Triangles of the Head and Neck Flashcards
What is present at vertebral level C3-C4?
Body of hyoid bone, upper margin thyroid cartilage, bifurcation of common carotid artery
What is present at vertebral level C5-C6?
Arch of cricoid cartilage, superior end of esophagus, superior end of trachea
What is another name for the posterior triangle?
Lateral cervical region
What are the borders of the posterior triangle?
SCM, trapezius, clavicle
What are the borders of the anterior triangle?
SCM, midline of neck, lower border of mandible
What triangles are found in the anterior triangle?
Submandibular, submental, carotid, muscular
What are the borders of the submandibular triangle?
Anterior belly of digastric, posterior belly of digastric, inferior border of mandible
What are the borders of the submental triangle?
Midline of neck, anterior belly of digastric, body of hyoid
What are the borders of the carotid triangle?
Posterior belly of digastric, superior belly of omohyoid, SCM
What are the borders of the muscular triangle?
Body of hyoid, superior belly of omohyoid, SCM
What muscles make up the floor of the posterior triangle?
Splenius capitus, levator scapulae, posterior/middle/anterior scalene
What are the branches off the subclavian artery?
Vertebral a, internal thoracic a, thyrocervical trunk (suprascapular a, transverse cervical a, inferior thyroid a), costocervical trunk (supreme intercostal a, deep cervical a), dorsal scapular a
What are the divisions of the subclavian artery?
I - vertebral a, internal thoracic a
II - (under anterior scalene m) costocervical trunk
III - dorsal scapular a
What arteries off the subclavian are located in the posterior triangle?
Transverse cervical a and suprascapular a (both off the thyrocervical trunk)
What veins are located in the posterior triangle?
External jugular vein (retromandibular v + posterior auricular v) and subclavian vein (joins with internal jugular vein to form brachiocephalic vein)
Clinically, what does it mean if you can see the external jugular vein?
Increased venous pressure = heart failure or obstruction of SVC
Why is the subclavian vein clinically relevant?
Used for central lines
What cutaneous nerves are located in the posterior triangle? What is this location called clinically?
Cervical plexus cutaneous nerves - lesser occipital, great auricular, transverse cervical, supraclavicular. Erb’s point.
What are the nerve roots of the posterior triangle cutaneous nerves?
Lesser occipital - C2
Great auricular - C2, C3
Transverse cervical - C2, C3
Suprascapular - C3, C4
What other nerves are located in the posterior triangle?
Spinal accessory nerve (CN XI), phrenic nerve, roots of brachial plexus, ansa cervicalis
What is the most common nerve that is accidentally cut?
Spinal accessory nerve (CN XI)
What does CN XI innervate?
SCM and trapezoid m
Where does CN XI lie?
Deep to SCM
What are the nerve roots of phrenic nerve?
C3, 4, 5 keep the diaphragm alive
Where does the phrenic nerve lie?
Anterior to anterior scalene m
Where does the brachial plexus exit?
Between anterior and middle scalene muscles
What arteries lie superficial to the phrenic nerve?
Transverse cervical a and suprascapular a
What does the ansa cervicalis n innervate?
Infrahyoid muscles
Where does the ansa cervicalis lie?
In the fascia of the carotid sheath
What is torticollis?
Contraction of SCM causing head to tilt and face to turn AWAY from affected side
What are the triangles located in the posterior triangle?
Occipital triangle and omoclavicular (subclavian) triangle
What are the suprahyoid muscles and what do they do?
Anterior/posterior bellies of digastric m, mylohyoid m, stylohyoid m (straddles posterior belly of digastric m), and geniohyoid muscle. Elevate the hyoid bone and larynx during swallowing and phonation
What are the infrahyoid (strap) muscles?
Sternohyoid m, omohyoid m, sternothyroid m, thyrohyoid m
What innervates the infrahyoid muscles?
Branches of the ansa cervicalis
What are the branches of the external carotid artery that are in the anterior triangle?
Superior thyroid a, lingual a, facial a, ascending pharyngeal a, occipital a, posterior auricular a (Seven Angry Ladies Fighting Over PMS)
What are the contents of the submandibular triangle?
Submandibular gland, submandibular lymph nodes, hypoglossal n (CN XII), nerve to mylohyoid, facial a/v
Where does the hypoglossal n lie?
On the hyoglossus m
What are the contents of the submental triangle?
Submental lymph nodes, veins that unite to form anterior jugular vein
What are the contents of the muscular triangle?
Thyroid , parathyroid glands, larynx, trachea, esophagus, common carotid a, superior thyroid a, inferior thyroid a, anterior jugular v, thyroid veins, ansa cervicalis, external laryngeal n, recurrent laryngeal n
What are the contents of the carotid triangle?
Carotid sheath, external carotid a branches, internal/external laryngeal n, hypoglossal n, spinal accessory n, ansa cervicalis
What does the carotid sheath contain (and in what order)?
Internal/common carotid arteries (medial)
IJV (lateral)
Vagus n (posterior)
Ansa cervicalis (anterior/embedded in sheath)
(plus deep cervical lymph nodes, carotid sinus n, and sympathetic nerve fibers)
Where does the carotid sheath go?
Base of skull to mediastinum in thorax
Hypoglossal n wraps around what artery in the carotid triangle?
The occipital a
What does the superior laryngeal n branch into?
Internal laryngeal n and external laryngeal n (in the carotid triangle)
What innervates the carotid sinus and carotid body?
Carotid sinus n (and vagus n)
What structures exit the jugular foramen?
Glossopharyngeal n (CN IX), vagus n (CN X), and spinal accessory n (CN XI)
With thoracic outlet syndrome, if the brachial plexus is compressed what happens?
Sensory loss to hand (ulnar n: C8-T1) (inferior trunk of brachial plexus)
How far does the lung extend into the root of the neck?
About 2 inches
What innervates the carotid sinus?
The superior cervical ganglion///the carotid sinus n from the glossopharyngeal n (CN IX)
What layer of fascia does the platysma muscle lie in?
Subcutaneous layer between the dermis and investing layer of deep cervical fascia
What are the layers of the deep cervical fascia?
- Investing layer
- Pretracheal layer
- Prevertebral layer
Which layer of fascia blends with the pericardium of the heart?
The pretracheal layer of deep cervical fascia
Which layer of fascia extends laterally as the axillary sheath into the arm?
The prevertebral layer of deep cervical fascia
What are the borders of the retropharyngeal space?
Buccopharyngeal fascia (anterior), prevertebral fascia (posterior), carotid sheaths (laterally)
Within the carotid sheath, where are the vagus nerve, IJV, and common carotid artery usually located?
Vagus nerve - posterior
IJV - anterior/lateral
Common carotid artery - anterio/medial
What artery and nerve run into the thyrohyoid membrane together?
Internal branch of superior laryngeal nerve and superior laryngeal artery
Which muscle of the larynx is an abductor? Which are adductors?
Posterior crico-arytenoid muscle is an abductor.
Transverse arytenoid, oblique arytenoid, and lateral crico-arytenoid muscles are adductors.
What do the two branches of superior laryngeal nerve do?
Internal laryngeal nerve (sensory) innervates sensory above vocal folds. External laryngeal nerve (motor) innervates the cricothyroid muscle
Where does larynx end and trachea begin?
At cricoid cartilage
Line through laryngeal ventricle at vocal folds separates lymph, blood supply, and innervation how? (above vs below)
Above: lymph = superior deep cervicals, blood = superior laryngeal a, sensory = internal branch of superior laryngeal n
Below: lymph = pretracheal and prelaryngeal to inferior deep cervicals, blood = inferior laryngeal a, sensory = inferior laryngeal n (from recurrent laryngeal n)
What are the five groups of lymph nodes in the head?
Occipital, mastoid, pre-auricular/parotid, submandibular, submental
Where are the superficial cervical LNs found vs the deep cervical LNs?
Superficial cervical LNs are along the EJV, deep cervical LNs are along the IJV
What does the R lymphatic duct drain?
R head, R neck, R chest, RUE
What does the thoracic duct drain?
L head, L neck, L chest, LUE, abdomen, pelvis, perineum, BLE
