Lymphatic drainage of head and neck

LYMPHATIC DRAINAGE OF HEAD & NECK

Dr. Nitin SharmaOral Medicine & Radiology

CONTENTS

IntroductionDevelopment of lymphatic system Functions of lymphatic systemComponents of lymphatic systemLymph nodesLymphatic drainage of head and neckApplied AspectsConclusionReferences

THE LYMPHATIC SYSTEM consists of (1)Complex capillary networks which collect the lymph

in the various organs and tissues;

(2) Elaborate system of collecting vessels which conduct the lymph from the capillaries to the large veins of the neck at the junction of the internal jugular and subclavian veins, where the lymph is poured into the blood stream; and

(3) Lymph nodes which are interspaced in the pathways of the collecting vessels filtering the lymph as it passes through them and contributing lymphocytes to it.

INTRODUCTION

Anatomy of the human body, by Henry Gray. 20th ed

http://www.bartleby.com/107/

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Lymphatic system consist of fluid called LYMPH

DEFINITION: Transparent, slightly yellowish liquid of alkaline nature found in lymphatic vessel and derived from tissue fluid.

Lymphatic system is absent in: - C.N.S. - Cornea - Superficial layer of skin - bones - alveoli of lung



DEVELOPMENT OF LYMPHATIC SYSTEM

Starts at 5th week of intrauterine life.

First signs of lymphatic system are seen in the form of a number of endothelium lined lymph sacs.



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SIX PRIMARY LYMPH SACS ARE FORMED.

2 Jugular sacs (right and left)At the junction of subclavian and

anterior cardinal veins.

2 iliac sac (right and left)At the junction of the iliac and

posterior cardinal vein.

Retroperitonial sac (Unpaired)Near the root of the mesentery.

Cisterna chyli (unpaired)Dorsal to retroperitonial sac



FUNCTIONS OF LYMPHATIC SYSTEMThe 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 lymph vessels.

new lymphocytes are manufactured in the lymph nodes;

antibodies and lymphocytes assist the body to build up an effective immunity to infectious diseases;

lymph nodes play an important role in the defense 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.

Anatomy and physiology - The unity of form and function (Saladin K. - 2003 - 3rd ed. - McGraw-Hill)

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.


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 which penetrate nearly every tissue of the body.

The gaps between lymphatic endothelial cells are so large that bacteria and other cells can enter along with the fluid.


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).

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.Anatomy and physiology - The unity of form and function (Saladin K. - 2003 - 3rd ed. - McGraw-Hill)

FLOW OF LYMPH

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, the protective gamma globulins of the body fluids.

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.

Peyers patches.

In some places, lymphocytes and other cells congregate in dense masses called lymphatic nodules (follicles).

They also form clusters called Peyers patches in the ileum, the last segment of the small intestine.


LYMPHATIC ORGANS

Understanding Human Anatomy and Physiology - Sylvia S. Mader

LYMPH NODES

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.

It is enclosed in a fibrous capsule with extensions (trabeculae) that incompletely divide the interior of the node into compartments.

The interior consists of a stroma of reticular connective tissue (reticular fibers and reticular cells) and a parenchyma of lymphocytes and antigen-presenting cells


Tonsils• The tonsils are patches of lymphatic tissue located at

the entrance to the pharynx, where they guard against ingested and inhaled pathogens.

• Each is covered by an epithelium and has deep pits called tonsillar crypts lined by lymphatic nodules.

• The crypts often contain food debris, dead leukocytes, bacteria, and antigenic chemicals.

• Below the crypts, the tonsils are partially separated from underlying connective tissue by an incomplete fibrous capsule.

• 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, each with a single crypt, concentrated in a patch on each side of the root of the tongue.

The palatine tonsils are the largest and most often infected.

LYMPHATIC DRAINAGE OF HEAD & NECK

Lymph nodes in the head and neck are arranged in two horizontal rings and two vertical chains on either side of the neck.

The outer, superficial, ring consists of the occipital, preauricular (parotid), submandibular and submental nodes, and the inner, deep, ring is formed by clumps of mucosa associated lymphoid tissue (MALT) located primarily in the naso- and oro-pharynx (Waldeyer's ring).

Waldeyer's ring

Waldeyer's tonsillar ring, consisting of an unpaired pharyngeal tonsil in the roof of the pharynx, paired palatine tonsils and lingual tonsils scattered in the root of the tongue.

The vertical chain consists of superior and inferior groups of nodes related to the carotid sheath.

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.

ClassificationNode 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 nodesAccessary lymph nodes

Mastoid (1-3) Superficial to sternocleidomastoid insertion

Posterior parietal scalpSkin 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 arteryAnterior parietal scalpAnterior surface of ear

Superior deep cervical lymph nodes

Textbook of Head and Neck Anatomy (Hiatt - Gartner, 4th Ed. 2010)

Parotid (up to 10 or more)

About parotid gland and under parotid fasciaDeep to parotid gland

External acoustic meatusSkin of frontal and temporal regionsEyelids, tympanic cavityCheek, nose (posterior palate)


FacialSuperficial(up to 12)MaxillaryBuccalMandibular

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 fossaNasal pharynx



Cervical Lymph Nodes

Superficial Anterior jugular vein between superficial cervical fascia and infrahyoid fascia

Skin, muscles, and viscera of infrahyoid region of neck


Deep Between viscera of neck and investing layer of deep cervical fascia

Adjoining parts of trachea, larynx, thyroid gland


Anterior cervical/Superficial

Submental (2-3) Submental triangle ChinMedial part of lower lipLower incisor teeth and gingivaTip of tongueCheeks

Submandibular lymph node to jugulo-omohyoid lymph node and superior deep cervical lymph nodes


Submandibular (3-6)

Submandibular triangle adjacent to submandibular gland

Facial nodesChinLateral upper and lower lipsSubmental nodesCheeks and nose, anterior nasal cavityMaxillary and mandibular teeth and gingivaOral palateLateral parts of anterior 2/3 of tongue

Superior deep cervical lymph nodes and jugulo-omohyoid lymph nodes

Superficial cervical (1-2)

Along external jugular vein superficial to sternocleidomastoid muscle

Lower part of ear and parotid region



Deep Cervical Lymph Nodes

Superior deep cervical

Surrounding internal jugular vein deep to sternocleidomastoid and superior to omohyoid muscle

Occipital nodesMastoid nodesPreauricular nodesParotid nodesSubmandibular nodesSuperficial cervical nodesRetropharyngeal nodes

Inferior deep cervical nodes

Jugulodigastric Junction of internal jugular vein and posterior digastric muscle

Palatine and lingual tonsilsPosterior palateLateral portions of the anterior 2/3 of tongue

Inferior deep cervical lymph nodes


Jugulo-omohyoid Above junction of internal jugular vein and omohyoid muscle

Posterior 1/3 of tongueSubmandibular nodesSubmental nodes

Inferior deep cervical lymph nodes

Inferior deep cervical

Along internal jugular vein below omohyoid muscle deep to the sternocleidomastoid muscle

Transverse cervical nodesAnterior cervical nodesSuperior deep cervical nodes

Jugular trunk

Retropharyngeal (1-3)

Retropharyngeal space Posterior nasal cavityParanasal sinusesHard and soft palateNasopharynx, oropharynxAnditory tube

Superior deep cervical nodes


Accessory (2-6) Along accessory nerve in posterior triangle

Occipital nodesMastoid nodesLateral neck and shoulder

Transverse cervical nodes

Transverse cervical (1-10)

Along transverse cervical blood vessels at level of clavicle

Accessory nodesApical axillary nodesLateral neckAnterior thoracic wall

Jugular trunk or directly into thoracic duct or right lymphatic duct or independently into junction of internal jugular vein and subclavian vein


Imaging-based nodal classification

Arch Otolaryngol Head Neck Surg. 1999;125:388-396.

1998 modification of the 1991 AAO-HNS (American Academy of Otolaryngology – Head and Neck Surgery) classification

Level I : Level IA Level IB

Level II : Level IIA Level IIB

Level IIILevel IVLevel V : Level VA

Level VBLevel VILevel VIISupraclavicular nodesRetropharyngeal nodes

APPLIED ASPECTS

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

Lymphadenopathy

Lymphadenopathy - enlargement of the lymph nodes.

It may be an incidental finding in patients being examined for various reasons, or it may be a presenting sign or symptom of the patient's illness.

Soft, flat, submandibular nodes (<1 cm) are often palpable in healthy children and young adults;

Generalized lymphadenopathy

It has been defined as involvement of three or more noncontiguous lymph node areas.

Generalized lymphadenopathy is frequently associated with nonmalignant disorders such as

Infectious mononucleosis, toxoplasmosis, AIDS, other viral infections, Systemic lupus erythematosus (SLE)

Acute and chronic lymphocytic leukemia's and malignant lymphomas also produce generalized lymphadenopathy in adults.

Localized or regional lymphadenopathy

Implies involvement of a single anatomic area.

The site of localized or regional adenopathy may provide a useful clue about the cause.

e.g. Occipital lymphadenopathy often reflects an infection of the scalp, and preauricular lymphadenopathy accompanies conjunctival infections.

Etiological classification of lymphadenopathy

Infectious diseasesViral Infectious mononucleosis, infectious hepatitis, herpes simplex, varicella-

zoster virus, rubella, measles, HIV

Bacterial Streptococci, staphylococci, cat-scratch disease, atypical mycobacterial infection, primary and secondary syphilis, diphtheria, leprosy

Fungal Histoplasmosis

Chlamydial Lymphogranuloma venereum, trachoma

Parasitic Toxoplasmosis, filariasis

Rickettsia Rickettsial pox, Q fever

Immunologic diseases Rheumatoid arthritis Juvenile rheumatoid arthritis Systemic lupus erythematosus Sjögren's syndrome Drug hypersensitivity—

diphenylhydantoin, allopurinol, carbamazepine, etc.

Primary biliary cirrhosis Graft-vs.-host disease

Malignant diseases Hematologic—Hodgkin's disease, non-Hodgkin's lymphomas, acute or chronic lymphocytic leukemia Metastatic—from numerous primary sites

Lipid storage diseases—Gaucher's, Niemann-Pick

Endocrine diseases-Hyperthyroidism, Adrenal insufficiency,

Other disorders Castleman's disease (giant lymph node hyperplasia) Sarcoidosis Dermatopathic lymphadenitis

Lymphomatoid granulomatos Histiocytosis X Familial Mediterranean fever

Sambandan T, Mabel C R, Cervical lymphadenopathy- a review; JIADS,2011,2,1:31-33.

Classification depending upon clinical presentation

Presentation Common Uncommon Rare Acute Unilateral

-Staphylococcus aureus -Group A streptococcus

-Group B streptococcus -Gram negative bacteria

-Anthrax

Acute Bilateral -Herpes Simplex Virus -Epstein-Barr virus -Cytomegalovirus-Group A streptococcus -Mycoplasma pneumoniae

-Roseola -Parvovirus B19

-Corynebacterium diphtheriae -Measles -Mumps -Rubella

Chronic Unilateral

-Nontuberculous mycobacterium -Cat-scratch disease

-Tuberculosis-Actinomycosis

-Nocardia-Aspergillosis

Chronic Bilateral

-Epstein-Barr virus-Cytomegalovirus

-HIV-Tuberculosis -Toxoplasmosis-Syphilis

-Brucellosis-Histoplasmosis

Courtney Hallum, MD, LPCH Blue Team and PEC Rotations, February 2009

Clinical assessment

History

Physical examination

Inspection

Palpation

Lymphadenopathy that has been present for less than 2 weeks has a very low chance of representing a malignant condition.

Additionally, lymphadenopathy that has been present for more than 1 year and has been stable in size over the year has a very low chance of being malignant.

HISTORY

Exposure history

A complete exposure history is essential to determining the etiology of lymphadenopathy.

Exposure to animals and biting insects, chronic use of medications, infectious contacts, and a history of recurrent infections are essential in the evaluation of persistent lymphadenopathy.

Travel-related exposures and immunization status should be noted

Personal and occupational history

Environmental exposures such as tobacco, alcohol, and ultraviolet radiation may raise suspicion for metastatic carcinoma of the internal organs, cancers of the head and neck, and skin malignancies.

Occupational exposures to silicon or beryllium may also lead to lymphadenopathy.

Sexual history and orientation are important in determining potential sexually transmitted causes of inguinal and cervical lymphadenopathy.

A thorough review of systems is important

Knowledge of associated factors is critical to determining the management of unexplained lymphadenopathy.

Constitutional symptoms such as fever, malaise, fatigue, cachexia, unexplained loss of weight, loss of appetite.

Fever: Adenopathy in the presence of fever points toward a broad differential, mainly consisting of infection or lymphoma

Evening raise Pel Ebstein fever

Arthralgia, muscle weakness, unusual rashes may indicate possibility of autoimmune diseases.

Symptoms associated with lymphadenopathy that should be considered red flags for malignancy include fevers, night sweats, and unexplained weight loss (>10% of normal body weight)

Associated symptoms

PHYSICAL EXAMINATION

The physical examination should be regionally directed by knowledge of the lymphatic drainage patterns and should include a complete lymphatic examination looking for generalized lymphadenopathy.

Inspection

Swellings at the known sites of lymph nodes should be considered to have arisen from them unless some outstanding clinical findings prove their origin to be otherwise.

All the normal anatomic sites should be inspected for any obvious enlargements.

When lymphadenopathy is localized, the clinician should examine the region drained by the nodes for evidence of infection, lesions or tumors.

Other nodal sites should also be carefully examined to exclude the possibility of generalized lymphadenopathy. The lymph nodes are examined in the same

fashion as any other swelling that means number, site, size, surface

Number: is important to know whether a single or multiple groups are involved.

• A few conditions are known to cause generalized lymphadenopathy

• Eg: Lymphomas, Tuberculosis, lymphatic leukemia, Brucellosis, Sarcoidosis etc…

Position: is important as it will not only give an idea as to which group of lymph node is affected, but also the diagnosis.

Eg: Hodgkin’s disease and the Tuberculosis affect the cervical lymph nodes in the earlier stages.

Overlying skin :

In acute lymphadenitis the skin becomes inflamed with redness, edema and brawny induration.

In chronic lymphadenitis such angriness is not seen

Skin over tuberculous lymphadenitis becomes red and glossy when they reach the point of bursting. Scar often indicates previous bursting of abscess or operation.

Over a rapidly growing lymphoma, the skin appears tense, stretched with dilated subcutaneous veins.

In secondary carcinoma, the skin may become fixed.

Palpation

Most of the lymph nodes are best palpated with the examiner standing behind the patient who is comfortably seated in a dental chair.

Palpation of the lymph nodes is ideally done commencing from the most superior lymph node and then working down to the clavicle region.

Nodes are palpated for consistency, size, tenderness, fixity to the surrounding structures.

Consistency

Enlarged lymph nodes should be palpated carefully with palmar aspect of 3 fingers.

While rolling the fingers over the lymph node, slight pressure has to be applied to know the consistency of the node.

Enlarged lymph nodes could be Soft (fluctuant)Elastic , rubberyFirm,Stony hardVariable

Tenderness

When a lymph node increases in size its capsule stretches and causes pain.

But pain may also be seen when there is hemorrhage into the necrotic center of a malignant node.

The presence or absence of tenderness does not necessarily differentiate benign from malignant nodes.

Matting

A group of lymph nodes that feels connected and move as a unit is said to be matted.

Nodes that are matted could be

Malignant:

Metastatic carcinoma

Lymphomas

Other:

Tuberculosis

Sarcoidosis

Size

Nodes are generally considered to be normal if they are up to 1cm in diameter.

Little information exists to suggest that a specific diagnosis can be based node on size alone.

Fixity to the surrounding tissues

The enlarged nodes should be carefully palpated to know if they are fixed to the skin, deep fascia, muscles.

Any primary malignant growth or secondary carcinoma is often fixed to the surroundings.

First the deep fascia and the underlying muscle, the surrounding structures and finally the skin is involved.

Upper deep cervical lymph nodes when involved secondarily from any carcinoma of its drainage area may involve the hypoglossal nerve and cause hemiparesis of the tongue which will be deviated towards the side of the lesion when asked to protrude out.

• They are palpated anterior to the tragus of the ear.

METHOD OF PALPATION

PRE AURICU

LAR NODES

POSTERIOR

AURICULAR

NODES

Are palpated behind the ear, on the mastoid process

OCCIPITAL NODES

Palpated at the base\lower border of skull

Sub mental

nodes

They are palpated under the chin

The clinician can stand behind the patient to palpate.

The patient is instructed to bend his/her neck slightly forward so that the muscles and fascia in that regions relax.

Fingers of both hands can be placed just below the chin, under the lower border of mandible and the lymph nodes should be tried to be cupped with fingers.

Sub mandibular

nodes

•Are palpated at the lower border of the mandible approximately at the angle of the mandible.•The patient is instructed to passively flex the neck towards the side that is being examined. This maneuver helps relaxing the muscles and fascia of neck, thereby allowing easy examination.•The fingers of the palpating hand should be kept together to prevent the nodes from slipping in between them.•The palmar aspect of the fingers is pushed on to the soft tissue below the mandible near the midline, then the clinician should then move the fingers laterally to draw the nodes outwards and trap them against the lower border of the mandible.

Superficial

cervical

nodes

Are situated superficial to upper part of sterno-cleido mastoid along its anterior border.

Posterior

superficial

nodesPalpated in the posterior triangle of the neck close to the anterior border of trapezius

• The laboratory investigation of patients with lymphadenopathy must be tailored to elucidate the etiology suspected from the patient's history and physical findings.

• Complete Blood Count, CBC provide useful data for the diagnosis of– acute or chronic leukemias,– EBV or CMV mononucleosis,– lymphoma with a leukemic component,– pyogenic infections, or– immune cytopenias in illnesses such as SLE.

Laboratory Investigation

• Serologic studies – may demonstrate – antibodies specific to components of EBV, CMV, HIV,

and other viruses;– antinuclear and anti-DNA antibody in case of SLE.

• Chest x-ray –– usually negative– the presence of a pulmonary infiltrate or

mediastinal lymphadenopathy would suggest tuberculosis, histoplasmosis, sarcoidosis, lymphoma, primary lung cancer, or metastatic cancer

– The decision to biopsy may be made early in a patient's evaluation or delayed for up to two weeks.

– Prompt biopsy should occur if the patient's history and physical findings suggest a malignancy;

E.g. a solitary, hard, nontender cervical node in an older patient who is a chronic user of tobacco;

– supraclavicular adenopathy; and

– solitary or generalized adenopathy that is firm, movable, and suggestive of lymphoma.

Lymph node biopsy

– It should not be performed as the first diagnostic procedure.

– Fine-needle aspiration should be reserved for thyroid nodules and for confirmation of relapse in patients whose primary diagnosis is known.

Fine-needle aspiration

Normal cervical nodes appear sonographically as somewhat flattened hypoechoic structures with varying amounts of hilar fat.

Ultrasonography

US appearance of normal lymph node shows flattened hypoechoic cigar-shaped structure.

Dentomaxillofacial Radiology (2000) 29, 133 - 143

Criteria for US:(1) A lymph node with definite internal echoes is defined as malignant.


(2) A lymph node with hilar but no definite internal echoes is defined as benign.

Dentomaxillofacial Radiology (2000) 29, 238 ± 244Dentomaxillofacial Radiology (2000) 29, 133 - 143

(3) A lymph node measuring 10 mm or more in the short axis is defined as malignant.(4) A lymph node with a L/S ratio of 3.5 or more is considered benign.(5) A lymph node which can not be associated to categories 1 to 4 is considered to be `questionable'.

Dentomaxillofacial Radiology (2000) 29, 238 ± 244Dentomaxillofacial Radiology (2000) 29, 133 - 143

Malignant infiltration alters the US features of the lymph nodes, resulting in enlarged nodes that are usually rounded and show peripheral or mixed vascularity.

Using these features, US has been shown to have an accuracy of 89%– 94% in differentiating malignant from benign cervical lymph nodes

Magnetic Resonance Imaging

T1-weighted images depict lymph nodes as being of intermediate signal intensity, similar to muscle, whilst T2-weighted images show them as hyperintense signal.


In conclusion, the lymphatic system and its organs are widespread and scattered throughout the body. It functions to service almost every region of 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 so devastating.

CONCLUSION

REFERENCES• Anatomy of the human body, by Henry Gray. 20th edition

• Anatomy and physiology - The unity of form and function (Saladin K. - 2003 - 3rd ed. - McGraw-Hill)

• Understanding Human Anatomy and Physiology - Sylvia S. Mader

• Textbook of Head and Neck Anatomy (Hiatt - Gartner, 4th Ed. 2010)

• Peter M. Som. Imaging-Based Nodal Classification for Evaluation of Neck Metastatic Adenopathy. Arch Otolaryngol Head Neck Surg. 1999;125:388-396.

• Sambandan T, Mabel C R, Cervical lymphadenopathy- a review; JIADS,2011,2,1:31-33.

• Courtney Hallum, MD, LPCH Blue Team and PEC Rotations, February 2009

• K Yuasa et al. Computed tomography and ultrasonography of metastatic cervical lymph nodes in oral squamous cell carcinoma. 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.

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Lymphatic drainage of head and neck

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