Neck and submandibular region Flashcards
Hyoid bone
18 muscles, 4 ligaments, 1 membrane attach here
Sternocleidomastoid muscle
- Efferent innervation: accessory nerve
- Afferent innervation: C2
- Function: draws head toward shoulder and rotates it, pointing chin cranially an to opposite side (singly). Flex the head (together)
Platysma
- Facial muscle in the superficial fascia
- Cervical branch of facial muscle
- Function: depresses lower jaw and neck, tenses and ridges skin of neck
Investing layer
Encloses all neck structures
Infrahyoid fascia
Surrounds the strap muscles
Carotid sheath
Formed by contributions of other fascia. Chief neurovascular channel in the neck
Pretracheal fascia
Encloses the thyroid gland
Prevertebral fascia
Encloses deep muscles of the neck
Retropharyngeal fascial space
Loose connective tissue potentially region where infection can spread along the viscera of the neck
Sensory branches of the cervical plexus formed from what?
Anterior primary rami of C2-4. C1 has no cutaneous sensory branches.
Supraclavicular nerves
Supply lower neck
Transverse cervical nerves
Supply anterior neck
Great auricular nerve
Supplies angle of mandible and areas of ear
Lesser occipital nerve
Supplies regions behind the ear
External jugular vein
Union of posterior auricular and branch of retromandibular veins
What does the dorsal ramus of C2 supply?
The sensory innervation to the back of the head
What path does the accessory nerve travel along?
Leaves cranial cavity through jugular foramen–>passes deep to SCM–>crosses posterior triangle
What supplies the strap muscles?
Branches of the ansa cervicalis
What forms the ansa cervicalis?
Anterior primary rami of C1-C3
Contents in the carotid sheath
Internal jugular vein, common carotid artery, vagus nerve
Internal jugular vein
Most lateral position. Joins subclavian vein on both sides to form brachiocephalic veins.
Where does the thoracic duct join?
Region of confluence between internal jugular and subclavian veins on the left side
Common carotid artery
Splits into internal and external carotid arteries near the upper border of thyroid cartilage.
Carotid sinus
Slight dilation of the internal carotid. BP regulating area (pressure receptor)
Carotid body
Chemoreceptor that responds to increased CO2 or decreased O2 in the blood.
What are the carotid body and sinus receptors innervated by?
The glossopharyngeal and some contribution by the vagus
Left common carotid artery originates where?
Arch of the aorta
Right common carotid artery originates where?
Brachiocephalic trunk
Vagus nerve
Embedded in posterior aspect of the carotid sheath. Branches: Superior laryngeal, recurrent laryngeal nerve.
Superior laryngeal nerve
Provides internal and external branches to larynx. Branch of the vagus nerve
Recurrent laryngeal nerve
Hooks around the subclavian artery on the right and arch of the aorta on the left within the thorax.
Ansa cervicalis
Motor component of the cervical plexus derived from C1-C3. Plexus of cervical motor nerves. C1 gives rise to anterior limb and C2-C3 give rise to the inferior limb. Innervates the “strap” muscles. Usually located on the top of the carotid sheath
Sternohyoid
-Depresses larynx and hyoid bone, steadies hyoid bone
Sternothyroid
Depresses larynx and thyroid cartilage
Thyrohyoid
Depresses larynx and hyoid bone, elevates thyroid cartilage. Innervated by the anterior primary rami of C1 that runs with the hypoglossal nerve
Omohyoid
Steadies hyoid bone, depresses and retracts hyoid bone and larynx
Geniohyoid
Elevates hyoid bone and tongue. Innervated by the primary rami of C1 that run with and leave the hypoglossal nerve
Internal carotid artery
Doesn’t have branches off neck. Supplies the brain and the contents of the orbit
External carotid artery
Main branches: Superior thyroid artery, lingual artery, facial artery, occipital artery, maxillary artery, superficial temporal artery.
Thyroid gland
2 lobes united by isthmus in midline. Endocrine gland located just below the thyroid cartilage. Arterial supply: superior and inferior thoracic artery.
Parathyroids
Small, oval glands on posterior surface of lateral lobes of the thyroid gland. Receives blood from the inferior thyroid arteries. Involved in regulating serum calcium levels.
Trachea
16-20 C shaped pieces of hyaline cartilage. Posterior part composed of smooth muscle and membrane
Esophagus
Immediately posterior to the trachea. Continuation of pharynx above. Usually in collapsed state–only expands when lumen contains material
Sympathetic trunk
Medial to carotid vessels. 3 superficial chain ganglia present (superior cervical the largest).
Gray rami
Extend between the ganglia and spinal nerves. Contain post-ganglionic sympathetic neurons
Cricothyrotomy
Cutting of the cricothyroid membrane. Can relieve acute respiratory obstruction if done correctly.
Accessory nerve
Starts in upper segments of spinal cord and passes rostrally between motor and sensory roots. Enters cranial cavity through foramen magnum and exits through the jugular foramen. Innervates the trapezius and SCM muscles
Vagus nerve
Motor to muscles of pharynx (except stylopharynx) and larynx. Sensory to larynx and part of the pharynx.
What supplies most of the sensory fibers to the pharynx?
The glossopharyngeal nerve
Prevertebral space
Between prevertebral fascia and buccopharyngeal fascia. Possible route for infection to spread from pharynx to posterior mediastatinum
Thymus
Lies behind the manubrium. 2 lobes joined together. Developed from the 3rd pharyngeal pouch. Site of T-lymphocyte precursor cells. Atrophies with age.
Brachiocephalic veins
Formed by union of subclavian and internal jugular veins. The two veins join together to form the superior vena cava at the site of the right margin of the sternum
Brachiocephalic trunk
First branch off the aorta. Gives rise to the right common carotid and right subclavian arteries
Branches from the aortic arch
Brachiocephalic trunk. Left common carotid artery. Left subclavian artery.
Thoracic duct
Drains into subclavian vein near its junction with the internal jugular vein. With injury, can get lymph flowing out and collecting in cavity
Phrenic nerve
On top of anterior scalene muscle. Supplies the diaphragm (each nerve supplies 1/2). From C3, C4, C5
Location of the brachial plexus and subclavian artery
Between the anterior and middle scalene muscles
Middle scalene muscle
Largest of the 3 scalene muscles
Left subclavian artery branches from where? The right?
Left: aortic arch. Right: brachiocephalic trunk
Branches of the subclavian artery?
Internal thoracic, thyrocervical trunk, vertebral, costocervical trunk
3 vessels that come off the thyrocervical trunk?
Inferior thyroid, transverse cervical artery, subscapular artery.
What nerve does the transverse cervical artery travel with?
The accessory nerve
Submandibular gland
One of the paired, major salivary glands
Digastric muscle: anterior belly innervation
Innervation: mylohyoid nerve (branch of CN V, V3)
Digastric muscle: posterior belly innervation
Facial nerve
Digastric muscle function
Raises hyoid bone and base of tongue, steadies hyoid bone, depresses mandible
Stylohyoid
Elevates hyoid bone and base of tongue. Innervated by facial nerve
Mylohyoid
Elevates hyoid bone, raises floor of mouth, depresses the mandible. Innervated by mylohyoid nerve (branch of inferior alveolar nerve)
Geniohyoid
In the floor of the mouth, covered by anterior belly of digastric any mylohyoid muscles.
Mandibular branch of V3
Moves along the lower border of the mandible
Hypoglossal nerve
Goes superificial to external carotid artery and then deep to the stylohyoid and posterior digastric muscles. Disappears above the mylohyoid muscle
Genticulate ganglon
Where taste fibers (supply 2/3 of anterior tongue) have their cell bodies located.
Spiral ganglia
Supply sensory fibers of the cochlea. Responsible for conducting the impulse of hearing. Bipolar neuron cells.
Vestibular ganglion
Responsible for conducting impulses related to balance.
Where are the motor fibers of the vagus nerve located?
In the nucleus ambiguous. (innervates the muscles of the pharynx and larynx
Where are the GVA cell bodies located?
Sensory ganglion outside of the jugular foramen
