Inguinal region

Recommended video: Regions of the abdomen [13:18]

Regions of the abdomen seen anteriorly.

The inguinal region, also known as the groin, is an anatomical space in the lower portion of the anterior abdominal wall, located superior to the thigh, lateral to the pubic tubercle, and inferomedial to the anterior superior iliac spine (ASIS).

Based on the nine region (quadrant) scheme, there are two inguinal regions on each side of the abdomen: left and right. The left inguinal region contains part of the small intestine, the descending colon, the sigmoid colon and, in females, the left ovary and the left fallopian tube. In contrast, the right inguinal region contains the small intestine, the cecum and appendix, the ascending colon and, in females, the right ovary and right fallopian tube.

The inguinal region also houses the inguinal lymph nodes which receive lymphatic drainage from the lower extremity, genitals, dorsal perineum and the inferior most aspect of the anterior abdominal wall. These range from approximately 12-14 lymph nodes and are divided into superficial and deep groups. The superficial inguinal lymph nodes and the great saphenous vein are enclosed by the superficial fascia of the hip and thigh.

A clinically important structure, the inguinal canal, is also located in the inguinal region. It is an oblique intramuscular slit running inferomedially, which serves as a conduit transmitting structures from the pelvis to the perineum.

There are two openings to the inguinal canal:

• The deep inguinal ring is found approximately 1cm above the midpoint of the inguinal ligament and lateral to the epigastric vessels. It is formed by the transversalis fascia which provides the posterior wall of the inguinal canal.
• The superficial inguinal ring is a triangular aperture in the aponeurosis of the external oblique. It is located about 1 cm superolateral to the pubic tubercle and bordered medially by the inferolateral border of rectus abdominis, laterally by the inferior epigastric vessels and inferiorly by the medial third of the inguinal ligament. These three borders are often referred to as Hesselbach's (inguinal) triangle and serve as an important landmark for the superficial ring.

The contents of the inguinal canal vary between males and females. In males, it contains the spermatic cord and its contents, while in females it contains the round ligament of uterus. Two nerves also traverse the inguinal canal in both males and females: these are the ilioinguinal nerve (T12, L1) and the genital branch of the genitofemoral nerve (L2).