Triangles of Neck and Larynx Flashcards
What features of the neck are at the C3-C4 level?
Body of the Hyoid Bone
Upper margin of Thyroid Cartilage
Bifurcation of Common Carotid artery
What features of the neck are at the C5-C6 level?
Arch of cricoid cartilage
Superior end of the esophagus
Superior end of the trachea
What are the borders of the Posterior Triangle?
Sternocleidomastoid M.
Trapezius M.
Clavicle
What are the borders of the Anterior Triangle?
Midline of the neck
Sternocleidomastoid M.
Lower border of the mandible
What are the 4 subdivisions of the anterior triangle? What are their borders?
Submandibular: anterior and posterior belly of the digastric m., inferior border of the mandible
Submental: midline of neck, anterior belly of digastric m., body of hyoid
Carotid: posterior belly of digastric, superior belly of omohyoidm., sternocleidomastoid
Muscular: body of hyoid, superior belly of omohyoid m., sternocleidomastoid m.
What makes up the floor of the Posterior Triangle?
Covered by prevertebral deep fascia Semispinalis capitis m. Splenius capitis m. Levator scapula m. Posterior, middle, and anterior scalene Ms.
What covers the Posterior Triangle from superficial to deep?
skin -> superficial fascia -> platysma -> investing layer of deep fascia
What arteries are found in the Posterior Triangle?
Subclavian a. Thyrocervical trunk Transverse cervical a. Dorsal Scapular a. Suprascapular a. part of the occipital a.
How does the transverse cervical a. run in the posterior triangle?
Branches off thyrocervical trunks and runs superficially and laterally across phrenic n. and anterior scalene m.
How does the suprascapular a. run in the posterior triangle?
Branches off thyrocervical trunk and runs inferolaterally across ant. scalene m. and phrenic n.
Travels with suprascapular n.
What veins are found in the posterior triangle and what are their courses?
External jugular v.: begins inferior to angle of mandible by union of post. retromandibular v. with post. auricular v. anterior to SCM, drains into subclavian v.
Subclavian v.: anterior to anterior scalene m., joins internal jugular v. to form brachiocephalic v.
Why is the external jugular v. clinically relevant?
if you can see it on a patient you know there is an increase in venous pressure which can indicate heart failure or an IVC issue
Why is the subclavian v. clinically relevant?
For putting in central lines, ports for drugs/cancer
What nerves are found in the posterior triangle?
Cutaneous branches of the cervical plexus
Spinal accessory m. (CN XI): deep to SCM, enters trapezius
Roots and trunks of the brachial plexus
Phlenic n (C3, C4, C5): anterior to anterior scalene, supplies diaphragm
Ansa cervicalis (superior and inferior roots): in fascia of carotid sheath
What are the 4 cutaneous branches of the cervical plexus, nerve roots, and what do they innervate?
Lesser Occipital (C2): skin of scalp and neck posterior to auricle Great Auricular (C2,C3): skin and sheath over parotid gland, mastoid process, auricle and angle of the mandible Transverse Cervical (C2,C3): skin of anterior cervical region Supraclavicular (C3, C4): skin over the clavicle and shoulder
What is the course of the spinal accessory n.?
Jugular foramen Anterior Triangle SCM Posterior Triangle Trapezius
What is Torticollis:
Contraction or shortening of the SCM that can cause the head to tilt towards and the face to turn away from the affected side
Can also be caused by tumor/hematoma that compresses spinal accessory
What are the two subtriangles of the posterior triangle? How are they divided?
Occipital: EJV, post. cervical plexus n., spinal acessory, trunks of brachial olexus, cerviocodrsal trunk, cervical lymph nodes
Omoclavicular (subclavian): subclavian artery, verin, supraclvaicular lymph nodes
Divided by inferior belly of the omohyoid m.
What are the suprahyoid muscles of the anterior triangle?
Mylohyoid
Stylohyoid
Digastric (ant. and post. bellies)
Geniohyoid
Form floor of oral cavity, stabilize tongue and hyoid bone, elevate larynx and hyoid when swallowing and talking
What are the infrahyoid/strap muscles of the anterior triangle?
Sternohyoid
Omohyoid
Sternothyroid
Thyrohyoid
depress hyoid and larynx
What arteries and branches are found in the anterior triangle?
Common carotid –> internal and external carotid at C3-C4
- internal carotid does not branch in neck
External carotid –> superior thyroid a., lingual a, facial a, ascending paryngeal a, occiptial a, posterior auricular a, maxillary a, superficial temporal a.
What are the roles of the carotid sinus and body? What are they innervated by?
Carotid sinus= baroreceptor (BP), in proximal part of ICA
Body= Chemoreceptor (oxygen levels), in cleft between ICA and ECA
innervated by carotid sinus nerve (branch of glossopharyngeal n. CN IX) and branches of vagus
What are the borders, floor, and content of the submandibular triangle?
Borders: inferior mandible, ant. and post. bellies of digastric
Floor: mylohyoid, hyoglossus, middle pharyngeal constrictor
Contents: submandibular gland, LNs, hypoglossal n, n. to mylohyoid, parts of facial a. and v.
What are the borders, floor, and content of the submental triangle?
Borders: body of hyoid, right and left anterior belly of digastric
Floor: mylohyoid muscles
Contents: submental LNs, small veins that unite to form anterior jugular v.
What are the borders, floor, and content of the muscular triangle?
Borders: superior belly of omohyoid, SCM, median plane of neck
Muscles: sternohyoid, sternothyroid, thyrohyoid
Contents: thyroid gland, parathyroid gland, larynx, trachea, esophagus, common carotid, superior thyroid, inferior thyroid, anterior jugular, thyroid veins, ansa cervicalis n., external laryngeal n, recurrent laryngeal n.
What are the borders, floor, and content of the carotid triangle?
Borders: superior belly of omohyoid, posterior belly of digastric, SCM
Floor: thyrohyoid, hygoglossus, middle and inferior constrictor muscles of the pharynx
Contents: carotid sheath, branches of external carotid a., internal and external laryngeal n., hypoglossal n., spinal accessory n, ansa cervicalis n.
- nerves exit through jugular foramen
What is contained in the carotid sheath and what makes up the borders?
Common Carotid a.: most anterior medial
Internal jugular vein: slightly posterior lateral
Vagus n: posterior, between artery and vein
What does the hypoglossal n. wrap around?
Wraps adjacent to occipital a. when comes out of hypoglossal canal
What are the branches of the Vagus n. (CN X)
Pharyngeal
Superior laryngeal –> Internal (sensory) and external (motor)
Carotid body branch
What are the branches of the external carotid artery in the carotid triangle?
Superior Thyroid a. -> superior laryngeal a. -> thyroid gland
Ascending Pharyngeal a. (medial branch)
Lingual a.
Facial a. –> ascending palatine a. and tonsillar a.
Occipital a.
Posterior auricular a.
Terminate into maxillary and superficial temporal in face
Where is the lingual a. found?
anterior to middle pharyngeal constrictor, deep to hypoglossal n., stylohyoid m., and post belly of digastric m., disappears deep to hyoglossus m.
What are the thoracic inlet and outlet? What are the contents?
Inlet: superior thoracic aperture where food and air may enter
Outlet: superior thoracic aperture where arteries and nerves emerge
Contents: apex of lung, subclavian a and v, brachial plexus, vagus n., phrenic n, thoracic duct, right lymphatic duct, sympathetic chain, trachea, exsophagus
What is the importance of the phrenic n.?
Sole motor supply of the diaphragm
Must be identified during thoracic surgery
Arises from the neck so patients who suffer spinal cord injuries below the beack can still breathe despite paralysis of lower limb
Lies superficial to anterior scalene
What makes up the cervical plexus?
Anterior rami C1-C4
superficial branches= sensory
- transverse cervical, great auricular, lesser occipital, supraclavicular
deep branches= motor
- hypoglossal n, phrenic n., superior (C1, C2 run with hypo) and inferior (C2, C3, innervate strap) ansa cervialis
What makes up the sympathetic trunk?
Superior cervical ganglion: C1-C2
Middle cervical ganglion: At C6 and cricoid cartilage
Inferior cervical ganglion: often fuses with 1st thoracic= stellate ganglion, anterior to transverse process of C7
What is in the superficial fascia?
Subcutaneous layer= thin connective tissue layer that lies between the dermis and investing layer of deep fascia
Contents: cutaneous nerves, blood and lymph vessels, superficial LNs, fat, and platysma m.