Location and Course of the Spermatic Cord
The cord begins at the epididymis and terminates at the deep (internal) inguinal ring. In adult males, its length ranges from 15–20 cm, gradually increasing during testicular descent.
Within the inguinal canal, the spermatic cord lies between the lower free margins of the internal oblique and transversus abdominis muscles and the inguinal ligament.
Its exact topography is closely related to the morphology of the inguinal triangle (Hesselbach's triangle) and ring:
- In a slit-like or oval ring, the internal oblique muscle well covers the deep ring and provides a sphincter/valvular function—upon contraction, it arches to compress the spermatic cord, offering strong protection against hernias.
- In a triangular ring, the muscle runs horizontally, lacking this valvular function, and the posterior wall of the canal is largely unprotected by muscle, creating favorable conditions for inguinal hernia formation.
Contents of the Spermatic Cord
The spermatic cord is a complex bundle consisting of vascular, neural, and ductal structures. Its main contents include:
- Ductus deferens (vas deferens).
- Arteries: Testicular artery (a. testicularis), artery of the ductus deferens (a. ductus deferentis, branching from the umbilical artery), and cremasteric artery (a. cremasterica).
- Veins: Pampiniform venous plexus (plexus pampiniformis), testicular veins, veins of the ductus deferens, and cremasteric vein (v. cremasterica).
- Nerves: Testicular plexus, plexus of the ductus deferens, genital branch of the genitofemoral nerve (ramus genitalis n. genitofemoralis), along with sympathetic and parasympathetic fibers. The ilioinguinalis nerve (n. ilioinguinalis) lies on the surface of the cord.
- Lymphatic vessels.
- Remnant of the processus vaginalis.
- Loose connective tissue and the cremaster muscle (m. cremaster).
Coverings of the Spermatic Cord
From superficial to deep, the spermatic cord is surrounded by three layers derived from the anterior abdominal wall structures:
- External spermatic fascia (fascia spermatica externa) — derived from the aponeurosis of the external oblique abdominal muscle at the superficial inguinal ring.
- Cremasteric muscle (m. cremaster) and its fascia (fascia cremasterica) — formed from the lower fascicles of the internal oblique abdominal muscle.
- Internal spermatic fascia (fascia spermatica interna) — a direct continuation of the transversalis fascia (fascia transversalis), which forms a funnel-shaped depression around the deep inguinal ring.
Clinical Significance in Surgery and Oncology
- Herniorrhaphy: In congenital inguinal hernias, the hernia sac represents a patent processus vaginalis and is intimately fused externally with the elements of the spermatic cord. During surgery, the neck of the sac is bluntly dissected from the cord elements. If adhesions are dense, a purse-string suture may be applied from the inside, 'stepping over' the cord to leave it outside the suture line. In tension-free or anatomical repairs like the Postempski procedure, the spermatic cord is relocated to the subcutaneous tissue, and the inguinal canal is completely obliterated.
- Oncology: Testicular germ cell tumors, including embryonal carcinoma, can invade the spermatic cord. According to the TNM staging system, tumor invasion into the spermatic cord corresponds to stage T3 or pT3.
- Infections: In acute chlamydial epididymo-orchitis, pain from the epididymis can radiate along the spermatic cord into the inguinal canal, lower back, and sacrum.