Dorsal Mesentery Derivatives

The dorsal mesogastrium gives rise to a series of ligaments interconnecting the organs in the left upper abdomen: the gastrosplenic, splenorenal, and gastrocolic ligaments and the greater omentum.

This network of ligaments in the left upper quadrant establishes local continuity between the stomach, spleen, pancreas, left kidney, and transverse colon and global continuity with the entire abdomen as extensions of the subperitoneal space.1,3,5,6,18-20

Sim Ligament

Fig. 13—7. Anatomic drawing of the subperitoneal space in the lower abdomen and pelvis.

Note the continuity of the space beneath the posterior parietal peritoneum and the abdominal and pelvic walls with the roots of the small intestine and sigmoid mesenteries and the pelvic ligaments. SIM* = root of small intestine mesentery; SM = root of sigmoid mesocolon; BL = broad ligament; BL = cut section through broad ligament showing contained vascular structures; CL = cardinal ligament; SLO = suspensory ligament of ovary; RL = round ligament. Attention is also focused on the continuity of the lower abdominal and pelvic organs created by the subperitoneal space. C = cecum and posterior parietal peritoneum cut away; note relationship of SIM* to C; O = ovary; UT = uterus; CX = cervix; UB = urinary bladder; R = rectum; Ur = ureter as it traverses the broad ligament with uterine artery crossing anteriorly; star = posterior parietal peritoneum cutaway and showing the subperitoneal space with ureter and artery. Note continuity with broad ligament. (Reproduced from Oliphant et al.14)

Fig. 13—7. Anatomic drawing of the subperitoneal space in the lower abdomen and pelvis.

Note the continuity of the space beneath the posterior parietal peritoneum and the abdominal and pelvic walls with the roots of the small intestine and sigmoid mesenteries and the pelvic ligaments. SIM* = root of small intestine mesentery; SM = root of sigmoid mesocolon; BL = broad ligament; BL = cut section through broad ligament showing contained vascular structures; CL = cardinal ligament; SLO = suspensory ligament of ovary; RL = round ligament. Attention is also focused on the continuity of the lower abdominal and pelvic organs created by the subperitoneal space. C = cecum and posterior parietal peritoneum cut away; note relationship of SIM* to C; O = ovary; UT = uterus; CX = cervix; UB = urinary bladder; R = rectum; Ur = ureter as it traverses the broad ligament with uterine artery crossing anteriorly; star = posterior parietal peritoneum cutaway and showing the subperitoneal space with ureter and artery. Note continuity with broad ligament. (Reproduced from Oliphant et al.14)

The dorsal mesocolon gives rise to the transverse mesocolon. Near the uncinate process of the pancreas, the root of the transverse mesocolon is confluent with the root of the small intestine mesentery. The right lateral extension of the transverse mesocolon over the duodenum and colon is designated the duodenocolic ligament and the left lateral extension is the phrenicocolic ligament.

Thus, the subperitoneal space subtended by the transverse mesocolon is in continuity with the subperitoneal space interconnecting the organs of the left upper quadrant, the small intestine mesentery, and the right lower abdomen via the root of the small intestine mesentery 1,3,5,6.21-25

The superior mesenteric artery extends from the aorta anteriorly and with its branches courses along within the subperitoneal space in the derivative of the mesentery proper.

The root of the mesentery extends obliquely from the distal duodenum at the lower border of the pancreas on the left side of L2 to the cecum in the right lower quadrant. The line of attachment passes from the duodenojejunal junction, where it is in continuity with the root of the transverse mesocolon over the third portion of the duodenum, obliquely across the aorta and inferior vena cava, the right ureter, and psoas muscle, to the right iliac region.26 The peritoneal reflections from the root of the mesentery in the region of the terminal ileum reflect to continue as the posterior peritoneum overlying the posterior and right lateral wall of the abdomen. The connective tissue within this portion blends and connects with the subperitoneal tissue in the retoperi-toneum of the right posterior lower abdomen wall. From the base of the small bowel mesentery the peritoneum of the posterior abdominal wall envelops the ventral surface of the ascending colon. The vasculature supplying these structures lies within the subperitoneal space between the base of the mesentery and the medial border of the ascending colon. The subperitoneal tissue in the right lower abdomen continues cephalad to the

Subperitoneal

Fig. 13—8. Anatomic drawing of the subperitoneal space showing the central vascular scaffold and its interconnection with the renal arteries and the three ventral branches of the aorta.

A portion of the right anterior renal fascia has been incised and the flap turned laterally. The right renal artery (RRA) and proximal right ureter (U) are seen within the right renal hilum. A portion of the inferior vena cava (IVC) has been removed' allowing visualization of the right celiac ganglion (CG) and lumbar ganglia (G). The ventral branches of the aorta (DA) are the celiac axis (CA), the superior mesenteric artery (SMA), and the inferior mesenteric artery (IMA). LRA = left renal artery. (Reproduced from Oliphant and Berne.17)

Fig. 13—8. Anatomic drawing of the subperitoneal space showing the central vascular scaffold and its interconnection with the renal arteries and the three ventral branches of the aorta.

A portion of the right anterior renal fascia has been incised and the flap turned laterally. The right renal artery (RRA) and proximal right ureter (U) are seen within the right renal hilum. A portion of the inferior vena cava (IVC) has been removed' allowing visualization of the right celiac ganglion (CG) and lumbar ganglia (G). The ventral branches of the aorta (DA) are the celiac axis (CA), the superior mesenteric artery (SMA), and the inferior mesenteric artery (IMA). LRA = left renal artery. (Reproduced from Oliphant and Berne.17)

diaphragm and caudad over the pelvic musculature along the right lateral pelvic wall. Thus, the root of the small bowel mesentery interconnects the upper abdomen and the right lower abdomen,20,26 which in turn is in continuity with the pelvis.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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