Occipital (2-4)
Superior nuchal line between sternocleidomastoid and trapezius
Occipital part of scalp
Superficial cervical lymph nodes
Accessary lymph nodes
Mastoid (1-3)
Superficial to sternocleidomastoid insertion
Posterior parietal scalp
Skin of ear, posterior external acoustic meatus
Superior deep cervical nodes Accessary lymph nodes
Preauricular (2-3)
Anterior to ear over parotid fascia
Drains areas supplied by superficial temporal artery
Anterior parietal scalp
Anterior surface of ear
Superior deep cervical lymph nodes
Parotid (up to 10 or more)
About parotid gland and under parotid fascia
Deep to parotid gland
External acoustic meatus
Skin of frontal and temporal regions
Eyelids, tympanic cavity
Cheek, nose (posterior palate)
Superior deep cervical lymph nodes
Facial
Superficial(up to 12)
Maxillary
Buccal
Mandibular
Distributed along course of facial artery and vein
Skin and mucous membranes of eyelids, nose, cheek
Submandibular nodes
Deep
Distributed along course of maxillary artery lateral to lateral pterygoid muscle
Temporal and infratemporal fossa
Nasal pharynx
Superior deep cervical lymph nodesSuperficial
Anterior jugular vein between superficial cervical fascia and infrahyoid fascia
Skin, muscles, and viscera of infrahyoid region of neck
Superior deep cervical lymph nodes
Deep
Between viscera of neck and investing layer of deep cervical fascia
Adjoining parts of trachea, larynx, thyroid gland
Superior deep cervical lymph nodes
Anterior cervical/Superficial
Submental (2-3)
Submental triangle
Chin
Medial part of lower lip
Lower incisor teeth and gingiva
Tip of tongue
Cheeks
Submandibular lymph node to jugulo-omohyoid lymph node and superior deep cervical lymph nodes
2. FUNCTIONS OF LYMPHATIC SYSTEM
• The lymphatic system has three functions:
• Fluid recovery.
• Immunity
• Lipid absorption
• The lymphatic vessels of the small intestine receive the special designation of
lacteals or chyliferous vessels.
3. THE MAIN FUNCTIONS OF THE LYMPHATIC SYSTEM ARE AS FOLLOWS
• To collect and transport tissue fluids from the intercellular spaces in all the
tissues of the body, back to the veins in the blood system;
• It plays an important role in returning plasma proteins to the bloodstream;
• Digested fats are absorbed and then transported from the villi in the small
intestine to the bloodstream via the lacteals and lymph vessels.
• New lymphocytes are manufactured in the lymph nodes;
4. • Antibodies and lymphocytes assist the body to build up an effective immunity
to infectious diseases;
• Lymph nodes play an important role in the defence mechanism of the body.
They filter out micro-organisms (such as bacteria) and foreign substances such as
toxins, etc.
• It transports large molecular compounds (such as enzymes and hormones)
from their manufactured sites to the bloodstream.
5. COMPONENTS OF LYMPHATIC SYSTEM
The components of the lymphatic system are :-
• lymph, the recovered fluid;
• Lymphatic vessels, which transport the lymph;
• Lymphatic tissue, composed of aggregates of lymphocytes and macrophages
that populate many organs of the body; and
• Lymphatic organs, in which these cells are especially concentrated and which
are set off from surrounding organs by connective tissue capsules.
6. LYMPH
• Lymph is usually a clear, colorless fluid, similar to blood plasma but low in protein. Its
composition varies substantially from place to place.
• Origin of Lymph :-
• 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.
• The gaps between lymphatic endothelial cells are so large that bacteria and other
cells can enter along with the fluid.
7. LYMPH
Origin of Lymph :-
• The overlapping edges of the endothelial cells act as valve like flaps that can open
and close.
• When tissue fluid pressure is high, it pushes the flaps inward (open) and fluid flows
into the lymphatic capillary. When pressure is higher in the lymphatic capillary than
in the tissue fluid, the flaps are pressed outward (closed).
8. Lymphatic Capillaries. (a) Relationship of the lymphatic capillaries to a bed of blood
capillaries. (b) Uptake of tissue fluid by a lymphatic capillary.
9. Lymphatic Vessels :-
• They have a tunica interna with an endothelium and
valve, a tunica media with elastic fibers and smooth
muscle, and a thin outer tunica externa.
• Their walls are thinner and their valves are more
numerous than those of the veins.
10. MECHANISM OF LYMPHATIC FLOW
• Lymph flows under forces similar to those that govern venous return, except that the
lymphatic system has no pump like the heart.
• Lymph flows at even lower pressure and speed than venous blood; it is moved primarily
by rhythmic contractions of the lymphatic vessels themselves, which contract when
stretched by lymph.
• The lymphatic vessels, like the veins, are also aided by a skeletal muscle pump that
squeezes them and moves the lymph along.
• Also like the medium veins, lymphatic vessels have valves that prevent lymph from
flowing backward.
11. • Since lymphatic vessels are often wrapped with an artery in a common sheath, arterial
pulsation may also rhythmically squeeze the lymphatic vessels and contribute to lymph
flow.
• A thoracic (respiratory) pump aids the flow of lymph from the abdominal to the thoracic
cavity as one inhales, just as it does in venous return.
• Finally, at the point where the collecting ducts join the subclavian veins, the rapidly
flowing bloodstream draws the lymph into it.
• Considering these mechanisms of lymph flow, it should be apparent that physical exercise
significantly increases the rate of lymphatic return.
12. LYMPHATIC CELLS AND TISSUES
• T lymphocytes (T cells). These are so-named because they develop for a time in the
thymus and later depend on thymic hormones. There are several subclasses of T cells.
• B lymphocytes (B cells). These are named after an organ in birds (the bursa of Fabricius)
in which they were first discovered. When activated, B cells differentiate into plasma
cells, which produce circulating antibodies, the protective gamma globulins of the body
fluids.
13. LYMPHATIC ORGANS
• Primary Lymphatic Organs :-
• Lymphatic (lymphoid) organs contain large numbers of lymphocytes, a type of white
blood cell that plays a pivotal role in immunity.
• The primary lymphatic organs are
• the red bone marrow and
• the thymus gland.
• Lymphocytes originate and/or mature in these organs.
14. PRIMARY LYMPHATIC ORGANS
• Red Bone Marrow
• It is the site of stem cells that are ever capable of dividing and producing blood cells.
• Some of these cells become the various types of white blood cells: neutrophils,
eosinophils, basophils, lymphocytes, and monocytes.
• In a child, most of the bones have red bone marrow, but in an adult it is limited to the
sternum, vertebrae, ribs, part of the pelvic girdle, and the proximal heads of the
humerus and femur.
15. RED BONE MARROW
• Red bone marrow is the site of stem cells that are ever capable of dividing and producing
blood cells. Some of these cells become the various types of white blood cells:
• neutrophils, eosinophils, basophils, lymphocytes, and monocytes .
• In a child, most bones have red bone marrow, but in an adult it is limited to the sternum,
vertebrae, ribs, part of the pelvic girdle, and the proximal heads of the humerus and
femur.
16. RED BONE MARROW
• The red bone marrow consists of a network of reticular tissue fibers, which support the
stem cells and their progeny.
• They are packed around thin-walled sinuses filled with venous blood. Differentiated
blood cells enter the bloodstream at these sinuses.
• Lymphocytes differentiate into the B lymphocytes and the T lymphocytes.
• Bone marrow is not only the source of B lymphocytes, but also the place where B
lymphocytes mature.
• T lymphocytes mature in the thymus.
17.
18. CLASSIFICATION
Node Location Afferent Efferent
Superficial Lymph Nodes of the Head
Occipital (2-4) Superior nuchal line
between
sternocleidomastoid and
trapezius
Occipital part of scalp Superficial cervical
lymph nodes
Accessary lymph
Mastoid (1-3) Superficial to
sternocleidomastoid
insertion
Posterior parietal scalp
Skin of ear, posterior external
acoustic meatus
Superior deep cervical
nodes Accessary
nodes
Preauricular (2-3) Anterior to ear over
parotid fascia
Drains areas supplied by
superficial temporal artery
Anterior parietal scalp
Anterior surface of ear
Superior deep cervical
lymph nodes
19.
20. Parotid (up to 10 or more) About parotid gland and
under parotid fascia
Deep to parotid gland
External acoustic meatus
Skin of frontal and
temporal regions
Eyelids, tympanic cavity
Cheek, nose (posterior
palate)
Superior deep cervical
lymph nodes
Facial
Superficial(up to 12)
Maxillary
Buccal
Mandibular
Distributed along course
of facial artery and vein
Skin and mucous
membranes of eyelids,
nose, cheek
Submandibular nodes
Deep Distributed along course
of maxillary artery lateral
to lateral pterygoid
muscle
Temporal and
infratemporal fossa
Nasal pharynx
Superior deep cervical
lymph nodes
21. Cervical Lymph Nodes
Superficial Anterior jugular vein
between superficial
cervical fascia and
infrahyoid fascia
Skin, muscles, and viscera
of infrahyoid region of
neck
Superior deep cervical
lymph nodes
Deep Between viscera of neck
and investing layer of
deep cervical fascia
Adjoining parts of
larynx, thyroid gland
Superior deep cervical
lymph nodes
Anterior cervical/Superficial
Submental (2-3) Submental triangle Chin
Medial part of lower lip
Lower incisor teeth and
gingiva
Tip of tongue
Cheeks
Submandibular lymph
node to jugulo-omohyoid
lymph node and superior
deep cervical lymph
nodes
22.
23. Submandibula
r (3-6)
Submandibular
triangle adjacent
to
gland
Facial nodes
Chin
Lateral upper and
lips
Submental nodes
Cheeks and nose,
anterior nasal cavity
Maxillary and
mandibular teeth and
gingiva
Oral palate
Lateral parts of
2/3 of tongue
Superior deep
cervical lymph
nodes and
jugulo-omohyoid
lymph nodes
Superficial
cervical (1-2)
Along external
jugular vein
superficial to
sternocleidomast
oid muscle
Lower part of ear and
parotid region
Superior deep
cervical lymph
nodes
24.
25.
26. Deep Cervical Lymph Nodes
Superior deep
cervical
Surrounding
internal jugular
vein deep to
sternocleidomastoi
d and superior to
omohyoid muscle
Occipital nodes
Mastoid nodes
Preauricular nodes
Parotid nodes
Submandibular
nodes
Superficial cervical
nodes
Retropharyngeal
nodes
Inferior deep
cervical nodes or
separate channel
to jugulo-
subclavian
junction
Jugulodigastric Junction of internal
jugular vein and
posterior digastric
muscle
Palatine and lingual
tonsils
Posterior palate
Lateral portions of
the anterior 2/3 of
tongue
Inferior deep
cervical lymph
nodes
27.
28. Jugulo-
omohyoid
Above junction of
internal jugular
vein and
muscle
Posterior 1/3 of
tongue
Submandibular
nodes
Submental nodes
Inferior deep
cervical lymph
nodes
Inferior deep
cervical
Along internal
jugular vein below
omohyoid muscle
deep to the
sternocleidomastoi
d muscle
Transverse cervical
nodes
Anterior cervical
nodes
Superior deep
cervical nodes
Jugular trunk
Retropharynge
al (1-3)
Retropharyngeal
space
Posterior nasal
cavity
Paranasal sinuses
Hard and soft
palate
Nasopharynx,
oropharynx
Anditory tube
Superior deep
cervical nodes
29.
30. Accessory (2-6) Along accessory
nerve in posterior
triangle
Occipital nodes
Mastoid nodes
Lateral neck and
shoulder
Transverse cervical
nodes
Transverse
cervical (1-10)
Along transverse
cervical blood
vessels at level of
clavicle
Accessory nodes
Apical axillary
nodes
Lateral neck
Anterior thoracic
wall
Jugular trunk or
directly into
thoracic duct or
right lymphatic
duct or
independently
junction of
jugular vein and
subclavian vein
1. Fluid recovery Each day, they lose an excess of 2 to 4 L of water and one-quarter to one-half of the plasma protein. The lymphatic system absorbs this excess fluid and returns it to the bloodstream by way of the lymphatic vessels.
2. Immunity. As the lymphatic system recovers excess tissue fluid, it also picks up foreign cells and chemicals from the tissues. On its way back to the bloodstream, the fluid passes through lymph nodes, where immune cells stand guard against foreign matter. When they detect it, they activate a protective immune response.
3. Lipid absorption. In the small intestine, special lymphatic vessels called lacteals absorb dietary lipids that are not absorbed by the blood capillaries
A lymphatic capillary consists of a sac of thin endothelial cells that loosely overlap each other like the shingles of a roof. The cells are tethered to surrounding tissue by protein filaments that prevent the sac from collapsing. Unlike the endothelial cells of blood capillaries, lymphatic endothelial cells are not joined by tight junctions. The gaps between them are so large that bacteria and other cells can enter along with the fluid.
Lymphatic vessels form in the embryo by budding from the veins, so it is not surprising that the larger ones have a similar histology.