Course and coverings
The spermatic cord forms at the deep inguinal ring, traverses the inguinal canal, leaves through the superficial inguinal ring and descends into the scrotum to end at the posterior border of the testis.
The deep inguinal ring is an opening in the transversalis fascia just above the midpoint of the inguinal ligament, lateral to the inferior epigastric vessels. The superficial inguinal ring is a triangular gap in the external oblique aponeurosis above and lateral to the pubic tubercle. As the testis descended, it pushed through each layer of the abdominal wall, and the cord picked up a covering from three of them.
| Covering | Derived from | Acquired at |
|---|---|---|
| Internal spermatic fascia | Transversalis fascia | Deep inguinal ring |
| Cremasteric muscle and fascia | Internal oblique | Within the inguinal canal |
| External spermatic fascia | External oblique aponeurosis | Superficial inguinal ring |
Transversus abdominis contributes no layer, because its lowest fibres arch over the cord rather than being pushed ahead of it.
Contents
The spermatic cord contains the ductus deferens and its vessels, the testicular vessels, nerves, lymphatics and the remnant of the processus vaginalis.
| Group | Structure | Notes |
|---|---|---|
| Duct | Ductus (vas) deferens | Firm, cord-like, lies posteriorly in the cord; carries sperm from the epididymis |
| Artery | Testicular artery | From the abdominal aorta at about L2 |
| Artery | Artery to the ductus deferens | Usually from the inferior or superior vesical artery |
| Artery | Cremasteric artery | From the inferior epigastric artery; supplies cremaster and coverings |
| Vein | Pampiniform plexus | A network of veins around the testicular artery, joining to form the testicular vein near the deep ring |
| Nerve | Genital branch of genitofemoral nerve | Motor to cremaster, sensory to anterior scrotal skin |
| Nerve | Testicular plexus | Sympathetic and visceral afferent fibres on the testicular artery |
| Other | Lymphatic vessels | From the testis to the para-aortic nodes |
| Other | Processus vaginalis remnant | A fibrous thread; if patent, the sac of an indirect hernia |
The ilioinguinal nerve runs through the inguinal canal on the front of the cord but outside its coverings, so it is strictly not a content of the cord, although many lists include it.
Blood supply, drainage and innervation
The testis and cord are supplied by three arteries that anastomose, and drained by a venous plexus that cools arterial blood before it reaches the testis.
The testicular artery arises from the aorta at about L2, descends on psoas and enters the cord at the deep ring. It anastomoses with the artery to the ductus deferens, which can keep the testis alive if the testicular artery is divided high. The pampiniform plexus wraps the artery and acts as a countercurrent heat exchanger. It condenses into the testicular vein, which drains into the IVC on the right and at a right angle into the left renal vein on the left.
Testicular lymph ascends with the vessels to the lumbar (para-aortic) nodes, not the inguinal nodes, which drain only the scrotal skin. Testicular pain travels with sympathetic fibres to T10 and is often felt around the umbilicus. The cremasteric reflex (L1, L2) raises the testis when the upper medial thigh is stroked: sensation via the femoral branch of the genitofemoral and the ilioinguinal nerves, motor via the genital branch of the genitofemoral nerve.
Clinical relevance
Cord anatomy underpins the diagnosis of groin and scrotal swellings and the surgery of hernia, vasectomy and testicular cancer.
- Indirect inguinal hernia: passes through the deep ring into a patent processus vaginalis, inside the coverings of the cord. A direct hernia pushes through the posterior wall medial to the inferior epigastric vessels and lies outside the internal spermatic fascia.
- Varicocele: dilatation of the pampiniform plexus, far commoner on the left because the left testicular vein enters the left renal vein at a right angle. A new left varicocele in an older man raises concern for a renal tumour blocking the renal vein.
- Testicular torsion: the testis twists on its cord, occluding the vessels; a surgical emergency.
- Vasectomy: the ductus deferens is felt as a firm cord at the back of the cord in the upper scrotum and divided there.
- Testicular cancer: removed by an inguinal (radical) orchidectomy, dividing the cord at the deep ring. A scrotal incision is avoided because it opens a new lymphatic route to the inguinal nodes.
- Hernia repair: the ductus, testicular vessels and ilioinguinal nerve must be preserved.