Anatomy - Inguinal hernia repair using TEP technique

Inguinal region from the inside: (1) A. and V. epigastrica inferior, (2) medial = direct inguinal hernia portal, (3) femoral hernia portal, (4) Lig. pectineale (Cooper), (5) Ductus deferens, (6) A. and V. iliaca externa, (7) A. and V. testicularis, (8) Tractus iliopubicus, (9) lateral = indirect inguinal hernia portal

The inguinal region (transition between the anterior abdominal wall and lower extremity) has several weak points through which a hernia sac with or without contents can protrude through the abdominal wall (women are more prone to femoral hernias, men to inguinal hernias). Below the inguinal ligament, the inguinal canal is divided into two compartments by a separation of the inguinal ligament (Arcus iliopectineus): the Lacuna vasorum and the Lacuna musculorum.

Lacuna vasorum

• Located next to the pubic bone, it serves as the passageway for the A. and V. iliaca externa (→ A. and V. femoralis, arrangement: artery lateral to the vein). Additionally, the R. femoralis of the N. genitofemoralis passes through it laterally, and the deep inguinal lymph nodes (Rosenmüller) are found caudally medial within it. The Lacuna vasorum represents the internal hernia gap for femoral hernias (through the femoral septum next to the V. femoralis).

Lacuna musculorum

• Located lateral to the Lacuna vasorum, it serves as the passageway for the M. psoas major and M. iliacus (together = M. iliopsoas) as well as the N. femoralis and N. cutaneus femoralis lateralis (cranially).

• The inguinal canal forms during the development of the gonads in the male embryo through the descent of the testes, which are drawn into the scrotum by the gubernaculum testis, as a tubular structure. The peritoneum carried along during this descent remains as an outpouching in the inguinal canal (Proc. vaginalis testis) and extends to the epididymis. The layers of the abdominal wall thus become comparable coverings in this pouch:
• Fascia transversalis → Fascia spermatica interna,
• M. obliquus internus abdominis → M. cremaster,
• Fascia of the M. obliquus externus abdominis → Fascia spermatica externa,
• no covering by the M. transversus abdominis, as it ends more cranially.
• Blood vessels (A. and V. testicularis) as well as the vas deferens (Ductus deferens) and nerves (N. ilioinguinalis from Pl. lumbalis) are also drawn into the scrotum and form the spermatic cord. Through obliteration of the Proc. vaginalis, the connection to the abdominal cavity closes, typically leaving only its entrance (Vestigium proc. vaginalis). In the female embryo, the ovaries do not completely descend due to the pull of the gubernaculum; instead, they remain beside the uterus, and only the round ligament of the uterus (Lig. teres uteri), as the former gubernaculum, persists in the inguinal canal. Inadequate obliteration of the Proc. vaginalis represents a weak point in the abdominal wall and the starting point for inguinal hernias.
• The inguinal canal runs approximately 4 cm long in a medio-caudal direction just above the inguinal ligament parallel to it and lies between the deep inguinal ring, as its cranial end, and the superficial inguinal ring, as its opening to the outer abdominal wall.

Deep inguinal ring

• Midway between the symphysis and the anterior superior iliac spine in the inner abdominal wall, lateral to the inferior epigastric artery/vein (in the lateral umbilical fold).

Superficial inguinal ring

• Above the pubic tubercle in the fascia of the M. obliquus externus abdominis, upper edge pointing cranially, lower edge formed by the inguinal ligament, sides = medial and lateral crus with intercrural fibers for stabilization.

• Anterior Wall

Fascia of the external oblique muscle, laterally reinforced by fibers of the internal oblique muscle → Inguinal ligament and → Cremaster muscle

• Posterior Wall

Fascia transversalis, medially reinforced by the Falx inguinalis (= tendon of the transversus abdominis muscle and internal oblique muscle)

• Superior Wall

Transversus abdominis muscle and internal oblique muscle (fiber direction from the inguinal ligament to the medial Falx inguinalis)

• Inferior Wall

Medial inguinal ligament (= Ligamentum reflexum) as well as a groove formed by the external oblique muscle for the spermatic cord.