A patient presents to the emergency depament complaining of fever, chills, and a painful mass adjacent to his anus. On examination, a tender, fluctuant mass is palpated. Purulent material is noted through the skin and the diagnosis of ischioanal abscess is made. The patient is taken to the operating room, and incision and drainage of the abscess is performed. During the procedure, the extent of the lesion is underestimated, and the inferior rectal nerve is damaged. This nerve is a direct branch of which of the following nerves?
The pudendal nerve is a branch of the sacral plexus that exits from the greater sciatic foramen, and then enters the lesser sciatic foramen, to lie in the pudendal canal on the lateral wall of the ischioanal fossa. The inferior rectal nerve is a branch of the pudendal nerve, which crosses the ischioanal fossa to reach the anal canal, where it innervates the external anal sphincter and provides sensory innervation to the area.The inferior gluteal nerve, a branch of the sacral plexus, exits through the greater sciatic foramen and innervates the gluteus maximus muscle.The pelvic splanchnic nerves are branches of the second, third, and fouh sacral nerves that carry preganglionic parasympathetic nerves to several pelvic organs.The sciatic nerve is a branch of the lumbosacral plexus that exits through the greater sciatic foramen, then enters the lower limb to innervate muscles of the posterior thigh, the leg, and the foot, and provides sensory innervation to the area as well.
Inferior gluteal nerve
Pelvic splanchnic nerve
Pudendal nerve
Sciatic nerve