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1. INDIAN DENTAL ACADEMY
Leader in continuing Dental Education

2. • At the end of the seminar the learner should be able
to know about
– LYMPH NODE
• ITS MORPHOLOGY & HISTOLOGY
• ITS CLASSIFICATION IN HEAD AND NECK REGION
• DRAINAGE OF LYMPH NODES IN HEAD AND NECK REGION
• CLINICAL SIGNIFICANCE

3. • Grays anatomy 40th edition.
• Guyton an Hall textbook of Medical Physiology 12th edition
• Cunningham’s Manual of practical Anatomy. 15th edition
Vol.3 Head & Neck and Brain.- G. J. Romanes
• K. Sembulingam – textbook of physiology -3rd edition
• Wheater’s Functional Histology.

4. • Oval or bean-shaped bodies / nodule.
• Situated in the course of lymphatic vessels
• These are encapsulated structure
• And usually the site for
– Antigen presentation
– Lymphocyte activation, differentiation and proliferation.

5. • Function :
– Generate mature antigen primed B- & T-
lymphocytes.
– Act as a drainage system by absorbing and
expelling
• Proteins
• Dead cells
• bacteria; microbes

6. • Of the estimated 450 lymph nodes in the body-
approximately
• 60-70 are located in head and neck region.
• 100 in thorax
• 250 in abdomen and pelvis app.

13. • Structure :
• Oval / bean / kidney shaped structure located along
the path of lymph vessel.
• Having concavity and convexity on opposite surface.
• Concave side shows slight depression-called as the
Hilus - through which the blood vessels enter and leave
along with the origin of Efferent Lymph vessel.

14. • Structure :
• Several afferent lymphatic vessel also enter the
capsule around the periphery.

15. • Structure :
• The lymph node consist of three component
– Parenchyma
– Stroma
– Sinus spaces

16. • Structure :
• The lymph node consist of three component
Parenchyma
Cortex
follicular
parafollicular
medulla
Medullary
sinus
Medullary
cords
Paracortex

17. CORTEX
PARACORTEX
MEDULLA
follicle
Sub
capsular
sinus
Para corticular
sinus
capsule
Medullary
cords
Medullary
sinus

18. • Structure :
• The lymph node consist of three component
Stroma
Connective tissue
capsule rich in
collagen
Trabeculae
Reticular fibers.

19. • Structure :
• The lymph node consist of three component
sinuses
Sub capsular /
cortical sinus
Medullary
sinus
Intermediate
sinus
Lymphatic cords

21. • Structure :
• Parenchyma(according to lymphocytic domain)
– Cortex
– Paracortex
– Medulla

22. • Structure :
• Parenchyma
• Cortex:
– Made up of follicles.
– It is also called the domain of B cells.
– Also it contains the follicular DCs

23. • Structure :
• Parenchyma
• Cortex:
– Two types of follicles
• Primary lymphoid follicles (without germinal center.)
• Secondary lymphoid follicles, have a pale
spherical center called germinal center

24. • Structure :
• Parenchyma
• Cortex:
– Germinal Center :
Stains paler in H&E
section due to
uncondensed nuclear
chromatin of newly
developing B-cell.

25. Germinal Center

27. • Structure :
• Parenchyma
• Cortex:
– Germinal Center :
• Role of germinal center is to provide micro-
environment for B cell response; so that affinity of
antibody to bind an antigen increase.
• This process occurs in various zones present with in
germinal center.

28. • Structure :
• Parenchyma
• Cortex:
– Germinal Center :
• It contain two zones with in it
– Dark Zone
– Light Zone

29. • Structure :
• Parenchyma
• Cortex:
– Germinal Center :
• Dark zone :
– Undeveloped B-cells (centroblast) undergoes rapid
proliferation
– Which is associated with the hypermutation of their
antibody molecules

30. • Structure :
• Parenchyma
• Cortex:
– Germinal Center :
• Light zone :
– After proliferation these B cells comes to light zone
(as centrocytes).
– Interact with Follicular DCs (FDCs), which contain
intact unprocessed antigen on their surfaces.

31. • Structure :
• Parenchyma
• Cortex:
– Germinal Center :
• Light zone :
– Centrocytes compete for antigen.
– Those cell which have antibody with highest
affinity survives ; rest of them dies.

32. • Structure :
• Parenchyma
• Cortex:
– Germinal Center :
• Light zone :
– T-cells helps in survival of these B –cells and
also helps in class switching of antibodies.
– Macrophages engulfs the died B-cells.

33. • Structure :
• Parenchyma
• Paracortex:
– It is devoid of
Germinal centers
– Lymphocytes are
arranged in irregular
manner
– It is also known as
domain of T cells

34. • Structure :
• Parenchyma
• Paracortex:
– It also contains the
• Interdigitating DCs
• Langerhans cells
( migrated from skin as
Veiled cells )

36. • Structure :
• Parenchyma
• Medullary cord:
– It is the domain of
B- cells and also have
macrophages, and
Plasma cells,
involves in antibodies
production.

37. • Structure :
• Parenchyma
• Medullary cord:
– Cells are less densely
packed
– With easily seen
reticulin network in
between.

38. • Structure :
• Parenchyma:
– Paracortical expansion is seen in
the cellular immunity response.
– Increased no. of follicles in case of
humoral immunity response.

39. • Structure :
• Stroma :
– Stroma is further divided into 3parts
• Connective tissue capsule rich in collagen,
• Trabeculae ,
• Reticular fibers.

40. • Structure :
• Stroma :
– Capsule is composed of
• Collagen fiber
• Elastin fiber(in deeper layer)
• Few fibroblast

41. • Structure :
• Stroma :
– Trabeculae is extension of capsule interior
into lymph node.
– They are continuous with the network of fine
type III collagen. which supports the lymphoid
tissue.

42. • Structure :
• Stroma :
– Reticulin fiber
• The reticulin bundles branch and
interconnected to form very dense network
in the cortex.
• Few of them are also found in germinal
center

43. • Structure :
• Stroma :
– Reticulin fiber
• They provide attachment for various of
cells mostly
– DCs
– Macrophages
– Lymphocytes

44. • Lymphatic channels & Blood Supply :
• Lymph node is permeated by numbers of
channels through which lymph percolates after
its entry from the afferent vessels
• All these channels are lined by endothelium &
Reticulin fibers crosses these channels at
various points.

45. • Lymphatic channels & Blood Supply :
• Lymphatic channels:
• Macrophages lines these channels so that
lymph exposed to their phagocytic activities and
also with B & T cells.
• These macrophages are supported by reticular
fibers.

46. • Lymphatic channels & Blood Supply :
• Lymphatic channels:
• Afferent vessels enters the lymph node at
various point on the periphery of lymph node.
• After entering it branches to form intracapsular
plexus.
• Then opens up into the sub capsular sinus

47. • Lymphatic channels & Blood Supply :
• Lymphatic channels:
• From these sub capsular sinus various radial
cortical sinus forms which leads in to the
medulla.
• In the medulla they coalesce to form larger
medullary sinus.

48. • Lymphatic channels & Blood Supply :
• Lymphatic channels:
• Medullary sinus confluent toward the hilus
portion of lymph node with the efferent lymph
vessel

50. • Lymphatic channels & Blood Supply :
• Blood supply :
• Blood vessels enter the lymph node through the
hilum portion
• Giving rise to straight branches which traverse
the medulla and give off many branches.

51. • Lymphatic channels & Blood Supply :
• Blood supply :
• In the cortex it forms the anostomosing loop
and form highly branched venules and vein.
• In the paracortical region there is a special type
of post capillary HEV (high endothelial venules)
is present.

52. • Lymphatic channels & Blood Supply :
• Blood supply :
• HEV are the special sites for blood-borne
lymphocyte extravasations (labile tight junction) in to
the lymphoid tissue.

54. • In head and neck :
• In the head and neck region there are almost
40-60 lymph nodes.
• They are classified or categorised as they are
essential as a guide for surgery planning and
management.

55. • In head and neck :
• Classification of Lymph node of head and neck
region according to its LEVELS
1. Level I:
a) Submental (IA)
b) Submandibular (IB)
2. Level II Upper jugular
3. Level III Middle jugular
4. Level IV Lower jugular

56. • In head and neck :
• Classification of Lymph node of head and neck
region according to its LEVELS
5. Level V
a) Posterior triangle group (Spinal accessory and
transverse cervical chains)
6. Level VI
a) Prelaryngeal
b) Pretracheal
c) Paratracheal

57. • In head and neck :
• Classification of Lymph node of head and neck
region according to its LEVELS
7. Level VII
a) Nodes of upper mediastinum

58. • In head and neck :
The level system is used for
describing the location of lymph
nodes in the
neck:
Level I, Submental and
Submandibular group;
Level II, Upper jugular group;
Level III, Middle jugular group;
Level IV, Lower jugular group;
Level V, Posterior triangle
group;
Level VI, Anterior
compartment.
Level VII, Nodes of Media
stinum (upper)

59. • In head and neck :
• Level I lymph nodes:
• Nodes within the triangular boundary of
• Anterior and Posterior belly of the digastric
muscles and the hyoid bone.

60. • In head and neck :
• Level I lymph nodes:
• IA Submental nodes: ,
• Lies in the submental triangle
• i.e. between right and left anterior bellies of
diagastric muscles and the hyoid bone.

62. • In head and neck :
• Level IA lymph nodes:
• Dark lines depict the boundaries of the submental (IA) and anterior
compartment (VI) lymph nodes.

63. • In head and neck :
• Level IA lymph nodes:
• These nodes are at greatest risk for harboring
metastases from cancers arising from the
– Floor of the mouth,
– Anterior oral tongue,
– Anterior mandibular alveolar ridge,
– Lower lip.

64. • In head and neck :
• Level I lymph nodes:
• IB Submandibular nodes:
• Lies within the boundaries of the
– Anterior and posterior bellies of the
digastric muscles,
– The stylohyoid muscle,
– And the body of the mandible.

65. • In head and neck :
• Level IB lymph nodes:
• Radiographically, the vertical plane at the
posterior aspect of the submandibular gland
forms a use means of demarcating
the posterior aspect of Level IB from IIA

66. • In head and neck :
• Level I lymph nodes:
• IB Submandibular
nodes: ,

67. • In head and neck :
• Level IB lymph nodes:
• The group includes the
– pre- and postglandular nodes,
– pre- and postvascular nodes.
• The submandibular gland is included in the
specimen when the lymph nodes within this
triangle are removed.

68. • In head and neck :
• Level IB lymph nodes:
• These nodes are at greatest risk for harboring
metastases from the cancers arising from
– oral cavity,
– anterior nasal cavity,
– soft tissue of midface,
– submandibular gland

69. • In head and neck :
• Level II lymph nodes: (upper jugular group)
• All nodes below skull base at jugular fossa to hyoid
bone,
– Anterior to posterior edge of sterno-
cleidomastoid muscle
– And posterior to submandibular gland

70. • In head and neck :
• Level II lymph nodes: (upper jugular group)
• Nodes located around the
– upper third of the internal jugular vein and
adjacent spinal accessory nerve
– extending from the level of the skull base (above)
to the level of the inferior border of the hyoid
bone (below).

71. • In head and neck :
• Level II lymph nodes: (upper jugular group)
• The anterior (medial) boundary lateral border of
the sternohyoid muscle and the stylohyoid muscle
• The posterior (lateral) boundary is the posterior
border of the sternocleidomastoid muscle

72. • In head and neck :
• Level II lymph nodes: (upper jugular group)
• Sublevel IIA nodes
– located anterior(medial) to the vertical plane
defined by the spinal accessory nerve.
• Sublevel IIB nodes
– located posterior (lateral) to the vertical plane
defined by the spinal accessory nerve.

73. • In head and neck :
• Level II lymph nodes: (upper jugular group)
• Sublevel IIA nodes
• Sublevel IIB nodes

74. • In head and neck :
• Level II lymph nodes: (upper jugular group)
• The upper jugular nodes are at greatest risk for
harboring metastases from cancers arising from
– Oral Cavity,
– Nasal Cavity,
– Nasopharynx, Oropharynx, Hypopharynx,
Larynx.
– Parotid Gland

75. • In head and neck :
• Level II lymph nodes: (upper jugular group)

76. • In head and neck :
• Level III lymph nodes: (middle jugular group)
• nodes located around the
– middle third of the internal jugular vein extending
from the inferior border of the hyoid bone (above) to
– the inferior border of the cricoid cartilage (below).

77. • In head and neck :
• Level III lymph nodes: (middle jugular group)
• Jugulo-omohyoid node, (which lies immediately above the superior
belly of the omohyoid muscle as it crosses the internal jugular vein) also
included in this level

78. • In head and neck :
• Level III lymph nodes: (middle jugular group)

79. • In head and neck :
• Level III lymph nodes: (middle jugular group)
• These nodes are at greatest risk for harboring
metastases from cancers arising from
– oral cavity,
– nasopharynx, oropharynx, hypopharynx, and
larynx

80. • In head and neck :
• Level IV lymph nodes: (lower jugular group)
• Lymph nodes located around the lower third of the
internal jugular vein extending from the
– inferior border of the cricoid cartilage (above)
– to the clavicle (below).

81. • In head and neck :
• Level IV lymph nodes: (lower jugular group)
• The anterior (medial) boundary is the lateral border of
the sternohyoid muscle.
• The posterior (lateral) boundary is the posterior border
of the sternocleidomastoid muscle.

82. • In head and neck :
• Level IV lymph nodes: (lower jugular group)

83. • In head and neck :
• Level IV lymph nodes: (lower jugular group)
• These nodes are at greatest risk for harboring
metastases from cancers arising from the
– Hypopharynx,
– Cervical esophagus,
– Larynx

84. • In head and neck :
• Level V lymph nodes: (posterior triangle group)
• This group is comprised predominantly of the lymph
nodes located along the
– Lower half of the spinal accessory nerve
– Transverse cervical artery.
• The supraclavicular nodes are also included in the
posterior triangle group

85. • In head and neck :
• Level V lymph nodes: (posterior triangle group)
• The superior boundary is the apex formed by a
convergence of the sternocleidomastoid and the
trapezius muscles,
• The inferior boundary is the clavicle,

86. • In head and neck :
• Level V lymph nodes: (posterior triangle group)
• The anterior (medial) boundary is the posterior border
of the sternocleidomastoid muscle,
• And the posterior (lateral) boundary is the anterior
border of the trapezius muscle

87. • In head and neck :
• Level V lymph nodes: (posterior triangle group)
• Sublevel VA is separated from Sublevel VB by a
horizontal plane marking the inferior border of the arch
of the cricoid cartilage.

88. • In head and neck :
• Level V lymph nodes: (posterior triangle group)

89. • In head and neck :
• Level V lymph nodes: (posterior triangle group)
• Sublevel VA includes the
– spinal accessory nodes,
• Sublevel VB includes the nodes following the
transverse cervical vessels and the supraclavicular
nodes

90. • In head and neck :
• Level V lymph nodes: (posterior triangle group)
• The posterior triangle nodes are at greatest risk for
harboring metastases from cancers arising from the
– nasopharynx and oropharynx  (Sublevel VA),
– thyroid gland (Sublevel VB)

91. • In head and neck :
• Level VI lymph nodes: (Anterior / Central compartment
group)
• Lymph nodes in this compartment include the
– Pre- and paratracheal nodes,
– Precricoid (Delphian) node,
– Perithyroidal nodes,
– Including the lymph nodes along the recurrent
laryngeal nerves.

92. • In head and neck :
• Level VI lymph nodes: (Anterior / Central compartment
group)
• The superior boundary is the hyoid bone,
• The inferior boundary is the suprasternal notch,
• And the lateral boundaries are the common carotid
arteries.

93. • In head and neck :
• Level VI lymph nodes: (Anterior / Central compartment
group)

94. • In head and neck :
• Level VI lymph nodes: (Anterior / Central compartment
group)
• These nodes are at greatest risk for harboring
metastases from cancers arising from the
– Thyroid gland,
– Glottic and subglottic larynx,
– Apex of the piriform sinus,
– Cervical esophagus