Anatomy

Origin

It arises by tendinous and fleshy fibers from the inner surface of the tuberosity of the ischium, behind the crus penis; and from the rami of the pubis and ischium on either side of the crus. 

Insertion

From the origin points fleshy fibers succeed, and end in an aponeurosis which is inserted into the sides and under surface of the crus penis.

Nerve

Perineal branch of the pudendal nerve.

Actions

It compresses the crus penis, and retards the return of the blood through the veins, and thus serves to maintain the organ erect.