied Anatomy of Median and Ulnar Nerve Branches in Operations for Forearm Muscles Neurotization." N.N. Priorov Journal of Traumatology and Orthopedics 21, no. 2 (June 15, 2014): 74–77. http://dx.doi.org/10.17816/vto20140274-77.
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To determine the potentialities of median nerve motor branches neurotization by the ulnar nerve and vice versa the anatomy of muscular branches of median and ulnar nerves in the forearm was studied in detail. Study was performed on 20 upper extremities from 10 adult cadavers. The number of branches, their length and precise place of divergence from the main trunk were assessed. It was stated that topographic anatomy of muscular branches of the median and ulnar nerves in the forearm was quite invariable. For neuratization from the median nerve the longest branches that passed to pronator teres muscles and superficial flexor muscle of fingers can be used; from the ulnar nerve - long branch to the ulnar flexor muscle of wrist.
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Golubev, I. O., and S. A. Zhuravlyov. "Applied Anatomy of Median and Ulnar Nerve Branches in Operations for Forearm Muscles Neurotization." Vestnik travmatologii i ortopedii imeni N.N. Priorova, no. 2 (June 30, 2014): 74–77. http://dx.doi.org/10.32414/0869-8678-2014-2-74-77.
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To determine the potentialities of median nerve motor branches neurotization by the ulnar nerve and vice versa the anatomy of muscular branches of median and ulnar nerves in the forearm was studied in detail. Study was performed on 20 upper extremities from 10 adult cadavers. The number of branches, their length and precise place of divergence from the main trunk were assessed. It was stated that topographic anatomy of muscular branches of the median and ulnar nerves in the forearm was quite invariable. For neuratization from the median nerve the longest branches that passed to pronator teres muscles and superficial flexor muscle of fingers can be used; from the ulnar nerve - long branch to the ulnar flexor muscle of wrist.
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Perlmutter, Steve I., Marc A. Maier, and Eberhard E. Fetz. "Activity of Spinal Interneurons and Their Effects on Forearm Muscles During Voluntary Wrist Movements in the Monkey." Journal of Neurophysiology 80, no. 5 (November 1, 1998): 2475–94. http://dx.doi.org/10.1152/jn.1998.80.5.2475.
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Perlmutter, Steve I., Marc A. Maier, and Eberhard E. Fetz. Activity of spinal interneurons and their effects on forearm muscles during voluntary wrist movements in the monkey. J. Neurophysiol. 80: 2475–2494, 1998. We studied the activity of 577 neurons in the C6–T1 spinal cord of three awake macaque monkeys while they generated visually guided, isometric flexion/extension torques about the wrist. Spike-triggered averaging of electromyographic activity (EMG) identified the units' correlational linkages with ≤12 forearm muscles. One hundred interneurons produced changes in the level of average postspike EMG with onset latencies consistent with mono- or oligosynaptic connections to motoneurons; these were classified as premotor interneurons (PreM-INs). Most PreM-INs (82%) produced postspike facilitations in forearm muscles. Earlier spike-related features, often beginning before the trigger spike, were seen in spike-triggered averages from 72 neurons. Postspike effects were present in one muscle for 64% of the PreM-INs. Neurons with divergent linkages to larger “muscle fields” usually generated postspike effects in synergistic muscles. Fifty-eight percent of the PreM-INs had postspike effects in flexor muscles only and 29% in extensor muscles only. Postspike effects were distributed relatively evenly among the primary flexor and extensor muscles studied. The mean percent change in EMG level from baseline and the mean onset latencies for postspike facilitations and postspike suppressions were similar. PreM-INs exhibited a variety of response patterns during the generation of isometric wrist torque. The response patterns and output effects of 24% of the PreM-INs were consistent with a strict reciprocal organization of flexor and extensor muscle control. For another 60% of the PreM-INs, there was a congruent relation between activity and output effects for only one direction of torque production. These neurons were active for both flexion and extension torques, including 37 neurons that exhibited bidirectional increases in discharge rate. The relatively small number of postspike suppressions observed suggests that inhibitory interneurons were silent when their target muscles were recruited. Compared with premotor neurons in the motor cortex, the red nucleus and the C8–T1 dorsal root ganglia, spinal PreM-INs affected flexor muscles in greater proportions and had smaller muscle fields. The magnitudes of postspike facilitations were similar in all premotor populations. Bidirectional activity, common for PreM-INs, was rare for corticomotoneuronal and premotor dorsal root ganglion cells, which discharge only for torques in their preferred direction.
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Guidi, Marco, Cesare Fusetti, and Stefano Lucchina. "Skeletal Muscle Metastases to the Flexor Digitorum Superficialis and Profundus from Urothelial Cell Carcinoma and Review of the Literature." Case Reports in Urology 2016 (2016): 1–5. http://dx.doi.org/10.1155/2016/2387501.
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Urothelial cell carcinoma (UCC) metastases to skeletal muscle are extremely rare and usually found in patients with advanced stage cancer. The most common sites of bladder cancer metastases are lymph nodes, lung, liver, and bones. Muscle is an unusual site of metastases from a distant primary cancer, due to several protective factors. We present a rare case of 76-year-old patient with metastases in the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) muscles, 2 years after a radical cystectomy for invasive UCC of the bladder. This case is the first description of a forearm lesion, with an extensive infiltration of the volar compartments of the forearm, and the first one with a clear functional impairment.
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Hong, Seok Woo, Jeong-Hyun Kang, Jong Seop Kim, and Hyun Sik Gong. "Association between forearm cortical bone properties and handgrip strength in women with distal radius fractures: A cross-sectional study." PLOS ONE 15, no. 12 (December 3, 2020): e0243294. http://dx.doi.org/10.1371/journal.pone.0243294.
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Objectives Mechanical and biochemical bone properties are influenced by muscles. However, the muscle-bone interaction has not been fully elucidated regarding the upper extremities. The objective of the present study was to evaluate the mechanical muscle-bone interaction at the forearm by evaluating the relationship between the properties of three-dimensional (3D) forearm cortical bone models derived from conventional computed tomography (CT) images and handgrip strength (HGS). Methods A total of 108 women (mean age, 75.2 ± 9.4 years; range, 62–101 years) with a distal radius fracture who took conventional CT scans for the assessment of the fracture were included in this study. Distal radius 3D models were reconstructed and the average cortical bone density (Cd) and thickness (Ct) of the region of interest (ROI), which might be affected by the forearm flexor muscles, were calculated using a 3D modeling software. Clinical parameters including HGS, lumbar and hip bone mineral densities (BMDs), and other demographic factors were also obtained. A multivariate linear regression analysis was performed to identify relevant factors associated with HGS. Results HGS was found to be independently associated with height and Cd, but no significant difference was found between HGS and Ct, age, weight, as well as lumber and hip BMDs. Conclusions Cortical bone density might be associated with HGS, which is generated by the forearm flexor muscles. Hence, the mechanical muscle-bone interaction in the upper extremities could be supported by the present study.
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Chakravarthi, Kosuri Kalyan. "Unilateral accessory muscles of forearm-and its clinical implications." Asian Journal of Medical Sciences 8, no. 2 (March 1, 2017): 94–96. http://dx.doi.org/10.3126/ajms.v8i2.10971.
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An accessory or aberrant musculature may stimulate a ganglion or a soft tissue tumour or if in close proximity to a nerve, it may cause pressure neuritis. Identification of these variations is important in defining the anatomical features for clinical diagnosis and surgical procedures. During routine cadaveric dissection of the forearm in the department of anatomy, we observed an accessory muscle in the flexor compartment and additional extensor carpi radialis longus muscle in the extensor compartment of the forearm in left upper limb of a middle aged female cadaver. The accessory muscle belly has taken its tendinous origin from the medial surface of the ulna deep to the flexor digitorum superficialis and crossed the median nerve from medial to lateral, when traced below in the carpal tunnel it merged with the tendon of the index finger of flexor digitorum superficialis. An additional extensor carpi radialis longus muscle with unusual course of radial nerve in the extensor compartment of the forearm was found on the medial side of brachioradialis and superficial to extensor carpi radialis longus and its tendon ended by getting inserted into the base of the dorsal surface of the second metacarpal bone. Although many anatomical variations of flexor digitorum superficialis and extensor carpi radialis longus muscle were reported in the past, we describe a rare case, first of its kind, which to our knowledge has not been mentioned in the literature till date. Such variations are clinically significant in the anatomical, surgical and radiological procedures. Asian Journal of Medical Sciences Vol.8(2) 2017 94-96
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CAETANO, EDIE BENEDITO, JOÃO PAULO NUNES TOLEDO, SÉRGIO APARECIDO DO AMARAL JÚNIOR, LUIZ ANGELO VIEIRA, BEATRIZ D’ANDREA PIGOSSI, and RENATO ALVES DE ANDRADE. "INNERVATION OF THE MEDIAN NERVE MOTOR BRANCHES IN THE FOREARM AND ITS CLINICAL SIGNIFICANCE." Acta Ortopédica Brasileira 28, no. 5 (October 2020): 251–55. http://dx.doi.org/10.1590/1413-785220202805235028.
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ABSTRACT Objective: To analyse the anatomical variations of the median nerve motor branches in the elbow region. Methods: Twenty upper limbs of 10 adult male cadavers were prepared by intra-arterial injection of a solution of 10% glycerol and formaldehyde. All cadavers belonged to the institution anatomy laboratory. Results: We found a great variability within the distribution of median nerve branches leading to forearm muscles. Only three limbs (14%) presented the normal standard of innervation described in anatomy treatises. The pronator teres muscle (PTM), flexor carpi radialis (FCR), palmaris longus (PL), and the flexor digitorum superficialis (FDS) received exclusive innervation from the median nerve in all forearms. The anterior interosseous nerve (AIN) also originated from the median nerve in all dissected limbs. Conclusion: A thorough understanding of the anatomy of the median nerve branches is important for performing surgeries such as: approach to the proximal third of the forearm, alleviation of pronator teres and anterior interosseous nerve compression syndromes, and distal nerve transfers. It also enables a better understanding the recovery of muscle function after a nerve injury. Level of Evidence IV, Case series.
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Paul, Rajendra D., Krishna Menon, and Chandra Nair. "Individual Differences in the Activity of Dominant Forearm Muscles during VDT Work." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 39, no. 13 (October 1995): 926–30. http://dx.doi.org/10.1177/154193129503901316.
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In two studies on VDT work, activity of dominant forearm muscles was measured using surface electromyography. In the first study (n = 12), subjects used only a keyboard; whereas in the second study (n = 8), subjects used both keyboard and mouse. In both studies, analysis of results indicated that inter-subject differences in forearm muscle effort were significantly different (p < 0.05). In the first study, the minimum-to-maximum ratio for average extensor muscle activity was 1:3.7. In the second study, the minimum-to-maximum ratio was 1:2.2 for the flexor muscle activity and 1:3.7 for the extensor muscle activity. These results support the notion of differences in individual workstyles proposed by Feuerstein (1995). Individual typing styles play an important role play an important role in the stress on forearm muscles during VDT work and should be included in employee training protocols.
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Bajpe, Roshni, Tarakeshwari R., and Shubha R. "Gantzer muscles; a study on 50 cadaveric upper limbs." National Journal of Clinical Anatomy 04, no. 04 (October 2015): 179–85. http://dx.doi.org/10.1055/s-0039-3401575.
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Abstract Background : Gantzer muscle is the name given to the additional head of Flexor Digitorum Profudus (FDP) or Flexor Pollicis Longus (FPL). It connects the superficial flexors and deep flexors of forearm. It sometimes may be related to Anterior Interosseous Nerve (AIN) and Ulnar artery causing Compressive Neuropathy or Vascular symptoms. Aim: To assess incidence of Gantzer muscle in South Indian population, its morphology and clinical significance. Materials and methods: The study was carried out on 50 upper limbs dissected by first year M.B.B.S students. Results : Nine upper limbs showed the presence of Gantzer muscle, three belonged to the right and six belonged to the left. Observations : Additional heads were associated as follows: From FDP-2 and from FPL-7. Innervation was either from Median nerve, Anterior Interosseous nerve or Ulnar nerve. Superficially median nerve was related, deep relations were Ulnar artery and Anterior Interosseous nerve. In one case, Median nerve and artery were related superficially. Conclusion: Gantzer muscle is important clinically as a cause of vascular or nerve compression.
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Pedowitz, Robert A., and Francois M. Toutounghi. "Chronic exertional compartment syndrome of the forearm flexor muscles." Journal of Hand Surgery 13, no. 5 (September 1988): 694–96. http://dx.doi.org/10.1016/s0363-5023(88)80126-6.
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Deuschl, Günther, Claudia Seifert, Florian Heinen, Michael Illert, and C. H. Lücking. "Reciprocal inhibition of forearm flexor muscles in spasmodic torticollis." Journal of the Neurological Sciences 113, no. 1 (November 1992): 85–90. http://dx.doi.org/10.1016/0022-510x(92)90269-q.
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OGINO, T., and K. OHNO. "A Case of Bipartite Median Nerve at the Wrist." Journal of Hand Surgery 16, no. 1 (February 1991): 96–97. http://dx.doi.org/10.1016/0266-7681(91)90140-j.
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We report a case of bipartite median nerve at the wrist associated with contracture of the flexor muscles in the forearm and anterior interosseous nerve palsy. The possibility of a bipartite median nerve must be borne in mind during operations on the distal forearm.
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Luger, Tessy, Robert Seibt, Monika Rieger, and Benjamin Steinhilber. "The Role of Motor Learning on Measures of Physical Requirements and Motor Variability During Repetitive Screwing." International Journal of Environmental Research and Public Health 16, no. 7 (April 6, 2019): 1231. http://dx.doi.org/10.3390/ijerph16071231.
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We investigated whether physical requirements and motor variability decreased over days in novices during a repetitive screwing task. Fifty-seven subjects performed one hour of repetitive screwing and fastening on three days, separated by 2–7 days. The average physical requirement and relative cycle-to-cycle variability (coefficient of variation, i.e., CV) were calculated from continuous recordings of electromyography of four arm muscles (biceps brachii, triceps brachii, flexor carpi radialis, extensor digitorum), forearm acceleration, and electrocardiography. Muscle activity levels, heart rate, and forearm acceleration decreased from day 1 to day 2 (range: ~4% to ~20%) and/or 3 (range: ~4% to ~28%). Not all muscles showed a similar pattern. Activity of the extensor digitorum and biceps brachii decreased already between days 1 and 2 (range: ~6% to ~13%), whereas activity of the flexor carpi radialis and triceps brachii decreased between days 1 and 3 (range: ~13% to ~20%). No changes in physical requirement were detected between days 2 and 3. Relative motor variability did not change across days, except that variability of forearm acceleration increased from day 1 to 3 (~5%). This study found consistent changes in physical requirements and indicated that several arm muscles show earlier decreases of muscular activity, like the extensor digitorum, compared to other body parts, like the flexor carpi radialis. Moreover, movement strategies may develop differently than muscle activation strategies, based on the different developments of physical requirements and motor variability. The development of physical requirements in industrial tasks is part of daily living and starts at task onset, highlighting the importance of task familiarization and the randomization of experimental conditions in scientific studies.
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Fleckenstein, J. L., D. Watumull, L. A. Bertocci, R. W. Parkey, and R. M. Peshock. "Finger-specific flexor recruitment in humans: depiction by exercise-enhanced MRI." Journal of Applied Physiology 72, no. 5 (May 1, 1992): 1974–77. http://dx.doi.org/10.1152/jappl.1992.72.5.1974.
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To evaluate the spatial distribution of human forearm musculature stressed by finger-specific exercise, magnetic resonance imaging was performed in conjunction with exercise protocols designed to separately stress the flexor digitorum superficialis and flexor digitorum profundus. These muscles were shown to consist of subvolumes selectively recruited by flexion of the individual fingers. Knowledge of the finger-specific regions of muscle recruitment during finger flexion could improve sampling accuracy in electromyography, biopsy, magnetic resonance spectroscopy, and invasive vascular sampling studies of hand exercise.
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Boutin, Robert, and Russell Fritz. "Musculotendinous Disorders in the Upper Extremity: Part 2. MRI of the Elbow, Forearm, Wrist, and Hand." Seminars in Musculoskeletal Radiology 21, no. 04 (August 3, 2017): 376–91. http://dx.doi.org/10.1055/s-0037-1604008.
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AbstractMuscle and tendon injuries about the elbow and more distal aspect of the upper arm are commonly evaluated and characterized with magnetic resonance imaging. This article reviews our experience with muscle and tendon injury as well as denervation of muscles. We focus on abnormalities of the biceps and the triceps tendons about the elbow as well as abnormalities of the flexor and extensor tendons about the elbow, forearm, wrist, and hand. We also discuss and illustrate our experience with lacerations, crush injuries, and muscle hernias in the forearm.
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Dellon, A. L., and Susan E. Mackinnon. "Musculoaponeurotic Variations along the Course of the Median Nerve in the Proximal Forearm." Journal of Hand Surgery 17, no. 6 (December 1992): 702. http://dx.doi.org/10.1016/0266-7681(92)90212-k.
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31 cadaver arms have been dissected to study the variations in the anatomy of the muscles and fibrous arches which might cause compression of the median nerve in the forearm. Pronator teres always had a superficial head and usually a deep head. Flexor digitorum superficialis varied greatly in its site of origin. The median nerve might be crossed by two, one or no fibro-aponeurotic arches. Gantzer's muscle, an accessory head of flexor pollicis longus, was present in 45% of cadavers. No ligament of Struthers was found. Possible sites and causes of nerve compression are discussed.
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Nathan, R. H. "The Isometric Action of the Forearm Muscles." Journal of Biomechanical Engineering 114, no. 2 (May 1, 1992): 162–69. http://dx.doi.org/10.1115/1.2891367.
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The isometric forces and moments generated at the hand segment by thirteen of the forearm muscles were measured on three test subjects. Small bipolar surface electrodes were used to activate each muscle separately. The direction of the force vector generated at the fingertips and the percentage torque generated about the longitudinal axis of the hand segment were measured and were modeled for one subject as a parabolic function of the position of the wrist and radioulnar joints in their ranges of motion. The results exhibited a high standard deviation. It is proposed that a significant component of this standard deviation is inherent in the biomechanics of the musculo-skeletal system. Variations in the test protocol were used to test this hypothesis. The standard deviation was found to be significantly larger in the flexor muscles than the extensors. It was concluded that the stability and elasticity of the soft tissue structures in the region of the wrist joint may significantly influence the direction of the generated joint moment vector.
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Rohilla, Aarti, Jyoti Rohilla, Kamal Singh, and Suresh Kanta Rathee. "Unilateral absence of musculocutaneus nerve and its clinical significance." International Journal of Research in Medical Sciences 5, no. 6 (May 27, 2017): 2827. http://dx.doi.org/10.18203/2320-6012.ijrms20172499.
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Musculocutaneous nerve arises from lateral cord and supplies the muscles of front of arm and then continues as lateral cutaneous nerve of forearm. Musculocutaneous nerve has frequent variations. Nerve may be doubled or even absent. There is unilateral absence of musculocutaneous nerve in this case. Musculocutaneous nerve arises from lateral cord and supplies the muscles of front of arm and then continues as lateral cutaneous nerve of forearm. Musculocutaneous nerve has frequent variations. Nerve may be doubled or even absent. There is unilateral absence of musculocutaneous nerve in this case. Musculocutaneous nerve was seen to be absent in one case on right side. Branches arise either from lateral cord or median nerve to supply the flexor muscles of arm. Total absent musculocutaneous nerve is quiet uncommon. Hence knowledge of this variation can help clinicians in understanding the cause of weakness or paralysis of flexor muscles of arm due to median nerve injury which is unusual.
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KUNG, PIN-CHENG, CHOU-CHING K. LIN, SHU-MIN CHEN, and MING-SHAUNG JU. "CONTROL OF FOREARM MODULE IN UPPER-LIMB REHABILITATION ROBOT FOR REDUCTION AND BIOMECHANICAL ASSESSMENT OF PRONATOR HYPERTONIA OF STROKE PATIENTS." Journal of Mechanics in Medicine and Biology 16, no. 02 (March 2016): 1650008. http://dx.doi.org/10.1142/s0219519416500081.
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Spastic hypertonia causes loss of range of motion (ROM) and contractures in patients with post-stroke hemiparesis. The pronation/supination of the forearm is an essential functional movement in daily activities. We developed a special module for a shoulder-elbow rehabilitation robot for the reduction and biomechanical assessment of pronator/supinator hypertonia of the forearm. The module consisted of a rotational drum driven by an AC servo motor and equipped with an encoder and a custom-made torque sensor. By properly switching the control algorithm between position control and torque control, a hybrid controller able to mimic a therapist’s manual stretching movements was designed. Nine stroke patients were recruited to validate the functions of the module. The results showed that the affected forearms had significant increases in the ROM after five cycles of stretching. Both the passive ROM and the average stiffness were highly correlated to the spasticity of the forearm flexor muscles as measured using the Modified Ashworth Scale (MAS). With the custom-made module and controller, this upper-limb rehabilitation robot may be able to aid physical therapists to reduce hypertonia and quantify biomechanical properties of the muscles for forearm rotation in stroke patients.
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Park, Shi-Hyun. "Biomechanical Effect of Forearm Flexor Muscles depending on Handle Sizes." Journal of the Korea Safety Management and Science 14, no. 2 (June 30, 2012): 41–48. http://dx.doi.org/10.12812/ksms.2012.14.2.041.
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Walsh, L. D., C. W. Hesse, D. L. Morgan, and U. Proske. "Human forearm position sense after fatigue of elbow flexor muscles." Journal of Physiology 558, no. 2 (July 2004): 705–15. http://dx.doi.org/10.1113/jphysiol.2004.062703.
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Hodgins, Justin L., David P. Trofa, Steve Donohue, Mark Littlefield, Michael Schuk, and Christopher S. Ahmad. "Forearm Flexor Injuries Among Major League Baseball Players: Epidemiology, Performance, and Associated Injuries." American Journal of Sports Medicine 46, no. 9 (June 13, 2018): 2154–60. http://dx.doi.org/10.1177/0363546518778252.
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Background: Despite evidence highlighting the importance of the forearm flexor muscles of elite baseball players, no studies have reported on the epidemiology of flexor strains and their associated outcomes. Purpose: To examine the incidence, associated injuries, and outcomes associated with forearm flexor injuries among major and minor league baseball players. Study Design: Cohort study; Level of evidence, 3. Methods: Injury data attributed to forearm flexor injuries among Major League Baseball (MLB) and minor league teams between 2010 and 2014 were obtained from the professional baseball Health and Injury Tracking System. This analysis included the number of players injured, seasonal timing of injury, days spent on the disabled list (DL), preinjury performance data, and subsequent injuries. Results: A total of 134 and 629 forearm flexor injuries occurred in MLB and the minor leagues, respectively. The mean player age was 28.6 and 22.8 years in the MLB and minor leagues, respectively. The mean time spent on the DL for MLB players was 117.0 days, as opposed to 93.9 days in the minor leagues ( P = .272). Interestingly, pitcher performance declined in all categories examined leading up to the season of injury, with significant differences in walks plus hits per inning pitched ( P = .04) and strike percentage ( P = .036). Of MLB players with a forearm injury, subsequent injuries included 50 (37.3%) shoulder, 48 (35.8%) elbow, and 24 (17.9%) forearm injuries. Among injured minor league players, subsequent injuries included 170 (27.0%) shoulder, 156 (24.8%) elbow, and 83 (13.2%) forearm injuries. These rates of subsequent injuries were significantly higher compared with the rates of injuries sustained among players without forearm injuries in both leagues ( P < .001). Finally, 26 (19.4%) MLB and 56 (8.9%) minor league players required an ulnar collateral ligament reconstruction, rates that were significantly higher compared with players without a flexor strain ( P < .001). Conclusion: Flexor-pronator injuries are responsible for considerable time spent on the DL for elite players in MLB and the minor leagues. The most significant findings of this investigation illustrate that a flexor strain may be a significant risk factor for subsequent upper extremity injuries, including an ulnar collateral ligament tear.
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Mukhtar Alam, Mohd, and Abid Ali Khan. "Electromyography-based Fatigue Assessment During Endurance Testing by Different Vibration Training Protocols." Iranian Rehabilitation Journal 19, no. 1 (March 1, 2021): 85–98. http://dx.doi.org/10.32598/irj.19.1.1150.1.
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Objectives: This study presents a method of assessing muscle fatigue during endurance testing at 50% maximal voluntary contraction (MVC) using electromyography (EMG) information as indirect indices of fatigability in the forearm muscles, namely, flexor digitorum superficialis (FDS); flexor carpi ulnaris (FCU); extensor carpi ulnaris (ECU) and extensor carpi radialis brevis (ECRB)." This study presents a method of assessing muscle fatigue during endurance testing at 50% maximal voluntary contraction (MVC) using electromyography (EMG) information as indirect indices of fatigability in the forearm muscles, namely, flexor digitorum superficialis (FDS); flexor carpi ulnaris (FCU); extensor carpi ulnaris (ECU) and extensor carpi radialis brevis (ECRB). Methods: A randomized comparative experimental design was used during endurance test with 8 VT protocols; based on different combinations of vibration frequency (35 & 45 Hz), amplitude (3±0.5g & 9±0.5g), and exposure duration (30 & 60 seconds), i.e., were given to the study participants for 4 days. A random sampling of participants was conducted from two groups (n=56/group), as follows: individuals with a Sedentary Lifestyle (SL) and a group of Construction Workers (CW). Results: Multivariate Analysis of Variance (MANOVA) results indicated a significant increase in EMG rms, median frequency, waveform length, mean absolute value (P<0.001), and the variance of EMG signal (P<0.05) (except in ECU for the SL group and ECRB for the CW group on the variance of EMG signal) after VT in all muscles of both research groups. Therefore, an increase in the EMG parameter value after a grip endurance task revealing an elevation in EMG signal amplitude is indicative of muscle fiber fatigue. Furthermore, the strongest correlation was found between grip endurance and WL (r=0.471, P<0.001), and EMG rms (r=0.401, P<0.001) of the ECU muscle in the SL group only. Discussion: The patterns of EMG signal represented the amplitude and spectral parameters of the signal, enabling real-time fatigue analysis. Additionally, surface EMG information is useful for indirectly evaluating performance fatigue during the endurance test.
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Alves Diniz, João Augusto Rodrigues, Bruna Miniz Rodrigues Falcão, Ediane Freitas Rocha, Joyce Galvão De Souza, Artur Da Nobrega Carreiro, Gildenos Xavier Medeiros, and Danilo José Ayres De Menezes. "Anatomical Description of the Forelimb Muscles of the Brown-Throated Sloth (Bradypus variegatus)." Acta Scientiae Veterinariae 46, no. 1 (October 25, 2018): 10. http://dx.doi.org/10.22456/1679-9216.88163.
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Background: Brown-throated sloths are mammals of the order Xenarthra, suborder Pilosa, family Bradypodidae. These folivorous and arboreal animals, which possess a peculiar type of arboreal quadrupedalism, move through the forest canopy by means of suspensory locomotion. On the ground, their extremely slow movements make them easy targets for road accidents, often leading to serious injury or even death. This paper describes the forelimb muscles of the brown-throated sloth (Bradypus variegatus), updating the literature on the subject to help veterinarians in clinical and surgical interventions on this species, and to provide data for comparative animal anatomy.Materials, Methods & Results: Five brown-throated sloths (Bradypus variegatus Schinz, 1825), two adults and three babies were dissected. The animals were donated by the Arruda Câmara Zoo and Botanical Park in João Pessoa, state of Paraíba, Brazil, where they were thawed and fixed in 10% formalin. The sloths’ forelimbs were dissected by lifting and folding over a skin flap to expose, identify and describe the underlying musculature. The dissection revealed the following muscles: supraspinatus, infraspinatus, deltoideus, teres major, subscapularis, coracobrachialis, brachialis, biceps brachii, triceps brachii, anconeus epitrochlearis, dorsoepitrochlearis, brachioradialis, supinator, pronator teres, pronator quadratus, extensor carpi radialis, extensor carpi ulnaris, extensor carpi obliquus, flexor carpi radialis, flexor carpi ulnaris, extensor digitorum communis, extensor digitorum lateralis, palmaris longus, flexor digitorum superficialis, flexor digitorum profundus, extensor indicis longus second finger, extensor indicis brevis second finger, extensor digitorum third finger, abductor digitorum second finger, abductor digitorum third finger, palmaris brevis, and interosseous muscles. Characteristics found in this species revealed differences in the muscular development of the upper forelimb, whose muscles are less developed than those of the lower forelimb, which are visibly more developed with greater muscle density. An interesting feature of this musculature is the presence of three flexor tendons, short and thick, originating from the flexor muscles, which give the hand of the brown-throated sloth a hook-like aspect.Discussion: Our observations indicate that some of the muscles are very similar to those of other animals of this order and also of domestic mammals. However, the most relevant characteristics resemble those of arboreal animals and humans, since the forearm and hand pronation and supination muscles are essential for their arboreal habits. Therefore, all the pronator and supinator muscles of the brown-throated sloth are well developed. Due to the functional adaptations of the species of the family Bradypodidae, the shoulder muscles, especially the deltoideus, are more developed, providing greater support to the shoulder joint, and their origin and insertion assist in faster and easier movements, albeit exerting less force. The group of flexor muscles in this species gives the forearm stronger and more concentrated action than the extensor muscles. This study enabled us not only to produce a more precise description of the muscles of the forelimb of this species but also to update the literature, since there are few relevant studies on the subject and the terms in the literature are outdated and no longer in use. Keywords: sloth, Bradypodidae, morph
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Allen, M. J., and M. R. Barnes. "Chronic Compartment Syndrome of the Flexor Muscles in the Forearm: A Case Report." Journal of Hand Surgery 14, no. 1 (February 1989): 47–48. http://dx.doi.org/10.1016/0266-7681(89)90014-4.
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A case is reported of a professional racing motor-cyclist who developed a chronic compartment syndrome of the flexor muscles in the forearm, confirmed by pressure measurements after exercise. Open fasciotomy of both the superficial and deep compartments cured the condition.
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Schieber, M. H., and W. T. Thach. "Trained slow tracking. I. Muscular production of wrist movement." Journal of Neurophysiology 54, no. 5 (November 1, 1985): 1213–27. http://dx.doi.org/10.1152/jn.1985.54.5.1213.
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Electromyographic (EMG) activity was recorded from those forearm muscles that act across the wrist as highly trained monkeys tracked slow hold-ramp-hold target trajectories with angular wrist position. During performance of this task, the forearm flexors and extensors had a common "basic pattern" of EMG activity. Flexor digitorum sublimis (FDS) and extensor digitorum communis (EDC), though commonly classified as prime movers of the fingers, were the most active flexor and extensor muscles during these movements at the wrist. The basic pattern of EMG activity was analyzed by varying independently 1) the movement direction, 2) the initial and final held wrist positions, 3) the ramp-movement velocity, and 4) the direction and magnitude of maintained external torque load. Most of the modulation of the basic pattern was related to wrist position: EMG amplitude was greatest at the extreme of muscle shortening. There was a slight difference in EMG activity between flexion and extension ramps that was related purely to the direction of movements, independent of wrist position, velocity, and external load; EMG amplitude was greater when a muscle was shortening and less when it was lengthening. During ramp movement, there was little or no observed EMG activity related to velocity (8-28 degrees/s). The magnitude of EMG activity varied in proportion to the external torque load, but this load-related component was additive, and the basic pattern of activity (related to direction and position) did not change with load. From these results we infer that a muscle's EMG activity was determined by 1) passive elastic properties of the wrist and the active length-tension characteristics of the muscle itself (position), 2) asymmetries in the muscle's contractile force depending on whether it was lengthening or shortening (direction), and 3) magnitude of the external torque load (force). By contrast, since no EMG activity was related to velocity in these slow movements, passive viscous properties and velocity-related cross-bridge kinetics were apparently so slight as to make undetectable the small additional EMG activity and contractile force presumably required to overcome them. A model of the muscle forces acting at the wrist incorporates these experimental observations.
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Mizuno, M., N. H. Secher, and B. Quistorff. "31P-NMR spectroscopy, rsEMG, and histochemical fiber types of human wrist flexor muscles." Journal of Applied Physiology 76, no. 2 (February 1, 1994): 531–38. http://dx.doi.org/10.1152/jappl.1994.76.2.531.
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The metabolic response to graded rhythmic forearm exercise determined by phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy was evaluated with respect to recruitment pattern of muscles and to fiber type composition of the nondominant arm in 14 untrained subjects. Rectified smoothed surface electromyography (rsEMG) over finger and wrist flexor muscles increased similarly and progressively at 30, 45, and 60% of maximal exercise intensity. On the basis of the 31P-NMR response pattern during exercise, subjects were separated into three groups: H group (n = 4), with a single high-pH P(i) peak; M group (n = 7), with two P(i) peaks reflecting two pH components; and L group (n = 3), with a single low-pH P(i) peak. The H group demonstrated a faster recovery of P(i) and phosphocreatine than the L group (P < 0.05). The M group displayed both types of P(i) recovery and an intermediate resynthesis rate of phosphocreatine. The M group had an even distribution of slow- and fast-twitch fibers in the flexor carpi radialis muscle, whereas subjects in the H and L groups possessed a predominance of slow- and fast-twitch fibers, respectively. The results suggest that during rhythmic forearm exercise the interindividual NMR variation in energy metabolism is related closely to fiber type composition of the muscle.
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Ratel, Sébastien, Anne Tonson, Yann Le Fur, Patrick Cozzone, and David Bendahan. "Comparative analysis of skeletal muscle oxidative capacity in children and adults: a 31P-MRS study." Applied Physiology, Nutrition, and Metabolism 33, no. 4 (August 2008): 720–27. http://dx.doi.org/10.1139/h08-039.
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The aim of the present study was to compare the oxidative capacity of the forearm flexor muscles in vivo between children and adults using 31-phosphorus magnetic resonance spectroscopy. Seven boys (11.7 ± 0.6 y) and 10 men (35.6 ± 7.8 year) volunteered to perform a 3 min dynamic finger flexions exercise against a standardized weight (15% of the maximal voluntary contraction). Muscle oxidative capacity was quantified on the basis of phosphocreatine (PCr) post-exercise recovery kinetics analysis. End-of-exercise pH was not significantly different between children and adults (6.6 ± 0.2 vs. 6.5 ± 0.2), indicating that indices of PCr recovery kinetics can be reliably compared. The rate constant of PCr recovery (kPCr) and the maximum rate of aerobic ATP production were about 2-fold higher in young boys than in men (kPCr: 1.7 ± 1.2 vs. 0.7 ± 0.2 min–1; Vmax: 49.7 ± 24.6 vs. 29.4 ± 7.9 mmol·L–1·min–1, p < 0.05). Our results clearly illustrate a greater mitochondrial oxidative capacity in the forearm flexor muscles of young children. This larger ATP regeneration capacity through aerobic mechanisms in children could be one of the factors accounting for their greater resistance to fatigue during high-intensity intermittent exercise.
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CHANTELOT, C., C. FEUGAS, H. MIGAUD, F. GUILLEM, D. CHAPNIKOFF, and C. FONTAINE. "Effect of the Steindler Procedure on the Median Nerve Branches to the Medial Epicondylar Muscles." Journal of Hand Surgery 25, no. 3 (June 2000): 276–80. http://dx.doi.org/10.1054/jhsb.2000.0381.
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Usually the median nerve gives off six branches to the muscles arising from the medial epicondyle, which could be tightened during Steindler’s procedure. We studied these branches before and after Steindler’s procedure in 20 fresh cadavers and observed a considerable variation in the origin of the branches. The muscular branches arising from the median nerve did not seem to limit the mobilization of the medial epicondyle when performing Steindler’s transfer. The limitation of the flexion observed after Steindler’s procedure was mainly related to the tension of the transferred forearm flexor muscles. The variability of the origin of the branch to the flexor digitorum superficialis muscle could explain a lesion of this branch when Steindler’s procedure is carried out with Brunelli’s modification. The lateral transfer and the anterior transfer on to the humeral shaft did not influence the limitation of elbow flexion or result in tightness in any nerve branch to the transferred muscles.
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NAKATANI, TOSHIO, ATSUSHI IZUMI, and SHIGENORI TANAKA. "Bilateral superficial median arteries." Journal of Anatomy 194, no. 3 (April 1999): 475–77. http://dx.doi.org/10.1017/s0021878299004690.
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A superficial artery may be present in the forearm, arising from the axillary, brachial or superficial brachial arteries and crossing over the origin of the flexor muscles of the forearm to reach the palm (Adachi, 1928; Bergman et al. 1988). When this superficial artery continues as the normal ulnar artery accompanying the ulnar nerve at the wrist, it is referred to as the superficial ulnar artery, with an incidence of ∼4%. When the artery passes below or superficial to the flexor retinaculum in the middle of the forearm, sometimes continuing to join the superficial palmar arch, it is called the superficial median artery, with an incidence of ∼1%. We have observed a relatively rare variation involving the presence of a superficial median artery in both upper limbs. We discuss the clinical importance and the developmental aspects of this arterial variation.
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Oksa, Juha, Michel B. Ducharme, and Hannu Rintamäki. "Combined effect of repetitive work and cold on muscle function and fatigue." Journal of Applied Physiology 92, no. 1 (January 1, 2002): 354–61. http://dx.doi.org/10.1152/jappl.2002.92.1.354.
Full textAbstract:
This study compared the effect of repetitive work in thermoneutral and cold conditions on forearm muscle electromyogram (EMG) and fatigue. We hypothesize that cold and repetitive work together cause higher EMG activity and fatigue than repetitive work only, thus creating a higher risk for overuse injuries. Eight men performed six 20-min work bouts at 25°C (W-25) and at 5°C while exposed to systemic (C-5) and local cooling (LC-5). The work was wrist flexion-extension exercise at 10% maximal voluntary contraction. The EMG activity of the forearm flexors and extensors was higher during C-5 (31 and 30%, respectively) and LC-5 (25 and 28%, respectively) than during W-25 ( P < 0.05). On the basis of fatigue index (calculated from changes in maximal flexor force and flexor EMG activity), the fatigue in the forearm flexors at the end of W-25 was 15%. The corresponding values at the end of C-5 and LC-5 were 37% ( P < 0.05 in relation to W-25) and 20%, respectively. Thus repetitive work in the cold causes higher EMG activity and fatigue than repetitive work in thermoneutral conditions.
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Lima, Fabiano Campos, Anastácia Vale Leite, André Luiz Quagliatto Santos, Dayane Kelly Sabec-Pereira, Eugênio Gonçalves Araújo, and Kleber Fernando Pereira. "MUSCULAR ANATOMY OF THE PECTORAL AND FORELIMB OF Caiman crocodilus crocodilus (LINNAEUS, 1758) (CROCODYLIA: ALLIGATORIDAE)." Ciência Animal Brasileira 17, no. 2 (June 2016): 285–95. http://dx.doi.org/10.1590/1089-6891v17i233788.
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Abstract Among the Brazilian crocodilian, Caiman crocodilus crocodilus is widely distributed, given its adaptation to diverse habitats and their generalist diet. Information about the reproductive and ethological character of this species is abundant, whereas morphological data are still scarce. This study aimed to identify and report the muscles and their origin and the insertion into the pectoral and forelimb of C. crocodilus crocodilus. We used two male specimens, adults, belonging to the collection of the UFG - Jataí. We performed usual procedures for dissection and further individualization, withdrawal of members, and observation of muscle origins and insertions. The musculature of C. crocodilus crocodilus generally conservative is similar to C. latirostris and A. mississippiensis. The muscles of the pectoral girdle showed little variation among crocodilians. In the forelimb, the triceps muscle has five distinct heads and biceps has only one. The extensor and flexor surface of the hand showed similar topography to A. mississippiensis. We described some differences in the origin and insertion of certain muscles, as well as the classification and topography of some flexor and extensor muscles in the forearm segment. The distal segments showed more variations, which probably reflects the variety of locomotor habits among crocodilians.
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Forman, Davis A., Garrick N. Forman, Bernadette A. Murphy, and Michael W. R. Holmes. "Sustained Isometric Wrist Flexion and Extension Maximal Voluntary Contractions on Corticospinal Excitability to Forearm Muscles during Low-Intensity Hand-Gripping." Brain Sciences 10, no. 7 (July 13, 2020): 445. http://dx.doi.org/10.3390/brainsci10070445.
Full textAbstract:
The wrist extensors demonstrate an earlier fatigue onset than the wrist flexors. However, it is currently unclear whether fatigue induces unique changes in muscle activity or corticospinal excitability between these muscle groups. The purpose of this study was to examine how sustained isometric wrist extension/flexion maximal voluntary contractions (MVCs) influence muscle activity and corticospinal excitability of the forearm. Corticospinal excitability to three wrist flexors and three wrist extensors were measured using motor evoked potentials (MEPs) elicited via transcranial magnetic stimulation. Responses were elicited while participants exerted 10% of their maximal handgrip force, before and after a sustained wrist flexion or extension MVC (performed on separate sessions). Post-fatigue measures were collected up to 10-min post-fatigue. Immediately post-fatigue, extensor muscle activity was significantly greater following the wrist flexion fatigue session, although corticospinal excitability (normalized to muscle activity) was greater on the wrist extension day. Responses were largely unchanged in the wrist flexors. However, for the flexor carpi ulnaris, normalized MEP amplitudes were significantly larger following wrist extension fatigue. These findings demonstrate that sustained isometric flexion/extension MVCs result in a complex reorganization of forearm muscle recruitment strategies during hand-gripping. Based on these findings, previously observed corticospinal behaviour following fatigue may not apply when the fatiguing task and measurement task are different.
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Nasir, Nursalbiah, Asyraf Hakimi Azmi, and Helmi Rashid. "Hand Dominance Effect During right (Accelerator) Throttle Gripping in Riding Simulation." International Journal of Engineering & Technology 7, no. 4.27 (November 30, 2018): 141. http://dx.doi.org/10.14419/ijet.v7i4.27.22502.
Full textAbstract:
This study investigated the difference in muscle activation of the muscles in right handed (RH) and left handed (LH) participants during riding of motorcycle simulator. Five participants (3 RH and 2 LH) with average age of 24.2±0.447 years old were recruited and they were requested to ride the simulator for certain period of times for three days. Two surface electromyogram (sEMG) electrodes were attached to right flexor carpi radialis (RFCR) and left flexor carpi radialis (LFCR) of the participants forearm. Electromyography (EMG) of flexor carpi radialis (FCR) are measured at both hands during the task. The results showed that muscle activation during first 5 minutes of riding task in day 1 of experiment (percentage of maximum voluntary contraction, %MVC) for RFCR in LH (non-dominant) participants was 97.4% and 87.7% in RH (dominant) participants. Therefore, this result indicates that non-dominant person needs to activate more muscle than RH person during control the accelerator throttle while riding.