Detailed anatomical study of nerve supply of flexor digitorum superficialis muscle

ABSTRACT

The motor points of the skeletal muscles have recently attracted much attention from researchers in the field of functional electrical stimulation. Knowledge of the location of the nerve branches and the entry points facilitates the exact insertion and the suitable selection of the number of electrodes required for each muscle for functional electrical stimulation. To study the detailed nerve supply of the flexor digitorum superficialis muscle that may help the physiotherapists in the follow up and rehabilitation of the paralyzed patients. Twenty adult male human cadaveric forearms [13 right and 7 left] were dissected to study the branches of the nerves supplying the flexor digitorum superficialis muscle. The number of branches and their points of penetration on the muscle were detected, measured, tabulated and statistically analyzed. Dissection of the nerve supply of the flexor digitorum superficialis muscle revealed that the muscle received muscular branches from the median, anterior interosseus and ulnar nerves [triple nerve supply] in three [15%] specimens [2 left and one right]. In 15 [75%] specimens [10 right and 5 left], the flexor digitorum superficialis muscle received muscular branches from 2 different nerves, multiple branches from the median nerve in all 15 specimens and either a single branch from the anterior interosseus nerve in 13 specimens [8 right and 5 left] or a single branch from the ulnar nerve in 2 right specimens. In the remaining 2 [10%] right specimens our of 20, the muscle received muscular branches from the median nerve only. The number of the muscular branches of the median nerve to the muscle ranged from 2 to 7 on the right specimens, and from 2 to 6 in the left specimens, while the number of points of entry of these branches to the flexor digitorum superficialis ranged from 2 to 9 in the right specimens and from 2 to 8 in the left one. The distance between the origin of the proximal branch of the median nerve supplying the muscle and the articular line of the elbow varied from 0.5 to 8.3cm in the right specimens, in the left specimens it was 0.7 to 7.8cm, while the distance between the points of entry of this proximal branch to the muscle and the articular line of the elbow was 2.4 to II.2cm in the right specimens and 2.6 to 9.3cm in the left one. The distal branch arose from the median nerve to the muscle had a distance of 9.2 to 19.7cm from the articular line of the elbow in the right specimens, while it was 10.2 to 17.5cm in tile left specimens The distance between the points of entry of this branch to the muscle and the articular line of the elbow ranged between 12.8 to 19.6cm in the right specimens and 13.5 to 17.9cm in the left one. The median nerve supplied the flexor digitorum superficialis muscle along its whole length [proximal, middle and distal thirds]. The muscular branch arose from the anterior interosseus or the ulnar nerves entered the muscle at its proximal third only. It is necessary for the surgeons and physiotherapists dealing with this muscle to be aware about its nervous pattern and they should anticipate that the proximal third of this muscle is the most important part as it may have double or triple nerve supply