Lecture 3 - Blood vessels Flashcards
Route of blood vessels from the heart to the common carotid artery on the right
- Aortic arch
- Brachiocephalic trunk
- Common carotid artery
What vessels arise from the subclavian artery
Vertebral artery
Internal thoracic artery
Thyrocervical artery
At what level does the common carotid artery birfucate
C4 - superior border of the thyroid cartilage
Route of the vertebral artery
- Ascends through the transverse foramina of C7
- Subarachnoid space
- Passes thorugh the foramen magnum
- Joins the vertebral artery of the other side to form the basillar artery
Where does the left common carotid artery arise from?
Aortic arch
Longer by 2cm so more easily damaged
Carotid sinus
C4 - where the CCA birfucates
ICA more bulbous due to carotid sinus
Stretch sensitive baroreceptors detect arterial BP changes
Carotid massage
Alleviate supraventricular tachycardia
How does the internal carotid artery enter the base of the skull?
Via the carotid canal in the petrous part of the temporal bone
Turns medially and horizontally
Through the cavernous sinus
Thyrocervical branches
Ascending and transverse cervical arteries- supply the neck
Suprascapular - supply shoulder
Inferior thyroid - lower pole of the thyroid gland
Common site of atheroma formation in the neck
Birfucation of the common carotid artery (C4)
Causes stenosis of the artery and increased pressure
Embolus travels to brain - TIA/ Stroke
When will a balloon stent operation be done
If the ICA is narrowed and there is more than 70% blood flow reduction to brain
Carotid body
Peripheral chemoreceptors which detect arterial O2
Innervated by the glossopharyngeal nerve (CN IX)
In chronic hypercapnia due to COPD, the carotid body causes the drive for increased ventilation
Cavernous sinus
Thin walled plexus of veins in the upper sphenoid bone
What structures run in the cavernous sinus?
Internal carotid artery CN III CN IV CN Va and vb CN VI (superior)
Throbus in the cavernous sinus or swelling can present as?
Loss of eye movements - CN III, IV, VI
Loss of general sensation in upper face and lips - Va and Vb
Opthalmic artery branches
Branch of the ICA gives rise to:
Supratrochlear
Supraorbital
Ethmoidal
External carotid artery branches
Superior thyroid - thyroid Ascending pharyngeal - phaynx Lingual - tongue Facial - face Occipital - back of head Posterior auricular - behind ear Maxillary - maxilla Superficial temporal - scalp
Why does the scalp bleed profusely if cut
Very rich anastomoses of blood vessels
Closely associated with the connective tissue therefore limited constriction
If there is a deep laceration involving the aponeurosis, its pulled in opposite directions therefore stays open
Layers of the scalp
Skin Connective tissue (dense) Aponeurosis Loose CT - contains blood vessels Periosteum
Main branches of the maxillary artery
Middle meningeal artery
Sphenopalatine
Blood supply to the nasal septum
Kiesselbach area
- Septal branch of the sphenopalatine artery (maxillary artery)
- Anterior ethmoid artery (opthalmic artery)
Medical name for nose bleed
epitaxis
Blood supply to the dura and skull
Middle meningeal artery
- Posterior to the pterion which is the weakest area of the skull
- Fracture can cause an extradural bleed
Superficial veins of the scalp
Superficial temporal veins
Occipital veins
Posterior auricular veins
Angular vein
Formed by the uniting of the supratrochlear and supraorbital veins at the medial angle of the eye
Drains into the facial vein
Veins that connect the scalp and dural venous sinuses
Emissary veins
Emissary veins
Thin walled
Valveless
Traverse bone to dural venous sinus
Infection from the scalp can spread to the cranial cavity and affect the meninges
Venous drainage of the face
Supraorbital Supratrochlear Angular vein Superior and inferior labial veins (lips) Facial vein Common facial vein IJV EJV
Where do deep facial veins drain into?
Pterygoid plexus
- infection from the facial vein can spread intracranially through the dural venous sinuses e.g. thrombophlebitis
Thrombophlebitis
Infected clot can travel intracranially via the facial nerve
Dural venous sinuses
Superior saggital sinus Inferior saggital sinus Transverse sinus Confluence of sinuses Sigmoid sinus - continues as the IJV through the jugular foramen Cavernous sinus
Measuring venous BP
Use the right IJV
45 degree angle with head slightly tilted
Pulsation through muscle
Height above sternal angle - above 5 cm
