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Jejunum and Ileum (Relations & Neurovasculature) - Coggle Diagram
Jejunum and Ileum (Relations & Neurovasculature)
Anatomical Relations (6 Spatial Boundaries)
The jejuno-ileal loops form a compact mass occupying the inframesocolic compartment and pelvic cavity
Posterior
Lumbar posterior wall
Retroperitoneum
Abdominal Aorta
IVC
Inferior Duodenopancreatic Block
Kidneys
1 more item...
Superior
Transverse colon and transverse mesocolon
Anterior
Greater omentum
Anterior abdominal wall
Inferior
Sigmoid (iliopelvic) colon
Right Side
Cecum
Ascending Colon
Left Side
Descending colon
Lateral Abdominal Wall
Arterial Supply (Superior Mesenteric Artery System)
Superior Mesenteric Artery (SMA) Trajectory
Arises from the anterior surface of the abdominal aorta at L1
Courses downward, anteriorly, and to the right through two main segments:
Initial Fixed Segment
Retropancreatic → Anterior to pancreas → Anterior to D3
Branches: Inferior pancreaticoduodenal art. & Inferior pancreatic art.
Terminal Mobile Segment
Travels between the 2 layers of the mesentery
Branches: Right-sided colic branches & Left-sided intestinal branches
Terminates near ileocecal junction
Intestinal Arterial Pattern & Arcades
From the left border of the SMA, approximately 15 intestinal arteries descend into the mesentery:
Extensive Anastomotic Loops (1st, 2nd, 3rd & 4th Order Arcades)
Juxta-Intestinal Arcades
Straight Arteries (Vasa Recta)
Anterior Branch (Supplies Anterior Surface)
Posterior Branch (Supplies Posterior Surface)
Venous Drainage (Satellite Pattern)
Empty into the Superior Mesenteric Vein (SMV), which travels along the right side of the SMA before joining the splenic vein to form the Portal Vein
Intestinal veins run satellite to the arterial arcades.
Lymphatic Drainage (3-Stage Chain)
Juxta-Intestinal Nodes → Intermediate Nodes → Central Lymph Nodes
Efferent Pathway: Central Group → Superior Mesenteric Lymph Nodes → Left Lumbar Trunk → Cisterna Chyli (origin of Thoracic Duct)
Innervation (Superior Mesenteric Plexus)
Autonomic nerve fibers wrap around the SMA and its branches:
Parasympathetic (Vagus - CN X)
Enhances intestinal motility and exocrine secretions
Sympathetic (Splanchnic Nerves)
Vasoconstriction, inhibition of peristalsis, and transmission of visceral pain (nociception)