IMAGING OF CV SYSTEM

DR.C.UDUGAMA

MBBS, PH,D

THE LYMPHATIC

SYSTEM

Goals

1. Discuss the organization of the lymphatic system, including the vessels, principal lymph nodes, thymus, and spleen

2. Explain the relationship between the lymphatic and circulatory systems, and the role of lymphoid tissue structures and lymphocytes in the body’s defense

OVERVIEW OF THE LYMPHATIC

SYSTEM

Includes, vessels, fluid, and nodes or non secreting "glands".

Lymphatic vessels convey fluid from the periphery to the veins.

The fluid, lymph (=clear spring water), is what seeps out of the blood at the peripheral capillaries. Composition is similar to plasma without the proteins

Lymphatic organs or tissues ("glands") are filtering areas and arenas of lymphocyte maturation and competency.

Accessory to cardiovascular system there are two

drainage systems

MAJOR FUNCTIONS OF LYMPHATIC

SYSTEM

Filtration of lymph

Return of seeped fluid to c.v. system

“Education” and production of immune system lymphocytes

Transport of digested lipids from small intestinal lacteals

LYMPH CAPILLARIES

Thin walled endothelium (no BM) with periodic one way valves. In general they parallel veins.

Closed ends allow fluid flow inward only

Pick up and recycle extra tissue fluid

Lymph circulation due to ?

Compare to Fig. 23.2

LOCATION OF LYMPH CAPILLARIES

Everywhere, except for CNS

and bone marrow, as well as

cornea and cartilage.

Special set of lymph capillaries

in villi of small intestine =

Lacteals

Damaged valves or blocked

lymph vessels ???

LYMPHATIC VESSELS

comparable in structure

to veins

Lymph capillaries

converge to become

collecting vessels and

end up as either

Thoracic duct or right

lymphatic duct

Thoracic (left lymphatic) duct

Left subclavian vein

Right

lymphatic

duct

Right

subclavian

vein

Cysterna Chyli

Fig 23.4

largest

LYMPH NODES

~ 500 ( 1mm to 25 mm)

Bean-shaped with hilus

several afferent vessels, one efferent vessel

Function?

Popular term “lymph gland” is misnomer. Why?

Contain lots of lymphocytes & Macrophages

Clinical application: Swollen lymph nodes

DISTRIBUTION OF LNS

Cervical lymph nodes - drain head and neck

Axillary lymph nodes - drain arms and breasts

Popliteal lymph nodes - drain legs, drain into

Inguinal lymph nodes - drain lower limb

Thoracic lymph nodes - drain thoracic viscera

Abdominal lymph nodes - drain pelvic region

Intestinal and mesenteric lymph nodes - drain abdominal

viscera

LEVEL OF CLINICAL

LYMPHOEDEMA

Is the final outcome of the dynamics of lymph formation and

flow.

• Transcapillary filtration rates

• Lymphatic transport capacity

• The overall collateral lymphatic reserve

• Level of lymphatic obstruction

CHRONIC LYMPHOEDEMA

Below Ankle Below Knee Above Knee

LYMPHOSCINTIGRAPHIC PROCEDURE

Injection of sub.

cute.Tc99SC

Imaging of the ankle and

calf

Imaging of the

pelvis

Normal Lymphoscintigram in relation to

anatomical location of lymph nodes

Below

ankle

Below

knee

Above

knee

LEVEL OF LYMPHOEDEMA

SEX DISTRIBUTION OF

PATIENTS WITH CHRONIC

LYMPHOEDEMA

S E X N o . o f a f f e c t e d l i m b s . ( 1 0 5 )

B e l o w A n k l e B e l o w

K n e e

A b o v e K n e e

F e m a l e 9 5 2 1 0

M a l e 7 2 0 7

T o t a l 1 6 7 2 1 7

LEVEL OF SCINTIGRAPHIC

OBSTRUCTION – BELOW ANKLE

Medial knee Femoral

Inguinal

LEVEL OF SCINTIGRAPHIC

OBSTRUCTION – BELOW KNEE

Mid

knee

Femora

l

Inguina

l

LEVEL OF SCINTIGRAPHIC

OBSTRUCTION – ABOVE

KNEE

I

U

Femoral Inguinal (U)

Ext Iliac (I)