Spleen

objectives Discuss the gross features of the spleen Give its blood and nerve supply Give its lymphatic drainage Describe the Inguinal Lymph nodes

Position of spleen The spleen lies in the left hypochondrium between the stomach and diaphragm. It has two ends, three borders and two surfaces.

Measurements: -1 inch (thickness) x 3 inches (Breadth) x 5 Inches (length). - Weight: 875 gram (7 ounces). - Surface anatomy: Behind left 9, 10, 11 ribs.

Surface anatomy : It lies parallel to the ribs number 9, 10 , and 11 on the left side. The long axis of the spleen lies parallel to the 10th rib. Its medial end lies 1 1/2 inches from the spine of T. 10, while the lateral end lies just behind the mid- axillary line.

Shape : 3 borders, 2 ends, 2 surfaces. A. Ends 1) lateral end (Broad) 2) medial end (tapering) B. Borders Upper(Anterior) border: Sharp & notched Lower (Posterior)border: (Broad) Intermediate border: thick, incomplete. Extends from the medial end till the hilum).

Surfaces 1- Diaphragmatic surface: Convex, Related to the diaphragm which separates it from 3 structures :------- - Lower part of left pleura, - Base of left lung, - Left 9, 10, 11 ribs.

2- Visceral surface: Concave, irregular, directed to the abdominal cavity. Contains the hilum and impressions for 4 abdominal organs: 1- Gastric impression (related to posterior wall of fundus of stomach). 2- Renal impression. 3- Colic impression (left colic flexure). 4- Pancreatic impression (tail of pancreas).

Peritoneal relations The spleen is completely covered by peritoneum of the greater sac except at the hilum. It is attached and related to the following ligaments: 1- Gastro-splenic ligament 2- Lieno-renal ligament.

Peritoneal connections 1-Gastrosplenic ligament: from the fundus and greater curvature of stomach to the hilum of spleen. 2- Lienorenal ligament: From the lower border of the hilum of spleen to the anterior surface of kidney.

CONTENTS The gastrosplenic ligament contains: - Short gastric vessels - Left gastroepiploic vessels - Lymph nodes The lieno-renal ligament contains: - Splenic vessels - Tail of pancreas - Lymph nodes

Arterial Supply: Splenic artery (branch of the coeliac trunk). It has a tortuous course at the upper border of the pancreas. It passes with the tail of the pancreas in the lieno-renal ligament. At the hilum it divides into 5 or 6 splenic branches.

Venous drainage: The spleen is drained by the splenic vein that passes on the posterior surface of the pancreas to unite with superior mesenteric vein to form the portal vein posterior to the neck of the pancreas.

Clinical notes: Splenomegaly It is an enlargement of the spleen beyond its normal size. Many disorders, including infections, anemias, can cause an enlarged spleen. Enlarged spleen extends downward and medially (due to the presence of the phrenico-colic ligament that prevents its direct downward descent). The splenic notch(s) may be felt by palpation through the anterior abdominal wall. Injury of the spleen is common due to fracture of the 9, 10, 11 ribs, automobile accidents, during playing contact sports, or due to penetrating wounds of the lower left thorax.

Accessory spleens Accessory spleens are common (10-15% of people). They are found at the hilum of spleen, the lieno-renal, or the gastro-splenic ligaments. The tail of pancreas is in close relation to the hilum of spleen so it could be injured during splenectomy (surgical removal of the spleen).

Spleenectomy Spleen removal is surgery to remove a diseased or damaged spleen the organ that helps the body fight infections. ...Its attachments to other organs are gently cut.

Inguinal lymph nodes

I- Superficial inguinal LNs: Inguinal lymph nodes I- Superficial inguinal LNs: Site: In the proximal region of the femoral triangle. No: 12- 20 Two groups: A- Horizontal group: i- Medial: It drains: Anterior abdominal wall below umbilicus, lower part of anal canal, external genitalia (male and female). ii- Lateral: It drains; buttock and back below iliac crest.

B- Vertical group: It drains the lower limb. It is present at the end of the great saphenous vein. All the above groups of LNs send efferents to deep inguinal and external iliac LNs.

Inguinal lymph nodes cont. II- Deep inguinal LNs: - Site: Deep to deep fascia on the medial side of the femoral vein. - No: 1-3. One of them may lie in the femoral canal (lymph node of Cloquet). - Afferent: from deep lymphatics of the lower limb and from superficial inguinal LNs. - Efferent: to external iliac LNs

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