Anatomic variation of the innervation of the flexor digitorum profundus muscle and its clinical implications

Abstract

In anterior interosseous nerve syndrome and ulnar neuropathy, paralysis or weakness of the flexor digitorum profundus (FDP) muscles has been shown to vary according to the degree of involvement of the median and ulnar nerves, respectively. We traced these nerves in 50 cadaveric specimens in which each FDP was completely separated. The specimens were classified into six anatomic and another six presumptive electromyography (EMG) types according to the innervation patterns of the entire and the proximal one-third of the FDP muscles, respectively. The diverse anatomic and presumptive EMG types in this study suggest that the FDP muscles of the 2nd to the 5th digits should be examined by functional tests and EMG in lesions of the median or ulnar nerve.

Vibration imaging for localization of functional compartments of the extrinsic flexor muscles of the hand

“…The complexity and overlap of the innervation of the muscles of the hand is well known (29,30); using this technique prior to repair could better delineate functional and nonfunctional muscles, potentially allowing for more effective interventions. Vibration imaging could also be applied postoperatively to assess muscle function in a noninvasive fashion that would be complementary to electromyography and high-resolution anatomic imaging.…”

“…Clinically, this technique may have application in identifying muscle function before surgical interventions such as for muscle or tendon transfers or nerve grafting to either the brachial plexus or more distal peripheral nerves innervating the hand in patients after trauma. The complexity and overlap of the innervation of the muscles of the hand is well known (29,30); using this technique before repair could better delineate functional and nonfunctional muscles, potentially allowing for more effective interventions. Vibration imaging could also be applied postoperatively to assess muscle function in a noninvasive manner that would be complementary to electromyography and high-resolution anatomic imaging.…”

Clinical, Physical, and Neurophysiological Impairments Associated With Decreased Function in Women With Carpal Tunnel Syndrome

“…Further, the flexor digitorum profundus muscle, which is also involved in the thumb-little finger pinch grip force, while primarily innervated by the ulnar nerve, also receives some of its innervations through branches from the median nerve. 27 Oh et al 38 suggested that because the flexor digitorum profundus tendons expand to the index and little fingers, this muscle may be affected in lesions of the median or ulnar nerve. It is possible that patients might attempt to overcome the weakness associated with first-digit flexion by producing excessive forces that do not correlate with functional levels.…”

“…Stepwise regression analyses revealed that pain intensity, finger pinch grip force between the thumb and little finger, depression severity, and cervical ROM in lateral flexion away from the side of the symptoms were significantly associated with the score on the functional status subscale and, when combined, explained 38 …”

“…Participants were classified as having minimal (abnormal segmental/ comparative tests only), moderate (abnormal median nerve sensory velocity conduction and distal motor latency), or severe (absence of median nerve sensory response and abnormal distal motor latency) CTS. 39 Individuals were also excluded from the study if they (1) had any sensory/motor deficit related to the ulnar or radial nerve; (2) were over 65 years of age; (3) had previous surgical intervention or steroid injections; (4) had multiple diagnoses of the upper extremity (eg, cervical radiculopathy); (5) had a history of neck, shoulder, or upper-limb trauma (whiplash); (6) had a history of systemic disease causing CTS (eg, diabetes mellitus or thyroid disease); (7) had a history of musculoskeletal medical conditions (eg, rheumatoid arthritis, fibromyalgia); (8) were pregnant; or (9) were of male gender. All subjects read and signed a consent form prior to enrollment, and the study was approved by the Ethics Board of the Universidad Rey Juan Carlos.…”