Prostatic urethra

• Runs through the prostate.
• Initially the epithelium is urothelium but changes to stratified columnar epithelium.
• The lamina propria contains gland and is located on an inner longitudinal and an outer circular smooth muscle layer.

Membranous urethra

• Is the shortest segment.
• It runs through the urogenital diaphragm.
• The lumen is irregular.
• Lacunae are found in places.
• The epithelium is stratified columnar.

Cavernous urethra

• Runs through the corpus spongiosum and opens on the glans.
• Stratified columnar epithelium lines the irregular lumen.
• Close to the opening the epithelium changes to unkeratinised stratified squamous epithelium.
• The lamina propria contains small mucinous glands, the glands of Littre.