The nerves composing this plexus are white in color and firm in texture; in the upper part of the plexus close to the origin of the superior mesenteric artery is the superior mesenteric ganglion.
22.
The uncinate process, unlike the remainder of the organ, passes posteriorly to the superior mesenteric vein ( it can pass posteriorly to the superior mesenteric artery, but this is less common ).
23.
The proximal two-thirds of the transverse colon is perfused by the middle colic artery, a branch of the superior mesenteric artery ( SMA ), while the latter third is supplied by branches of the inferior mesenteric artery ( IMA ).
24.
Generally this anomalous source is the superior mesenteric artery or more rarely the abdominal aorta, producing what has been described as a " replacing right hepatic artery ", passing through the hepatobiliary triangle and running posterior and parallel to the cystic duct.
25.
Of note, the splenic flexure, or the junction between the transverse and descending colon, is supplied by the most distal portions of both the inferior mesenteric artery and superior mesenteric artery, and is thus referred to medically as a shock.
26.
The ampulla of Vater is an important landmark halfway along the second part of the duodenum that marks the anatomical transition from foregut to midgut, and hence the point where the celiac trunk stops supplying the gut and the superior mesenteric artery takes over.
27.
The superior mesenteric artery passes down in front of the left half across the uncinate process; the superior mesenteric vein runs upward on the right side of the artery and, behind the neck, joins with the lienal vein to form the portal vein.
28.
One non-malignant cause of a secondary varicocele is the so-called " Nutcracker syndrome ", a condition in which the superior mesenteric artery compresses the left renal vein, causing increased pressures there to be transmitted retrograde into the left pampiniform plexus.
29.
Other important structures are also located at this level, they include; fundus of the gall bladder, celiac trunk, superior mesenteric artery, termination of spinal cord, beginning of fillum terminalis, renal vessels, middle suprarenal arteries, and hila of kidneys.
30.
The splenic flexure is a watershed region as it receives dual blood supply from the terminal branches of the superior mesenteric artery and the inferior mesenteric artery, thus making it prone to ischemic damage in cases of low blood pressure because it does not have its own primary source of blood.
