Triangles of the Neck and Larynx Flashcards
Vertebral level C3-4 marked by
Body of hyoid bone
Upper margin of thyroid cartilage
Bifurcation of common carotid artery
Vertebral level C5-6 marked by
Arch of cricoid cartilage
Superior end of esophagus
Superior end of trachea
Posterior triangle borders
Anterior- posterior sternocleidomastoid
Posterior- anterior trapezius
Inferior- clavicle
Anterior triangle borders
Midline of neck
Sternocleidomastoid
Lower border of mandible
Submandibular division of anterior triangle borders, floor, contents
Anterior belly of digastric muscle
Posterior belly of digastric
Inferior border of mandible
Floor- Mylohyoid, hypoglossus, middle pharyngeal constrictor
Contents- submandibular gland & lymph nodes, hypoglossal N, nerve to mylohyoid, parts of facial A/V
Submental division of anterior triangle borders, floor, contents
Midline of neck Anterior belly of digastric Body of hyoid Floor- Mylohyoid muscles Contents- submental lymph nodes and small veins that unite to form anterior jugular vein
Carotid division of anterior triangle borders, floor
Posterior belly of digastric
Superior belly of omohyoid
Sternocleidomastoid
Floor- thyrohyoid, hyoglossus, middle/inferior constrictor muscles of pharynx
Muscular division of anterior triangle borders, muscles
Body of hyoid
Superior belly of omohyoid
Sternocleidomastoid
Muscles- sternohyoid, sternothyroid, thyrohyoid
Posterior triangle roof and floor
Floor- semispinalis capitis, splenius capitis, levator scapula, posterior/middle/anterior scalene
Roof- skin, superficial fascia, platysma, investing layer of deep fascia
Arteries in posterior triangle
Subclavian Thyrocervical trunk Transverse cervical Dorsal scapular Suprascapular Part of occipital artery
Transverse cervical artery path
Runs superficially and laterally across the phrenic nerve and anterior scalene muscle
Suprascapular artery path
Branch of the thyrocervical trunk, passes inferiolaterally across the anterior scalene muscle and phrenic nerve. Travels with suprascapular nerve
Veins of posterior triangle
External jugular and subclavian
EJV begins inferior to angle of mandible by union of posterior retromandibular vein with posterior auricular vein anterior to SCM. Drains into subclavian vein
Subclavian is anterior to anterior scalene muscle and joins with internal jugular vein to form brachiocephalic vein.
Nerves of the posterior triangle
Spinal accessory, roots and trunks of brachial plexus, phrenic
Lessor occipital- skin of neck and scalp posterior to auricle
Great auricular- skin and sheath over parotid gland, mastoid process, auricle and angle of mandible
Transverse cervical- skin of anterior cervical region
Supraclavicular- skin over the clavicle and shoulder
Spinal accessory nerve path
Deep to SCM, lies in deep fascia, enters trapezius
Phrenic nerve path
Anterior to anterior scalene muscle, supplies diaphragm
Torticollis
Contraction or shortening of SCM that causes the head to tilt towards and the face to turn away from the affected side
Suprahyoid muscles
Located in anterior triangle, elevate hyoid and larynx Mylohyoid Stylohyoid Digastric anterior/posterior bellies Geniohyoid
Infrahyoid muscles
Located in anterior triangle, depress hyoid and larynx Sternohyoid Omohyoid Sternothyroid Thyrohyoid
Arteries of the anterior triangle
Common carotid- bifurcates into internal and external carotid at C3-4
Internal carotid does not branch in neck, contains carotid sinus (baroreceptor) in proximal portion and carotid body (chemoreceptor) in cleft between ICA/ECA
External carotid artery branches and description
Superior thyroid- gives rise to superior laryngeal, supplies thyroid
Lingual- anterior to middle pharyngeal constrictor, deep to hypoglossal nerve, posterior belly of digastric and stylohyoid muscle. Disappears deep to hyoglossus
Facial- gives rise to ascending palatine and tonsillar arteries, found deep to submandibular gland/angle of mandible (pulse point)
Ascending pharyngeal- only medial branch, medial to ICA
Occipital- passes superficial to ICA and hypoglossal N.
Posterior auricular- ascends b/w external acoustic meatus and mastoid process, terminates into maxillary and superficial temporal arteries in the face
Contents of the muscular division of anterior triangle
Viscera- thyroid/parathyroid glands, larynx, trachea and esophagus
Arteries- common carotid, superior/inferior thyroid
Veins- anterior jugular, superior/middle/inferior thyroid
Nerves- ansa cervicalis, external laryngeal, recurrent laryngeal
Contents of carotid division of anterior triangle
Carotid sheath- contains common/internal carotid arteries, internal jugular vein, vagus nerve, deep cervical lymph nodes, carotid sinus, sympathetic fibers
Arteries- branches of external carotid
Nerves- internal/external laryngeal, hypoglossal, spinal accessory, ansa cervicalis
Carotid sheath contents
Carotid arteries- medial
Internal jugular vein- lateral
Vagus n- posterior
Ansa cervicalis- anterior or embedded in sheath
Vagus nerve branches
Pharyngeal branch
Superior laryngeal- internal/external branches
Carotid body branch
Thoracic inlet/outlet contents
Apex of lung Subclavian artery and vein Brachial plexus Vagus nerve Phrenic nerve Thoracic duct Right lymphatic duct Sympathetic chain Trachea/esophagus
Subclavian steal syndrome/vertebrobasilar insufficiency
Subclavian artery occlusion or hemodynamically significant stenosis proximal to the origin of the vertebral artery results in lower pressure in the distal subclavian artery. As a result, blood is “stolen” from the cerebral circulation to perfuse the arm. Blood flows up the contralateral vertebral artery to the basilar artery, and retrograde down the ipsilateral vertebral artery away from the brainstem
Phrenic nerve importance
Phrenic nerve is the sole motor supply to the diaphragm, so it must be identified and preserved during surgery
Because the phrenic nerve arises from the neck, patients who suffer spinal cord injuries below the neck are still able to breath effectively despite paralysis of lower limbs
Sympathetic trunk
Extends superiorly to C1 or base of skull
Superior cervical ganglion- C1-2
Middle cervical ganglion- located at C6 at the level of cricoid cartilage, smallest of the 3, may be absent
Inferior cervical ganglion- in 80% of people the inferior cervical ganglion fuses with the 1st thoracic ganglion and is termed the stellate ganglion
Located anterior to transverse process of C7
Contents of superficial cervical fascia
Cutaneous nerves Blood/lymph vessels Superficial lymph nodes Fat Platysma muscle- muscle of facial expression, innervated by fascial nerve CN VII
Investing layer of deep cervical fascia
Most superficial layer of deep, surrounds entire neck
Encloses SCM and trapezius
Encloses parotid and submandibular glands
Attaches to occipital/temporal bones, zygomatic arches, inferior border of mandible, hyoid bone and spinous processes of cervical vertebrae
Extends to manubrium, clavicles, acromion and spines of scapula
Pretracheal layer of deep cervical fascia
Located only in anterior region of neck
Blends with fibrous pericardium of heart
Muscular layer with infrahyoid muscles, buccopharyngeal fascia and a visceral layer
Prevertebral layer of deep cervical fascia
Encloses vertebral column and associated muscles
Extends laterally as the axillary sheath into the arm
Extends from cranial base to mediastinum
Retropharyngeal space
Posterior to the pharynx, bound by buccopharyngeal fascia anteriorly, prevertebral fascia posteriorly and the carotid sheaths laterally
Extends superiorly to base of skull and inferiorly to mediastinum
Retropharyngeal abscess
Develops secondary to lymphatic drainage or contiguous spread of upper respiratory/oral infections
Swelling can cause difficulty swallowing and speaking and can be life threatening
Thyroid location, arteries, veins
C5-T1
Superior thyroid artery supplies anterior/superior
Inferior thyroid supplies posterior/inferior
Thyroid ima artery- found in 10%, anterior to trachea
Veins- superior/middle/inferior thyroid veins form thyroid plexus of veins
Relationships- recurrent laryngeal nerves and ligaments of thyroid
RLN ascend in groove b/w trachea and esophagus, they pass deep to the posteromedial surface of the lateral lobes of the thyroid gland
Ligaments bind thyroid gland to trachea and cricoid cartilage of larynx
Larynx
Vertebral levels C3-6
Connected to pharynx and trachea
Functions in phonation and patent airway
Thyroid cartilage
Located at C4
Laryngeal prominence- adams apple
Superior thyroid notch
Superior/inferior thyroid horn
Cricoid cartilage
Located at C6
Signet ring shaped
Thyrohyoid membrane
Aperture for internal branch of superior laryngeal nerve and superior laryngeal artery
Laryngeal cavity
Extends from laryngeal inlet, through which it communicates with the laryngopharynx, to the inferior border of the cricoid cartilage. It is continuous with the trachea
Laryngeal vestibule
Between the laryngeal inlet and the vestibular folds
Laryngeal ventricle
Between the vestibular and vocal folds
Infraglottic cavity
B/w vocal folds and the inferior border of the cricoid cartilage
Rima glottidis
Space between the vocal folds
Cricothyroid muscle innervation/action
External laryngeal nerve from CN X
Stretches and tenses vocal ligament
Thyro-arytenoid innervation and action
Inferior laryngeal nerve (terminal portion of recurrent laryngeal nerve from CN X)
Relaxes vocal ligament
Posterior crico-arytenoid innervation/action
Inferior laryngeal nerve
Abducts vocal folds
Lateral crico-arytenoid innervation/action
Inferior laryngeal nerve
Adducts vocal folds (interligamentous portion)
Transverse and oblique arytenoids innervation/action
Inferior laryngeal nerve
Adduct arytenoid cartilages- adducting intercartilagenous portion of vocal folds, closing posterior rima glottidis
Vocalis innervation/action
Inferior laryngeal nerve
Relaxes posterior vocal ligament while maintaining (or increasing) tension of anterior part
Superior/inferior laryngeal arteries
Superior- accompanies internal branch of superior laryngeal nerve. Supplies superior larynx above vocal folds
Inferior- accompanies inferior laryngeal nerve. Supplies inferior larynx below vocal folds
Superior laryngeal nerve
Branches into internal and external branches
Internal innervates sensory above the vocal folds
External innervates the cricothyroid muscle
Internal laryngeal nerve
Terminal branch of the recurrent laryngeal nerve
Innervates all intrinsic muscles of larynx except cricothyroid
Provides sensory below vocal cords
Superficial lymph nodes
Drain face and scalp
Occipital- drain posterior scalp and neck
Mastoid- drain posterolateral scalp
Pre-auricular/parotid- drain ainterior auricle, anterolateral scalp, upper half of face
Submandibular- follow facial artery, drain gingivae, teeth, tongue, upper lip and lateral lower lip
Submental- drain center lower lip, chin, floor of mouth, tip of tongue and lower incisor teeth
Superficial cervical nodes receives drainage from what nodes
Occipital, mastoid nodes along external jugular vein
Eventually drain into deep cervical nodes
Deep cervical nodes receive drainage from what nodes
Pre-auricular/parotid, submandibular and submental
Located along internal jugular vein
Jugulodigastric is most superior node at C3-4
Jugulo-omohyoid is associated with lower deep cervical nodes at C6
