Anatomy - Inguinal hernia repair, Rutkow Plug

The inguinal region (transition between the anterior abdominal wall and lower extremity) has several weak points through which a hernial sac with or without contents can protrude through the abdominal wall (women more femoral hernias, men more inguinal hernias). As the area below the inguinal ligament, the inguinal canal is divided into two compartments by a division 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 external iliac artery and vein (→ femoral artery and vein, arrangement: artery lateral to the vein). Additionally, the femoral branch of the genitofemoral nerve passes through it laterally, and the deep inguinal lymph nodes (Rosenmüller) are found caudally medially within it. The lacuna vasorum represents the internal hernial gap for femoral hernias (through the femoral septum next to the femoral vein).

Lacuna musculorum

• Located lateral to the lacuna vasorum, it serves as the passageway for the psoas major muscle and iliacus muscle (together = iliopsoas muscle), as well as the femoral nerve and lateral femoral cutaneous nerve (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, forming a tubular structure. The peritoneum carried along during this descent remains as a protrusion 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 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 the obliteration of the Proc. vaginalis testis, the connection to the abdominal cavity closes, and typically only its entrance (Vestigium proc. vaginalis testis) remains. In the female embryo, the ovaries do not completely descend due to the pull of the gubernaculum, but remain beside the uterus. Only the Lig. teres uteri, as the former gubernaculum, persists in the inguinal canal. Inadequate obliteration of the Proc. vaginalis testis represents a weakness of 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 Anulus inguinalis profundus, as its cranial end, and the Anulus inguinalis superficialis, as its opening to the outer abdominal wall.

Anulus inguinalis profundus

• Midway between the symphysis and the anterior superior iliac spine in the inner abdominal wall, lateral to the A./V. epigastrica inferior (in the Plica umbilicalis lateralis).

Anulus inguinalis superficialis

• 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 = Crus mediale and laterale with intercrural fibers for stabilization.