Head & Neck 3 Flashcards
Describe the sources of arterial blood supply to the head and neck
Hint: 2 sources
Common carotids
Verteberal arteries
What are the vertebral arteries branches of?
Subclavian arteries
What parts of the head and neck are supplied by the vertebral arteries?
The posterior neck and posterior parts of the brain
How do the vertebral arteries travel in the neck?
Through the transverse foramina of the cervical vertebrae (except C7)
What structure do the vertebral arteries pass through after reaching the top of the vertebrae?
Subarachnoid space - between the atlas and occipital bone
What structure do the vertebral arteries pass through after the subarachnoid space?
The foramen magnum
What artery is formed by the convergence of the vertebral arteries?
Basilar
What aspect of the brainstem does the basilar artery run along?
Anterior
From what structure does the right common carotid arise?
Brachiocephalic trunk
From what structure does the left common caortid arise?
Arch of the aorta
Where does the sympathetic trunk run in the neck in relation to the carotid sheath?
Outside, medially and behind
Where do the common carotids terminate and what do they become?
At the level of the upper border of the thyroid cartilage to become the internals and externals
What can a carotid massage alleviate?
Supra-ventricular tachycardia
What is a carotid massage?
Firm rubbing of the crotid sinus (found at the point of temination)
Which arteries supply the neck?
Ascending and transverse cervical - branches of the thyrocervical trunk
How does the internal carotid enter the skull?
Carotid canal
What is the carotid body?
Part of the common carotid below the sinus lined with chemoreceptors
What is the clinical significance of the point of bifurcation of the common carotid?
Atheroma formation common - rupture of clot can cause stroke or TIA
Superior boundary of the carotid triangle please
Posterior belly of digastric
Carotid trangle: lateral boundary?
SCM
Medial boundary of carotid triangle if you please
Syuperior belly of omohyoid
Carotid triangle: contents?
Hint: 2
Internal jugular
Bifurcation of common carotid
Other than the internal jugular, what else can be accessed via the carotid triangle?
Hint: 2
Vagus and hypoglossal nerves
Name the terminal branches of external carotid
Hint: 2
Superficial temporal
Maxillary
How many non-terminal branches of the external carotid are there?
6
Now see how many branches of the external carotid you can name
Hint: 6
Superior thyroid Lingual Facial Ascending pharyngeal Occipital Posterior auricular
Why does loss of blood supply to the scalp not lead to bone death?
Middle meningeal artery supplies skull - i.e. not arteries of the scalp
Briefly describe the lymphatic system
Network of drainage vessels
Throughout body
Return lymph to blood circulation
In what structures does lymph primarily form?
Capillary beds
Why does lymph fomr at these structures?
Net filtration does not equal net absorption at capillary beds
Which part of the lymph system is responsible for collecting lymph at the capillary beds?
Lymphatic capillarys
What does lymph contain?
Hint: 6
Tissue fluid Small proteins Lipids Damaged cells Bacteria Cancer cells
How much lymph does the body produce a day?
3-4L
120-180ml/hour
2-3ml/min
What functional features differentiate the lymphatic system from the cardiovascular system?
No central pump
One-directional flow
How many steps are there in lymphatic flow?
6; capillary -> afferent vessels -> nodes -> efferent vessels -> trinks -> ducts
How is one-directional flow maintiained?
Valves that constrict passively (from muscle or arterial pulsation) or by intrinsic constriction
What is the terminal drainage point of the lymphatic system?
Hint: 2 points
Right lymphatic duct & Thoracic duct drain into R&L Subclavian veins respectively
What is significantly different about the right lymphatic duct and the thoracic duct?
The right only drains the right upper 1/4 of the body, with thoracic covering the remainder
What is lymphoedema?
Abnormal collection of protein rich fluid causing tissue swelling due to compromised lymphatic drainage
What can cause lymphoedema?
Hint: 5
Removal of nodes Infections Damage to system e.g. cancer treatment Lack of limb movement Congenital
What are lymph nodes made of?
Connective tissue - tough fibrous outer capsule & internal reticular tissue
What do lymph nodes contain and why?
B&T lymphocytes - nodes are a route for spread of infection
What mkaes the lymphatic system effective in fighting infection?
All lymph substances pass though at least one node - nodes are physical and phagocytic filters
What is lymphadenopathy?
Swollen lymph node
What are the common causea of lymphadenopathy?
Infection
Malignancy
What differentiates an infected swollen lymph node from one that is exhibiting malignancy?
Infection = tneder & mobile Malignant = hard & non-tender
What two broad groups can lymph nodes be classified by?
Regional (superficial, drains specific areas)
Terminal (deep, receives drainage from regional)
How many lymph nodes are there in the body and specifically the neck?
800 - 300 in the neck
Where are the regional lymph nodes found in the neck?
Superficial cervical fascia
Where are the terminallymph nodes found in the neck?
Deep to the investing layer of the deep cervical fascia
Which four structures are cervical lymph nodes found around?
Mandible
Aurice
Occiput
SCM
What is Waldeyer’s ring?
Annular collection of lymphatic tissue around the superior pharynx consisting of the tonsils (pharyngeal, palatine and lingual)
What is the importance of the supraclavicuar lymph nodes?
They are the route for transport of lymph from thoracic cavity and abdomen
What is the left supraclavicular lymph node also known as?
Virchow’s node
Which lymph node is most commonly enlarged?
Jugulo-digastric - responsible for palatine tonsil, oral cavity, posterior 1/3 tongue, pharynx, larynx
