Dissection of the abdomen with bilateral hernias - Erler Zimmer 3D anatomy Series MP1130

This model of the abdomen with bilateral hernias is part of the exclusive Monash 3D anatomy series, a comprehensive series of human dissections reproduced with ultra-high resolution color 3D printing.

This 3D model represents one of the largest and most complex in the series, consisting of a partial torso from the diaphragm to the proximal thigh with a complete abdominal cavity preserving several levels of dissection. This 3-D model also records the rare simultaneous occurrence of indirect and direct inguinal hernias, allowing consideration of the anatomical basis for both conditions. Given the scale of the dissection, this 3D model description is divided into discrete parts based on views and regions.

The diaphragm
In the upper aspect of the model, the diaphragm is preserved and, although slightly distorted due to the removal of the thoracic ribs through dissection, both the domes and costodiaphragmatic recesses can be appreciated. Fibrous pericardium is present on the superior surface of the central tendon, with the terminal part of the inferior vena cava visible in the foramen cavale. Just lateral to the foramen cavale is the esophagus within the esophageal hiatus, then the descending thoracic aorta approaching the aortic hiatus just ventral to the thoracic vertebrae.

The epigastric and hypochondriac regions.
Within the abdomen, the anterior abdominal wall, the greater omentum, and much of the gastrointestinal tract were removed along with the parietal peritoneum over the posterior abdominal wall to expose the retroperitoneal organs and structures. In the upper abdomen, the terminal portion of the esophagus was retained and can be seen entering the cavity just lateral to the left lobe of the liver. Removal of the stomach exposed the extension of the pancreas from the head (positioned within the arch of the duodenum) to the tail extending to the spleen capsule retained in the left hypochondrium. Superior to the pancreas, the splenic artery and common hepatic arteries can be observed extending through the narrowed space between the pancreas, diaphragm, and liver. The splenic follows its archetypal "circuitous route" to the spleen, and divides sharply before reaching the hilum (and adjacent to the splenic vein). The common hepatic can be seen dividing into the gastroduodenal (again visible as a cut vessel just below the duodenum) and issuing the right gastric artery; these vessels lie superficial to the hepatic portal vein. The superior mesenteric artery and vein can be seen passing anteriorly near the head of the pancreas and the horizontal part of the duodenum, and the retained ileocolic artery can be traced back to the cecum of the large intestine in the right lower quadrant of the abdomen. The inferior mesenteric vein can be, in part, appreciated, originating from the retained superior rectal vein that ascends from the non-sectioned true pelvis and extends through the superficial aspect of the descending thoracic aorta.

Inferior to the liver, the gallbladder can be observed only between the left and right anatomic lobes. On the left, the passage of the renal artery and vein can be seen just deep to the pancreas, and the ureters descending from the partially exposed kidney can be seen through the superficial aspect of the exposed major and minor psoas muscles.

The umbilical and lumbar regions
Most of the organs occupying the umbilical and lumbar regions of the abdomen have been removed to expose structures in the posterior abdominal wall. On the midline, the descending abdominal aorta and inferior vena cava dominate the region, with isolated testicular arteries and veins traceable to the inguinal regions. Two right lumbar arteries originating from the aorta are visible, and despite the removal of the mesenteries and most of the colon, the inferior mesenteric artery giving rise to the left colic, sigmoid and superior rectal arteries can be seen. On the right side of the specimen, inferior to the kidney, the subcostal, ileohypogastric and ileoingual nerves along the circumflex iliac artery are exposed.

The hypogastrium and iliac regions.
On the midline, the bifurcation of the descending abdominal aorta into the common iliacs (and subsequent division into the internal and external iliacs) can be seen deep to some of the overlying structures (e.g., testicular vessels, ureters) previously observed. On the right side, the obturator artery can be seen crossing from its origin toward the anterior aspect of the pelvis. The mirror fusion of the external, internal and common iliac veins in the inferior vena cava is also preserved. Within the boundaries of the true pelvis the peritoneum has been retained over the region, covering the urinary bladder adjacent to the pubic symphysis and obscuring the rectum as it descends from the sigmoid colon. In the right iliac region, the end of the ileum and the cecum with appendix fill the iliac fossa, with the appendix (and appendicular artery) visible just superficial to the testicular artery, vein, and genital branch of the genitofemoral nerve descending to the inguinal canal. In the left region, the sigmoid colon descends through the iliac fossa. As it approaches the anterior abdominal wall, a contribution of the epiploic appendage to the indirect hernia can be seen just lateral to the retained inferior epigastric artery.

The inguinal region and the perineum
A distinctive and unique feature of this model is the dissection of simultaneous direct and indirect hernias preserved on the right and left sides, respectively. While most of the anterior abdominal wall was removed, the inferior epigastric arteries (and accompanying veins) were retained to allow interpretation of the hernias. On the right side, there was a clear outflow of the medial parietal peritoneum from the inferior epigastric artery, representing an indirect hernia event. On the left side, the herniary sac extends laterally from the inferior epigastric artery and into the open spermatic cord, with continuity of the epiploic appendage from the sigmoid colon into the sac.
The skin over the perineum was removed to demonstrate both the structure of the penis (with the spongy body and cavernous bodies in contrast) and the position of the testes and spermatic cords relative to the anterior abdominal wall. On the right side, which is affected by a direct hernia in this individual, the spermatic cord was left unsectioned allowing an appreciation of the external spermatic band from the inguinal region to the testis. On the left side, the spermatic cord has been opened and is dominated by the enlarged and varicose testicular vein (reflecting the impact of the indirect hernia exposed within the cord) just superior to the epididymis and exposed tunica albuginea of the testis.

The thigh
Anterior dissections were performed in the femoral triangle region on both thighs with variable preservation of contents. On the right side, the femoral sheath was removed to expose the femoral artery, vein, and deep inguinal lymph nodes. The femoral artery was dissected with a portion removed to expose the origin of the deep femoral and to better appreciate the drainage of the great saphenous vein into the femoral vein. Just lateral to these structures the terminal component of the femoral nerve is visible. On the left side, a slightly wider dissection window was opened to expose more muscles of the anterior and medial thigh compartment below, from the sartorius and iliopsoas laterally to the pectus and long adductor medially. The femoral artery was preserved,
The model ends at the mid-thigh level, and although not a primary focus of the model, it is possible to see the spatial organization of structures in the cross-section. This includes the anteriorly positioned femoral diaphysis with tightly packed anterior compartment muscles and the passage of the femoral artery and vein into the subsartorial canal.

What advantages does the Monash University anatomical dissection collection offer over plastic models or plastinated human specimens?

• Each body replica has been carefully created from selected patient X-ray data or human cadaver specimens selected by a highly trained team of anatomists at the Monash University Center for Human Anatomy Education to illustrate a range of clinically important areas of anatomy with a quality and fidelity that cannot be achieved with conventional anatomical models-this is real anatomy, not stylized anatomy.
• Each body replica has been rigorously checked by a team of highly trained anatomists at the Center for Human Anatomy Education, Monash University, to ensure the anatomical accuracy of the final product.
• The body replicas are not real human tissue and therefore not subject to any barriers of transportation, import, or use in educational facilities that do not hold an anatomy license. The Monash 3D Anatomy dissection series avoids these and other ethical issues that are raised when dealing with plastinated human remains.