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Question 9#

Which is CORRECT regarding neuroanatomy of the bladder?

A. Parasympathetic nerves arise from T10-L2
B. Sympathetic nerves arise from T11-L2
C. Somatic nerves arise from L2-L4
D. Pudendal nerve has fibres that originate from Onuf’s nucleus at the medial border of anterior horn
E. All of the above

Correct Answer is B

Comment:

Answer B

The “wiring” of the bladder consists of an excitatory input by efferent parasympathetic nerves originating in the S₂−S₄ intermediolateral columns of the spinal cord. The sympathetic input to the bladder arises from neurons originating from the intermediolateral column of the T₁₁−L₂ spinal cord segments, in order to innervate the trigone and bladder neck smooth muscle.

The lower urinary tract is innervated by three types of peripheral nerves: parasympathetic (cholinergic) nerves, sympathetic (noradrenergic) nerves and somatic (cholinergic) nerves. The lateral border of the ventral horn (Onuf’s nucleus) is the origin of the cholinergic motor neurones to the external urethral sphincter. Fibres travel via the pudendal nerves (S₂ and S₃) to contract this sphincter.