Download Spleen - HIMSK

SPLEEN,
THYMUS AND
TONSILS
Dr Rania Gabr
OBJECTIVES
 Discuss
the gross features of the
spleen
 Give its blood supply
 Discuss the gross anatomy of the
thymus and tonsils
 Give their function and blood supply
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.

S
URFACE 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 midaxillary 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 the
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 (1015% 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).
Thymus
• Roughly a bi-lobed structure
• DEVELOPMENT- bilateral 3rd
pharyngeal pouches
• EVOLUTION- largest at birth or
during infancy
• Increases slightly during 1st
decade of life and decreases
thereafter.
Thymus
Introduction
It is a flattened lymphoid organ located in the
upper anterior mediastinum & lower part of
the neck
Thymus
It consists of two
lateral lobes placed
in close contact
along the middle
line, situated partly
in the thorax, partly
in the neck.
In the thorax, It is Con . .
covered by the
sternum.
Below, it rests upon
the pericardium, being
separated from the
aortic arch and great
vessels by a layer of
fascia
In the neck it lies on
the front and sides of
the trachea.
The two lobes generally differ in size;
they are occasionally united, so as to
form a single mass; and sometimes
separated by an intermediate lobe.
The thymus is of a pinkish-gray color,
soft, and lobulated on its surfaces.
It is about 5 cm. in length, 4 cm. in
breadth below, and about 6 mm. in
thickness.
At birth it weighs about 15 grams, at
puberty it weighs about 35 grams;
after this it gradually decreases to 25
grams at twenty five years, less than
15 grams at sixty, and about 6 grams
at seventy years.
Vasculature
Blood Supply
A rich arterial supply to the thymus is derived mainly
from the:
1.Anterior intercostal &
2.Mediastinal branches of the internal thoracic arteries
 Veins of the thymus end in the left brachiocephalic,
internal thoracic & inferior thyroid veins.
 The lymphatic vessels of the thymus end in the
parasternal, brachiocephalic & tracheobrochial
lymphnodes.
The Tonsils
Definition: Ovoid lymphoid tissue
with fibrous capsule
laterally over the “superior
constrictor “muscles.
Its surface is covered with
stratified squamous
epithiluim & crypts.
It has a medulla & cortex
like all other lymphoid
tissues.
It is part of the Waldeyer`s
ring.
The Tonsils
Waldeyer's ring is a continuous band
of lymphoid tissue that surrounds the
upper pharynx.
The superior portion of the ring is
located in the nasopharynx and is
composed of the adenoids, Laterally
the palatine tonsils and, Anteriorly
the lingual tonsils to complete the
ring.
Tonsillar crypts extend deeply into
the body of the tonsil and are
surrounded by lymphoid nodules.
Debris and foreign particles collect
within the crypts.
• Function:
• Concerned with immune
mechanism.
• - 1st line of defense. The
lymphoid tissues produce
lymphocytes.
• - T-cells produce plasma cells &
help in antibody formation.
• Active phase lasts until 8-10
years of age.
• This function should not alter the
decision to remove the tonsils if
a valid indication for
tonsillectomy exists.
Blood Supply:
Arterial supply:
- Tonsilar branch of facial artery from
the ext. carotid.
- Descending palatine -------- > internal
maxillary artery.
- Ascending palatine -------- facial artery
- Ascending pharyngeal ---- external
carotid.
- Dorsalis linguae ------- lingual artery
Venous drainage :
occurs through the Para
tonsillar vein, and the
vessels also pass through
to the pharyngeal plexus
or facial vein after
piercing the superior
constrictor.
Nerve supply :
to the tonsil is from the
glossopharyngeal nerve.
Tonsillar tumors or infections may result in ear pain due to
referred pain conducted by cranial nerve IX:
Glossopharyngeal nerve.