bounded by mandible and digastric m. (anterior and posterior bellies)
bounded by anterior bellies of L and R digastric mm.
bounded by sternocleidomastoid, superior belly of omohyoid, and midline
bounded by posterior belly of digastric, sternocleidomastoid, and superior belly of omohyoid
-contents w/in carotid sheath: common carotid a., internal jugular v., vagus n. and sometimes CNIX, lymph nodes, superior root of ansa cervicalis
-contents outside sheath: CNXI, XII, inferior root ansa cervicalis, branches of CNX, branches of external carotid a.
unique bone that does not articulate with any others, U-shaped body with lesser and greater horns, keeps larynx open and supports tongue and other muscles
group of muscles that elevate the larynx and inferior pharynx, elevate floor of mouth to move food backward, stabilize hyoid during speech/swallowing, includes: digastric m., stylohyoid m., mylohyoid m., and geniohyoid m.
Origin: posterior belly- mastoid process of temporal bone, anterior belly- digastric fossa of posterior mandible
Insertion: intermediate tendon to hyoid bone
Innervation: posterior- facial nerve, anterior belly- n. to mylohyoid (V3)
Action-depresses mandible, elevates hyoid
Origin: styloid process of temporal bone
Insertion: body of hyoid bone
Innervation: cervical branch of Facial n.
Function: elevates, retracts hyoid
*characteristically splits around digastric m.
Origin: mylohyoid line of mandible
Insertion: body of hyoid, itself at midline
Innervation: mylohyoid n. (V3)
Function: elevates and protracts hyoid
Origin: inferior mental spine of mandible
Insertion: body of hyoid
Function: protracts hyoid
Origin: manubrium & medial section of clavicle
Insertion: body of hyoid
Innervation: C1, C2, C3 (via ansa cervicalis)
Function: depresses, stabilizes hyoid
Origin: posterior surface of manubrium
Insertion: thyroid cartilage at oblique line (raphe)
Innervation: C2, C3 (via ansa cervicalis)
Function: depress thyroid cartilage, lengthens vocal cords
*deep to sternohyoid m.
Origin: thyroid cartilage at oblique line (raphe)
Insertion: body and greater horn of hyoid
Innervation: C1 (hitchikes on hypoglossal n.)
Function: depresses hyoid/elevates larynx, shortens vocal cords
Origin: scapula, just medial to suprascapular notch
Insertion: hyoid bone
Innervation: C1, C2, C3
Function: depresses, retracts hyoid, moves hyoid when turning head
superior and inferior bellies
muscles that give mobility to larynx and pharynx, flexors of neck
-innervated by ansa cervicalis
provides innervation for infrahyoid muscles, superior root runs with hypoglossal n., inferior root from cervical plexus, no actually recurring fibers
-does not supply thyrohyoid
branches of external carotid a.
8 branches: superior thryoid, ascending pharyngeal, lingual, facial, occipital, posterior auricular, maxillary and superficail temporal aa.
superior thyroid a.
first branch off external carotid a., supplies thyroid
-gives off superior laryngeal artery which runs through thyrohyoid membrane
ascending pharyngeal artery
small and deep branch of external carotid (2nd branch), runs to posteriolateral pharynx
3rd branch off external carotid a., runs behind posterior belly of the digastric to supply the tongue
very tortuous branch of external carotid a. that supplies the face, branches at similar location as occipital a.
branch off external carotid a., branches at same level as facial a., runs along posterior belly of digastric to supply the posterior scalp and sternocleidomastoid
twists around hypoglossal n.
Posterior auricular a.
branch off external carotid a., just superior to posterior belly of digastric, supplies the parotid gland, ear, tympanic membrane, scalp
branch off external carotid a. that supplies maxillary area, many branches
superficial temporal a.
terminal branch of external carotid a., supplies temporalis m. and scalp
structure located at bifurcation of common carotid a. that responds to blood gas (high pCO2, low pO2), innervated by glossopharyngeal n.
dilation of internal carotid right at common carotid bifurcation that has mechanoreceptors to respond to low blood pressure, innervated by glossopharyngeal n.
runs posterior to anterior scalene m. to divide into 3 sections; branches to internal thoracic a., thyrocervical trunk, costocervical trunk, vertebral a., and dorsal scapular a., becomes axillary a. at 1st rib
internal thoracic artery
branch off subclavian a., branches supply ribs, terminates as superior epigastric a.
branch off subclavian a. that gives rise to inferior thyroid a. (terminal), superficial cervical a., and suprascapular a.
-sometimes transverse cervical a.
inferior thyroid a.
terminal branch of thyrocervical trunk, gives ascending cervical a.
branches off subclavian a. to give rise to superior intercostal a. and deep cervical a.
most medial branch of subclavian a., runs up to foramen magnum to enter skull, characteristically runs between longus colli and anterior scalene mm.
forms when subclavian and internal jugular veins come together
from axillary v., receives blood from external and anterior jugular veins (variable)
C3,C4,C5, runs along anterior scalene m., supplies diaphragm
CNX, gives left and right recurrent laryngeal nn.
-right recurrent loops around subclavian a., left around arch of aorta
-supplies pharynx, esophagus, trachea, and larynx
lymph drainage of entire body except R head and neck, drains into left brachocephalic vein at. junction of subclavian and internal jugular vv.
right lymphatic duct
R side equivalent of thoracic duct except just lymph from right head and neck
perform between 2nd and 3rd tracheal rings, complicated by inferior thyroid veins and thyroid ima artery (if present), also must be aware of recurrent laryngeal branches of vagus
largest endocrine gland, inferior to crycoid cartilage, 2 lobes connected via isthmus
extra lobe of thyroid extending straight up, occurs in 50% of cases, remnant of thyroglossal duct
thyroid ima a.
branch off brachiocephalic trunk that supplies thyroid, only present in 10% of the population, can complicate tracheotomy
superior thyroid vein
drains blood from superior portion of thyroid to internal jugular vein
middle thyroid vein
drains blood from middle portion of thyroid to internal jugular vein
inferior thyroid veins
drains blood from inferior portion of thyroid to brachiocephalic vein, may interfere with tracheotomy
four small glands found on posterior side of thyroid, essential for calcium balnce and must be spared in thyroidectomy
superficial layer of deep fascia that surround the neck and encapsulates the sternocleidomastoid and trapezius mm.
fascia that surround the thyroid gland, trachea, and esophagus and then merges with carotid sheath
fascia that surrounds the vertebral column and prevertebral muscles
space between the pre-vertebral and pre-tracheal fascia that allows passage of fluids between neck and mediastinum and can therefore allow infection to travel