Anatomical variations of pronator teres muscle: predispositional role for nerve entrapment

Caetano, Edie Benedito; Vieira, Luiz Ângelo; Sprovieri, Fábio Antonio Anversa; Petta, Guilherme Camargo; Nakasone, Mauricio Tadeu; Serafim, Bárbara Lívia Correa

doi:10.1016/j.rboe.2017.02.003

Cited by 10 publications

(20 citation statements)

References 11 publications

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“…Of importance, as with ours, Caetano et al's 9 and Jamieson and Anson's 16 findings included the median nerve never running superficial to the PT. Caetano et al 9 observed hypoplasia of the deep head of the PT in 21 of 100 dissections, while we observed it in 5 of 32 cadaveric dissections. In this situation, we observed that a single branch at the origin of the median nerve distal to the elbow joint innervated the PT; however, it entered the PT at different points.…”

Section: Discussionsupporting

confidence: 70%

“…When both PT heads were present, the median nerve passed between them in all our observations, as well as in the dissections of Caetano et al 9 Conversely, Jamieson and Anson 16 noted the median nerve passing under the two heads of the PT in 18 cases and piercing the superficial head in 6 cases among 300 dissections. Of importance, as with ours, Caetano et al's 9 and Jamieson and Anson's 16 findings included the median nerve never running superficial to the PT. Caetano et al 9 observed hypoplasia of the deep head of the PT in 21 of 100 dissections, while we observed it in 5 of 32 cadaveric dissections.…”

Section: Discussionsupporting

confidence: 60%

“…We observed the absence of the deep head of the PT in 1 among our 32 cadaveric dissections. Caetano et al 9 observed the lack of the deep PT head in 14 of 100 dissections, while Jamieson and Anson 16 noted its absence in 26 of 300 observations. When both PT heads were present, the median nerve passed between them in all our observations, as well as in the dissections of Caetano et al 9 Conversely, Jamieson and Anson 16 noted the median nerve passing under the two heads of the PT in 18 cases and piercing the superficial head in 6 cases among 300 dissections.…”

Section: Discussionmentioning

confidence: 98%

“…Caetano et al 9 observed the lack of the deep PT head in 14 of 100 dissections, while Jamieson and Anson 16 noted its absence in 26 of 300 observations. When both PT heads were present, the median nerve passed between them in all our observations, as well as in the dissections of Caetano et al 9 Conversely, Jamieson and Anson 16 noted the median nerve passing under the two heads of the PT in 18 cases and piercing the superficial head in 6 cases among 300 dissections. Of importance, as with ours, Caetano et al's 9 and Jamieson and Anson's 16 findings included the median nerve never running superficial to the PT.…”

Section: Discussionmentioning

confidence: 98%

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Distal pronator teres motor branch transfer for wrist extension restoration in radial nerve paralysis

Bertelli

Nehete

Duarte

et al. 2021

Journal of Neurosurgery

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OBJECTIVEThe authors describe the anatomy of the motor branches of the pronator teres (PT) as it relates to transferring the nerve of the extensor carpi radialis brevis (ECRB) to restore wrist extension in patients with radial nerve paralysis. They describe their anatomical cadaveric findings and report the results of their nerve transfer technique in several patients followed for at least 24 months postoperatively.METHODSThe authors dissected both upper limbs of 16 fresh cadavers. In 6 patients undergoing nerve surgery on the elbow, they dissected the branches of the median nerve and confirmed their identity by electrical stimulation. Of these 6 patients, 5 had had a radial nerve injury lasting 7–12 months, underwent transfer of the distal PT motor branch to the ECRB, and were followed for at least 24 months.RESULTSThe PT was innervated by two branches: a proximal branch, arising at a distance between 0 and 40 mm distal to the medial epicondyle, responsible for PT superficial head innervation, and a distal motor branch, emerging from the anterior side of the median nerve at a distance between 25 and 60 mm distal to the medial epicondyle. The distal motor branch of the PT traveled approximately 30 mm along the anterior side of the median nerve; just before the median nerve passed between the PT heads, it bifurcated to innervate the deep head and distal part of the superficial head of the PT. In 30% of the cadaver limbs, the proximal and distal PT branches converged into a single trunk distal to the medial epicondyle, while they converged into a single branch proximal to it in 70% of the limbs. The proximal and distal motor branches of the PT and the nerve to the ECRB had an average of 646, 599, and 457 myelinated fibers, respectively.All patients recovered full range of wrist flexion-extension, grade M4 strength on the British Medical Research Council scale. Grasp strength recovery achieved almost 50% of the strength of the contralateral side. All patients could maintain their wrist in extension while performing grasp measurements.CONCLUSIONSThe distal PT motor branch is suitable for reinnervation of the ECRB in radial nerve paralysis, for as long as 7–12 months postinjury.

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Section: Discussionsupporting

confidence: 70%

Section: Discussionsupporting

confidence: 60%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 98%

See 2 more Smart Citations

Distal pronator teres motor branch transfer for wrist extension restoration in radial nerve paralysis

Bertelli

Nehete

Duarte

et al. 2021

Journal of Neurosurgery

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“…In all primate specimens, the PT inserts halfway the radius (15/15), and fusion with the FCR (macaque: 3/7, gibbon: 1/8), the FDS (macaque: 3/7) or B (gibbon: 1/8) may occur. Poor development or absence of the ulnar head seems to be a common variation in humans (Jamieson and Anson, 1952;Caetano et al, 2017), which is supported by phylogenetic development, as in most mammals (except anthropoid apes) the ulnar head is completely missing (Macalister, 1868;McMurrich, 1903). In humans, the median nerve passes between both heads of the PT, which enhances the risk of entrapment of the median nerve, also called the 'pronator teres syndrome' (Nigst and Dick, 1979;Hartz et al, 1981;Fuss and Wurzl, 1990).…”

Section: Forearm Rotatorsmentioning

confidence: 99%

The forearm and hand musculature of semi‐terrestrial rhesus macaques (Macaca mulatta) and arboreal gibbons (Fam. Hylobatidae). Part I. Description and comparison of the muscle configuration

2020

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Primates live in very diverse environments and, as a consequence, show an equally diverse locomotor behaviour. During locomotion, the primate hand interacts with the superstrate and/or substrate and will therefore probably show adaptive signals linked with this locomotor behaviour. Whereas the morphology of the forearm and hand bones have been studied extensively, the functional adaptations in the hand musculature have been documented only scarcely. To evaluate whether there are potential adaptations in forelimb musculature to locomotor behaviour, we investigated the forearm and hand musculature of the highly arboreal gibbons (including Hylobates lar, Hylobates pileatus, Nomascus leucogenys, Nomascus concolor, Symphalangus syndactylus) and compared this with the musculature of the semi‐terrestrial rhesus macaques (Macaca mulatta) by performing complete and detailed dissections on a sample of 15 unembalmed specimens. We found that the overall configuration of the upper arm and hand musculature is highly comparable between arboreal gibbons and semi‐terrestrial macaques, and follows the general primate condition. Most of the identified differences in muscle configuration are located in the forearm. In macaques, a prominent m. epitrochleoanconeus is present, which potentially helps to extend the forearm and/or stabilize the elbow joint during quadrupedal walking. The m. flexor carpi radialis shows a more radial insertion in gibbons, which might be advantageous during brachiation, as it can aid radial deviation. The fingers of macaques are controlled in pairs by the m. extensor digiti secondi et tertii proprius and the m. extensor digiti quarti et quinti proprius—a similar organization can also be found in their flexors—which might aid in efficient positioning of the hand and fingers on uneven substrates during quadrupedal walking. In contrast, extension of the little finger in gibbons is controlled by a separate m. extensor digiti minimi, whereas digits 2 to 4 are extended by the m. extensor digitorum brevis, suggesting that simultaneous extension of digits 2–4 in gibbons might be important when reaching or grasping an overhead support during brachiation. In conclusion, the overall configuration of the forelimb and hand musculature is very similar in gibbons and macaques, with some peculiarities which can be linked to differences in forelimb function and which might be related to the specific locomotor behaviour of each group.

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Two muscular variations in the elbow associated with the anterior interosseous nerve

et al. 2021

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The coexistence of different muscular-neurovascular variations is of significant clinical importance. A male cadaver, 76 years old at death, was subjected to routine anatomical dissection; the procedure was performed for research and teaching purposes at the Department of Anatomical Dissection and Donation, Medical University of Lodz. The right forearm and hand were dissected using standard techniques according to a strictly specified protocol. The presence accessory head of the flexor pollicis longus may potentially compress the anterior interosseous nerve. The present case report describes a rare variant of the ulnar head of the pronator teres, characterized by two independent bands (i.e., two proximal attachments). The main band originates from the coronoid process and the second originates from the tendon of the biceps brachii. This type of attachment could potentially affect the compression of the ulnar artery running between the two bands. Additionally, the accessory head of the flexor pollicis longus was observed, which started on the medial epicondyle; its coexistence with a high division median nerve creates a potential pressure site on the anterior interesosseous nerve.

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Anatomical variations of pronator teres muscle: predispositional role for nerve entrapment

Cited by 10 publications

References 11 publications

Distal pronator teres motor branch transfer for wrist extension restoration in radial nerve paralysis

Distal pronator teres motor branch transfer for wrist extension restoration in radial nerve paralysis

The forearm and hand musculature of semi‐terrestrial rhesus macaques (Macaca mulatta) and arboreal gibbons (Fam. Hylobatidae). Part I. Description and comparison of the muscle configuration

Two muscular variations in the elbow associated with the anterior interosseous nerve

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