A patient with external haemorrhoids develops pain while passing stools. Nerve mediating this pain is:

A patient with external haemorrhoids develops pain while passing stools. Nerve mediating this pain is:

A. Hypogastric nerve
B. Pudendal nerve
C. Splanchnic visceral nerve
D. Sympathetic plexus

Answer is B. Pudendal Nerve.

External haemorrhoids occur below the pectinate line and are very painful. This region is supplied by Inferior Rectal nerve (S2, S3, S4), a somatic nerve, which in turn is a branch of the pudendal nerve.

In contrast, the anal canal above the pectinate line is supplied by Sympathetic (Inferior Hypogastric plexus, L1 and L2) and Parasympathetic (Pelvic Splanchnic, S2, S3, S4) They carry pain fibres from the internal haemorrhoids.