5) Lymphatic Drainage Flashcards
What does the lymphatic system consist of?
Lymph nodes
Lymphoid organs - spleen, thymus, tonsils
Drainage vessels
Lymph (fluid)
Where is the lymphatic system absent?
Eyeball, inner ear and cartilage
Describe the formation of lymph:
Tissue fluid forced out of capillary due to high hydrostatic pressure. Not all tissue fluid is reabsorbed and remaining fluid moving into lymph vessels is called lymph
What does lymph consist of?
Tissue fluid, small proteins, lipids, damaged cells, bacteria (+cancer cells)
How much lymphatic fluid is produced per day?
3-4L
What are the features of lymphatic flow?
Unidirectional, low pressure and no central pump
Describe lymphatic flow from capillaries to ducts:
Lymph capillaries -> lymph vessels (afferent) -> node -> efferent vessel (one) -> lymphatic trunks -> lymphatic ducts
What causes lymph flow to remain unidirectional?
Unidirectional drainage at capillary
Valves so no backflow
Passive constriction due to pulsation of artery or muscle contraction
Intrinsic constriction by SMCs
Where does the lymph system drain into?
Subclavian veins
Which duct drains more lymph?
Left (thoracic) duct
What is lymphoedema?
Abnormal collection of protein-rich fluid causing tissue swelling due to compromised lymphatic system
What are some causes of lymphoedema?
Removal/enlargement of LNs (after cancer treatment) Infections Damage to lymph system Lack of limb movement Congenital e.g. McIlroy's
Name a cause of pitting and non-pitting oedema:
Pitting - heart failure
Non-pitting - lymphoedema
What are lymph nodes?
Connective tissue structures with tough outer capsule and reticular CT inside
What are contained within lymph nodes?
Large collections of lymphocytes and macrophages
What is the clinical term used to describe swollen lymph nodes?
Lymphadenopathy
What causes swollen LNs?
Infection
Malignancy
How can lymph nodes be classified?
Regional - superficial, draining specific area
Terminal - deep
Where can lymph nodes be palpated?
Neck (cervical) Armpit (axillary) Diaphragm Spleen Abdominal Pelvic Groin
What are cervical regional and terminal lymph nodes separated by?
Investing layer of deep cervical fascia
Give examples of the superficial cervical lymph nodes:
Submental, submandibular, pre and post auricular, occipital, superficial cervical, anterior cervical and posterior cervical
What is Waldeyer’s ring?
Annular collection of lymphatic tissues (nodules) surrounding superior pharynx
Pharyngeal tonsil, 2 palantine tonsils and 2 lingual tonsils
What are the names of the deep cervical lymph nodes?
Jugulo-digastric, jugulo-omohyoid and supra-clavicular
What does the jugulo-digastric LN drain?
Behind mandible and drains palatine tonsil and tongue
Swollen in tonsillitis
What does the jugulo-omohyoid LN drain?
Drains tongue, oral cavity, trachea, oesophagus and thyroid
What does the supra-clavicular LN drain?
Thoracic cavity and abdomen
What are important signs seen in supra-clavicular LNs?
Both on left:
Virchow’s - abdomen and thorax malignancy
Trosier’s sign - metastatic abdominal malignancy
What do swollen LNs caused by infection feel like?
Tender and mobile
What do swollen LNs caused by malignancy feel like?
Hard, matted and non-tender
