Week 2 - Anterior Triangle of the Neck Flashcards
Borders of the anterior triangle of the neck ?
Inferior border of mandible, anterior border of sternocleidomastoid, midline of the neck.
Subdivisions of the anterior triangle ?
Submandibular, submental, carotid and muscular triangles.
Function of suprahyoid muscles ?
Elevate hyoid muscle and larynx.
Name suprahyoid muscles ?
Mylohyoid, digastric, stylohyoid, geniohyoid.
Name infrahyoid muscles ?
Sternohyoid, omohyoid, thyrohyoid, sternothyroid.
Innervation of mylohyoid ?
Inferior alveolar branch of CNV3.
Action of mylohyoid ?
Elevates hyoid and floor of mouth.
Reinforces floor of oral cavity.
Innervation of digastric ?
Anterior belly - inferior alveolar branch of CNV3.
Posterior belly - digastric branch of CNVII (facial nerve).
Actions of digastric ?
Anterior belly - raise hyoid bone and open mouth by lowering mandible.
Posterior belly - elevate and retracts hyoid.
Innervation of stylohyoid ?
CNVII (facial nerve).
Action of stylohyoid ?
Pull hyoid bone upwards (posterosuperior direction).
Innervation of geniohyoid ?
Anterior ramus of C1 (hitchhikes with hypoglossal CNXII).
Action of geniohyoid ?
Elevates and pulls hyoid forward when mandible is fixed.
Pulls mandible downwards and inwards if hyoid is fixed.
What are the two superficial infrahyoid muscles ?
Sternohyoid and omohyoid.
What are the two deep infrahyoid muscles ?
Thyrohyoid and sternothyroid.
Innervation of sternohyoid ?
Anterior rami of C1 to C3 (via ansa cervicalis).
Action of sternohyoid ?
Depress hyoid after elevation in swallowing.
Innervation of omohyoid ?
Anterior rami of C1 to C3 (via ansa cervicalis).
Action of omohyoid ?
Depress and fixes hyoid.
Innervation of thyrohyoid ?
Anterior rami of C1 (hitchhikes with hypoglossal CNXII).
Action of thyrohyoid ?
Depress hyoid and raise larynx.
Innervation of sternothyroid ?
Anterior rami of C1 to C3 (via ansa cervicalis).
Action of sternothyroid ?
Draws larynx downwards.
Where is the thyroid gland found ?
Visceral compartment of neck (with trachea and oesophagus).
Extends from thyroid cartilage superiorly to 5th tracheal ring.
What is the arterial supply of thyroid gland and what are they a branch of ?
Superior thyroid artery - first branch of external carotid.
Inferior thyroid artery - branch of subclavian.
What is the venous drainage of thyroid gland and where do they drain into ?
Thyroid venous plexus.
Superior thyroid vein - to internal jugular vein.
Middle thyroid vein - to internal jugular vein.
Inferior thyroid vein - to brachiocephalic vein.
What is the blood supply to parathyroid gland ?
Inferior thyroid arteries.
What is the venous drainage of parathyroid gland ?
Thyroid venous plexus.
Sympathetic innervation of parathyroid and thyroid gland ?
Thyroid branches of cervical ganglia.
How is the parathyroid and thyroid gland regulated ?
Pituitary gland.
What is contained in the carotid sheath ? And how are they positioned in relation to one another ?
Common carotid artery (medial).
Internal jugular vein (lateral).
Vagus nerve (CNX) (posterior).
Where does the carotid sheath run from and to where ?
Skull base to aortic arch.
What nervous structure lies on the anterolateral surface of the carotid sheath ?
Ansa cervicalis.
Where does the right common carotid artery branch off of ?
Brachiocephalic trunk.
Where does the left common carotid artery branch off of ?
Directly from aortic arch.
At what level does the common carotid artery branch and become the external and internal carotid artery ?
Around C3-C4 level.
Once CCA divides into ECA and ICA, what branch continues within the carotid sheath ?
Internal carotid artery.
What does the internal carotid artery supply ?
Brain.
ICA has no branches.
What does the external carotid artery supply ?
Face and scalp.
What mnemonic can be used to remember branches of external carotid artery ?
Some anatomists like freaking out, poor medical students.
Name the branches of the external carotid artery.
Superior thyroid
Ascending pharyngeal
Lingual
Facial
Occipital
Posterior auricular
Maxillary
Superficial temporal
What is a branch of the superficial temporal artery ?
Transverse facial.
What mneumonic can be used to remember the branches of the internal jugular vein ?
Medical schools only let fun people in.
What are the branches of the internal jugular vein ?
Middle thyroid.
Superior thyroid.
Occipital.
Lingual.
Facial.
Pharyngeal.
Inferior petrosal sinus.
What is the function of the internal jugular vein ?
Drains blood from brain, skull and neck.
What mnemonic can be used to remember the branches of the external jugular vein ?
PAST
What are the branches of the external jugular vein ?
Posterior external jugular.
Anterior jugular.
Suprascapular.
Transverse cervical.
What is the carotid sinus ?
Enlargement/dilation at bifurcation of commons carotid artery.
What is the function of the carotid sinus ?
Contains baroreceptors and pressoreceptors - important in monitoring blood pressure and maintaining with homeostatic values (baroreceptors are sensitive to stretch).
What nerve innervates the carotid sinus ?
CNIX and CNX, by carotid sinus nerve.
APs travels from baroreceptors through CNIX to cardio-regulatory and vasomotor cortex in medulla.
What is the carotid body ?
Small organ on medial side of bifurcation of CCA near carotid sinus.
What is the function of the carotid body ?
Contains chemoreceptors - monitor blood oxygen, CO2 and pH. Responds to emergency situations by increasing respiration, BP and cardiac rate.
What nerve innervates the carotid body ?
CNIX via carotid sinus nerve and CNX - afferent fibres from carotid body travel to cardio-regulatory and vasomotor cortexes in medulla.
Where is the anterior jugular vein situated ?
Midline at hyoid bone level.
Where do anterior jugular veins from right and left communicate ?
Jugular venous arch.
Where is the external jugular vein located ?
Outside carotid sheath.
Begins at mandible, joins retromandibular and posterior auricular, then crosses SCM and drains into subclavian.
What two veins drain into the retromandibular vein ?
Superficial temporal and maxillary veins.
What 3 structures cross the SCM ?
Transverse cervical nerve, external jugular vein and great auricular nerve.
What is the transverse cervical nerve a branch of ?
Anterior rami of C2-C3.
What is the function of the transverse cervical nerve ?
Cutaneous innervation of SCM and anterior triangle.
What is ansa cervicalis a branch of ?
Anterior rami of C1-C3.
What is the function of ansa cervicalis ?
Motor innervation of infra-hyoid muscles.
At what vertebral level does the brachial plexus start ?
C5 to T1.
What 5 cranial nerves are found in the neck ?
Facial, glossopharyngeal, vagus, spinal accessory, hypoglossal.
What structures does the facial nerve supply in the neck ?
Platysma, posterior belly of digastric, stylohyoid.
What structures does the glossopharyngeal nerve supply in the neck ?
Pharyngeal muscles and carotid sinus.
What 3 cranial nerves exit via the jugular foramen ?
Glossopharyngeal, vagus, accessory.
