Introduction
- The spleen
is the largest lymphatic organ.
- It plays
an important role in immunity and blood filtration.
- It is a highly
vascular organ and is part of the reticuloendothelial system.
Location and
Position
- Located in
the left upper quadrant of the abdomen (left hypochondrium).
- Lies behind
the stomach, between the fundus of stomach and diaphragm.
- Lies at
the level of 9th to 11th ribs (posteriorly).
Shape and Size
- Shape: Oval or
wedge-shaped.
- Size: About 12
cm long, 7 cm wide, and 3-4 cm thick.
Weight and Colour
- Weight: Around 150–200
grams in adults.
- Colour: Dark
purplish or bluish-red due to its rich blood supply.
External Features
Ends
- Anterior
end: Broad and directed forward.
- Posterior
end: Rounded and directed backward.
Borders
- Superior
border: Shows notches (important for palpation).
- Inferior
border: Rounded and smooth.
- Intermediate
border: Faces medially, where the hilum is present.
Surfaces
- Diaphragmatic
surface
- Visceral
surface
Relations
Diaphragmatic
Surface
- Convex and
smooth
- Lies in
contact with:
- Diaphragm
- Left
pleura
- Lung
- Ribs (9th
to 11th)
Visceral Surface
- Concave
and irregular
- Contains hilum
(entry/exit of vessels and nerves)
Visceral Relations
and Impressions
- Gastric
impression – related to fundus of stomach
- Renal
impression – related to left kidney
- Colic
impression – related to splenic flexure of colon
- Pancreatic
impression – related to tail of pancreas
Blood Supply
Arterial Supply
- Supplied
by splenic artery, a branch of the celiac trunk
- Enters at
the hilum, divides into branches within the spleen
Venous Drainage
- Drained by
splenic vein, which joins the superior mesenteric vein to
form the portal vein
Nerve Supply
- From celiac
plexus
- Sympathetic
fibers control vasoconstriction
Functions of Spleen
- Filtration of blood
(removes old/damaged RBCs)
- Acts as a blood
reservoir
- Produces lymphocytes
- Participates
in immune responses
- Hematopoiesis in fetal
life
Clinical Anatomy
Palpation
- Normally not
palpable.
- Palpable
when enlarged (below costal margin) – feel for notches on superior
border.
Splenomegaly
- Enlargement of spleen
due to infections (malaria, typhoid), blood cancers, portal hypertension
- Can become
massive and cross the midline
Splenectomy
- Surgical
removal of spleen
- Done in
trauma, tumors, or hypersplenism
- Post-splenectomy
patients are prone to infections (especially by encapsulated
bacteria)
Tags
ANATOMY