Download Lymph nodes

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The lymphatic (lymphoid) system is essentially a drainage
system, which is concerned with return of a fluid called "lymph"
back to the blood stream.
It consists of lymphatic tissues and lymphatic vessels.
Its components are not in continuous order, but are scattered
throughout the body and it services almost all regions.
Lymphatic tissues are a type
of connective tissue that
contains large numbers of
lymphocytes.
Lymphatic tissue is organized
into the following organs: the
thymus, lymph nodes, spleen,
and lymphatic nodules.
Lymphatic tissue is essential
for the immunologic defenses
of the body against bacteria
and viruses.
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Lymphatic vessels are
tubes that assist the
cardiovascular system in
the removal of tissue fluid
from the tissue spaces of
the body; the vessels then
return the fluid to the blood.
Lymphatic vessels are
found in all tissues and
organs of the body except:
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Central nervous system.
Eyeball & internal ear.
Epidermis of skin.
Cartilage & bone.
LYMPH VESSELS
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Lymph vessels are either superficial or deep:
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Superficial lymphatics: more numerous than veins in the
subcutaneous tissue and anastomosing freely, converge
toward and follow the venous drainage.
These vessels eventually drain into deep lymphatics that
accompany the arteries and also receive the drainage of
internal organs.
Both superficial and deep lymphatics traverse lymph
nodes as they course proximally, becoming larger as
they merge with vessels draining adjacent regions.
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The lymphatics that carry lymph to a lymph node are referred to as
afferent vessels; those that transport it away are efferent vessels.
The larger lymphatics enter large collecting vessels,
called lymphatic trunks, which unite to form either
the right lymphatic duct or the thoracic duct:
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Right lymphatic duct.
Thoracic duct.
Functions of the lymphatic system
The functions of the lymphatic system are just as varied as its
locations. These functions fall into 3 categories:
 Fluid balance:
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Absorption and transport of dietary fat:
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The small lymphatic capillaries pick up excess interstitial fluids and
proteins, which accumulate in the tissue spaces. These capillaries then
drain into larger vessels, which return these materials to the venous
system near the heart.
Many digested fats are too large to enter the blood capillaries and are
instead absorbed into lymphatic capillaries. Special lymphatic capillaries,
called lacteals (L .lacteus, milk), receive all lipid and lipid-soluble
vitamins absorbed by the intestine. Visceral lymphatics then convey the
milky fluid ,chyle (G. chylos, juice), to the thoracic duct and into the
venous system.
Formation of a defense mechanism for the body:
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When foreign protein drains from an infected area, antibodies specific to
the protein are produced by immunological cells (lymphocytes) and
dispatched to the infected area.
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Peritoneal covering:
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The spleen is surrounded by peritoneum, which passes from it at the
hilum to the:
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Blood supply:
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Arteries
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The large splenic artery is the largest branch of the celiac artery. It has a
tortuous course as it runs along the upper border of the pancreas. The
splenic artery then divides into about 6 branches, which enter the spleen at
the hilum.
Veins
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Greater curvature of the stomach as the gastrosplenic ligament (carrying the
short gastric and left gastroepiploic vessels).
Left kidney as the splenicorenal ligament (carrying the splenic vessels and
the tail of the pancreas).
The splenic vein leaves the hilum and runs behind the tail and the body of
the pancreas. Behind the neck of the pancreas, the splenic vein joins the
superior mesenteric vein to form the portal vein.
Lymph drainage:
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The lymph vessels emerge from the hilum and pass through a few lymph
nodes along the course of the splenic artery and then drain into the
celiac nodes.
Clinical Notes
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Splenic Enlargement
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A pathologically enlarged spleen extends downward and
medially.
The left colic flexure and the phrenicocolic ligament prevent
a direct downward enlargement of the organ.
As the enlarged spleen projects below the left costal margin,
its notched anterior border can be recognized by palpation
through the anterior abdominal wall.
Trauma to the Spleen
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Although anatomically the spleen gives the appearance of
being well protected, automobile accidents of the crushing or
run-over type commonly produce laceration of the spleen.
Penetrating wounds of the lower left thorax can also damage
the spleen.
Lymphatic drainage of the upper limb
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Superficial lymph vessels:
The superficial lymph vessels draining the
superficial tissues of the upper arm pass upward to
the axilla.
 Those from the lateral side of the arm follow the
cephalic vein to the infraclavicular group of nodes;
those from the medial side follow the basilic vein to
the lateral group of axillary nodes.
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The deep lymphatic vessels: draining the
muscles and deep structures of the arm drain
into the lateral group of axillary nodes.
Axillary Lymph Nodes
Site
Afferent
Efferent
Anterior
(pectoral)
group
At the lower border of
pect. minor (along lat.
thorathic artery)
Lat.
part of breast
Front of trunk (above
umbilicus)
Central
Lateral
(Brachial)
group
Along the lateral wall
of axilla (along
axillary vein)
Most
Central
Posterior
(subscapular)
group
Along lower border of
subscapularis (along
subscapular artery)
Back
of trunk (above
iliac crest)
Tail of breast
From the previous 3
groups
Central
Central group
At the base of axilla
in fat of axilla (closely
related to intercostobrachial N
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From the previous 3
groups
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Apical group
Near the apex of
axilla (behind clavipectoral fascia)
From
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of lymphatics of
UL
previous groups
Upper part of breast
group
Apical group
group
Apical group
Few lymph vessels pass to deep
cervical LN
group
Apical group
Apical group
Lymph vessels of this group unite
to form subclavian lymph trunk
which opens into:
1.
2.
on left side: in thoracic duct
on right side: in right lymph duct
Lymphatic drainage of the lower limb
Inguinal lymph nodes: are divided into superficial & deep groups.
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Superficial inguinal LNS
 They lie in the superficial fascia below the inguinal ligament
and can be divided into a horizontal and a vertical group.
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The horizontal group lies just below and parallel to the inguinal
ligament.
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The medial members of the group receive superficial lymph vessels from
the anterior abdominal wall below the level of the umbilicus, perineum,
urethra, external genitalia of both sexes (but not the testes) and lower
1l2 of anal canal.
The lateral members of the group receive superficial lymph vessels from
the back below the level of the iliac crests.
The vertical group lies along the terminal part of the great saphenous
vein and receives most of the superficial lymph vessels of the lower
limb.
The efferent lymph vessels from the superficial inguinal
nodes pass through the saphenous opening in the deep
fascia and join the deep inguinal nodes.
Lymphatic drainage of the thorax
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Thoracic Wall:
The lymph vessels of the skin of the
anterior thoracic wall drain
 to the anterior axillary nodes.
The lymph vessels of the skin of the
posterior thoracic wall drain
 to the posterior axillary nodes.
The deep lymph vessels of the
anterior parts of the intercostal spaces
drain
 to the internal thoracic nodes (along
the internal thoracic vessels)  to the
thoracic duct on Lt.side and the
bronchomediastinal trunk on Rt. side.
The deep lymph vessels of the
posterior parts of the intercostal
spaces drain
 to the posterior intercostal nodes
(lying near the heads of the ribs(  to
the thoracic duct.
Lymphatic drainage of the abdomen
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Abdominal Wall:
Superficial The lymph vessels of the skin of
lymph
anterior abdominal wall above the
vessels
level of the umbilicus drain
 to the anterior axillary
nodes.
The lymph vessels of the skin of
anterior abdominal wall below the
level of the umbilicus drain
 to the superficial
inguinal nodes.
The lymph vessels of the skin of
the back above the level of the
iliac crests drain
 to the posterior axillary
nodes.
The lymph vessels of the skin of  to the superficial
the back below the level of the iliac inguinal nodes.
crests drain
Deep
lymph
vessels
The deep lymph vessels follow
the arteries and drain
 into the internal
thoracic, external iliac,
posterior mediastinal and
para-aortic nodes.
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Abdominal cavity:
Lymph
nodes
Lymph
vessels
The
lymph nodes are closely related to the aorta and form a
preaortic and a Rt. & Lt. lateral aortic (para-aortic) chain.
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preaortic lymph nodes lie around the origins of the celiac,
superior mesenteric & inferior mesenteric arteries and are called
as the celiac, superior mesenteric & inferior mesenteric lymph
nodes, respectively. They drain the lymph from the gastrointestinal tract, extending from the lower 1/3 of esophagus to
halfway down the anal canal, and from the spleen, pancreas,
gallbladder, and greater part of the liver. The efferent lymph
vessels form the large intestinal trunk.
The para-aortic lymph nodes drain lymph from the kidneys and
suprarenals; from the testes in the male and from the ovaries,
uterine tubes, and fundus of the uterus in the female; from the
deep lymph vessels of the abdominal walls; and from the
common iliac nodes. The efferent lymph vessels form the right
and left lumbar trunks.
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thoracic duct starts in the abdomen as an elongated
lymph sac, the cisterna chyli, which receives the intestinal
trunk, the right and left lumbar trunks & some small lymph
vessels that descend from the lower part of the thorax.
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Regional nodes: are arranged as follows:
Name
Site
They receive lymph from
Occipital
nodes
Over occipital bone
on the back of skull.
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Retroauricular
nodes
Behind ear over
mastoid process.
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Parotid nodes
On or within the
parotid gland.
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Buccal nodes
Over buccinator
muscle.
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Submandibular Superficial to the
submandibular
nodes
Back of the scalp.
Scalp above the ear, auricle & the ext.
auditory meatus.
Scalp above the parotid gland, eyelids,
parotid gland & auricle.
Lateral side of scalp & face.
Front of scalp, nose, cheek, upper lip &
lower lip (except the central part), frontal,
gland just below the maxillary & ethmoid sinuses, upper &
lower margin of jaw.
lower teeth (except the lower incisors);
anterior 2/3 of tongue (except the tip),
floor of mouth & gums.
Submental
nodes
In submental
triangle just below
the chin
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Tip of tongue, floor of anterior part of
mouth, incisor teeth, center part of the
lower lip, and skin over the chin.
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Name
Site
They receive lymph from
Retropharyn
geal nodes
behind pharynx & infront
of vertebral column.
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Laryngeal
nodes
in front of the larynx
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Nasal pharynx, the auditory tube,
and the vertebral column.
Larynx.
Paratracheal alongside the trachea.
nodes
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Anterior
cervical
nodes
Along the course of ant.
jugular veins.
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Superficial
cervical
nodes
Along course of ext.
 Skin over the angle of the jaw, the
jugular vein superficial to skin over the lower part of the parotid
sternomastoid.
gland, and the lobe of the ear.
Deep
cervical
nodes
Form a vertical chain
along the course of IJV
within the carotid sheath
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Neighboring structures, including
the thyroid gland.
Skin and superficial tissues of the
front of the neck.
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All the groups of regional nodes.
The efferent lymph vessels from the deep cervical lymph nodes join to form
the jugular trunk, which drains into the thoracic duct or Rt. lymphatic duct.
Clinical Notes
Disease of the Lymphatic System
Lymphangitis, Lymphadenitis, and
Lymphedema:
 Lymphangitis and lymphadenitis:
are 2ry inflammation of lymphatic
vessels and lymph nodes,
respectively.
 These conditions may occur when
the lymphatic system is involved in
chemical or bacterial transport after
severe injury or infection.
 The lymphatic vessels, not
normally evident, may become
apparent as red streaks in the skin,
and the nodes become painfully
enlarged.
 Lymphedema or edema: is a
localized accumulation of interstitial
fluid, occurs when lymph does not
drain from an area of the body, e.g.
if cancerous lymph nodes are
surgically removed from the axilla,
lymphedema of the limb may
occur.
Spread of cancer:
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Cancer invades the body by growing into
adjacent tissue or by dissemination of tumor
cells to sites distant from the original or primary
tumor )metastasis).
Metastasis occurs by one of three ways:
 Direct seeding of the serous membranes of
body cavities.
 Lymphogenous spread via lymphatic
vessels.
 Hematogenous spread via blood vessels.
Lymphogenous spread is the most common
route for the initial dissemination of carcinomas
(epithelial tumors), the most common type of
cancer.
Hematogenous spread is the most common
route for the metastasis of the less common
(but more malignant )sarcomas( C.T. cancers.
Because veins are more abundant and have
thinner walls that offer less resistance,
metastasis occurs more often by venous than
arterial routes. Since the blood-borne cells
follow venous flow, the liver and lungs are the
most common sites of secondary sarcomas.