Which of the muscle is supplied by both tibial and common peroneal part of the sciatic nerve?
**Core Concept**
The sciatic nerve is a mixed nerve that arises from the lumbosacral plexus, primarily composed of fibers from the L4-S3 nerve roots. It divides into two main branches: the tibial nerve and the common peroneal nerve. The tibial nerve is responsible for innervating the posterior compartment of the leg, while the common peroneal nerve innervates the anterior compartment.
**Why the Correct Answer is Right**
The correct answer requires knowledge of the innervation of the muscles in the posterior and anterior compartments of the leg. The long head of the biceps femoris muscle is the only muscle in the hamstrings that is innervated by the common peroneal nerve, in addition to its innervation by the tibial nerve. This is due to the dual nerve supply, which allows for the co-contraction of muscles in the posterior and anterior compartments of the leg.
**Why Each Wrong Option is Incorrect**
**Option A:** The gastrocnemius and soleus muscles are primarily innervated by the tibial nerve and do not receive a dual nerve supply.
**Option B:** The tibialis posterior muscle is innervated by the tibial nerve and receives no contribution from the common peroneal nerve.
**Option C:** The peroneus longus and peroneus brevis muscles are innervated by the common peroneal nerve and do not receive a dual nerve supply.
**Clinical Pearl / High-Yield Fact**
The dual nerve supply of the long head of the biceps femoris muscle allows for the co-contraction of the hamstrings and the anterior compartment muscles, which is essential for maintaining balance and stability during activities such as walking and running.
**Correct Answer:** C. Biceps femoris (long head).