Neck and Submandibular Region Flashcards
Why is the laryngeal prominence (thyroid cartilage adam’s apple) a helpful landmark in terms of vasculature of the neck?
It’s at the level where the common carotic artery bifurcates into external and internal branches
What bone lies above the thyroid cartilage? WHat is it’s purpose?
the hyoid bone
It is a U-shaped bone consisting of a bocy an dposterolateral free portions - the greater cornua
it’s mostly for muscular and ligaentous attachments related to the naterior neck and tongue
How are the sternocleidomastoid muscles innervated?
Efferent innervation is from the accessory nerve
Afferent innervation is from C2, but the fibers run with the accessory nerve
Where does the sternocleidomastoid originate and insert?
originates on the sternum and medial end of the clavicle (by the jugular notch) and inserts into the mastoid process behind the ear
What two landmarks does the sternocleidomastoid divide the neck into?
the posterior and anterior triangles
What is the function of the sternodleidomastoids?
Individually, they draw the head toward the shoulder and rotate, pointing the chin cranially an dto the opposite side.
Together, they flex the neck
What is torticollis?
Can be congenital or spasmodic
It’s a contraction or shortening of the cervical muscles producing twisting of the neck and slanting of the head
typically the sternocleidomastoids - treatment may involve surgical release of the SCM
What muscle largely covers the SCM and inserts below the clavicle?
WHat is it’s function
the platysma - innervated by CN7
it depresses the lower jaw and lip
tenses and rdiges the skin of the neck
The deep cervical fascia is arranged in layers that cover the musculature and other structures of the neck. What are the 5 layers nad what do they cover?
- Investing Layer - covers ALL structures
- Infrahyoid layer - covers the strap muscles
- Visceral layer = pretracheal layer - surrounds the chief cervical viscera
- Prevertebral layer - surrounds the cervical vertebral column and associated musculature
- carotid sheath (formed by contributions from other layers) surrounds the neurovascular channel
Why is the retropharyngeal space important clinically?
It estends from the powerior mediastinum behind the heart up to the base of the skull.
Its an area of loose cnonective tissue that is a potential pathway for pathogenic organisms to track along vehind hte viscera of the neck
From what levels do the sensory branches of the cervical plexus come from?
the anterior primary rami of C2, C3, and C4
What are the 4 sensory nerves in the neck that come off the cervical plexus? Where do they emerge?
- supraclavicular nerves
- transverse cervical nerves
- great auricular nerve
- lesser occipital nerve
they come out from behind the mid-posterior border of the SCM
What are the two SUPERFICIAL veins of th enekc?
the external jugular
anterior jugular (runs along the anterior neck and empties into external jugular)
What happens in paralysis of the platysma muscle?
the skin will fall away from the neck in folds
Prominence of the external jugular vein on exam may suggest what chronic condition?
CHF
What happens if the external juglar vein is severed lateral to the SCM?
- it’s held open by the surrounding fascia
- negative intrathoracic pressure will suck air into the vein, causing a churning noise in the thorx and cyanosis = this is a venous air embolism
- This wille ventually fill the right side of the ehart with froth, nearly stopping blood flow thorugh it, resulting in dyspnea
this is why application of firm pressure to the severed jugular vein is very important
What are the contents of the carotid sheath?
- internal jugular vein
- common carotid artery
- vagus nerve
The internal jugular vein joins the subclavian vein to form what?
What lymphatic channel joins this region of ocnfluence?
the brachiocephalic veins
the thoracid duct is the lymphatic channel (the largest one in the body actually)
At the bifurcation of the common carotid into the internal and external carotids there is a slight dilation called the _____
what is it’s purpose?
the carotid sinus
it’s an arterial blood pressure regulating area (pressure receptor)
What other receptor is located near the carotid sinus and what is its function?
the carotid body
it’s a chemoreceptor that responds to either increased CO2 tension or decreased O2 tension in the blood
Both the carotid sinus and the carotid body are innervated by what nerve?
the glossopharyngeal nerve (with some minor contributionsf orm the vagus)
What are the major branches of the vagus nerve in the neck?
the superior laryngeal nerve (external and internal branches)
recurrent laryngeal nerve
What is another term for the infrahyoid muscles and what are they?
the strap muscles
- sternohyoid
- sternothyroid
- thyrohyoid
- omohyoid
How are the strap muscles innervated?
by the ansa cervicalis, formed by the anterior primary rami of C1-C3
Note that some of the C1 fibers joint CN12 and later leave i to supply the thyrohyoid and genioyoid
Where does the sternohyoid attach and what is its function?
hyoid bone to the manubrium of the sternum and medial end of clavicle
it depresses tte larynx and hyoid bone, steadies the hyoid
Where does the sternothyroid muscle attach and what is its function?
extends form the thyroid cartilage to the posterior surface of the manubrium of sternum
depresses the larynx and thyroid carilage
Where does the thyrohyoid muscle attach and what is its function?
extends from the hyoid bone to the oblique line of the thyroid cartilage
it depresses the larynx na dhyoid bone while elevating the thyroid cartilage
Where does the omohyoid muscle attach and what is its function?
extends from the inferior border of hyoid down to the superior border of the scapula near the suprascapular notch
it steadies the hyoid bone, depresses and retracts the hyoid bone an dlarynx
What is the suprahyoid muscle that extends from the inferior mental spins of the mandible down to the body of the hyoid bone?
the geniohyoid muscle
Which carotid artery gives branches to the face and which does not?
the external does, the internal doesn’t branch til it’s in the cranial cavity
What are the main branches of the external carotid artery?
1 . superior thyroid artery
- lingual artery
- facial artery
- Occipital artery
- maxillary artery
- superficial temporal artery
(also the ascending pharyngel artery and the posterio auricular artery)
What endocrine gland is located anterior to the trachea?
the thyroid gland
What two arteries supply the thyroid gland?
the superior thryoid artery (off the external carotid)
the inferior thyroid artery (from the thyrocervical trunk)
What are the small oval glands situated on the posterior surfaces of the lateral lobes of the thyroid gland?
the parathyroid glands
What lies posteiror to the trachea?
the esophagus
What are the 3 scalene muscles? Which is smallest, biggest?
anterior
middle (biggest)
posterior (smallest)
What nerve lies on the anterior surfae of the anterior scalene?
the phrenic nerve
What plexus of nerves lies in the posterior triangle of the neck?
the brachial plexus
The subclavian artery appears in the posterior triangle of the neck -w hat are it’s four branches?
- internal thoracic
- thyrocervical trunk
- vertebral
- costocervical trunk
What lymph nodes run along the external jugular vein and what nodes run along the carotid sheath?
the superficial cervical nodes are along the external jugular
the deep cervical nodes are along hte carotid sheath
Where do the preganglionic fibers in the cerbical sympathetic trunk originate?
int he lateral gray horne (intermedioateral cell column) of the spinal cord segments T1-5 -
What are the three ganglia associated with the cervical sympathetic trunk? WHere are they located in relation to the vertebral column?
- interior or stellate (cervicothoracic) ganglion - this is the fusion of the lowest cervical and the highes thoracic ganglia
- Middle cervical ganglion at the 6th cervical vertebra
- Superior cervical ganglion at the 1st and 2nd cervical vertebrae
Postganglionic fibers from the superior cervical ganglion continue up into the skull as what nerve?
the internal carotid nerve, wrapped around the internal carotid artery to become a nerve plexus distributed in the skull
What nerve is as risk during thyroidectomyies?
the recurrent laryngeal
What happens in accidental parathyroid gland removal
tetany due to decreased serum calcium levels (regulated by the parathyroid gland)
Severence of the phrenic nerve will result in paralysis of what muscle?
it’s corresponding half of the diaphragm
What nerve block is used for regional anesthesia for posterio rneck repairs? Where do you make the injection?
a cervical plexus block
inject along the posterior border of the SCM - especially near junction of the middle and superior thirds - this is the nerve point of the neck
WHat nerve block would you do prior to surgical repairs of the upper limb? Where is the injection made?
A supraclavicular brachial plexus block
Inject superior to the midpoint of the clavicle
How does the suprascapular nerve get injured and what is the result?
with fracture of the middle 1/3 of the clavicle
you lose lateral rotation of the humerus as the glenohumeral joint, resulting in a “water’s tip” position of the extremity
When would you do a cervicothoracic ganglion block?
it relieves vascular spasms involving the brain and upper limb
What is Horner Syndrome?
lesion of the sympathetic trunk in the neck…
- contraction of the pupil
- drooping of the superior eyelide (ptosis)
- sinking in of the eye (exophthalmos)
- vasodilation and abscence of sweating on the face and neck due to lack of synthaetic nerve supply to blood vessels and sweat glands
What is the major component of the submandibular region?
the submandibular gland
What are the 4 muscles within the submandibular region?
- digastric
- Stylohyoid
- Mylohyoid
- Geniohyoid
What are the attachments for the digastric muscle (both bellies)?
anterior belly - digastric fossa of the mandible down to the greater horn of hyoid bone
posterior belly - mastoid notch of the temporal bone down to the hyoid bone
What is the function of the digastric muscle?
it raises the hyoid bone and base of tongue
steadies the hyoid
depresses the mandible
How are the two bellies of the digastric innervated?
anterior belly is innervated by the mylohyoid nerve (branch of the inferior alveolar nerve)
posterior belly is innervated by the facial nerve
What are the attachments for the stylohyoid bone?
superiorly to the styloid process of the temporal bone
inferiorly to the body of the hyoid bone
so from the styloid to the hyoid…stylohyoid
What is the function of the stylohyoid muscle?
elevates the hyoid bone and base of tongue
How is the stylohyoid innervated?
facial nerve
What are the attachments for the mylohyoid muscle?
speriorly to the mylohyoid line of the mandible
inferiorly to the raphe and body of the hyoid bone
What is the function of the mylohyoid muscle?
elevates the hyoid
rasies floor of mouth
depresses mandible
How is the mylohyoid muscle innervated?
by the mylohyoid nerve, a branch of the inferior alveolar nerve
What muscle is in the floor of the mouth, covered wiht the anterior belly of hte digastric and mylohyoid muscles?
the geniohyoid muscle
How are the salivary glands innervated?
Preganglionic fibers from CN7 leave via the chorda tympani and hitchhike on the lingual branch of V3.
they synapse onto postganglionic cell bodies in the submandibular ganglion
the postganglionic fibers go to the submandibular gland, sublingual gland and mucosal glands
What vessel is formed by the union of the internal jugular vein and the sublcavian vein?
the brachiocephalic vein
The right and left brachiocephalic veins join together to form the….
superior vena cava
What is the first arterial branch of the arch of the aorta?
the brachiocephalic trunk, which gives rise to the right common carotid and subclavian arteries
(the left common carotid and sublcavian arteries come off the aortic arch)
WHere does the thoracic duct drain lymph?
into the vascular system via the left subclavian vein near its junciton with the left internal jugular vein
THe subclavian artery passes ___ to the anterior scalene.
posterior
The lobes of the thyroid are connected by the …
isthmus
What do you call it when there’s an arm of the thyroid gland that runs superiorly alon the thyroid cartilage?
a pyramidal lobe
The thyroid gland overlies what levels of the tracheal rings
3rd and 4th
What arteries supply the thyroid gland?
the superior and inferior thyroid arteries
What are the two ganglia for the vestibulocochlear nerve?
cochlear portion = spiral ganglion within the ochlea
vestibular portion = vestibular ganglion
What’s special about the neurons in the spiral ganglion?
They are bipolar neurons
Where is the nucleus for the motor fibers of the vagus nerve?
the nucleus ambiguus of the brainstem
