The inguinal region, located near the groin, is found in the lower part of the anterior abdominal wall, and it contains several important structures that enter and leave the abdomen. Understanding the anatomy of the inguinal region is important for understanding common clinical conditions such as hernias, and many others!
Speaking of which, hernias occur when an organ or tissue protrudes through the wall of the muscle or tissue that normally contains it. The majority of hernias occur in the abdominal cavity or the inguinal region, through which subcutaneous fat, abdominal omental fat, or even abdominal viscera can protrude. In order for a hernia to happen, there is typically a weak point along the abdominal wall, such as a weak linea alba, previous surgical interventions that weaken the abdominal wall muscles, or pregnancy.
First, let’s look at anterior abdominal wall hernias. They can be divided into 4 categories: epigastric, umbilical or periumbilical, spigelian and incisional hernias. Epigastric hernias are caused by a weakened linea alba and are basically defects in the abdominal midline between the umbilicus and the xiphoid process. Then, there are umbilical or paraumbilical hernias, which are hernias through the umbilical ring or around the umbilicus. These are often found in children, because the umbilical ring is weak at birth, but can also be acquired in adults and frequently affect pregnant or obese individuals.
Spigelian hernias are found along the semilunar lines which are skin folds from the inferior costal margin of the 9th costal cartilage to the pubic tubercles and overly the tendinous insertions of the rectus abdominis muscle, as abdominal tissue can protrude through these areas of tendinous insertions. Finally, an incisional hernia can develop at the site of a prior surgical incision as the muscle and fascia is typically weakened, for example over the surgical site for an appendectomy.