Learning Objectives
- Identify the anatomical position and the protection provided by ribs 9-11.
- Master the peritoneal ligaments (Splenorenal and Gastrosplenic) and their contents.
- Understand the segmental blood supply and its surgical implications.
- Correlate splenic structure with the clinical presentation of splenic rupture and splenomegaly.
Anatomical Position & Relations
The spleen is an intraperitoneal organ located in the Left Hypochondrium. It is roughly the size of a fist and is protected by the left ribcage.
- Surface Anatomy: It lies deep to ribs 9, 10, and 11. A fractured rib in this area is a major risk factor for splenic injury.
- Palpation: A healthy spleen is not palpable. In splenomegaly, the notched superior border moves inferomedially toward the umbilicus.
Anatomical Relations
- Anterior: Stomach.
- Posterior: Left dome of the diaphragm, left lung, and ribs 9-11.
- Inferior: Left colic (splenic) flexure.
- Medial: Left kidney and the tail of the pancreas.
Splenic Ligaments
The spleen is connected to adjacent organs by two primary ligaments derived from the greater omentum:
| Ligament | Connections | Contents (High-Yield) |
|---|---|---|
| Gastrosplenic | Spleen to Greater Curvature of Stomach | Short gastric vessels, left gastro-omental vessels. |
| Splenorenal | Spleen to Left Kidney | Splenic artery/vein, Tail of the Pancreas. |
Vasculature: The Segmental Rule
The spleen is one of the most vascular organs in the body, receiving blood from the Splenic Artery (the largest branch of the coeliac trunk).
- Segmental Supply: The splenic artery divides into ~5 branches at the hilum. These branches do not anastomose.
- Surgical Note: This allows for subtotal splenectomy, where a surgeon can remove only the damaged segment, preserving immune function.
- Venous Drainage: The Splenic Vein joins the Superior Mesenteric Vein (SMV) to form the Hepatic Portal Vein.
Clinical Relevance
- Splenic Rupture: Blunt trauma to the LUQ can shatter the thin capsule. Because it is highly vascular, this leads to rapid intraperitoneal hemorrhage and shock.
- Post-Splenectomy Sepsis: Without a spleen, patients are highly vulnerable to encapsulated bacteria (e.g., S. pneumoniae, H. influenzae). Life-long vaccinations and antibiotics are often required.
- Kehr’s Sign: Referred pain to the left shoulder caused by splenic blood irritating the diaphragm (phrenic nerve, C3-C5).
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