Spleen Flashcards
Location of spleen
Left hypochondrium and partly in the epigastrium.
It is wedged b/w fundus of stomach and diaphragm
Shape and Dimensions of Spleen
Tetrahedral in shape when colic impression is prominent or else can be triangular or wedge shaped
It is highly vascular, soft and dark purple in colour. Dimensions show a lot of variation
AVERAGE (Rule of odds/Harris dictum of odds)
1 inch/2.5cm-Thick
3 inch/7.5cm - Broad
5 inches/ 12.5 cm - Long
7 ounces in weight
Relates to 9th-11th Rib with its axis along the Left 10th rib
NOTE: Normally spleen not palpable
Position of Spleen (Axis)
Obliquely oriented, the spleen has its long axis along the left 10th rib. It is directed downwards, forwards and laterally making an angle of 45 degrees with the horizontal plane.
External Features of Spleen
2 Ends
:Anterior/Lateral end - Expanded and appears more like a border. Directed downwards and forwards and reaches the midaxillary line
:Posterior/Medial end - Rounded. Directed upwards, backwards and medially. Rests on upper pole of left kidney. At level of T10
2/3 Borders (according to BDC 3)
: Superior Border - Characteristically notched near the anterior end. Separates the gastric impression from the diaphragmatic surface.
: Inferior Border - Rounded border. It separates the renal impression from the diaphragmatic surface.
: Sometimes a third intermediate border is observed which is rounded and directed to the right. Separates the Renal impression and the gastric impression.
2 Surfaces
: Diaphragmatic Surface - Convex and smooth
: Visceral Surface - Concave and irregular. Has the hilum.
2 Angles
: Anterobasal angle - Junction between the superior border and the with lateral end. Most forward projecting part of the spleen. AKA Clinical angle of spleen (first palpated in enlarged spleen)
: Posterobasal angle - Junction of inferior border with lateral end of spleen
Hilum of the spleen is located on the inferomedial part of the gastric impression along the long axis of the spleen
Anatomical Correlation of the notches on the Spleen Superior border
The spleen develops as lobulations and then most fuse to form one organ and the persisting demarcations are seen as the notches.
Therefore, the notches are indicative of the lobular development of the spleen.
Peritoneal Relations of Spleen
Spleen is surrounded by peritoneum
Ligaments -
Gastrosplenic Ligament - Extends from the anterior lip of hilum of spleen to greater curvature of stomach. Contains the short gastric vessels and associated lymphatics and sympathetic nerves
Lienorenal Ligament - Extends from the posterior lip of the hilum of spleen to the anterior surface of the left kidney. Contains tail of pancreas, splenic vessels and associated pancreaticosplenic lymph nodesand lymphatics and sympathetic nerves
Phrenicocolic Ligament (AKA Sustentaculum Lienis) While the phrenicocolic ligament is not directly attached to the spleen, it provides it support from the anterior end. It is a horizontal peritoneal fold connecting the splenic flexure of the colon to the diaphragm opposite the 11th rib in the midaxillary line. It hence limits the upper end of paracolic gutter.
Visceral Relations of Spleen
- Fundus of stomach - Gastric Impression - Largest and most concave impression on spleen surface which lies b/w superior and intermediate borders
- Anterior Surface of Left Kidney - Renal Impression - lies b/w inferior and intermediate border
- Splenic Flexure of Colon - Colic Impression - Occupies a triangular area adjacent to the anterior end of spleen. The phrenicocolic ligament is related in its lower part
- Tail of Pancreas - Pancreatic Impression - Lies b/w hilum and colic impression
The diaphragmatic surface is related to the diaphragm separating it from the Costodiaphragmatic recess of pleura, lung, 9th, 10th, and 11th ribs on the left side.
Arterial Supply of Spleen
Supplied by the Splenic artery (should know details of this)
It is tortuous in its course to allow for movement of spleen during respiration.
It passes through the leinorenal ligament to reach the hilum of the spleen where it divides into 5 or more branches which enter the spleen to supply it.
Within the spleen it divides repeatedly to for successfully the straight vessels called penicilli which further divide into ellipsoids and arterial capillaries.
Spleen has superior and inferior vascular segments separated by an avascular plane. Each segment can be divided into 2 disc like segments and one cap like segment
Venous Drainage of Spleen
Splenic vein is formed at the hilum of the spleen. It runs a straight course behind the pancreas and joins the superior mesenteric vein behind the neck of the pancreas to form the portal vein.
Tributaries - Short gastric, Left gastroepiploic, Pancreatic and inferior mesenteric veins.
Lymphatic Drainage of Spleen
Few lymphatics arise from the spleen connective tissue capsule including the trabeculae and drain into the pancreaticosplenic lymph nodes situated along the splenic artery
Apart from this, no lymphatics per se for splenic tissue
Nerve Supply for Spleen
Sympathetic fibres are derived from the coeliac plexus which are vasomotor in nature. They also supply some smooth muscles in the capsule
Palpation of spleen
A normal spleen is not palpable. Enlarged spleen can be palpated under the left costal margin during inspiration(only after getting enlarged 2.5-3 times normal size). Palpation is assisted by turning patient to right side.
