**4. Diaphragmatic or hiatal hernia**

The diaphragm consists of striated muscle and has a collagenous central tendon, which is cranially blended with the pericardium. The esophageal hiatus is a 2-3 cm long muscular tunnel with a diameter of 3.5 cm, located 2-3 cm to the left at the peripheral muscular part of the diaphragm. The right crus and dorsal median arcuate ligament encircle the esophagus. Through the esophageal hiatus, besides the esophagus, pass the vagus trunks, sensory phrenico-abdominal branch of left phrenic nerve to the pancreas and peritoneum, esophageal vessels and retro-esophageal fat.

The natural anti-reflux mechanism is complex with several synergistic elements. A crucial element in preventing reflux is the circular muscular lower esophageal sphincter (LES) of 3.5 cm, extending from the distal esophagus down to the angle of His. The LES is autonomically controlled by vagal stimulation through intramural plexuses and enterohormones. Normally at least 1 cm of the LES is held intra-abdominally by the circular bilaminar phrenico-esophageal ligament. The ventral descending leaf connects the adventitia and muscular coat of the distal esophagus to the hiatus and is continuous with the lesser omentum at the right side of the esophagus. The supradiaphragmatic ascending leaf is

hernia can be difficult to visualize due to lack of peritoneal involvement through the hernia defect. Frequently epigastric hernias present incarcerated and in general only contain omentum or preperitoneal fat. Because of the small defect the hernia defect mostly need to

A Spigelian hernia is relatively rare, but more often diagnosed since the introduction of CTscan and laparoscopy. The Spigelian hernia occurs along the semilunar line at the level of the absence of the posterior rectus sheath (semicircular line, below the umbilicus). Almost all Spigelian hernias are interparietal due to the intact external oblique aponeurosis covering the hernia. A large Spigelian hernia is most often found laterally and inferior to its defect in

The Spigelian hernia has different factors of etiology (Lange & Kleinrensink, Surgical

Muscular gap between linea semilunaris and medial boundaries of oblique and

Maximal width of aponeurosis of transversus abdominis muscle at crossing of

Parallelism of fibers of internal oblique and transversus abdominis muscles between

Blending of aponeuroses of internal oblique and transversus abdominis muscle into one

Clinical diagnosis of a Spigelian hernia is challenging, but imaging with ultrasonography or CT-scan will confirm the presence of the hernia. Up to 20% of Spigelian hernias present incarcerated and therefore elective repair is indicated when diagnosed. The technique of laparoscopic repair is similar to other ventral hernia repairs. Compared to open repair, laparoscopic repair of Spigelian hernias is associated with a decreased morbidity, shorter

The diaphragm consists of striated muscle and has a collagenous central tendon, which is cranially blended with the pericardium. The esophageal hiatus is a 2-3 cm long muscular tunnel with a diameter of 3.5 cm, located 2-3 cm to the left at the peripheral muscular part of the diaphragm. The right crus and dorsal median arcuate ligament encircle the esophagus. Through the esophageal hiatus, besides the esophagus, pass the vagus trunks, sensory phrenico-abdominal branch of left phrenic nerve to the pancreas and peritoneum,

The natural anti-reflux mechanism is complex with several synergistic elements. A crucial element in preventing reflux is the circular muscular lower esophageal sphincter (LES) of 3.5 cm, extending from the distal esophagus down to the angle of His. The LES is autonomically controlled by vagal stimulation through intramural plexuses and enterohormones. Normally at least 1 cm of the LES is held intra-abdominally by the circular bilaminar phrenico-esophageal ligament. The ventral descending leaf connects the adventitia and muscular coat of the distal esophagus to the hiatus and is continuous with the lesser omentum at the right side of the esophagus. The supradiaphragmatic ascending leaf is

be enlarged to reduce the hernial sac and its content.

the space directly posterior to the external oblique muscle.

Anatomy of the Abdomen, Elsevier gezondheidszorg, 2002):

semicircular and semilunar lines.

**4. Diaphragmatic or hiatal hernia** 

esophageal vessels and retro-esophageal fat.

arcuate line and Hesselbach's triangle.

separate structure, caudally to arcuate line.

transversus abdominis muscles, caudally to umbilicus,

hospital stay and low recurrence rate (Moreno-Egea et al., 2002).

**3.6 Spigelian hernia** 

elastic and permits movement during swallowing and breathing. The extrinsic component of the anti-reflux mechanism is the pinching action of the right crus of the diaphragm. The right crus narrows the hiatus and increases the angle between the ventrally bended distal esophagus and the cardia. The LES and crus normally supplement each other in preventing acid reflux during swallowing or acute increased intra-abdominal pressure (Lange & Kleinrensink, Surgical Anatomy of the Abdomen, Elsevier gezondheidszorg, 2002).

A diaphragmatic or hiatal hernia occurs after enlargement of the hiatus and is a common disorder of the digestive tract. Cranial movement of the esophagus with protrusion of abdominal content (stomach in general) into the thoracic cavity can occur through the widened hiatus. This natural antireflux function is often disrupted by the presence of a hiatal hernia and is strongly associated with gastro-esophageal reflux disease (GERD). Hiatal hernias larger than 3 cm are a risk factor for erosive GERD and Barrett's esophagus.
