The Carotid Triangle and Neurovascular Structures Flashcards
What is found in the carotid triangle?
Thyroid gland
Larynx
Pharynx
Carotid sheath
Branches of cervical plexus
Superior root of ansa cervicalis
Deep cervical lymph nodes
Parts of CN XI and XII
What is found and where in the vascular compartment of the neck?
Medially - CCA, ICA and parts of ECA
Laterally - IJV
Posteriorly - CN X
Where do the CCAs come from?
Right - branch of the brachiocephalic trunk
Left - direct branch from the aorta
Where do the ICA and ECA branch from the CCA?
At C3/C4
What is the carotid sinus?
Enlargement/dilation at bifurcation of CCA containing baroreceptors/pressoreceptors in wall of ICA
What does the carotid sinus do?
It monitors blood pressure
Baroreceptors are sensitive to stretch
Helps keep blood pressure within homeostatic values
What innervates the carotid sinus?
CN IX via carotid sinus nerve and CN X
APs travel from the baroreceptors through CN IX to the cardioregulatory and vasomotor centres in the medulla
What is the carotid body?
Small organ (2-5mm) which houses chemoreceptors located at the bifurcation of the CCA near the carotid sinus
What does the carotid body do?
Monitors blood O2, CO2, pH and temperature
Responds in emergency situations by increasing respiration, blood pressure and cardiac rate
What innervates the carotid body?
CN IX via carotid sinus nerve and CN X
Afferent fibres from the carotid body travel to the cardioregulatory and vasomotor centres in the medulla
What are the branches of the external carotid artery?
Superior thyroid
Ascending pharyngeal
Occipital
Lingual
Facial
Posterior auricular
Superficial temporal
Maxillary
Which branches of the external carotid artery are terminal?
Superficial temporal
Maxillary
Where does the IJV drain blood from?
Brain
Skull
Face
Part of the neck
Where does the IJV run?
Continuation of the sigmoid sinus
Exits skull via the jugular foramen and enters the carotid sheath
Runs lateral to the CCA
Joins subclavian vein to become the brachiocephalic vein (L and R)
Which veins drain into the IJV?
Inferior petrosal sinus
Pharyngeal
Occipital
Facial
Lingual
Superior thyroid
Middle thyroid
Where does the EJV run?
Begins at angle of mandible, joining retro mandibular and posterior auricular veins
Crosses over SCM
Pierces into fascia to enter and drain into the subclavian vein
Which veins drain into the EJV?
Posterior external jugular
Transverse cervical
Suprascapular
Anterior jugular
Where does the anterior jugular veins run?
Arise near the hyoid bone and run on either side of the midline through subcutaneous tissue communicating across the midline via the jugular venous arch
Drains into EJV, will sometimes drain directly into the subclavian vein
What does CN VII innervates in the neck
Cervical branch innervates platysma
Digastric branch innervates digastric
Supplies stylohyoid
Where does CN IX run in the neck and what does it supply?
Exits the jugular foramen and travels downward between the IJV and ICA
Some branches travel downward to the carotid sinus and body, pharynx (sensory) and stylopharyngeus (motor)
Where does CN X run in the neck?
Exits jugular foramen and travels downward within carotid sheath
Motor branch to the pharynx arises as well as a branch to the carotid body, the superior laryngeal nerve and a cardiac branch
Recurrent laryngeal nerves arise inferiorly near to the subclavian artery (R) or arch of aorta (L)
Where does CN XI run in the neck and what does it supply?
Exits jugular foramen and travels downward between the IJV and ICA
Crosses the lateral surface of the IJV to descend to the posterior triangle of the neck
Innervates SCM and trapezius
Where does CN XII run in the neck?
Exits the hypoglossal canal and is between the IJV and ICA
Crosses the ICA and ECA laterally on its way to the oral cavity
No branches to the anterior triangle of the neck
Where does the transverse cervical nerve come from and what does it supply?
Anterior rami of C2, C3
Supplies cutaneous innervation over SCM and anterior triangle
Where does the ansa cervicalis come from and what does it supply?
Anterior rami of C1-C3
Innervates infrahyoid muscles
Where does the cervical plexus come from and what does it supply?
Anterior rami of C1, C2-C4
Supplies the infrahyoid muscles, diaphragm (via phrenic), skin of anterior/lateral neck and inferior head
Where does the brachial plexus run and what does it branch into?
From C5 - T1
Branches in neck to dorsal scapular nerve, C5 branch to phrenic and suprascapular nerve
