Question

All of the following are composite muscles, except:

• A. Flexor carpi ulnaris
• B. Flexor digitorum profundus
• C. Pectineus
• D. Biceps femoris

Hint:

A composite muscle has a dual nerve supply; find the one fed by only one nerve.

Answer 1

The Correct Option is A

Step 1: A composite (or hybrid) muscle is a muscle that develops from two different muscle masses or is supplied by two different nerves, reflecting its dual embryological origin.

Step 2: Recognise the classic composite muscles. Flexor digitorum profundus is supplied by two nerves: the median nerve (anterior interosseous branch) to its radial half and the ulnar nerve to its medial half, so it is composite (option B). Pectineus is supplied by the femoral nerve and frequently also by the obturator (or accessory obturator) nerve, so it is composite (option C). Biceps femoris has two heads with two different nerve supplies: the long head from the tibial part of the sciatic nerve and the short head from the common peroneal (fibular) part of the sciatic nerve, so it is composite (option D).

Step 3: Flexor carpi ulnaris is supplied entirely by a single nerve, the ulnar nerve, and develops from the common flexor mass. It is therefore NOT a composite muscle.

Step 4: The except answer is the muscle with a single, uniform nerve supply.

Answer: A. Flexor carpi ulnaris