Question
This picture shows the nerve (with yellow) supplying motor part to external anal sphincter is derived from
A. L5-S1 roots
B. S1-S2 roots
C. L2-L3 roots
D. S2-S3 roots
Show Answer
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Correct Answer » D
Explanation
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Pudendal nerve supplying motor part to external anal sphincter is derived from S2-4 roots. It provides motor innervation to perineal muscles, sphincter urethrae and levator ani. It is sensory to genitalia
- Tibial nerve (L5, S1-3)– It is motor to most of the posterior thigh, posterior leg and plantar surface of the foot.
- Lateral femoral cutaneous nerve (L2,3) – It is sensory to the lateral thigh.
- Femoral nerve (L2-4)– It is motor to iliacus, psoas major, psoas minor, and muscles of the anterior thigh.
- Common peroneal nerve (L4-5, S1-2) – It is motor to the short head of biceps femoris, muscles of the lateral leg, anterior leg and dorsum of foot via superficial and deep peroneal branches.
- Superior gluteal nerve (L4,5 S1)– It is motor to the gluteus medius and minimus, and the tensor fascia lata.
- Inferior gluteal nerve (L5, S1-2)– It is motor to gluteus maximus
