2. Is a network of lymphatic vessels that returns tissue fluid
to the venous system and helps to protect the body from
disease.
The components of the lymphatic system are:
(1) lymph, the recovered fluid
(2) lymphatic vessels, which transport the lymph;
(3) lymphatic tissue, composed of aggregates of
lymphocytes and macrophages that populate many
organs of the body; and
(4) lymphatic organs, in which these cells are especially
concentrated and which are set off from surrounding
organs by connective tissue capsules.
THE LYMPHATIC SYSTEM:DON. SIYUM A..
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3. FUNCTIONS OF THE
LYMPHATIC SYSTEM:
3
1. To returns water and proteins from the interstitial fluid
to the blood.
2. To transport fat absorbed from the Gastro intestinal
tract to the blood (in the form of chyle).
3. To defend the body (both cellular and humoral defence)
4. Haemopoiesis, production of cell like lymphocytes and
monocytes.
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4. Lymph is usually a clear, colorless fluid, similar to blood
plasma but low in protein. Its composition varies
substantially from place to place.
After a meal, for example, lymph draining from the small
intestine has a milky appearance because of its high lipid
content.
Lymph may also contain bacteria, viruses, cellular debris
or even traveling cancer cells.
🞭 Lymph originates in microscopic vessels called lymphatic
capillaries. These vessels penetrate nearly every tissue
of the body but are absent from the central nervous
system, cartilage, bone, and bone marrow.
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The lymphatic vessels function to collect this excess
tissue fluid from the loose connective tissue around
blood capillaries and return it to the bloodstream.
Any blockage of the lymphatic vessels causes the
affected body region to swell with excess tissue fluid, a
condition called edema.
The lymphatic vessels also perform another, related
function.
Blood proteins leak slowly but steadily from blood
capillaries into the surrounding tissue fluid, and the
lymphatic vessels return these leaked proteins to the
bloodstream.
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7. LYMPHATIC OBSTRUCTION.
MOSQUITO-BORNE
ROUNDWORMS INFECT THE
LYMPH NODES AND BLOCK THE
FLOW OF LYMPH AND
RECOVERY OF TISSUE FLUID.
• THE RESULTING CHRONIC EDEMA LEADS TO
FIBROSIS AND ELEPHANT-LIKE THICKENING OF THE
SKIN. THE EXTREMITIES ARE TYPICALLY AFFECTED
AS SHOWN
• HERE; THE SCROTUM OF MEN AND BREASTS OF
WOMEN ARE OFTEN SIMILARLY
• AFFECTED.
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8. THERE ARE SEVERAL ORDERS OF LYMPHATIC
VESSELS
8
The smallest vessels, those that first receive lymph, are
the lymphatic capillaries.
These vessels drain into larger lymphatic collecting
vessels, along which are scattered lymph nodes.
The collecting vessels then drain into lymph trunks,
which unite to form lymph ducts, which empty into the
veins at the root of the neck.
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11. LYMPHATIC
CAPILLARIES
11
The highly permeable vessels that collect the excess
tissue fluid, are located near blood capillaries in the loose
connective tissue. Once inside the lymphatic vessels, this
fluid is called lymph.
Although the high permeability of lymphatic capillaries
allows the uptake of large quantities of tissue fluid and
large protein molecules, it also allows any bacteria,
viruses, or cancer cells in the loose connective tissue to
enter these capillaries with ease.
Lymph cannot leak out of the lymphatic capillary because
backflow forces the minivalve flaps together.
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These pathogenic agents can then travel throughout the
body via the lymphatic vessels. However, this threat is
averted in part by the lymph nodes, which destroy most
pathogens in the lymph.
Lymphatic capillaries are widespread, occurring almost
everywhere blood capillaries occur.
However, lymphatic capillaries are absent from bone and
teeth, from bone marrow, and from the entire central
nervous system, where excess tissue fluid drains
through the nervous tissue into the cerebrospinal fluid.
The cerebrospinal fluid then returns this tissue fluid to
the blood at the superior sagittal sinus.
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13. LYMPHATIC
COLLECTING VESSELS
13
From the lymphatic capillaries, lymph enters lymphatic
collecting vessels, which accompany blood vessels.
In general, the superficial lymphatic collecting vessels in
the skin travel with superficial veins, whereas the deep
lymphatic collecting vessels of the trunk and digestive
viscera travel with the deep arteries.
Lymphatic collecting vessels are narrow and delicate, so
they usually are not seen in the dissecting laboratory.
They have the same tunics as blood vessels (tunica
intima, tunica media, and tunica externa), but their walls
are always much thinner.
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15. LYMPH
NODES
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Lymph nodes serve two functions:
To cleanse the lymph and alert the immune system to
pathogens.
There are about 500 lymph nodes in the human body.
Large clusters of superficial lymph nodes in the cervical,
axillary, and inguinal regions, plus some important
groups of deep nodes.
The superficial cervical nodes along the jugular veins and
carotid arteries receive lymph from the head and neck.
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Axillary nodes in the armpit and the inguinal nodes in the
superior thigh filter lymph from the upper and lower
limbs, respectively.
Nodes in the mediastinum, such as the deep
tracheobronchial nodes, receive lymph from the thoracic
viscera. Deep nodes along the abdominal aorta, called
aortic nodes, filter lymph from the posterior abdominal
wall.
Finally, deep nodes along the iliac arteries, called iliac
nodes, filter lymph from pelvic organs and the lower
limbs.
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18. LYMPH
TRUNKS
18
After leaving the lymph nodes, the largest lymphatic
collecting vessels converge to form lymph trunks.
These trunks drain large areas of the body and are large
enough to be found by a skilled dissector.
The five major lymph trunks, from inferior to superior:
1. Lumbar trunks.
These paired trunks, which lie along the sides of the
aorta in the inferior abdomen.
receive all lymph draining from the lower limbs, the
pelvic organs, and from some of the anterior
abdominal wall.
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21. 2. INTESTINAL
TRUNK.
21
This unpaired trunk, which lies near the posterior
abdominal wall in the midline, receives fatty lymph from
the stomach, intestines, and other digestive organs.
3. Bronchomediastinal trunks
Ascending near the sides of the trachea, these paired
trunks collect lymph from the thoracic viscera and
thoracic wall.
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23. 4. SUBCLAVIAN
TRUNKS
23
Located near the base of the neck, these paired trunks
receive lymph from the upper limbs; they also drain the
inferior neck and the superior thoracic wall.
5. Jugular trunks
Located at the base of each internal jugular vein, these
paired trunks drain lymph from the head and neck.
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24. LYMPH
DUCTS
24
• The lymph trunks drain into the largest lymphatic vessels,
the lymph ducts . have two lymph ducts
1. Thoracic duct
located at the union of the lumbar and intestinal trunks,
is the cisterna chyli, which lies on the bodies of
vertebrae L1 and L2.
In the superior thorax, it turns left and empties into the
venous circulation at the junction of the left internal
jugular and left subclavian veins.
It enters the thoracic cavity through the aortic hiatus of
the diaphragm.
Alternatively, any or all of these three lymph trunks can
empty separately into the Near by veins.
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The thoracic duct is often joined by the left jugular,
subclavian, and/or bronchomediastinal trunks just
before it joins with the venous circulation.
The thoracic duct drains three-quarters of the body:
the left side of the head, neck, and thorax; the left
upper limb; and the body’s entire lower half.
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28. 2. RIGHT LYMPHATIC
DUCT
28
The upper right quadrant of the body is drained by the
right jugular, subclavian, and bronchomediastinal
trunks.
In about 20% of people, these ducts join to form a short
right lymphatic duct.
When present, this duct empties into the neck veins at or
near the junction of the right internal jugular and
subclavian veins.
More commonly, the three trunks open independently
into the neck veins.
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30. LYMPHATIC DRAINAGE OF THE
LOWER LIMB
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LYMPHATIC DRAINAGE OF THE
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Superficial and deep lymph vessels.
Superficial and deep lymph nodes.
Superficial lymph vessels :
origin from medial/lateral plantar plexus of lymphatics
Many of them follow the great saphenous vein and end
in the superficial inguinal lymph nodes.
Few of them follow the small saphenous vein and end in
to the popliteal lymph nodes
Deep lymph vessels :
Few, follow the deep veins, drain into the deep inguinal
lymph nodes.
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33. INGUINAL
LYMPH NODES
33
The inguinal lymph nodes are divided into:
Superficial Inguinal Lymph Nodes
The superficial nodes lie in the superficial fascia below
the inguinal ligament.
Deep Inguinal Lymph Nodes
The deep nodes are located beneath the deep fascia and
lie along the medial side of the femoral vein;
The efferent vessels from these nodes enter the
abdomen by passing through the femoral canal to lymph
nodes along the external iliac artery.
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36. 5/3/2022
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LYMPHATIC DRAINAGE OF THE
UPPER LIMB
The superficial vessels accompany the superficial veins in
the fore arm until the elbow, where they enter lymph
nodes (cubital).
From the elbow most of the vessels run with the basilic
vein to the superficial axillary lymph nodes.
The deep vessels follow the arteries and they similarly
open in to the superficial axillary nodes.
The lymph from the superficial axillary nodes is drained
to the Deep axillary lymph nodes and then to the
subclavian trunk.
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37. AXILLARY
LYMPH NODES
37
Five principal groups:
Pectoral (anterior): lies along the medial wall of axilla.
Receive lymph from the anterior thoracic wall.
Subscapular (posterior): receive lymph from the
posterior thoracic wall and scapula.
Humeral (lateral):receive lymph from upper limb.
Central: receive lymph vessels from the above three
groups.
Apical: receive lymph from all groups and lymph
vessels accompanying cephalic vein.
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41. LYMPHATIC DRAINAGE OF THE
NECK
41
Superficial Lymph Nodes
The superficial cervical lymph nodes lie along the external
jugular vein superficial to the sternocleidomastoid
muscle.
They receive lymph vessels from the occipital and
mastoid lymph nodes and drain into the deep cervical
lymph nodes.
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43. THE LYMPH NODES OF THE
THORAX:
43
are divided into parietal and visceral lymph nodes.
Parietal lymph nodes.
1. Parasternal node:
Four or five on each side, are at the anterior ends of the
intercostals spaces, alongside the internal thoracic
artery.
Their afferents from the mammary gland, anterior
abdominal wall above the umbilicus and anterior group
of the diaphragmatic lymph nodes.
Their efferents to the bronchiomediastinal trunk.
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44. 2. INTERCOSTAL
NODE:
44
Are in the posterior part of the intercostals spaces in
relation with the heads and necks of the ribs.
Their afferents from the postrolateral aspect of the chest
and the mammary gland.
Their efferents to the thoracic duct or right lymphatic
duct.
3. Phrenic or diaphragmatic node:
are on the thoracic surface of the diaphragm, and consist
of anterior, right and left lateral and posterior groups.
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45. VISCERAL LYMPH
NODES
45
1. Anterior mediastinal node:
are placed in the anterior part of the superior
mediastinum, in front of the bracheocephalic vein and
trunk.
Their receive afferents from the thymus, thyroid,
pericardium and diaphragm.
Their efferents unite with the tracheobronchial lymph
nodes to form the right and left bronchiomediastinal
trunks.
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46. 2. POSTERIOR
MEDIASTINAL NODE
46
Are behind the pericardium, close to the esophagus and
descending thoracic aorta,
Their afferents are derived from the esophagus,
posterior part of the pericardium and diaphragm.
Their efferents end in the thoracic duct and
tracheobronchial nodes.
3. Tracheobronchial node:
Are arranged in five main groups, and it efferents unite
with the parasternal and anterior mediastinal and form
the right and left bronchiomediastinal trunks.
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47. LYMPHATIC DRAINAGE
OF THE LUNGS
47
The lungs contain an extensive network of superficial and
deep lymphatic vessels.
Generally the lymph from the lungs flows in the direction
of the hilum and consecutively passes through the
following lymph node groups.
1.Pulmonary lymph nodes: found around the segmental
bronchi.
2.Bronchopulmonary (hilar) lymph nodes: found at the hili
of the lungs.
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48. 3.TRACHIOBRONCHIAL LYMPH
NODES: LOCATED AT THE
BIFURCATION OF THE
TRACHEA. 48
4. Paratracheal lymph nodes: lie on both side of the
trachea.
From the paratracheal lymph nodes the lymph flows
together with lymph from the parasternal lymph node
into the right and left bronchomediastinal trunks.
The right bronchomediastinal trunk drains into the right
lymphatic trunk whereas the left one into the thoracic
duct.
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50. LYMPH DRAINAGE OF THE
ANTEROLATERAL
ABDOMINAL WALL
SUPERFICIAL LYMPH VESSELS
50
The lymph drainage of the skin of the anterior abdominal
wall above the level of the umbilicus is upward to the
anterior axillary (pectoral) group of nodes.
Below the level of the umbilicus, the lymph drains
downward and laterally to the superficial inguinal nodes.
The lymph of the skin of the back above the level of the
iliac crests is drained upward to the posterior
(Subscapular) axillary group of nodes
Below the level of the iliac crests, it drains downward to
the superficial inguinal nodes.
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53. Deep lymph vessels
The deep lymph vessels follow the arteries and drain into
the internal thoracic, external iliac, posterior
mediastinal, and para-aortic (lumbar) nodes.
Lymphatic drainage of the pelvis
Pelvic organs drain through the external, internal iliac &
sacral lymph nodes.
All these drain into common iliac & lumbar aortic lymph
nodes
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External iliac lymph nodes:
lie on the corresponding external iliac vessels & drain
lymph from the LL, urinary bladder & prostate (or
uterus & vagina)
Internal iliac lymph nodes:
surround internal iliac vessels & their branches
receive from all pelvic viscera, deep parts of
peritoneum, gluteal & thigh regions
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58. COMMON
ILIAC NODES
58
Common iliac nodes are approximately 6 in number
Along the common iliac vessels
External iliac nodes, internal iliac nodes
lumbar (lateral aortic) chain of nodes
lower limb; pelvic organs, perineum, lower part of the
anterior abdominal wall
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60. Cisterna chyli Don. Siyum A.
Notes
cisterna chyli is an enlargement of the lower end of the
thoracic duct; it occurs in about 25% of individuals
Location
between the abdominal aorta and the inferior vena cava
anterior to the body of the L1 or L2 vertebra
Afferents from
right and left lumbar trunks; possibly the intestinal trunk
Efferents to
thoracic duct
Regions drained
all of the body below the respiratory diaphragm; all of
the abdominal and pelvic viscera
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62. DEVELOPMENT OF THE LYMPHATIC
SYSTEM
62
The lymphatic system begins to develop at the end of
the sixth week.
Approximately 2 weeks after the primordia of the
cardiovascular system.
Lymphatic vessels develop in a manner similar to that
previously described for blood vessels and make
connections with the venous system.
The early lymphatic capillaries join each other to form a
network of lymphatics.
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63. DEVELOPMENT OF LYMPH SACS
AND LYMPHATIC DUCTS
63
There are six primary lymph sacs present at the end of
the embryonic period:
Two jugular lymph sacs near the junction of the
subclavian veins with the anterior cardinal veins (the
future internal jugular veins)
Two iliac lymph sacs near the junction of the iliac veins
with the posterior cardinal veins
One retroperitoneal lymph sac in the root of the
mesentery on the posterior abdominal wall
One chyle cistern (cisterna chyli) located dorsal to the
retroperitoneal lymph sac.
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Lymphatic vessels soon connect to the lymph sacs and
pass along main veins; to the head, neck, and upper
limbs from the jugular lymph sacs;
To the lower trunk and lower limbs from the iliac
lymph sacs; and to the primordial gut from the
retroperitoneal lymph sac and the chyle cistern.
Two large channels (right and left thoracic ducts)
connect the jugular lymph sacs with this cistern.
Soon a large anastomosis forms between these
channels.
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66. THORACIC
DUCT
66
The thoracic duct develops from the caudal part of the
right thoracic duct, the anastomosis between the left
and right thoracic ducts, and the cranial part of the left
thoracic duct.
The right lymphatic duct is derived from the cranial
part of the right thoracic duct.
The thoracic duct and right lymphatic duct connect
with the venous system at the venous angle between
the internal jugular and subclavian veins.
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