The document discusses the lymphatic system and lymph nodes. It describes the components and function of the lymphatic system in transporting lymph and immune cells throughout the body. It details the different types of lymph nodes, their locations in the head and neck region, and which areas of the body drain into specific lymph nodes. The causes and clinical evaluation of swollen or enlarged lymph nodes (lymphadenopathy) are also covered.

2.  Introduction
 Description of lymph nodes
 Function of lymph nodes
 Distribution of lymph nodes
 Lymphadenopathy
 Causes of lymphadenopathy
 Clinical evaluation of lymphadenopathy
 Investigations

3.  The lymphatic system is the part of the
immune system comprising a network of
conduits called lymphatic vessels that carry a
clear fluid called lymph (from Latin lympha
"water") in a unidirectional pathway.
 The widely and extensively dispersed vessel
system collects tissue fluids from all regions
of the body to eventually convey them
towards the heart.

4. 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.

5.  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.
◦ The gaps between lymphatic endothelial cells are
so large that bacteria and other cells can enter
along with the fluid.

6. ◦ 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).

7.  Afferent
 Efferent

8.  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,
they produce circulating antibodies.

9.  Macrophages. These cells, derived from monocytes
of the blood, they 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.)

10.  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 mature in these
organs.

11.  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.

12.  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.

14.  The secondary lymphatic organs are
◦ the spleen,
◦ the lymph nodes and
◦ other organs, such as the tonsils, Peyer patches,
and the appendix.
 All the secondary organs are the places where
lymphocytes encounter and bind with antigens,
after which they proliferate and become actively
engaged cells.

15.  The spleen is the body’s largest lymphatic organ.
 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.

16.  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,
much like the lymph nodes do the lymph.
 Lymphocytes and macrophages of the white
pulp are quick to detect foreign antigens in the
blood and activate immune reactions.

17.  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.

18.  Lymph nodes are bean shaped organs found in clusters
along the distribution of lymph channels of the body.
 Every tissue supplied by blood vessels is supplied by
lymphatic's except placenta and brain.
 There are over 800 lymph nodes in the body and
around 300 are located in the head and neck

19. 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.

20. Between the capsule and
parenchyma is a narrow space
called the subcapsular sinus,
which contains reticular fibers,
macrophages, and dendritic cells.
The parenchyma is divided into
an outer cortex and, near the
hilum, an inner medulla.
The cortex consists mainly of
ovoid lymphatic nodules.
When the lymph node is fighting a
pathogen, these nodules acquire
light-staining germinal centers
where B cells multiply and
differentiate into plasma cells.

21.  The medulla consists
largely of a branching
network of medullary
cords composed of
lymphocytes, plasma cells,
macrophages, reticular
cells, and reticular fibers.
 The lymph node is a
―bottleneck‖ that slows
down lymph flow and
allows time for cleansing it
of foreign matter.
 The macrophages and
reticular cells of the
sinuses remove about 99%
of the impurities before
the lymph leaves the node.

On its way to the bloodstream, lymph
flows through one lymph node after
another and thus becomes quite
thoroughly cleansed of most impurities.

22.  The superficial nodes are located in the subcutaneous
connective tissue, and deeper nodes lie beneath the
fascia & muscles and within various body cavities.
 They are numerous and tiny, but some may have size as
large as 0.5 to 1 cm in diameter.
 The superficial nodes are the gateways for assessing the
health of the entire lymphatic system

23.  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.

24.  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.

25.  Ectopic or tertiary lymphoid tissues develop
at sites of inflammation or infection in
peripheral, non-lymphoid organs.
 Most important of these sites are those
tissues with direct contact with the
―external‖ environment, primarily the skin
and mucosal lining of the gastrointestinal,
pulmonary, and genitourinary tracts.

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

27.  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).

28.  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.

29.  UPPER HORIZONTAL GROUP OF LYMPH
NODES:
 Submental
 Submandibular
 Parotid
 Postauricular
 Occipital

30.  LATERAL CERVICAL NODES:
they include nodes
superficial and deep to
sternocleidomastoid muscle
and in the posterior
triangle.
 Superficial external juglar
group
 Deep group:
 Internal juglar chain (upper,
middle and lower)
 Spinal accessory
 Transverse cervical chain

31.  ANTERIOR CERVICAL NODES:
 Anterior jugular chain
 Juxtavisceral chain:
 Prelaryngeal
 Pretracheal
 paratracheal

32.  Lymph nodes in the neck have
been divided into seven levels.

33. LEVEL I

The sub-mental and sub-mandibular
nodes.

They lie above the hyoid bone, below
the mylohoid muscle and anterior to
the back of the sub-mandibular
gland.
LEVEL IA

The sub-mental nodes.

They lie between the medial margins
of the anterior bellies of the
diagastric muscles.
LEVEL IB

The sub-mandibular nodes.

On each side, they lie lateral to the
level IA nodes and anterior to the
back of each sub-mandibular gland.

34. LEVEL II

The upper internal jugular nodes.

They extend from the skull base to the level
of the bottom of the body of hyoid bone.

They are posterior to the back of the sub-
mandibular gland and anterior to the back of
sternocleidomastoid muscle
LEVEL IIA
 A level II node that lies either anterior,
medial, lateral or posterior to the internal
jugular vein. If posterior to the vein, the
node is inseparable from the vein.
LEVEL IIB
 A level II node that lies posterior to the
internal jugular vein.

35.  These nodes are at greatest risk for harboring
metastases from the cancers arising from the
oral cavity, anterior nasal cavity, soft tissue
structures of the midface, and submandibular
gland.

36. LEVEL III

The middle jugular nodes.

They extend from the level of the bottom
of the body of the hyoid bone to the level
of the bottom of the cricoid arch.

They lie anterior to the back of
sternocleidomastoid muscle.

37.  These nodes are at greatest risk for harboring
metastases from cancers arising from the oral
cavity, nasopharynx, oropharynx,
hypopharynx, and larynx.

38. LEVEL IV:

The low jugular nodes.

They extend from the level of the
bottom of the cricoid arch to the
level of the clavicle.

39. LEVEL V

The nodes in the posterior
triangle.

They lie posterior to the back of
the sternocleidomastoid muscle.

LEVEL VA

Upper level V nodes extend from
the skull base to the level of the
bottom of the cricoid arch.
LEVEL VB

Lower level V nodes extend from
the level of the bottom of the
cricoid arch to the level of the
clavicle.

40.  The posterior triangle nodes are at greatest
risk for harboring metastases from cancers
arising from the nasopharynx and
oropharynx (Sublevel VA), and the thyroid
gland (Sublevel VB)

41. LEVEL VI

The upper visceral nodes.

They lie between the carotid arteries
from the level of the bottom of the
body of the hyoid bone to the level of
the top of the manubrium
.

42.  These nodes are at greatest risk for harboring
metastases from cancers arising from the
thyroid gland, glottic and subglottic larynx,
apex of the, and cervical esophagus

43. LEVEL VII

The superior mediastinal nodes.

They lie between the carotid
arteries below the level of the top
of the manubrium .

44.  They lie at or caudal to the level of the
clavicle and lateral to the carotid artery on
each side of the neck.

45.  Within 2 cm of the skull base, they lie medial
to the internal carotid arteries.

46. • The scalp drains into the
occipital, mastoid and
parotid nodes.
• Lower eye lid and anterior
cheek drains into buccal
LNs.
• The cheeks drain into the
parotid, buccal and
submandibular nodes.
• The upper lips and sides of
the lower lips drain into
the submandibular nodes.

47. • While the middle third of the lower lip drains into
the submental nodes
• The skin of the neck drains into the cervical nodes.
• 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.

48. • Lymph vessels in the
floor of the mouth pierce
the mylohyoid muscle
and travel to the
submental and
submandibular lymph
nodes.
• Some medially located
lymphatics in the tongue
also cross the midline.

49.  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.

50.  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

51.  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;
 Healthy adults may have palpable inguinal nodes of
up to 2 cm, which are considered normal.

52.  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 [Epstein-Barr virus (EBV) or
cytomegalovirus (CMV)],toxoplasmosis, AIDS, other
viral infections,
◦ systemic lupus erythematosus (SLE), and
◦ mixed connective tissue disease.
 Acute and chronic lymphocytic leukemias and malignant
lymphomas also produce generalized adenopathy in
adults.

53.  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 adenopathy often reflects an
infection of the scalp, and preauricular
adenopathy accompanies conjunctival
infections and cat-scratch disease.

55.  Immunologic diseases
 Rheumatoid arthritis
 Juvenile rheumatoid arthritis
 Mixed connective tissue disease
 Systemic lupus erythematosus
 Dermatomyositis
 Sjögren's syndrome
 Serum sickness
 Drug hypersensitivity—diphenylhydantoin, hydralazine,
allopurinol, primidone, gold, carbamazepine, etc.
 Angioimmunoblastic lymphadenopathy
 Primary biliary cirrhosis
 Graft-vs.-host disease
 Silicone-associated
 Autoimmune lymphoproliferative syndrome

56.  Malignant diseases
◦ Hematologic—Hodgkin's disease, non-Hodgkin's
lymphomas, acute or chronic lymphocytic
leukemia, hairy cell leukemia, malignant
histiocytosis, amyloidosis
◦ Metastatic—from numerous primary sites
 Lipid storage diseases—Gaucher's, Niemann-Pick,
Fabry, Tangier
 Endocrine diseases—hyperthyroidism, Adrenal
insufficiency, Thyroiditis.

57.  Other disorders
◦ Castleman's disease (giant lymph node hyperplasia)
◦ Sarcoidosis
◦ Dermatopathic lymphadenitis
◦ Lymphomatoid granulomatosis
◦ Histiocytic necrotizing lymphadenitis (Kikuchi's disease)
◦ Sinus histiocytosis with massive lymphadenopathy (Rosai-
Dorfman disease)
◦ Mucocutaneous lymph node syndrome (Kawasaki's disease)
◦ Histiocytosis X
◦ Familial Mediterranean fever
◦ Severe hypertriglyceridemia
◦ Vascular transformation of sinuses
◦ Inflammatory pseudotumor of lymph node
◦ Congestive heart failureAbbreviations: CMV,
cytomegalovirus; EBV, Epstein-Barr virus.

58.  History
 Physical examination
◦ Inspection
◦ palpation

59.  The rate of malignant aetiologies of
lymphadenopathy is very low in childhood,
but increases with age.
 Lymph nodes are palpable as early as
neonatal period and a majority of healthy
children have palpable cervical lymph nodes.
 Vast majority of cases of lymphadenopathy in
children have infectious etiology.

60.  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
 However, exceptions to the latter may include
indolent non-Hodgkin’s and low-grade
Hodgkin’s lymphomas

61.  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

62.  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.

63.  May raise suspicion for certain neoplastic
causes of lymphadenopathy, such as
carcinomas or tuberculosis.

64.  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)

65.  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.

66.  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.

67. ◦ 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.

68.  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…

69.  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.

70.  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.

71.  Over a rapidly growing lymphoma, the skin
appears tense, stretched with dilated
subcutaneous veins.
 In secondary carcinoma, the skin may
become fixed.

72.  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.

73.  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 , rubbery
Firm,
Stony hard
Variable

74.  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.

75.  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
 Lymphogranuloma venerum

76.  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.

77.  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.
 Cases are not uncommon when patient may complain of dyspnoea &
dysphagia due to pressure on trachea or esophagus by enlarged
lymph nodes from Hodgkin’s disease or secondary carcinoma.

78.  They are palpated anterior to
the tragus of the ear.

79. Are palpated behind the ear,
on the mastoid process

80. Palpated at the baselower
border of skull

81. 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.

82. 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.

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

84. Palpated in the posterior triangle of
the neck close to the anterior
border of trapezius

85.  Examination of the cervical nodes can be
accomplished by instructing the patients to turn
the neck away from the side to be examined.
 This position distends the Sterno mastoid muscle
and facilitate easier examination of the lymph
nodes of anterior and posterior chain.
 Finger tips of the hand are placed along the
posterior border of muscle while the thumb
provides counter pressure from the anterior
aspect of the muscle

89.  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.

90.  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

91. ◦ The indications for biopsy are imprecise, yet it is a
valuable diagnostic tool.
◦ 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.

92. ◦ 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.

93.  Normal cervical nodes appear sonographically as
somewhat flattened hypoechoic structures with
varying amounts of hilar fat.
Dentomaxillofacial Radiology (2000) 29, 133 - 143
US appearance of normal lymph nodeshows
flattened hypoechoic cigar-shaped structure.

94.  Criteria for US:
 (1) A lymph node with definite internal echoes
is defined as malignant.
Dentomaxillofacial Radiology (2000) 29, 238 ± 244

95.  (2) A lymph node with hilar but no definite
internal echoes is defined as benign.
Dentomaxillofacial Radiology (2000) 29, 238 ± 244

96.  (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 ± 244

97.  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
Dentomaxillofacial Radiology (2000) 29, 133 - 143

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

99. (a) T1 weighted and (b) T2 weighted sagittal MRI scans demonstrate a
large pathological deep cervical lymph node (level two/ three) which is
of intermediate signal on T1 and high signal on T2
Dentomaxillofacial Radiology (2000) 29, 133 - 143

100.  Most head and neck PET imaging is performed
with the radiolabelled glucose analogue FDG
Fluorodeoxyglucose which has increased
uptake in viable malignant tumour due to
enhanced glycolysis.
 The result can be expressed as a standardised
uptake value (SUV), with those values greater
than two being considered abnormal.
 PET scanning provides functional rather than
anatomical imaging.
Dentomaxillofacial Radiology (2000) 29, 133 – 143

102.  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.

103. REFERENCES:
1. A clinical manual of general surgery, 5th edition, S. das.
2. Greenberg, Glick, Ship. Burket’s Oral Medicine. 10th edition.
3. Diagnostic oral medicine,1st edition ,2003, BK Venkataraman.
4. Greenberg, Glick, Ship. Burket’s Oral Medicine. 11th edition.