Nerves of the Spermatic Cord
The three primary nerves traveling through the spermatic cord in men are: (1) the ilioinguinal nerve, (2) the iliohypogastric nerve, and (3) the genital branch of the genitofemoral nerve 1, 2, 3.
Anatomical Distribution and Characteristics
Primary Nerve Components (Trifecta Nerve Complex)
The spermatic cord contains a median of 25 small diameter nerve fibers (less than 1 mm) distributed in three primary anatomical zones 2:
- Cremasteric muscle fibers: Contains the highest density with approximately 19 nerves per patient 2
- Perivasal tissues and vasal sheath: Contains approximately 9 nerves per patient, running parallel to the vas deferens 2
- Posterior cord lipomatous/perivessel tissues: Contains approximately 3 nerves per patient 2
Specific Nerve Locations
Iliohypogastric nerve: Runs approximately horizontally and ventrally to the internal oblique muscle, perforating the external oblique aponeurosis at a mean of 3.8 cm (range 2.5-5.5 cm) cranially from the external ring 3
Ilioinguinal nerve: When present, runs ventrally and parallel to the spermatic cord, dorsally from the aponeurosis of the external oblique muscle 3
Genital branch of the genitofemoral nerve: Has a more complex course running laterocaudally at the level of the internal inguinal ring, with identification being more comprehensive than the other two nerves 3. This nerve is critical for regulation of gubernacular length and obliteration of the processus vaginalis during testicular descent 4
Nerve Fiber Composition
Immunohistochemical analysis reveals that the spermatic cord and fascia contain dense nerve distributions 1:
- Sensory and sympathetic nerve fibers represent the majority of nerves in the spermatic cord 1
- Approximately 50% of nerves are identified near the vas deferens 1
- Approximately 20% of nerves are identified in the spermatic fascia 1
- Sensory and autonomic nerve fibers are typically co-localized in the same nerve bundle 1
- A few parasympathetic nerve fibers (vasoactive intestinal polypeptide-positive) are also present 1
Clinical Relevance
Understanding this nerve distribution is surgically important during microsurgical varicocelectomy, denervation procedures for chronic orchialgia, and inguinal hernia repair 1, 2, 3. The bilateral distribution of nerves is similar (approximately 10 nerves per spermatic cord), with the vas and perivasal structures containing comparable numbers of nerve fibers 5.