Urethra at a glance
- What it is
- The urethra is the tube carrying urine out of the bladder; in males it also carries semen.
- Location
- In males it runs about 18 to 20 cm from the bladder neck through the prostate, the external sphincter region and the penis to the external meatus. In females it is about 4 cm long and opens in front of the vagina.
- Function
- It conducts urine for voiding and, in males, conveys semen during ejaculation.
- Body system
- Urinary · single, midline structure
- FMA ID
- FMA19667 (Foundational Model of Anatomy)
Key facts
- Male parts: preprostatic (intramural), prostatic, membranous and spongy (penile).
- The internal sphincter (smooth muscle) is well developed in males; the external sphincter (skeletal muscle) gives voluntary control.
Clinical relevance
Bulbar urethral injury follows straddle falls; membranous urethral injury follows pelvic fractures. Strictures can follow both.
Structures next to the urethra
The nearest named structures in the 3D model, measured from the centre of each part:
- Corpus cavernosum of penis · reproductive
- Corpus spongiosum of penis · reproductive
- Deep dorsal vein of penis · cardiovascular
- Dorsal artery of penis · cardiovascular
- Skin · skin
- Epididymis · reproductive
- Testis · reproductive
- Prostate · reproductive
- Glans penis · reproductive
- Deferent duct · reproductive
References
- Foundational Model of Anatomy: Urethra (FMA19667). EMBL-EBI Ontology Lookup Service.
- OpenStax. Anatomy and Physiology 2e, §25.3 Gross Anatomy of the Kidney. Rice University, 2022.
- Mitsuhashi N. et al. (2009). BodyParts3D: 3D structure database for anatomical concepts. Nucleic Acids Research 37, D782–D785. Data © The Database Center for Life Science, CC BY 4.0.
Related anatomy
Explore the whole body in the interactive 3D human anatomy model, or browse the A–Z list of human structures.