AT II: Carotid Triangle & Neuromuscular Structures Flashcards
Describe the positioning of the carotid sheath
Sheath runs from foramen of carotid canal (base of skull) to the aortic arch
What are the contents of the carotid sheath?
Medially: Common carotid artery (Splits into Internal and External CA)
Laterally: Internal jugular vein
Posteriorly: CN X
Where does the right common carotid artery branch from?
Branch of the Brachiocephalic trunk
Where does the left common carotid artery branch from?
Directly from arch of aorta
Where do the internal carotid artery & external carotid artery branch off the common carotid artery?
around C3/C4
Where is the carotid sinus and what is the function?
enlargement/dilation at the bifurcation of common carotid artery which contains baroreceptors.
Monitors blood pressure and helps maintain it
What is the nerve supply of the carotid sinus?
Innervated by CN IX (Glossopharyngeal) via carotid sinus nerve
& CN X (Vagus)
Where is the carotid body and what is the function?
Small organ which houses chemoreceptors located at the bifurcation of CCA
Monitors blood O2, CO2, pH & Temp. Adjusts body to keep these stable
What is the nerve supply of the carotid body?
Innervated by CN IX (Glossopharyngeal) via carotid sinus nerve
& CN X (Vagus)
What are the branches of the external carotid artery?
- Superior thyroid artery
- Ascending pharyngeal artery
- Lingual artery
- Facial artery
- Occipital artery
- Posterior auricular artery (Posterior to ear)
- Superficial temporal artery
- Maxillary artery
What veins drain into the Internal jugular vein?
- Inferior petrosal sinus
- Pharyngeal vein
- Occipital vein
- Facial vein
- Lingual vein
- Superior thyroid vein
- Middle thyroid vein
Where does the IJV exit the skull from?
From the jugular foramen & enters the carotid sheath
Where does the internal jugular vein lead to?
Joins onto brachiocephalic vein
What veins drain into the external jugular vein?
- Posterior external jugular
- Transverse cervical vein
- Suprascapular vein
- Anterior jugular vein
What is the origin of the EJV and what anatomical landmark does cross?
Begins at angle of mandible
Crosses over the sternocleidomastoid
Where does the EJV drain to?
The subclavian vein
Where do anterior jugular veins arise from and where do they drain into?
Run either side of the midline of neck
Drains into EJV; in some instances directly into subclavian vein
Briefly describe the general course & distribution of CN IX (glossopharyngeal)
exits jugular foramen in skull, travels downward between IJV & ICA
Most of the nerve travels forward to oral cavity but some downward to CAROTID SINUS (& body), pharynx
Briefly describe the general course & distribution of CN X (vagus)
exits jugular foramen in skull & travels downwards WITHIN carotid sheath (with IJV & CCA [ICA])
Branches to pharynx, and carotid body also leads to recurrent laryngeal nerves
Briefly describe the general course & distribution of CN XI (spinal accessory)
Exits jugular foramen in skull, downwards between IJV & ICA then crosses lateral surface of IJV to descend to the postderior triangle of the neck.
Innervates SCM & Trapezius
Briefly describe the general course & distribution of CN XII (Hypoglossal)
Exits hypoglossal canal, between IJV & ICA, crosses the ECA laterally on its way to the oral cavity.
What is the transverse cervical nerve and what does it innervate?
Branch of of cervical plexus (C2, C3). Supply cutaneous innervation over the SCM & anterior triangle
What does the ansa cervicalis innervate?
Anterior rami of C1-C3 - innervates infrahyoid muscles
What is the brachial plexus and what does it innervate?
A trunk of nerves found in neck found at C5-T1
What is the brachial plexus and what does it innervate?
A trunk of nerves found in neck found at C5-T1
