SlideShare a Scribd company logo
1 of 57
LYMPHATIC DRAINAGELYMPHATIC DRAINAGE
OF HEAD AND NECKOF HEAD AND NECK
Presented by:
Dr.Ayesha Taha (JR I)
Department of Pedodontics
and Preventive Dentistry
SPPGIDMS, Lucknow
Contents :-
Introduction
Functions of Lymphatic System
Components of Lymphatic System
Lymph Nodes of Head & Neck
Lymphatic Drainage
Conclusion
Introduction
Of all the body systems, the lymphatic system is
perhaps the least familiar to most people. Yet without
it, neither the circulatory system nor the immune
system could function—circulation would shut down
from fluid loss, and the body would be overrun by
infection for lack of immunity.
The lymphatic system is an endothelium-lined network
of blind-ended capillaries found in nearly all tissues,
draining via collecting vessels into large vascular trunks
that eventually empty via an evolutionarily conserved
drainage point into the blood circulatory system.
Functions of Lymphatic System
The lymphatic system has three functions:
1. Fluid recovery
Each day, we 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
3. Lipid absorption.
In the small intestine, special lymphatic vessels called
lacteals absorb dietary lipids that are not absorbed by
the blood capillaries.
Components of Lymphatic system
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.
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.
Flow of Lymph :-
Lymph takes the following route from the tissues back
to the bloodstream:
Thus, there is a continual recycling of fluid from blood to
tissue fluid to lymph and back to the blood.
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.
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.
Macrophages:
These cells, derived from monocytes of the blood,
phagocytize foreign matter (antigens) and “display”
fragments of it to certain T cells, thus alerting the
immune system to the presence of an enemy.
Macrophages and other cells that do this are
collectively called antigen-presenting cells (APCs).
Dendritic cells:
These are APCs found in the epidermis, mucous
membranes, and lymphatic organs. (In the skin, they
are often called Langerhans cells.)
Reticular cells:
These are branched cells that contribute to the stroma
(connective tissue framework) of the lymphatic organs
and act as APCs in the thymus.
Mucosa-associated Lymphatic
Tissue.
The simplest form of
lymphatic tissue is diffuse
lymphatic tissue—a sprinkling of
lymphocytes in the mucous
membranes and connective
tissues of many organs.
It is particularly
prevalent in body passages that
are open to the exterior—the
respiratory, digestive, urinary,
and reproductive tracts—where
it is called Mucosa-Associated
Lymphatic Tissue (MALT).
Peyers patches:
In some places, lymphocytes and
other cells congregate in dense
masses called lymphatic nodules
(follicles).
Lymphatic nodules are, however,
a relatively constant feature of
the lymph nodes and tonsils.
They also form clusters called
Peyers patches in the ileum, the
last segment of the small
intestine.
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
Red bone marrow and
Thymus gland
Lymphocytes originate and/or mature in these 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.
THYMUS
The thymus is a member of both the lymphatic and
endocrine systems.
It houses developing lymphocytes and secretes hormones
that regulate their activity.
It is located between the sternum and aortic arch in the
superior mediastinum.
The thymus is very large in the fetus and grows slightly
during childhood, when it is most active.
After age 14, however, it begins to undergo involution
(shrinkage) so that it is quite small in adults.
THE SECONDARY LYMPHATIC ORGANS: are
the spleen,
the lymph nodes and
other organs, such as the tonsils.
All the secondary organs are the places where lymphocytes
encounter and bind with antigens, after which they
proliferate and become actively engaged cells.
SPLEEN
The spleen is the body’s largest lymphatic organ. It is
located in the left hypochondriac region, just inferior
to the diaphragm and dorsolateral to the stomach.
Its parenchyma exhibits two types of tissue named
for their appearance in fresh specimens (not in
stained sections):
red pulp, which consists of sinuses gorged with
concentrated erythrocytes, and
white pulp, which consists of lymphocytes and
macrophages aggregated like sleeves along small
branches of the splenic artery.
Functions:
It produces blood cells in the
fetus and may resume this role in
adults in the event of extreme
anemia.
It monitors the blood for foreign
antigens.
Lymphocytes and macrophages of
the white pulp are quick to detect
foreign antigens in the blood and
activate immune reactions.
Position of the spleen in the
upper left quadrant of the
abdominal cavity.
The spleen is an “erythrocyte graveyard”—old, fragile
RBCs rupture as they squeeze through the capillary walls
into the sinuses. Splenic macrophages phagocytize their
remains, just as they dispose of blood-borne bacteria and
other cellular debris.
The spleen also compensates for excessive blood volume by
transferring plasma from the bloodstream into the
lymphatic system.
A person can live without a spleen, but is somewhat more
vulnerable to infections.
LYMPH NODES
It serve two functions:
to cleanse the lymph and
alert the immune system to pathogens.
There are hundreds of lymph nodes in the body.
They are especially concentrated in the cervical, axillary,
and inguinal regions close to the body surface, and in
thoracic, abdominal, and pelvic groups deep in the body
cavities.
Most of them are embedded in fat.
A lymph node is an elongated or bean-shaped structure,
usually less than 3 cm long, often with an indentation
called the hilum on one side.
Anatomy of a Lymph Node.
(a) Bisected lymph node showing pathway of lymph flow.
(b) Detail in the boxed region.
TONSIL
The tonsils are patches of lymphatic tissue located at the
entrance to the pharynx, where they guard against
ingested and inhaled pathogens.
There are three main sets of tonsils:
 a single medial pharyngeal tonsil (adenoids) on the wall of the
pharynx just behind the nasal cavity,
a pair of palatine tonsils at the posterior margin of the oral
cavity, and
numerous lingual tonsils, concentrated in a patch on each side
of the root of the tongue.
The palatine tonsils are the largest and most often infected.
All lymph vessels of the head and neck drain into
the deep cervical nodes, either directly from the
tissues or indirectly via nodes in outlying groups.
Lymph is returned to the systemic venous
circulation via either the right lymphatic duct or
the thoracic duct.
All lymph vessels of the head and neck drain into
the deep cervical nodes, either directly from the
tissues or indirectly via nodes in outlying groups.
Lymph is returned to the systemic venous
circulation via either the right lymphatic duct or
the thoracic duct.
LYMPHATIC DRAINAGE OF HEAD &
NECK
The lymph nodes in the head
and neck region can be
grouped into:
• Superficial nodes
• Deep nodes
Classification of nodes
in head and neck region
 The superficial cervical lymph nodes lie above theabove the
investing layer of the deep fasciainvesting layer of the deep fascia.
 They consist of a few small nodes that lie
superficial to the external jugular and anterior
jugular veins.
The superficial Lymph nodesThe superficial Lymph nodes
The superficial lymph nodes
1. Occipital
2. Mastoid (retro auricular/ post-auricular)
3. Parotid (pre-auricular)
4. Buccal
5. Submandibular
6. Submental
7. Anterior cervical
8. Superficial cervical
SuperficialSuperficial
cervical nodescervical nodes
1. Upper deep cervical
2. Lower deep cervical
3. Waldyer’s ring
4. Nodes of midline
The Deep lymph nodes:The Deep lymph nodes:
1. The upper deep cervical:
Jugulo-digastric group: lie along the upper part of
internal jugular vein deep to the sternomastoid muscle.
Structures drained: Tonsil and Tongue.
2. The lower deep cervical:
Jugulo-omohyoid group: arranged along the lower part
internal jugular vein deep also to the sternomastoid
muscle.
Structures drained: Tongue.
Deep cervical nodes
3.The waldyer’s ring:The ring consists of the (from
superior to inferior):
1 Pharyngeal Tonsils (or nasopharyngeal tonsil(s), due
to the location; also known as 'adenoid(s)' when
inflamed/swollen.
2 Tubal Tonsil (bilaterally).
2 Palatine Tonsils (commonly called "the tonsils" in
the vernacular, less commonly termed "faucial
tonsils"; located in the oropharynx.
1 lingual Tonsils (on the posterior tongue)
4. Midline nodes are termed in
correspondence to the anatomical area
where they exist:
A. Infrahyoid
B. Prelaryngeal
C. Pretracheal
D. Paratracheal
The skin of the head and neck drains :
• The scalp drains into the occipital, mastoid and
parotid nodes.
• Lower eye lid and anterior cheek drains into buccal
nodes.
• The cheeks drain into the parotid, buccal and
submandibular nodes.
• The upper lips and sides of the lower lips drain into
the submandibular nodes.
• While the middle third of the lower lip drains into the
submental nodes.
• The skin of the neck drains into the cervical nodes.
The drainage of the oral structures
• The Gingivae drain into the submandibular, submental
and upper deep cervical lymph nodes.
• The palate drains via lymph vessels that pass through
the pharyngeal wall to the upper deep cervical nodes.
• Anterior part of mouth floor drain into submental and
upper deep cervical
• while posterior part into submandibular and upper deep
cervical.
Drainage of oral structures
Lymph drainage of external noseLymph drainage of external nose
Lymph drainage of external nose is primarily
to the submandibular group of nodes although
lymph from the root of the nose drains to
superficial parotid nodes.
Lymphatic drainage of nasal cavity
Lymph vessels from the anterior region of the nasal cavity pass
superficially to join those draining the external nasal skin, and
end in the submandibular nodes.
The rest of the nasal cavity, paranasal sinuses, nasopharynx
and pharyngeal end of the pharyngotympanic tube, all drain to
the upper deep cervical nodes either directly or through the
retropharyngeal nodes.
The posterior nasal floor drains to the parotid nodes.
Lymphatic drainage of tongue:
The lymphatic drainage of the tongue can be divided into 3
main regions: Marginal, Central and Dorsal.
The anterior region of the tongue drains into marginal and
central vessels, and the posterior part of the tongue behind
the circumvallate papillae drains into the dorsal lymph
vessels.
The more central regions drain bilaterally into sub-mental
and sub-mandibular nodes.
Lymphatic drainage of teeth:
The lymph vessels from the teeth usually run directly into
the ipsi-lateral submandibular lymph nodes.
Lymph from the mandibular incisors, however, drains into
the submental lymph nodes.
Occasionally, lymph from the molars may pass directly into
the jugulo-digastric group of nodes.
APPLIED ASPECT:
When a lymph node is under challenge from a foreign
antigen, it may become swollen and painful to the touch— a
condition called lymphadenitis.
Commonly palpated and accessible lymph nodes are - the
cervical, axillary, and inguinal.
Lymph nodes are common sites of metastatic cancer
because cancer cells from almost any organ can break loose,
enter the lymphatic capillaries, and lodge in the nodes.
Lymphadenopathy is a collective term for all lymph node
diseases.
Differential Diagnosis of cervical Lymphadenopathy based
on palpatory findings. TEXTURE OF LYMPH NODES
Conclusion :-
In conclusion, the lymphatic system and its organs are
widespread and scattered throughout the body.
Because the vessels of the lymphatic system span the
entire body it becomes an easy portal for the spread of
cancer and other diseases, which is why disorders and
diseases of this system can be very devastating.
A sound knowledge of the regional lymph nodes of the
head and neck is very important for dentists because it
is a reliable guide towards the origin of problem, and
because of the possible involvement of the lymphatic
system in the spread of infection or the spread of
malignant tumour cells (metastasis).
Textbook of Head and Neck Anatomy (Hiatt – Gartner) 4th
Ed. 2010
Grant's Atlas of Anatomy,13th
Ed.
Gray's Anatomy – 40th
Ed.
Anatomy of the Human Body - Henry Gray
Saladin: Anatomy & Physiology: The Unity of Form and Function, 3rd
Edition
Embryology Atlas , John F Neas
Life Map – Embryonic development & stem cell compendium
Butler M G, Isogai S, Weinstein B M. Lymphatic development, Birth
Defects Res C Embryo Today. 2009 September ; 87(3): 222–231.
Albrecht I, Christofori G, Molecular mechanisms of
lymphangiogenesis in development and cancer; Int. J. Dev. Biol.
55: 483-494
References :-
Ferrer R, Lymphadenopathy: Differential Diagnosis and Evaluation;
Am Fam Physician. 1998 Oct 15;58(6):1313-1320
Som P M, Hugh D C, Mancuso A A, An imaging-based classification
for the cervical nodes designed as an adjunct to recent clinically
based nodal classification;Arch Otolaryngol Head Neck Surg.
1999;125:388-396.
Oliver G, Detmar M, The rediscovery of the lymphatic system: old
and new insights intothe development and biological function of
the lymphatic vasculature; Genes Dev. 2002,16: 773-783
Sambandan T, Mabel C R, Cervical lymphadenopathy- a review;
JIADS,2011,2,1:31-33.
Torabi M, Aquino S L, Harisinghani M G, Current concept in lymph
node imaging; J Nucl Med, 2004; 45:1509-1518.
Connor SEJ, Olliff JFC, Imaging of malignant cervical
lymphadenopathy – a review; Dentomaxillofacial Radiology,
2000;29:133-143.
“The earliest evidence of ancient dentistry -an amazingly detailed dental
work on a mummy from ancient Egypt that archaeologists have dated to
2000 BCE. The work shows intricate gold work around the teeth. This
mummy was found with two donor teeth that had holes drilled into
them. Wires were strung through the holes and then around the
neighboring teeth.” Source: metalonmetal blog.

More Related Content

What's hot

The maxillary nerve
The maxillary nerveThe maxillary nerve
The maxillary nerve
Sara Mehrez
 
Tongue development, applied anatomy and prosthetic implications
Tongue development, applied anatomy and prosthetic implicationsTongue development, applied anatomy and prosthetic implications
Tongue development, applied anatomy and prosthetic implications
Dr. KRITI TREHAN
 

What's hot (20)

Maxillary sinus
Maxillary sinusMaxillary sinus
Maxillary sinus
 
Salivary glands
Salivary glandsSalivary glands
Salivary glands
 
Maxillary nerve dental surgery
Maxillary nerve dental surgeryMaxillary nerve dental surgery
Maxillary nerve dental surgery
 
Lymphatic drainage of head and neck and its
Lymphatic drainage of head and neck and itsLymphatic drainage of head and neck and its
Lymphatic drainage of head and neck and its
 
Mandibular nerve dental surgery
Mandibular nerve dental surgeryMandibular nerve dental surgery
Mandibular nerve dental surgery
 
Lymphatic of head and neck
Lymphatic of head and neckLymphatic of head and neck
Lymphatic of head and neck
 
Saliva
SalivaSaliva
Saliva
 
Lymphatic drainage of head and neck by DR. C.P. ARYA ( B.Sc. ;B.D.S. ;M.D.S. ...
Lymphatic drainage of head and neck by DR. C.P. ARYA ( B.Sc. ;B.D.S. ;M.D.S. ...Lymphatic drainage of head and neck by DR. C.P. ARYA ( B.Sc. ;B.D.S. ;M.D.S. ...
Lymphatic drainage of head and neck by DR. C.P. ARYA ( B.Sc. ;B.D.S. ;M.D.S. ...
 
Maxillary sinus
Maxillary sinusMaxillary sinus
Maxillary sinus
 
Maxillary artery
Maxillary arteryMaxillary artery
Maxillary artery
 
Arterial supply of head and neck
Arterial supply of head and neckArterial supply of head and neck
Arterial supply of head and neck
 
Muscles of mastication
Muscles of masticationMuscles of mastication
Muscles of mastication
 
Examination of lymph nodes of head and neck
Examination of lymph nodes of head and neckExamination of lymph nodes of head and neck
Examination of lymph nodes of head and neck
 
Blood and nerve supply of teeth
Blood and nerve supply of teethBlood and nerve supply of teeth
Blood and nerve supply of teeth
 
The maxillary nerve
The maxillary nerveThe maxillary nerve
The maxillary nerve
 
VENOUS DRAINAGE OF HEAD, FACE, NECK AND BRAIN
VENOUS DRAINAGE OF HEAD, FACE, NECK AND BRAINVENOUS DRAINAGE OF HEAD, FACE, NECK AND BRAIN
VENOUS DRAINAGE OF HEAD, FACE, NECK AND BRAIN
 
Mandibular nerve
Mandibular nerveMandibular nerve
Mandibular nerve
 
Trigeminal nerve 1
Trigeminal nerve 1Trigeminal nerve 1
Trigeminal nerve 1
 
Salivary Gland
Salivary GlandSalivary Gland
Salivary Gland
 
Tongue development, applied anatomy and prosthetic implications
Tongue development, applied anatomy and prosthetic implicationsTongue development, applied anatomy and prosthetic implications
Tongue development, applied anatomy and prosthetic implications
 

Viewers also liked (8)

Lymphatics of the head & neck
Lymphatics of the head & neckLymphatics of the head & neck
Lymphatics of the head & neck
 
venous supply of head & neck
venous supply of head & neckvenous supply of head & neck
venous supply of head & neck
 
Lymphatics of the head and neck
Lymphatics of the head and neckLymphatics of the head and neck
Lymphatics of the head and neck
 
Lymphatic drainage of head and neck 1
Lymphatic drainage of head and neck 1Lymphatic drainage of head and neck 1
Lymphatic drainage of head and neck 1
 
LYMPHATICS HEAD AND NECK
LYMPHATICS HEAD AND NECKLYMPHATICS HEAD AND NECK
LYMPHATICS HEAD AND NECK
 
Lymphatic drainage of head & neck
Lymphatic drainage of head & neckLymphatic drainage of head & neck
Lymphatic drainage of head & neck
 
Lymphatic system
Lymphatic systemLymphatic system
Lymphatic system
 
Lymph and lymphatic system
Lymph and lymphatic systemLymph and lymphatic system
Lymph and lymphatic system
 

Similar to Lymphatic drainage of head and neck- Dr.Ayesha

Lymphatic system
Lymphatic systemLymphatic system
Lymphatic system
Jose Escanuela
 
Lymphatic System New PPT slides.pdf
Lymphatic System New PPT slides.pdfLymphatic System New PPT slides.pdf
Lymphatic System New PPT slides.pdf
Rudauli College of Pharmacy, Ayodhya (Uttar Pradesh)
 
THE LYMPHATIC SYSTEM// LYMPH CIRCULATION//LYMPH VESSELS// LYMPH ORGANS
THE LYMPHATIC SYSTEM// LYMPH CIRCULATION//LYMPH VESSELS// LYMPH ORGANS THE LYMPHATIC SYSTEM// LYMPH CIRCULATION//LYMPH VESSELS// LYMPH ORGANS
THE LYMPHATIC SYSTEM// LYMPH CIRCULATION//LYMPH VESSELS// LYMPH ORGANS
Wasim Ak
 
Anatomy & Physiology - LYMPHATIC SYSTEM PPT By wincy Thirumurugan
Anatomy & Physiology - LYMPHATIC SYSTEM PPT By wincy ThirumuruganAnatomy & Physiology - LYMPHATIC SYSTEM PPT By wincy Thirumurugan
Anatomy & Physiology - LYMPHATIC SYSTEM PPT By wincy Thirumurugan
thiru murugan
 

Similar to Lymphatic drainage of head and neck- Dr.Ayesha (20)

examination of lymph nodes
examination of lymph nodesexamination of lymph nodes
examination of lymph nodes
 
Lymphatic system.docx
Lymphatic system.docxLymphatic system.docx
Lymphatic system.docx
 
Lymphatic system [autosaved]
Lymphatic system [autosaved]Lymphatic system [autosaved]
Lymphatic system [autosaved]
 
LYMPH NODES
LYMPH NODESLYMPH NODES
LYMPH NODES
 
lymphatic drainage mimansa.pptx
lymphatic drainage mimansa.pptxlymphatic drainage mimansa.pptx
lymphatic drainage mimansa.pptx
 
Lymphadenopathy approach
Lymphadenopathy approachLymphadenopathy approach
Lymphadenopathy approach
 
Lymphatic system
Lymphatic systemLymphatic system
Lymphatic system
 
Lymphatic system
Lymphatic systemLymphatic system
Lymphatic system
 
Lymphatic drainage of head & neck
Lymphatic  drainage  of head & neckLymphatic  drainage  of head & neck
Lymphatic drainage of head & neck
 
11. LYMPHATIC SYSTEM.pptx
11. LYMPHATIC SYSTEM.pptx11. LYMPHATIC SYSTEM.pptx
11. LYMPHATIC SYSTEM.pptx
 
11. LYMPHATIC SYSTEM.pptx
11. LYMPHATIC SYSTEM.pptx11. LYMPHATIC SYSTEM.pptx
11. LYMPHATIC SYSTEM.pptx
 
Lymphatic system
Lymphatic systemLymphatic system
Lymphatic system
 
The lymphatic system
The lymphatic systemThe lymphatic system
The lymphatic system
 
Lymphatic system
Lymphatic systemLymphatic system
Lymphatic system
 
lymphatic system-converted.pdf
lymphatic system-converted.pdflymphatic system-converted.pdf
lymphatic system-converted.pdf
 
Lymphatic System New PPT slides.pdf
Lymphatic System New PPT slides.pdfLymphatic System New PPT slides.pdf
Lymphatic System New PPT slides.pdf
 
Lymphatic immune system
Lymphatic immune systemLymphatic immune system
Lymphatic immune system
 
THE LYMPHATIC SYSTEM// LYMPH CIRCULATION//LYMPH VESSELS// LYMPH ORGANS
THE LYMPHATIC SYSTEM// LYMPH CIRCULATION//LYMPH VESSELS// LYMPH ORGANS THE LYMPHATIC SYSTEM// LYMPH CIRCULATION//LYMPH VESSELS// LYMPH ORGANS
THE LYMPHATIC SYSTEM// LYMPH CIRCULATION//LYMPH VESSELS// LYMPH ORGANS
 
Anatomy & Physiology - LYMPHATIC SYSTEM PPT By wincy Thirumurugan
Anatomy & Physiology - LYMPHATIC SYSTEM PPT By wincy ThirumuruganAnatomy & Physiology - LYMPHATIC SYSTEM PPT By wincy Thirumurugan
Anatomy & Physiology - LYMPHATIC SYSTEM PPT By wincy Thirumurugan
 
ANATOMY OF THE LYMPHATIC SYSTEM
ANATOMY OF THE LYMPHATIC SYSTEMANATOMY OF THE LYMPHATIC SYSTEM
ANATOMY OF THE LYMPHATIC SYSTEM
 

Recently uploaded

College Call Girls in Haridwar 9667172968 Short 4000 Night 10000 Best call gi...
College Call Girls in Haridwar 9667172968 Short 4000 Night 10000 Best call gi...College Call Girls in Haridwar 9667172968 Short 4000 Night 10000 Best call gi...
College Call Girls in Haridwar 9667172968 Short 4000 Night 10000 Best call gi...
perfect solution
 
Russian Escorts Girls Nehru Place ZINATHI 🔝9711199012 ☪ 24/7 Call Girls Delhi
Russian Escorts Girls  Nehru Place ZINATHI 🔝9711199012 ☪ 24/7 Call Girls DelhiRussian Escorts Girls  Nehru Place ZINATHI 🔝9711199012 ☪ 24/7 Call Girls Delhi
Russian Escorts Girls Nehru Place ZINATHI 🔝9711199012 ☪ 24/7 Call Girls Delhi
AlinaDevecerski
 
Call Girls Bhubaneswar Just Call 9907093804 Top Class Call Girl Service Avail...
Call Girls Bhubaneswar Just Call 9907093804 Top Class Call Girl Service Avail...Call Girls Bhubaneswar Just Call 9907093804 Top Class Call Girl Service Avail...
Call Girls Bhubaneswar Just Call 9907093804 Top Class Call Girl Service Avail...
Dipal Arora
 
VIP Service Call Girls Sindhi Colony 📳 7877925207 For 18+ VIP Call Girl At Th...
VIP Service Call Girls Sindhi Colony 📳 7877925207 For 18+ VIP Call Girl At Th...VIP Service Call Girls Sindhi Colony 📳 7877925207 For 18+ VIP Call Girl At Th...
VIP Service Call Girls Sindhi Colony 📳 7877925207 For 18+ VIP Call Girl At Th...
jageshsingh5554
 

Recently uploaded (20)

Call Girls Bareilly Just Call 8250077686 Top Class Call Girl Service Available
Call Girls Bareilly Just Call 8250077686 Top Class Call Girl Service AvailableCall Girls Bareilly Just Call 8250077686 Top Class Call Girl Service Available
Call Girls Bareilly Just Call 8250077686 Top Class Call Girl Service Available
 
Call Girls Ludhiana Just Call 9907093804 Top Class Call Girl Service Available
Call Girls Ludhiana Just Call 9907093804 Top Class Call Girl Service AvailableCall Girls Ludhiana Just Call 9907093804 Top Class Call Girl Service Available
Call Girls Ludhiana Just Call 9907093804 Top Class Call Girl Service Available
 
College Call Girls in Haridwar 9667172968 Short 4000 Night 10000 Best call gi...
College Call Girls in Haridwar 9667172968 Short 4000 Night 10000 Best call gi...College Call Girls in Haridwar 9667172968 Short 4000 Night 10000 Best call gi...
College Call Girls in Haridwar 9667172968 Short 4000 Night 10000 Best call gi...
 
VIP Call Girls Indore Kirti 💚😋 9256729539 🚀 Indore Escorts
VIP Call Girls Indore Kirti 💚😋  9256729539 🚀 Indore EscortsVIP Call Girls Indore Kirti 💚😋  9256729539 🚀 Indore Escorts
VIP Call Girls Indore Kirti 💚😋 9256729539 🚀 Indore Escorts
 
(Low Rate RASHMI ) Rate Of Call Girls Jaipur ❣ 8445551418 ❣ Elite Models & Ce...
(Low Rate RASHMI ) Rate Of Call Girls Jaipur ❣ 8445551418 ❣ Elite Models & Ce...(Low Rate RASHMI ) Rate Of Call Girls Jaipur ❣ 8445551418 ❣ Elite Models & Ce...
(Low Rate RASHMI ) Rate Of Call Girls Jaipur ❣ 8445551418 ❣ Elite Models & Ce...
 
💎VVIP Kolkata Call Girls Parganas🩱7001035870🩱Independent Girl ( Ac Rooms Avai...
💎VVIP Kolkata Call Girls Parganas🩱7001035870🩱Independent Girl ( Ac Rooms Avai...💎VVIP Kolkata Call Girls Parganas🩱7001035870🩱Independent Girl ( Ac Rooms Avai...
💎VVIP Kolkata Call Girls Parganas🩱7001035870🩱Independent Girl ( Ac Rooms Avai...
 
Premium Call Girls Cottonpet Whatsapp 7001035870 Independent Escort Service
Premium Call Girls Cottonpet Whatsapp 7001035870 Independent Escort ServicePremium Call Girls Cottonpet Whatsapp 7001035870 Independent Escort Service
Premium Call Girls Cottonpet Whatsapp 7001035870 Independent Escort Service
 
Top Rated Bangalore Call Girls Mg Road ⟟ 9332606886 ⟟ Call Me For Genuine S...
Top Rated Bangalore Call Girls Mg Road ⟟   9332606886 ⟟ Call Me For Genuine S...Top Rated Bangalore Call Girls Mg Road ⟟   9332606886 ⟟ Call Me For Genuine S...
Top Rated Bangalore Call Girls Mg Road ⟟ 9332606886 ⟟ Call Me For Genuine S...
 
Russian Escorts Girls Nehru Place ZINATHI 🔝9711199012 ☪ 24/7 Call Girls Delhi
Russian Escorts Girls  Nehru Place ZINATHI 🔝9711199012 ☪ 24/7 Call Girls DelhiRussian Escorts Girls  Nehru Place ZINATHI 🔝9711199012 ☪ 24/7 Call Girls Delhi
Russian Escorts Girls Nehru Place ZINATHI 🔝9711199012 ☪ 24/7 Call Girls Delhi
 
Lucknow Call girls - 8800925952 - 24x7 service with hotel room
Lucknow Call girls - 8800925952 - 24x7 service with hotel roomLucknow Call girls - 8800925952 - 24x7 service with hotel room
Lucknow Call girls - 8800925952 - 24x7 service with hotel room
 
Best Rate (Patna ) Call Girls Patna ⟟ 8617370543 ⟟ High Class Call Girl In 5 ...
Best Rate (Patna ) Call Girls Patna ⟟ 8617370543 ⟟ High Class Call Girl In 5 ...Best Rate (Patna ) Call Girls Patna ⟟ 8617370543 ⟟ High Class Call Girl In 5 ...
Best Rate (Patna ) Call Girls Patna ⟟ 8617370543 ⟟ High Class Call Girl In 5 ...
 
Call Girls Kochi Just Call 8250077686 Top Class Call Girl Service Available
Call Girls Kochi Just Call 8250077686 Top Class Call Girl Service AvailableCall Girls Kochi Just Call 8250077686 Top Class Call Girl Service Available
Call Girls Kochi Just Call 8250077686 Top Class Call Girl Service Available
 
Call Girls Bhubaneswar Just Call 9907093804 Top Class Call Girl Service Avail...
Call Girls Bhubaneswar Just Call 9907093804 Top Class Call Girl Service Avail...Call Girls Bhubaneswar Just Call 9907093804 Top Class Call Girl Service Avail...
Call Girls Bhubaneswar Just Call 9907093804 Top Class Call Girl Service Avail...
 
All Time Service Available Call Girls Marine Drive 📳 9820252231 For 18+ VIP C...
All Time Service Available Call Girls Marine Drive 📳 9820252231 For 18+ VIP C...All Time Service Available Call Girls Marine Drive 📳 9820252231 For 18+ VIP C...
All Time Service Available Call Girls Marine Drive 📳 9820252231 For 18+ VIP C...
 
Best Rate (Hyderabad) Call Girls Jahanuma ⟟ 8250192130 ⟟ High Class Call Girl...
Best Rate (Hyderabad) Call Girls Jahanuma ⟟ 8250192130 ⟟ High Class Call Girl...Best Rate (Hyderabad) Call Girls Jahanuma ⟟ 8250192130 ⟟ High Class Call Girl...
Best Rate (Hyderabad) Call Girls Jahanuma ⟟ 8250192130 ⟟ High Class Call Girl...
 
VIP Service Call Girls Sindhi Colony 📳 7877925207 For 18+ VIP Call Girl At Th...
VIP Service Call Girls Sindhi Colony 📳 7877925207 For 18+ VIP Call Girl At Th...VIP Service Call Girls Sindhi Colony 📳 7877925207 For 18+ VIP Call Girl At Th...
VIP Service Call Girls Sindhi Colony 📳 7877925207 For 18+ VIP Call Girl At Th...
 
Call Girls Siliguri Just Call 8250077686 Top Class Call Girl Service Available
Call Girls Siliguri Just Call 8250077686 Top Class Call Girl Service AvailableCall Girls Siliguri Just Call 8250077686 Top Class Call Girl Service Available
Call Girls Siliguri Just Call 8250077686 Top Class Call Girl Service Available
 
Top Rated Bangalore Call Girls Richmond Circle ⟟ 9332606886 ⟟ Call Me For Ge...
Top Rated Bangalore Call Girls Richmond Circle ⟟  9332606886 ⟟ Call Me For Ge...Top Rated Bangalore Call Girls Richmond Circle ⟟  9332606886 ⟟ Call Me For Ge...
Top Rated Bangalore Call Girls Richmond Circle ⟟ 9332606886 ⟟ Call Me For Ge...
 
Manyata Tech Park ( Call Girls ) Bangalore ✔ 6297143586 ✔ Hot Model With Sexy...
Manyata Tech Park ( Call Girls ) Bangalore ✔ 6297143586 ✔ Hot Model With Sexy...Manyata Tech Park ( Call Girls ) Bangalore ✔ 6297143586 ✔ Hot Model With Sexy...
Manyata Tech Park ( Call Girls ) Bangalore ✔ 6297143586 ✔ Hot Model With Sexy...
 
Premium Bangalore Call Girls Jigani Dail 6378878445 Escort Service For Hot Ma...
Premium Bangalore Call Girls Jigani Dail 6378878445 Escort Service For Hot Ma...Premium Bangalore Call Girls Jigani Dail 6378878445 Escort Service For Hot Ma...
Premium Bangalore Call Girls Jigani Dail 6378878445 Escort Service For Hot Ma...
 

Lymphatic drainage of head and neck- Dr.Ayesha

  • 1. LYMPHATIC DRAINAGELYMPHATIC DRAINAGE OF HEAD AND NECKOF HEAD AND NECK Presented by: Dr.Ayesha Taha (JR I) Department of Pedodontics and Preventive Dentistry SPPGIDMS, Lucknow
  • 2.
  • 3. Contents :- Introduction Functions of Lymphatic System Components of Lymphatic System Lymph Nodes of Head & Neck Lymphatic Drainage Conclusion
  • 4. Introduction Of all the body systems, the lymphatic system is perhaps the least familiar to most people. Yet without it, neither the circulatory system nor the immune system could function—circulation would shut down from fluid loss, and the body would be overrun by infection for lack of immunity. The lymphatic system is an endothelium-lined network of blind-ended capillaries found in nearly all tissues, draining via collecting vessels into large vascular trunks that eventually empty via an evolutionarily conserved drainage point into the blood circulatory system.
  • 5. Functions of Lymphatic System The lymphatic system has three functions:
  • 6. 1. Fluid recovery Each day, we 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
  • 7. 3. Lipid absorption. In the small intestine, special lymphatic vessels called lacteals absorb dietary lipids that are not absorbed by the blood capillaries.
  • 9. 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.
  • 10. 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.
  • 11. Flow of Lymph :- Lymph takes the following route from the tissues back to the bloodstream: Thus, there is a continual recycling of fluid from blood to tissue fluid to lymph and back to the blood.
  • 12.
  • 13. 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. 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.
  • 14. Macrophages: These cells, derived from monocytes of the blood, phagocytize foreign matter (antigens) and “display” fragments of it to certain T cells, thus alerting the immune system to the presence of an enemy. Macrophages and other cells that do this are collectively called antigen-presenting cells (APCs). Dendritic cells: These are APCs found in the epidermis, mucous membranes, and lymphatic organs. (In the skin, they are often called Langerhans cells.)
  • 15. Reticular cells: These are branched cells that contribute to the stroma (connective tissue framework) of the lymphatic organs and act as APCs in the thymus.
  • 16. Mucosa-associated Lymphatic Tissue. The simplest form of lymphatic tissue is diffuse lymphatic tissue—a sprinkling of lymphocytes in the mucous membranes and connective tissues of many organs. It is particularly prevalent in body passages that are open to the exterior—the respiratory, digestive, urinary, and reproductive tracts—where it is called Mucosa-Associated Lymphatic Tissue (MALT).
  • 17. Peyers patches: In some places, lymphocytes and other cells congregate in dense masses called lymphatic nodules (follicles). Lymphatic nodules are, however, a relatively constant feature of the lymph nodes and tonsils. They also form clusters called Peyers patches in the ileum, the last segment of the small intestine.
  • 18. 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 Red bone marrow and Thymus gland Lymphocytes originate and/or mature in these organs.
  • 19.
  • 20. 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.
  • 21. THYMUS The thymus is a member of both the lymphatic and endocrine systems. It houses developing lymphocytes and secretes hormones that regulate their activity. It is located between the sternum and aortic arch in the superior mediastinum. The thymus is very large in the fetus and grows slightly during childhood, when it is most active. After age 14, however, it begins to undergo involution (shrinkage) so that it is quite small in adults.
  • 22.
  • 23. THE SECONDARY LYMPHATIC ORGANS: are the spleen, the lymph nodes and other organs, such as the tonsils. All the secondary organs are the places where lymphocytes encounter and bind with antigens, after which they proliferate and become actively engaged cells.
  • 24. SPLEEN The spleen is the body’s largest lymphatic organ. It is located in the left hypochondriac region, just inferior to the diaphragm and dorsolateral to the stomach. Its parenchyma exhibits two types of tissue named for their appearance in fresh specimens (not in stained sections): red pulp, which consists of sinuses gorged with concentrated erythrocytes, and white pulp, which consists of lymphocytes and macrophages aggregated like sleeves along small branches of the splenic artery.
  • 25. Functions: It produces blood cells in the fetus and may resume this role in adults in the event of extreme anemia. It monitors the blood for foreign antigens. Lymphocytes and macrophages of the white pulp are quick to detect foreign antigens in the blood and activate immune reactions. Position of the spleen in the upper left quadrant of the abdominal cavity.
  • 26. The spleen is an “erythrocyte graveyard”—old, fragile RBCs rupture as they squeeze through the capillary walls into the sinuses. Splenic macrophages phagocytize their remains, just as they dispose of blood-borne bacteria and other cellular debris. The spleen also compensates for excessive blood volume by transferring plasma from the bloodstream into the lymphatic system. A person can live without a spleen, but is somewhat more vulnerable to infections.
  • 27. LYMPH NODES It serve two functions: to cleanse the lymph and alert the immune system to pathogens. There are hundreds of lymph nodes in the body. They are especially concentrated in the cervical, axillary, and inguinal regions close to the body surface, and in thoracic, abdominal, and pelvic groups deep in the body cavities. Most of them are embedded in fat. A lymph node is an elongated or bean-shaped structure, usually less than 3 cm long, often with an indentation called the hilum on one side.
  • 28. Anatomy of a Lymph Node. (a) Bisected lymph node showing pathway of lymph flow. (b) Detail in the boxed region.
  • 29. TONSIL The tonsils are patches of lymphatic tissue located at the entrance to the pharynx, where they guard against ingested and inhaled pathogens. There are three main sets of tonsils:  a single medial pharyngeal tonsil (adenoids) on the wall of the pharynx just behind the nasal cavity, a pair of palatine tonsils at the posterior margin of the oral cavity, and numerous lingual tonsils, concentrated in a patch on each side of the root of the tongue. The palatine tonsils are the largest and most often infected.
  • 30. All lymph vessels of the head and neck drain into the deep cervical nodes, either directly from the tissues or indirectly via nodes in outlying groups. Lymph is returned to the systemic venous circulation via either the right lymphatic duct or the thoracic duct. All lymph vessels of the head and neck drain into the deep cervical nodes, either directly from the tissues or indirectly via nodes in outlying groups. Lymph is returned to the systemic venous circulation via either the right lymphatic duct or the thoracic duct. LYMPHATIC DRAINAGE OF HEAD & NECK
  • 31. The lymph nodes in the head and neck region can be grouped into: • Superficial nodes • Deep nodes Classification of nodes in head and neck region
  • 32.  The superficial cervical lymph nodes lie above theabove the investing layer of the deep fasciainvesting layer of the deep fascia.  They consist of a few small nodes that lie superficial to the external jugular and anterior jugular veins. The superficial Lymph nodesThe superficial Lymph nodes
  • 33. The superficial lymph nodes 1. Occipital 2. Mastoid (retro auricular/ post-auricular) 3. Parotid (pre-auricular) 4. Buccal 5. Submandibular 6. Submental 7. Anterior cervical 8. Superficial cervical
  • 34.
  • 35.
  • 36.
  • 38. 1. Upper deep cervical 2. Lower deep cervical 3. Waldyer’s ring 4. Nodes of midline The Deep lymph nodes:The Deep lymph nodes:
  • 39. 1. The upper deep cervical: Jugulo-digastric group: lie along the upper part of internal jugular vein deep to the sternomastoid muscle. Structures drained: Tonsil and Tongue. 2. The lower deep cervical: Jugulo-omohyoid group: arranged along the lower part internal jugular vein deep also to the sternomastoid muscle. Structures drained: Tongue.
  • 41. 3.The waldyer’s ring:The ring consists of the (from superior to inferior): 1 Pharyngeal Tonsils (or nasopharyngeal tonsil(s), due to the location; also known as 'adenoid(s)' when inflamed/swollen. 2 Tubal Tonsil (bilaterally). 2 Palatine Tonsils (commonly called "the tonsils" in the vernacular, less commonly termed "faucial tonsils"; located in the oropharynx. 1 lingual Tonsils (on the posterior tongue)
  • 42.
  • 43. 4. Midline nodes are termed in correspondence to the anatomical area where they exist: A. Infrahyoid B. Prelaryngeal C. Pretracheal D. Paratracheal
  • 44. The skin of the head and neck drains : • The scalp drains into the occipital, mastoid and parotid nodes. • Lower eye lid and anterior cheek drains into buccal nodes. • The cheeks drain into the parotid, buccal and submandibular nodes. • The upper lips and sides of the lower lips drain into the submandibular nodes. • While the middle third of the lower lip drains into the submental nodes. • The skin of the neck drains into the cervical nodes.
  • 45. The drainage of the oral structures • The Gingivae drain into the submandibular, submental and upper deep cervical lymph nodes. • The palate drains via lymph vessels that pass through the pharyngeal wall to the upper deep cervical nodes. • Anterior part of mouth floor drain into submental and upper deep cervical • while posterior part into submandibular and upper deep cervical.
  • 46. Drainage of oral structures
  • 47. Lymph drainage of external noseLymph drainage of external nose Lymph drainage of external nose is primarily to the submandibular group of nodes although lymph from the root of the nose drains to superficial parotid nodes.
  • 48. Lymphatic drainage of nasal cavity Lymph vessels from the anterior region of the nasal cavity pass superficially to join those draining the external nasal skin, and end in the submandibular nodes. The rest of the nasal cavity, paranasal sinuses, nasopharynx and pharyngeal end of the pharyngotympanic tube, all drain to the upper deep cervical nodes either directly or through the retropharyngeal nodes. The posterior nasal floor drains to the parotid nodes.
  • 49. Lymphatic drainage of tongue: The lymphatic drainage of the tongue can be divided into 3 main regions: Marginal, Central and Dorsal. The anterior region of the tongue drains into marginal and central vessels, and the posterior part of the tongue behind the circumvallate papillae drains into the dorsal lymph vessels. The more central regions drain bilaterally into sub-mental and sub-mandibular nodes.
  • 50.
  • 51. Lymphatic drainage of teeth: The lymph vessels from the teeth usually run directly into the ipsi-lateral submandibular lymph nodes. Lymph from the mandibular incisors, however, drains into the submental lymph nodes. Occasionally, lymph from the molars may pass directly into the jugulo-digastric group of nodes.
  • 52. APPLIED ASPECT: When a lymph node is under challenge from a foreign antigen, it may become swollen and painful to the touch— a condition called lymphadenitis. Commonly palpated and accessible lymph nodes are - the cervical, axillary, and inguinal. Lymph nodes are common sites of metastatic cancer because cancer cells from almost any organ can break loose, enter the lymphatic capillaries, and lodge in the nodes. Lymphadenopathy is a collective term for all lymph node diseases.
  • 53. Differential Diagnosis of cervical Lymphadenopathy based on palpatory findings. TEXTURE OF LYMPH NODES
  • 54. Conclusion :- In conclusion, the lymphatic system and its organs are widespread and scattered throughout the body. Because the vessels of the lymphatic system span the entire body it becomes an easy portal for the spread of cancer and other diseases, which is why disorders and diseases of this system can be very devastating. A sound knowledge of the regional lymph nodes of the head and neck is very important for dentists because it is a reliable guide towards the origin of problem, and because of the possible involvement of the lymphatic system in the spread of infection or the spread of malignant tumour cells (metastasis).
  • 55. Textbook of Head and Neck Anatomy (Hiatt – Gartner) 4th Ed. 2010 Grant's Atlas of Anatomy,13th Ed. Gray's Anatomy – 40th Ed. Anatomy of the Human Body - Henry Gray Saladin: Anatomy & Physiology: The Unity of Form and Function, 3rd Edition Embryology Atlas , John F Neas Life Map – Embryonic development & stem cell compendium Butler M G, Isogai S, Weinstein B M. Lymphatic development, Birth Defects Res C Embryo Today. 2009 September ; 87(3): 222–231. Albrecht I, Christofori G, Molecular mechanisms of lymphangiogenesis in development and cancer; Int. J. Dev. Biol. 55: 483-494 References :-
  • 56. Ferrer R, Lymphadenopathy: Differential Diagnosis and Evaluation; Am Fam Physician. 1998 Oct 15;58(6):1313-1320 Som P M, Hugh D C, Mancuso A A, An imaging-based classification for the cervical nodes designed as an adjunct to recent clinically based nodal classification;Arch Otolaryngol Head Neck Surg. 1999;125:388-396. Oliver G, Detmar M, The rediscovery of the lymphatic system: old and new insights intothe development and biological function of the lymphatic vasculature; Genes Dev. 2002,16: 773-783 Sambandan T, Mabel C R, Cervical lymphadenopathy- a review; JIADS,2011,2,1:31-33. Torabi M, Aquino S L, Harisinghani M G, Current concept in lymph node imaging; J Nucl Med, 2004; 45:1509-1518. Connor SEJ, Olliff JFC, Imaging of malignant cervical lymphadenopathy – a review; Dentomaxillofacial Radiology, 2000;29:133-143.
  • 57. “The earliest evidence of ancient dentistry -an amazingly detailed dental work on a mummy from ancient Egypt that archaeologists have dated to 2000 BCE. The work shows intricate gold work around the teeth. This mummy was found with two donor teeth that had holes drilled into them. Wires were strung through the holes and then around the neighboring teeth.” Source: metalonmetal blog.

Editor's Notes

  1. 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
  2. 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.
  3. Lymphatic vessels form in the embryo by budding from the veins, so it is not surprising that the larger ones have a similar histology.
  4. The lymphatic capillaries converge to form collecting vessels. These often travel alongside veins and arteries and share a common connective tissue sheath with them. Numerous lymph nodes occur along the course of the collecting vessels, receiving and filtering the lymph. The collecting vessels converge to form larger lymphatic trunks, each of which drains a major portion of the body. The principal lymphatic trunks are the lumbar, intestinal, intercostal, bronchomediastinal, subclavian, and jugular trunks. Their names indicate their locations and parts of the body they drain; the lumbar trunk also drains the lower extremities. The lymphatic trunks converge to form two collecting ducts, the largest of the lymphatic vessels: (1) The right lymphatic duct begins in the right thoracic cavity with the union of the right jugular, subclavian, and bronchomediastinal trunks. It receives lymphatic drainage from the right arm and right side of the thorax and head and empties into the right subclavian vein (fig. 21.6a). (2) The thoracic duct, on the left, is larger and longer. It begins as a prominent sac in the abdominal cavity called the cisterna chyli and then passes through the diaphragm and up the mediastinum. It receives lymph from all parts of the body below the diaphragm and from the left arm and left side of the head, neck, and thorax (fig. 21.6b). It empties into the left subclavian vein.
  5. The T stands for thymus-dependent.
  6. 1. which come and go as pathogens invade the tissues and the immune system answers the challenge.