Anatomy of Spleen
Introduction:
Lymphatic organ connected to vascular system.Site: it lies obliquely in the post. Part of the Lt. hypochondrium wedged between the fundus of stomach and the diaphragm.
Surface anatomy: it lies opposite the ribs 9,10, and 11.
N.B: normally, the spleen is not palpable as it does not extend below costal margin.
The Spleen:Size and Weight: (easy to remember by the add numbers 1, 3, 5, 7, 9, and 11) The average spleen is 1” thick, 3” broad, 5” long, 7 ounces (200gm) in weight, and is related to the 9-11 ribs.
Shape and Features: it is shaped as cupped hand:
2 ends: med. (post.) and lat. (ant.)
2 borders: upper and lower
2 surfaces: diaphragmatic and visceral.
Shape and Features
• Medial (post.) end: is rounded and directed upwards, backwards and medially.• Lateral (ant.) end: is expanded and directed downwards, forwards.
• Upper border: is sharp and notched near the ant. End and terminates laterally by the angle.
• Lower border: is thick, rounded, and smooth (no notches)
• Diaphragmatic surface: is convex, smooth and related to the diaphragm.
• Visceral surface: concave, irregular and related to abdominal viscera. It presents the hilum.
Relations of the Spleen:
• The Diaphragmatic surface: is related to diaphragm which separates the spleen from Lt. Pleura and Lt. Lung.• The Visceral surface:
• Gastric impression: it is a large concave area between the hilum and the upper border (related to post. Wall of the fundus of stomach).
• Renal impression: a small shallow impression between the hilum and the lower border (related to the front of the left kidney).
• Pancreatic impression: s small impression below lateral end of hilum (related to tail of pancreas)
• Colic impression: a flat area close to lat. end of the spleen (related to the Lt. colic flexure).
Hilum of the Spleen:
It is a longitudinal slit in the visceral surface between the gastric and colic impressions.It transmits:
• Terminal branches of splenic artery.
• Tributaries of splenic vein.
• Automatic nerves and lymphatics.
It gives attachment to 2 ligaments:
• Linorenal lig.
• Gastrosplenic lig.
Peritoneal Relations of the Spleen:
The spleen is completely covered with peritoneum of the greater sac except the pancreatic impression.Stability of the Spleen:
Depend on:
• Intra-abdominal pressure.
• Position of the surrounding organs.
• Ligaments: As mentioned previously.
Peritoneal ligaments of the Spleen:
Linorenal Ligament:Attachments: it extend between lower part of hilum of spleen and the front of upper half of the Lt. kidney.
Contents:
• Splenic vessels.
• Tail of pancreas.
• Lymphatics and pancreatico-splenic L.Ns.
• Extraperitoneal fatty tissue.
• Autonomic nerve fibers.
Peritoneal ligaments of the Spleen:
Gastrosplenic Ligament:Attachments: it extend between upper part of hilum of spleen and the front of upper 1\3 of the greater curvature of the stomach.
Contents:
• Short gastric vessels.
• Lt. gastric-epiploic vessels.
• Lymphatics and pancreatico-splenic L.Ns.
• Extraperitoneal fatty tissue.
• Autonomic nerve fibers.
Arterial Supply of the Spleen:
Splenic artery:Arises as the largest branch of the coeliac trunk.
It runs a tortuous course along the upper border of the body of the pancreas.
It enters the linorenal lig. To reach the hilum of the spleen to end by dividing into 5-6 branches.
Venous Drainage of the Spleen:
Splenic Vein:Aries at the hilum of the spleen then enters the linorenal ligament.
It runs a straight course behind the pancreas.
It ends by joining the superior mesenteric v. to form the portal v.