The spleen is a wedge-shaped, highly vascular organ located in the left hypochondrium. It filters blood and plays an important role in immunity. The spleen lies obliquely along the 10th rib at a 45 degree angle. It has two surfaces - a diaphragmatic surface and a concave, irregular visceral surface with impressions for adjacent organs. The splenic artery supplies the spleen and the splenic vein drains into the portal vein. The spleen filters blood, removes old red blood cells, and plays a role in immune responses through lymphocyte activation and plasma cell production.

3. INTRODUCTION:-
 Spleen(Greek splen and Latin lien) is a
lymphatic organ connected to the blood vascular
system. It acts as a filter for blood and plays an
important role in the immune response of the
body.
 The Spleen is a wedge-shaped organ lying
mainly in the left hypochondrium , and partly in
the epigastrium
 The spleen lies against the diaphragm, in the area
of rib 9th to 10th .

7. DIMENSIONS:
- The spleen is soft, highly vascular and dark
purple in colour .
 The size and weight of spleen are markedly
variable .
 On an average the spleen in
 1 inch thick,
 3 inch broad,
 5 inch long,
 7 ounces in weight,
 and is related to 9th to 11th ribs .
1,3,5,7,9,11
Harris Dictor phenomemenon

9. POSITION:-
 The spleen lies obliquely along the long axis of 10th rib.
 Thus it is directed downwards, forward and laterally, making an angel
of about 45 degree with the horizontal plane .

11. The spleen has
 2 ends,
 3 boarders
 2 surfaces
 2 angles
 Hilum .
TWO ENDS:-
 The ANTERIOR END is expanded and is more like a border. It
is directed downward and forwards, and reaches the
midaxillary line .
 POSTERIOR END is rounded . It is directed upwards,
backwards and medially, and rests on the upper pole of the left
kidney.

13. Three borders:-
The superior border is characteristically notched
near the anterior end .
The inferior border is rounded .
The intermediate border is also rounded and is
directed towards right .
Two surfaces:-
 The diaphragmatic surface is convex and smooth
.
 The visceral surface is concave and irregular .

17. Two angles:-
 Anterobasal angle – It is the
junction of superior border with
lateral and anterior end of spleen
.
 When spleen is enlarged this
part felt first, so this is called
‘clinical angle of spleen’
 Posterobasal angle – Junction of
inferior border with lateral or
anterior end of spleen .
Hilum:-
 Hilum lies between the superior
and intermediate border,
• pierce by branches and
tributaries of splenic vessels

18. (a) Peritoneal relations
(b) Visceral reations
Peritoneal relations
The spleen surrounded by peritoneum and suspended by following
ligaments .
(a) Gastrosplenic ligament expands from the hilum of the spleen to
the greater curvature of stomach . It. Obtains the short gastric
vessel and associated lymphatic and sympathetic nerves.
(b) Lienorenal ligament expands from the hilum of the spleen to
the anterior surface of left kidney. It contain the tail of
pancreas, the splenic vessels and associated pancreaticosplenic
lymph nodes, lymphatic sand sympathetic nerves
(c) Phrenicoclic ligaments is not attached to the spleen, but
supports its anterior end. It is the horizontal fold of
peritoneum extending from the splenic flexure of colon to the
diaphragm . Also called sustentaculum lienis.

22. RELATIONS
Visceral
surface

24. 4 impression present are visceral surface of
spleen for abdominal organ and other
structures-
 Gastric impression
 Renal impression
 pancreatic impression
 Hilum lies on the inferomedial part of the gastric
impression along the long axis of the spleen .
Diaphragmatic surface-
The surface separates the spleen from the
costodiaphragmatic recess of pleura, lung and
9th,10th, 11th ribs of the left side.

27. ARTERIAL SUPPLY-
 SPLENIC ARTERY OR LIENAL ARTERY {the largest branch of
coeliac trunk }
 superior border of the pancreas .
 splenorenal ligament
divides into numerous branches
 enters the hilum of the spleen .
Approaching the spleen
 the splenic artery gives off short gastric arteries,
 gastrosplenic ligament to supply the fundus of the stomach.
***gastro-omental artery, (which runs along the grater cuvature of
stomach) & anstomoses with the ****right gastro-omental artery .

29. SPLENIC ARTERY

31. VENOUS SUPPLY:-
The splenic vein is formed at the hilum of the spleen . It
runs a straight course behind the pancreas . It joins the
superior mesenteric vein behind the neck of pancreas
to form the portal vein. Its tributaries are the short
gastric, left gastroepiploic, pancreatic and inferior
mesentric veins.

32. HISTOLOGYOF SPLEEN:-
There are two types of tissues in spleen (specialised for its
main function
• White pulp contains lymphoid aggregations, mostly
lymphocytes and macrophages which are arranged around
the arteries . The lymphocytes are both T( mainly T-helper)
and B-cells .
• Red pulp is vascular, and has parencyhma and lots of
vascular sinus . These are sinuosoids – a specialised type
of capillary, which is very leaky .
these cell population includes:
a. All types of lymphocytes (small, medium and large)
b. All types of blood cells (RBC, WBC and Platelets) and
c. The fixed and free macrophages . Lymphocytes are
freely transformed into plasma cells which can produce
large amount of antibodies the immunoglobins .

37. :-
• Splenic tissue proper has no lymphatics .
• A few lymphatics arise from the connective tissue of the
capsule and trabeculae .
• Drain into the pancreato splenic lymph nodes situated
along the splenic artery .
 Sympathetic fibres are derived from the coeliac plexus.
They are vasomotor in nature .
 They also supply some smooth muscle present in the
capsule .

40. 1. Haemopoiesis – The spleen is an important haemopoitic
organ during life. Lymphopoiesis continues through life
.
In adult spleen haemopoiesis can restart in certain
disease like chronic myeloid leukemia and
myesclerosis .
2. Phagocytosis – The spleen is an important component
of reticuloendothelial system .
3. Immuneresponses – Under antigenic stimulation, there
occurs increased lymphopoiesis for cellular responses
and increased formations of plasma cells to the
humoral responses .
4. Storage of RBC:- RBC can be stored in the spleen and
released in to the circulation when needed .

44. :-
A normal spleen is not palpable,
but a enlarged spleen can be
felt under the left costal margin
.
 Enlargement of spleen is
called splenomegaly.
 Sometimes the spleen
becomes very large ,it then
projected towards the right
iliac fossa in the direction of
the axis of the 10th rib .

45.  Surgical removal of spleen.
 During this operation of damage to tail of the
pancreas to be avoided.
:-
 Since there are segmental branches of splenic
artery, only one segment can be removed
according to the state of spleen .
 Spleen can be punctured at the 9th or 10th
intercostal surface in the mid axillary line using
a lumbar punctured needle.

59. MULTIPLE CHOICE QUESTIONS
1. Spleen position to the which region of abdomen
(I) epigastric
(ii) left hypochondric
(iii) umbilical
(iv) both i & ii
2. Spleen lies making how much angle with horizontal plane
(i) 30 (ii) 45 (iii) 60 (iv) 120
3. Shape of visceral surface
(i) concave (ii) convex (iii) irregular (iv) both i & iii
4. Clinical angle of spleen felt in which part of spleen
(i) posterobasal angle
(ii) diaphragmatic surface
(iii) visceral surface
(iv) anterobasal angle

60. 5. From hilum of spleen to the greater curvature of spleen, which ligaments extends,
(i) lienoenal ligament. (ii) gastrosplenic ligament
(iii) phrenicolic ligament. (iv) none of these
6. Visceral surface related to
(i) fundas of stomach (ii) anterior surface of left kidney
(iii) splenic flexor of the colon (iv) all of these
7. According to open circulation theory, the capillaries end open into
(i) red pulp (iii) green pulp
(ii) white pulp (iv) all of these
8. How does spleen helps in immune response
(i) by releasing stored WBC (ii) increased lymphopoiesis
(iii) increased formation of plasma cell
(iv) both ii & iii
9. Splenic puncture occurs in which intercostal space
(i) 9th & 10th (iii) 10th & 11th (iii) 7th & 8th (iv) 6th & 7th
10. Splenomegaly shows which condition of spleen
(i) shrunken spleen (ii) Enlarged spleen
(iii) surgical removal of spleen (iv) none of these