Innervation of the Superficial Flexor Muscles of the Lower Leg of the Formosan Monkey

With Special Reference to the Medial Sural Cutaneous Nerve

Abstract

The mode of nerve supply to the superficial flexor muscles (gastrocnemius, soleus, and plantaris muscles) of the lower leg was studied in a large number of Formosan monkeys (Macaca cyclopis) by gross anatomical inspection.
The superficial flexor muscles on the lower leg of primates have generally been reported to be innervated by direct branches from the tibial nerve. However, these muscles in the Formosan monkey were usually found to be supplied by branches from the medial sural cutaneous nerve. The medial sural cutaneous nerve of the Formosan monkey may thus, unlike that in man, be essentially called a musculocutaneous nerve. In addition, the condition of bifurcation of the muscular branches was used to classify the nerve supply of the triceps surae into 8 types, comprising 13 forms.