Sacral plexus

Question 1

Outline the sacral plexus.

Answer 1

• This is a flat, triangular formation on the front of the piriformis muscle.
• It is formed out of the lumbosacral trunk and the upper 4 anterior sacral rami.
• These rami divide and unite as they converge to the greater sciatic foramen, forming the branches of the sacral plexus.

Question 2

What are the branches of the sacral plexus?

Answer 2

• Nerve to quadratus femoris (L4, 5, S1)
• Superior gluteal nerve (L4, 5, S1)
• Inferior gluteal nerve (L5, S1, 2)
• Nerve to obturator internus (L5, S1, 2)
• Nerve to piriformis (S1, 2)
• Perforating cutaneous nerve (S2, 3)
• Posterior femoral cutaneous nerve (S1, 2, 3)
• Pelvic splanchnic nerve (S2, 3, 4)
• Pudendal nerve (S2, 3, 4)
• Perineal branch (of S4).
• Sciatic nerve
• Common peroneal (fibular) nerve (L4, 5, S1, 2)
• Tibial nerve (L4, 5, S1, 2, 3)