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.
What is the action and innervation of platysma m.?
Facial expression
Facial N. (CN VII)
What are the 3 layers of the deep cervical fascia?
Investing
Pretracheal
Prevertebral
(Carotid Sheath)
What does the investing layer surround? What are its attachments?
Surrounds entire neck
Encloses SCM and trapezius muscles
Parotid and submandibular glands
Attaches to occipital and temporal bones, zygomatic arches, inferior border of mandible, hyoid bone and spinous processes of cervical vertebrae
Extends to manubrium of sternum, clavicles, and acromions and spines of the scapula
Clinically: mumps pain
Where is the pretracheal layer found? What does it surround?
Only in anterior neck
Blends with pericardium of heart
Muscular layer (infrahyoid muscles), buccopharyngeal fascia, and visceral layer
What does the prevertebral layer enclose? Where does it extend?
vertebral column and associated muscles
Extends laterally as axillary sheath
Extends cranial base to mediastinum
What is the retropharyngeal space? What is its clinical significance?
Posterior to pharynx bound by buccopharyngeal fascia anterior, prevertebral fascia posteriorly, and carotid sheath laterally
Abscess develop secondary to lymph drainage or continuous spread of URI or oral infections –> difficulty swallowing speaking, life threatening
Where is the thyroid located?
Deep to sternothyroid and sternohyoid muscles
Vertebral levels C5-T1
Isthmus anterior to 2nd-3rd tracheal rings
What arteries supply the different parts of the thyroid gland?
Superior thyroid a.: anterior-superior aspects of gland
Inferior thyroid a.: posterior-inferior aspects of gland
Thyoid ima a: in 10% of people, located anterior to trachea
What veins make up the thyroid plexus?
Superior, middle, and inferior thyroid veins
What nerves are associated with the thyroid gland? What is their path?
Recurrent laryngeal nerves ascend in a groove between trachea and esophagus
Pass deep to the posteromedial surface of the lateral lobes of the thyroid gland
What is the thyroid gland bound to?
Ligaments bind gland to trachea and cricoid cartilage of larynx
Where is the larnyx located? What is it connected to? What is its function?
Vertebral levels C3-C6
Connected to the pharynx and trachea
Phonation and patent airway
What types of cartilage makes up the laryngeal skeleton?
Thyroid Cricoid Epiglottic Arytenoid Corniculate Cuneiform
What are the features/characteristics of thyroid cartilage?
Located at C4 Laminae Laryngeal porminence aka Adam's apple Superior thyroid notch Superior and inferior thyroid horn
What are the features/characteristics of cricoid cartilage?
Located at C6
Signet ring shaped
Laminae
Arch
What are the 2 membranes of the larynx?
Thyrohyoid= aperture for internal branch of superior laryngeal n. and superior laryngeal a.
Cricothyroid= lateral and medial membranes
What membrane do you go through for a cricothyrotomy?
Cricothyroid membrane, used to establish an airway
What are the 2 ligaments of the larynx?
Thyroepiglottic (run obliquely)
Vocal (transverse)
Describe the location of laryngeal cavity
Extends from the laryngeal inlet through which it communicates with the laryngopharynx to the inferior border of the cricoid cartilage
Continuous with the trachea
Describe the location of the laryngeal vestibule
Between the laryngeal inlet and vestibular folds
Describe the location of the laryngeal ventricle
between the vestibular and vocal folds
Describe the location of the infraglottic cavity
between the vocal folds and the inferior border of the cricoid cartilage
Describe the location of the rima glottidis
Space between the vocal folds
What is the innervation and action of the cricothyroid m.?
External laryngeal n. (CN X)
Stretches and tense vocal ligament (especially when making high pitch)
What is the innervation and action of the thyro-arytenoid m.?
Inferior laryngeal n. (from CN X, terminal part of recurrent laryngeal)
Relaxes vocal ligament (low pitch)
What is the innervation and action of the posterior cricoarytenoid?
Inferior laryngeal n. (from CN X, terminal part of recurrent laryngeal)
ABducts vocal folds
What is the innervation and action of the lateral crico-arytenoid?
Inferior laryngeal n. (from CN X, terminal part of recurrent laryngeal)
ADducts vocal folds
What is the innervation and action of the transverse and oblique arytenoids?
ADduct arytenoid cartilages, closing posterior rima glottidis
What muscles are involved in phonation? Whispering?
Lat, oblique, and transverse ADducters
Lateral and oblique ADducters
What are the courses of the superior and inferior laryngeal arteries? What do they supply?
Superior: accompanies internal branch of superior laryngeal n.
Supplies superior larynx above vocal folds
Inferior: accompanies inferior laryngeal n.
supplies larynx below vocal folds
What are the branches of the superior laryngeal n.? What do they innervate?
Internal branch= sensory above the vocal folds
External branch= motor, cricothyroid muscle
What are the innervations of the internal laryngeal n.?
Terminal branch of recurrent laryngeal
Innervates all intrinsic muscles of the larynx except cricothyroid
Sensory below vocal folds
How does the course of the left and right recurrent laryngeal nerves differ?
Left: loops under aortic arch
Right: loops under subclavian
Where are the superficial lymph nodes found? What are the five groups?
Form a ring around the head
Occipital Mastoid Pre-auricular and parotid Submandibular: Submental
What does the occipital superficial lymph node drain?
posterior scalp and neck
What does the mastoid (retro-auricular/posterior auricular) LN drain?
posteroalteral half of scalp
What does the pre-auricular and parotid LNs drain?
anterior auricle, anterolateral scalp, upper half of face
What does the submandibular LN drain?
follow facial a., drains part of gingivae, teeth, tongue, upper lip, lateral lower lip
What does the submental LN drain?
part of lower lip, chin, floor of mouth, tip of tongue, lower incisor teeth
What superficial LNs pass superficial to the cervical nodes along EJV? What pass deep?
Occipital and mastoid nodes
preauricular, parotid, submandibular, and submental LNs
What are the superficial cervical LNs? What do they receive lymph from? What do they drain into?
Collection of nodes along the external jugular veins
Receive from posterior and posterolateral regions fo the scalp
Drain into deep cervical nodes
What are the deep cervical LNs? How are they divided?
Collection of nodes along internal jugular vein
Divided into upper (superior) and lower (inferior)
- most superior= jugulodigastric, located C3,C4 by posterior belly of digastric
- inferior= Jugulo-omohyoid= located C6, inferior to tendon of omohyoid m.
What does the right lymphatic duct receive lymph from? What foes the thoracic duct receive lymph from?
Right= right hand, forearm, arm, abdomen, neck, head
Thoracic duct= everything else including all lower limb
What are causes of cervical pain?
Inflamed lymph nodes: malignant tumor in head, primary cancer in thorax or abdomen
Muscle strain
Protruding IV discs
Cervical osteoarthritis
How can a hyoid bone be fractured? What deficits are seen?
Manually strangled by compression of throat
Depression of the body of the hyoid onto the thyroid cartilage –> inability to elevate the hyoid and move it anteriorly between the tongue –> swallowing and maintenance of the separation of the alimentary –> aspiration pneumonia
What can cause paralysis of the platysma?
Injury to the cervical branch of the facial nerve –> cause the skin to fall away from the neck in slack folds
Need to be careful to preserve when suturing neck, have to make sure platsyma fibers aren’t contracted in different directions
What is the course of the needle for a central line?
Needle punctures the skin inferior to thumb (middle of clavicle) and advance medially toward tip of index finger (jugular notch) until tip enters the right venous angle posterior to sternoclavicular joint
Need to be careful can puncture the pleura and lung causing pneumothorax
If too posterior can enter subclavian artery
How do you preform a right cardiac catheterization?
Puncture IJV so can enter right brachiocephalic vein into the SVC
Sometimes have to enter EJV, not ideal because angle of subclavian vein
How can you damage the spinal accessory nerve? What are symptom?
Stab, bullet, surgical procedures in lateral cervical region, tumors at the cranial base or cancerous cervical LNs, fractures of the jugular foramen
Weakness in turning head to side opposite of damage
Drooping of the shoulder because innervates trapezius
What provides blood when the external carotid or subclavian arteries are ligated?
Descending branch of the occipital artery which anastomoses with the vertebral and deep cervical arteries
What is carotid sinus hypersensitivity?
Exceptional responsiveness of carotid sinuses –> external pressure on carotid sinus cause slowing of heart rate, fall in BP, and cardiac ischemia –> fainting
How do you palpate for the IJV? What side is preferred?
Palpate common carotid and insert the needle into IJV lateral to it at a 30 degree angle and direct inferolaterally toward the ipsilateral nipple
What is vertebra-basilar insufficiency?
Blood flow to the vertebral and basilar arteries is restricted, thereby providing transient insufficient blood flow to the posterior portions of the brain
Can result in stroke or death
What is subclavian steal syndrome?
Occlusion of the subclavian artery causing retrograde blood flow in the vertebral artery or the internal thoracic artery,
Arm may be supplied by blood flowing in a retrograde direction down the vertebral artery at the expense of the vertebrobasilar circulation. This is called the subclavian steal.
