Triangles of the Neck and Larynx Flashcards
What structures are found at the level of C3-C4?
Body of hyoid bone, upper margin of thyroid cartilage, and bifurcation of common carotid artery
What structures are found at the level of C5-C6?
Arch of cricoid cartilage, superior end of esophagus, and superior end of trachea
What are the boundaries of the anterior triangle?
Midline of the neck, sternocleidomastoid, and lower border of mandible
What are the boundaries of the posterior triangle?
Sternocleidomastoid, trapezius, and clavicle
What are the different triangles of the anterior triangle?
Submandibular, submental, carotid, and muscular
What are the boundaries of the submandibular triangle?
Anterior/posterior belly of digastric and inferior border of mandible
What are the boundaries of the submental triangle?
Midline of the neck, anterior belly of the digastric, and body of the hyoid
What are the boundaries of the carotid triangle?
Posterior belly of digastric, superior belly of omohyoid, and sternocleidomastoid
What are the boundaries of the muscular triangle?
Body of hyoid, superior belly of omohyoid, and median plane of the neck and sternocleidomastoid
What makes up the floor of the posterior triangle?
Semispinalis capitis, splenius capitis, levator scapula, and posterior/middle/anterior scalenes
What are the contents of the posterior triangle?
Arteries: transverse cervical, suprascapular, dorsal scapular, part of occipital, and subclavian
Veins: external jugular and subclavian
Nerves: lesser occipital, great auricular, transverse cervical, suprascapular, spinal accessory, phrenic, roots of brachial plexus, and ansa cervicalis
What are the branches of the thyrocervical trunk?
Inferior thyroid, transverse cervical, dorsal scapular, and suprascapular arteries
Which veins join to become the external jugular vein?
Posterior retromandibular and posterior auricular veins, anterior to SCM
The subclavian vein joins with what vein to form the brachiocephalic vein?
Internal jugular vein
What nerves make up Erb’s Point?
Lesser occipital, great auricular, transverse cervical, and suprascapular nerves
The skin and sheath over the parotid gland, mastoid process, auricle, and angle of the mandible is innervated by what nerve?
Great auricular nerve
The skin over the clavicle and over the shoulder is innervated by what nerve?
Supraclavicular nerve
The skin of the neck and scalp posterior to the auricle is innervated by what nerve?
Lesser occipital nerve
The skin of the anterior cervical region is innervated by what nerve?
Transverse cervical nerve
What nerve innervates the trapezius?
Spinal accessory nerve (CN XI)
What nerve innervates the diaphragm?
Phrenic nerve
The ansa cervicalis is found in what structure?
Fascia of carotid sheath
Why is the spinal accessory nerve clinically significant?
Can be easily damaged due to traumas or even during simple procedures such as biopsy of a lymph node; also the most commonly cut nerve
What is torticollis?
Contraction or shortening of SCM that causes the head to tilt toward and the face to turn away from the affected side; can be associated with damage to the spinal accessory nerve
What are the contents of the occipital triangle?
Part of EJV, posterior branches of cervical plexus, spinal accessory nerve (CNXI), trunks of brachial plexus, cervicodorsal trunk, and cervical lymph node
What are the contents of the omoclavicular (subclavian) triangle?
Third part of subclavian artery, suprascapular artery, part of subclavian vein, and supraclavicular lymph nodes
What divides the posterior triangle into its subtriangles, the occipital and omoclavicular triangles?
Inferior belly of omohyoid
What are the suprahyoid muscles and what is their function?
Mylohyoid, stylohyoid, digastric, and geniohyoid muscles; elevate the hyoid and larynx
What are the infrahyoid muscles and what is their function?
Sternohyoid, omohyoid, sternothyroid, and thyrohyoid muscles; depress the hyoid and larynx
Where would you find the carotid sinus and carotid body and what is their function, respectively?
Carotid Sinus: proximal part of ICA (internal carotid artery); baroreceptor
Carotid Body: cleft between ICA and ECA; chemoreceptor
What are the branches off the ECA?
Superior thyroid, lingual, facial, ascending pharyngeal, occipital, posterior auricular, maxillary, and superficial temporal arteries
What are the contents of the submandibular triangle?
Submandibular gland, submandibular lymph nodes, hypoglossal nerve (CN XII), mylohyoid nerve, and parts of facial artery and vein
What are the contents of the submental triangle?
Submental lymph nodes and small veins that unite to form the anterior jugular vein
What makes up the floor of the submandibular triangle?
Mylohyoid, hypoglossus, and middle pharyngeal constrictor
What makes up the floor of the submental triangle?
Mylohyoid muscles
What are the muscles of the muscular triangle?
Sternohyoid, sternothyroid, thyrohyoid
What are the contents of the muscular triangle?
Viscera: thyroid gland, parathyroid glands, larynx, trachea, esophagus
Arteries: common carotid, superior/inferior thyroids
Veins: anterior jugular, superior/middle/inferior thyroids
Nerves: ansa cervicalis, external laryngeal, recurrent laryngeal
What makes up the floor of the carotid triangle?
Thyrohyoid, hypoglossus, middle/inferior constrictor muscles of the pharynx
What is found in the carotid sheath?
Common and internal carotid arteries, IJV, vagus nerve, deep cervical lymph nodes, carotid sinus nerve, and sympathetic nerve fibers
What are the contents of the carotid triangle?
Carotid sheath, branches of the external carotid artery, internal/external laryngeal nerves, hypoglossal nerve, spinal accessory nerve, and ansa cervicalis
What are the branches of the vagus nerve (CNX)?
Pharyngeal branch, superior laryngeal branch (which branches into internal/external branches), and carotid body branch
The superior thoracic aperture where arteries and nerves emerge is called what?
Thoracic outlet
The superior thoracic aperture where food and air may enter is called what?
Thoracic inlet
What are the contents of the thoracic outlet/inlet?
Apex of lung, subclavian artery/vein, brachial plexus, vagus nerve, phrenic nerve, thoracic duct, right lymphatic duct, sympathetic chain, trachea, and esophagus
Why is the phrenic nerve clinically relevant?
It is the sole motor supply to the diaphragm, so it must be identified during thoracic surgery and preserved; because it arises from the neck, patients who suffer spinal cord injuries below the neck are still able to breathe effectively despite any paralysis of the lower limbs
What are the nerves from the cervical plexus?
Meningeal nerve (C1-2), superior/inferior root of ansa cervicalis (C1-3), and phrenic nerve (C3-5)
Cervical plexus is C1-4, so phrenic nerve has roots from cervical plexus (C3-4) and brachial plexus (C5)
What is found at the level of C1-C2?
Superior cervical ganglion
What structure extends superiorly to C1 or to the base of the skull?
Sympathetic trunk
What is found at the level of C6 and the cricoid cartilage?
Middle cervical ganglion
Smallest of 3 ganglion
What is found anterior to the transverse process of C7? Why is this significant?
Inferior cervical ganglion; in 80% of people, it fuses with the 1st thoracic ganglion and is then termed the stellate (cervicothoracic) ganglion
What are the contents of the superficial fascia, what is the function of the muscle found here, and what nerve innervates this muscle?
Cutaneous nerves, blood and lymph vessels, superficial lymph nodes, fat, and platysma muscle; platysma is the muscle of facial expression and is innervated by the facial nerve (CNVII)
What are the 3 layers of the deep cervical fascia and where can you find each layer?
Investing Layer: most superficial, surrounds entire neck
Pretracheal Layer: located only in the anterior region of the neck and blends with fibrous pericardium of heart
Prevertebral Layer: encloses vertebral column and associated muscles, extends laterally as the axillary sheath into the arm, and extends from the cranial base to the mediastinum
Why is the retropharyngeal space clinically significant?
Can get abscesses that develop secondary to lymphatic drainage or spread of upper respiratory or oral infections; when this space swells is can cause difficulty in swallowing and speaking and can be life threatening
What structure is found at vertebral levels C5-T1?
Thyroid
What structure is found at vertebral levels C3-C6?
Larynx
Where would you find the laryngeal cavity?
Extends from laryngeal inlet, communicates with the laryngopharynx, to the inferior border of the cricoid cartilage; continuous with trachea
Where would you find the laryngeal vestibule?
Between laryngeal inlet and vestibular folds
Where would you find the laryngeal ventricle?
Between the vestibular and vocal folds
Where would you find the infraglottic cavity?
Between vocal folds and the inferior border of the cricoid cartilage
Where would you find the rima glottidis?
Space between the vocal folds
These are known as the false vocal cords?
Vestibular folds
These are known as the true vocal cords?
Vocal folds
What is the innervation and function of the cricothyroid muscle?
External laryngeal nerve (from CN X); stretches and tenses vocal ligament
What is the innervation and function of the thyro-arytenoid muscle?
Inferior laryngeal nerve (terminal part of recurrent laryngeal nerve from CN X); relaxes vocal ligament
What is the innervation and function of the posterior crico-arytenoid muscle?
Inferior laryngeal nerve (terminal part of recurrent laryngeal nerve from CN X); abducts vocal folds
only ABductor
What is the innervation and function of the lateral crico-arytenoid muscle?
Inferior laryngeal nerve (terminal part of recurrent laryngeal nerve from CN X); adducts vocal folds
What is the innervation and function of the transverse and oblique arytenoid muscles?
Inferior laryngeal nerve (terminal part of recurrent laryngeal nerve from CN X); adducts arytenoid cartilages
What is the innervation and function of the vocalis muscle?
Inferior laryngeal nerve (terminal part of recurrent laryngeal nerve from CN X); relaxes posterior vocal ligament while maintaining (or increasing) tension of the anterior part
Above the vocal folds, the larynx is supplied by what artery and nerve? What about below the vocal folds?
Above: superior laryngeal artery and internal branch of superior laryngeal nerve
Below: inferior laryngeal artery and inferior laryngeal nerve
There are 5 groups of lymph nodes that form a ring around the head and drain the face and scalp. What are the 5 groups?
Occipital, mastoid, pre-auricular and parotid, submandibular, and submental
What group of lymph nodes drains to the superficial cervical lymph nodes? Deep cervical lymph nodes?
Superficial: occipital and mastoid
Deep: pre-auricular and parotid, submandibular, and submental
What are the superficial and deep cervical lymph nodes?
Superficial: nodes along EJV; eventually drain into deep cervical nodes
Deep: nodes along IJV; divided into superior and inferior nodes; superior is called jugulodigastric and inferior is called jugulo-omohyoid
What does the right lymphatic duct drain? Left?
Right: right side of head, neck, chest, and right UE
Left: literally everything else including LE
