The male urethra
The urethra, from its origin in the bladder to its end at the apex of the penis, initially crosses the prostate, then exhibits a concave curve facing upwards and towards the pubic symphysis passing through the uro-genital diaphragm, which contains the external urethral or voluntary sphincter. It then penetrates the corpus spongiosum and finally runs along the entire length of the penis, this time forming a concave curve facing downwards and backwards.
Proceeding from the exterior towards the urethral lumen, the histological structure is constructed of a connective band created by a tunicae muscolaris in the proximal segment, by vascular lacunae (corpus spongiosum) in the distal part and by a mucous membrane.
The urethral mucous membrane is constructed of a multi-layered simple epithelium with multiple glands.
The blood vessels and nerves of the urethra originate predominantly from the collateral and terminal branches of the pudendal artery, veins and nerves. They are responsible for vascularisation and motor and sensory innervation of the organ.