1. Human Biology 2
Dr. Ahmed Osman

2. Lymphatic system
•Definition
•Function of lymph (nodes)
•Dynamics of circulation
•Role in dental practice
•Clinical applications
(Regional lymph
nodes).

3. Lymphatic system
 As blood flows through the
capillaries of the body, two
opposing forces are exerted.
 Blood pressure tends to force fluid
through the walls of the capillaries
into the tissue spaces, whereas the
osmotic pressure of the blood
tends to draw fluid into the vessels.

4. Lymphatic system
• Fluid tends to pass out of vessels on the arterial side.
• About 90% of this fluid returns to the blood vessels, the
remaining 10% entering lymph vessels that eventually carry
this lymph back to the venous circulation after passing
through the lymph nodes.

5.  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.

6. • It is responsible for the removal of interstitial fluid from tissues i.e. act as "drains" to collect
the excess fluid and return it to the venous blood just before it reaches the heart preventing
massive edema (which can cause tissue destruction: “pressure necrosis”).
•Returns back to circulation, the protiens that may have escaped into interstitial spaces.
 Lymphatic tissue is a specilized connective tissue - reticular
connective, that contains large quantities of lymphocytes(filter
fluids prior to adding it to circulation).
 It transports immune cells to and from the lymph nodes in to the
bones
 The lymph transports antigen-presenting cells (APCs), such as
dendritic cells, to the lymph nodes where an immune response is
stimulated.
 works with the circulatory system to deliver nutrients, oxygen, and
hormones from the blood to the cells that make up the tissues of
the body.
 It absorbs and transports fatty acids and fats as chyle to the
circulatory system

9. Circulation at the rate of 125 mL/hour.
The “pump” is: breathing & muscle contractions

10. 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).
Role in headache?

11. Clinical significance:
2. Diagnostic value
3. Aid in prediction of treatment outcome
(modification of treatment plan/course)
4. Prediction of disease history and therefore
prognosis.
5. Lymph vessels can also transmit other
substances such as injected material or
neoplastic cells.

12. Classification of nodes
in head and neck region

13. Classification of nodes
in head and neck region
The lymph nodes in the head and neck region
can be grouped into:
• Superficial nodes
• Deep nodes.

14.  The superficial cervical lymph nodes lie
above the investing layer of the deep fascia.
fascia
 They consist of a few small nodes that lie
superficial to the external jugular and
anterior jugular veins.

15. 1. Submental
2. Submandibular
3. Buccal
4. Parotid (pre-auricular)
5. Mastoid (retro auricular/ post-auricular)
6. Occipital
7. Superficial cervical
8. Anterior cervical.

16. Superficial
cervical nodes

18. Upper deep cervical
c Lower deep cervical
c Waldyer’s ring
c Nodes of midline

19. Deep cervical nodes
 The upper deep cervical (Jugulo-digastric
group: lie along the upper part of internal
jugular vein deep to the sternomastoid.
 The lower deep cervical (jugulo-omohyoid
gp): arranged along the lower part of IJV also
deep to the SMm.

20. Deep cervical nodes

21.  The waldyer’s ring is formed by: lingual, palatine,
tubal, and pharyngeal tonsils.
 Midline nodes are termed in correspondence to the
anatomical area where they exist:
w Infrahyoid
d Prelaryngeal
d Pretracheal
d Paratracheal

22.  Efferents of lower deep cervicals then collect
into larger lymph vessel called the “jugular
lymph trunk”.
 This trunk joins another two lymph trunks
lymph (subclavian and brachiocephalic trunks)
to form the so called the “lymph ducts” (right or
left).
 This “duct” finally opens into the angle between
internal jugular and subclavian veins to drain its
contents back to venous circulation.

23. Thoracic duct
The right and left lymph ducts are NOT of equal size.
The left lymph duct (also called the “Thoracic duct” )
which is considered the largest lymphatic vessel in
the body.
It collects most of the lymph in the body (except
that from the right arm and the right side of the
chest, neck and head, which is collected by the
right lymphatic duct).

24. Thoracic duct
• It begins down as low as level of L2
(at the cisterna chyli) and extends upward to
drain into the region near the junction of the
left subclavian and internal jugular veins, with
tributaries from the cervical, subclavian and
mediastinal trunks.

25. Lymphatic drainage

26. 600-700
lymph nodes
present in
the average
human body

27. Clinical applications
 The first sign of a malignancy (especially an
intra-abdominal one) may be an enlargement
of the lymph node that lies in the left
supraclavicular area, in the vicinity where the
thoracic duct empties into the left subclavian
vein (Virchow’s node).
 When the thoracic duct is blocked or
damaged a large amount of lymph can
quickly accumulate in the pleural cavity,
(Chylothorax).

30. • 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.
While the middle third of the lower lip drains into
the submental nodes
• The skin of the neck drains into the cervical nodes.

31. • 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.
• Teeth drain into the submandibular and deep
cervical lymph nodes.
• Anterior part of mouth floor drain into
submental and upper deep cervical while
posterior part into submandibular and upper
deep cervical.

32. Drainage of oral structures

33. Drainage of oral structures

34. Lymphatic drainage of tongue
• In relation to the lymph drainage of the tongue, the farther
backward the origin of the vessel, the lower down is the
lymph node in which it ends.
• 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.

37. Lymphatic drainage of tongue
What is radical neck dissection?& why?