Triangles of Neck & Larynx (Part 1) Flashcards
What vertebral level is the body of the hyoid bone?
C3
What vertebral level is the upper margin of thyroid cartilage?
C3-C4
What vertebral level is the bifurcation of the common carotid artery?
C3-C4
What is the vertebral level of the arch of the cricoid cartilage?
C6
What is the vertebral level of the superior end of the esophagus?
C5-C6
What is the vertebral level of the superior end of the trachea?
C6
***Starts below the cricoid cartilage
What are the borders of the Anterior Triangle of the neck?
Midline of neck
Sternocleidomastoid (SCM)
Lower border of mandible
What are the borders of the Posterior Triangle of the neck?
SCM
Trapezius
Clavicle
What are the triangle subdivisions of the Anterior Triangle of the neck?
Submandibular
Submental
Carotid
Muscular
What are the boundaries of the Submandibular Triangle?
Anterior Belly of Digastric
Posterior Belly of Digastric
Inferior border of Mandible
What are the boundaries of the Submental Triangle?
Midline of Neck
Anterior Belly of Digastric
Body of Hyoid
What are the boundaries of the Carotid Triangle?
Posterior Belly of Digastric
Superior Belly of Omohyoid
SCM
What are the boundaries of the Muscular Triangle?
Body of Hyoid
Superior Belly of Omohyoid
SCM
Midline of Neck
In the Posterior Triangle, the floor is covered by what?
Prevertebral layer of deep fascia
What is in the floor of the Posterior Triangle?
Splenius Capitis Semispinalis Capitis Levator Scapulae Scalenes (Anterior, Posterior, Middle) Brachial Plexus
What covers the Posterior Triangle, form superficial to deep?
Skin
Superficial fascia
Platysma
Investing Layer of Deep fascia
What are the arteries that lie within the Posterior Triangle?
Subclavian A. Transverse Cervical A. Dorsal Scapular A. Suprascapular A. Part of Occipital A.
***Thryocervical Trunk is not within the Posterior Triangle, but its branches are (Transverse Cervical A. and Suprascapular A.)
The Transverse Cervical A. has deep and superficial branches within the Posterior Triangle. What is the deep branch called?
Dorsal Scapular A.
This artery in the Posterior Triangle runs superficially and laterally across the Phrenic N. and Anterior Scalene M.
Transverse Cervical A.
***Branch of Thyrocervical Trunk
This artery in the Posterior Triangle passes inferolaterally across the Anterior Scalene M. and Phrenic N.
Suprascapular A.
***Travels with Suprascapular N. and branch of Thyrocervical Trunk
What veins are within the Posterior Triangle?
External Jugular V. (EJV)
Subclavian V.
The EJV begins inferior to the angle of the Mandible by uniting what two veins anterior to the SCM?
Posterior Retromandibular V.
Posterior Auricular V.
The Subclavian V. empties into what vein?
Brachiocephalic V.
At what point does the Subclavian V. become the Brachiocephalic V.?
Where the Internal Jugular V. empties into it.
If you can see a person’s EJV bulging when they’re at rest, what could this mean?
There is increased venous pressure, which could indicate heart failure.
Cutaneous branches of the Cervical Plexus emerge around the middle of the posterior SCM (in Posterior Triangle) at a point called…
Erb’s Point
Nerve Point of the Neck
What are the cutaneous nerves that come out of Erb’s Point within the Posterior Triangle?
Lesser Occipital N.
Great Auricular N.
Transverse Cervical N.
Supraclavicular N.
This nerve supplies the skin of the neck and scalp posterior to the auricle.
Lesser Occipital N. (C2)
***From Erb’s Point
This nerve supplies the skin and sheath over the Parotid Gland, Mastoid Process, Auricle, and angle of Mandible.
Great Auricular N. (C2-3)
***From Erb’s Point
This nerve supplies the skin of the anterior cervical region.
Transverse Cervical N. (C2-3)
***From Erb’s Point
This nerve supplies the skin over the clavicle and over the shoulder.
Supraclavicular N. (C3-4)
***From Erb’s Point
What are motor nerves that lie within the Posterior Triangle?
Suprascapular N. Spinal Accessory N. Phrenic N. Roots of Brachial Plexus Ansa Cervicalis
This nerve is deep to the SCM as well as innervates it, and lies in deep fascia and goes on to enter the Trapezius to innervate it.
Spinal Accessory N. (CN XI)
This nerve is directly anterior to the Anterior Scalene and supplies the diaphragm.
Phrenic N. (C3, 4, 5)
This nerve lies in the fascia of the Carotid Sheath and supplies motor innervation to the Infrahyoid ms.
Ansa Cervicalis
***Has a Superior Root and Inferior Root
This nerve is the most common nerve accidentally cut. Its location makes it very susceptible to damage.
Spinal Accessory N. (CN XI)
***Comes out from under SCM and has section that is wide open with no protection until it reaches the Trapezius. This is the area most susceptible for damage.
This comes out between the Anterior and Middle Scalenes.
Brachial Plexus
What lies within the Carotid Sheath?
Internal Jugular V. (Lateral)
Common Carotid A. (Medial)
Vagus N. (CN X)
If I turn my head to the right, is the SCM on the right or the left contracting?
SCM on the left
***Always the opposite!
An injury to the Spinal Accessory N. could cause this, which is a contraction or shortening of the SCM that causes the head to tilt toward and the face to turn away from the affected side.
Torticollis
The Posterior Triangle can be divided into sub-triangles by the Inferior Belly of the Omohyoid. These triangles are…
Occipital Triangle
Omoclavicular (Subclavian) Triangle
In the Anterior Triangle, there is a group of Suprahyoid muscles that elevate the Hyoid and Larynx. These are…
Mylohyoid
Stylohyoid
Digastric (Anterior and Posterior Bellies)
Geniohyoid
In the Anterior Triangle, there is a group of Infrahyoid muscles that depress the Hyoid and Larynx. These are…
Sternohyoid
Omohyoid
Sternothyroid
Thyrohyoid
This muscle straddles the Posterior Belly of the Digastric.
Stylohyoid
What are the arteries within the Anterior Triangle?
Common Carotid A.
Internal Carotid A.
External Carotid A.
This artery runs between the bifurcation of the Internal and External Carotid As.
Ascending Pharyngeal A.
The Common Carotid A. bifurcates into the Internal Carotid A. and the External Carotid A. at what vertebral level?
C3-C4
The Internal Carotid A. does not branch in the neck, but it has a ________ ________ located in the proximal part.
Carotid Sinus
***Baroreceptor sensitive to increase in blood pressure
This is located in the cleft between the Internal Carotid A. and the External Carotid A.
Carotid Body
***Chemoreceptor for oxygen levels
These are terminal branches of the External Carotid A. that are located in the face.
Maxillary A.
Superficial Temporal A.
These are the terminal branches of the External Carotid A. that are located in the Anterior Triangle.
Superior Thyroid A. Lingual A. Facial A. Ascending Pharyngeal A. Occipital A. Posterior Auricular A.
This subdivision of the Anterior Triangle has the inferior border of the Mandible, and the Anterior and Posterior Digastric Bellies for its border.
Submandibular Triangle
What makes up the floor of the Submandibular Triangle?
Mylohyoid
Hyoglossus
Middle Pharyngeal Constrictor
What are the contents of the Submandibular Triangle?
Submandibular Gland Submandibular LNs Hypoglossal N. (CN XII) N. to Mylohyoid Parts of Facial A. and V.
This nerve lies on top of the Hyoglossus M.
Hypoglossal N. (CN XII)
This subdivision of the Anterior Triangle has the body of the Hyoid, and right and left Anterior Bellies of the Digastric for its border.
Submental Triangle
What makes up the floor of the Submental Triangle?
Mylohyoid muscles
What are the contents of the Submental Triangle?
Submental LNs
Small veins that unite to form Anterior Jugular V.
This subdivision of the Anterior Triangle has the Superior Belly of Omohyoid, SCM, and midline of the neck for its border.
Muscular Triangle
What muscles lie within the Muscular Triangle?
Sternohyoid
Sternothyroid
Thyrohyoid
What arteries lie within the Muscular Triangle?
Common Carotid A.
Superior Thyroid A.
Inferior Thyroid A.
***Superior Thyroid branches off External Carotid A. and Inferior Thyroid branches off Thyrocervical Trunk
What veins lie within the Muscular Triangle?
Anterior Jugular V. Thyroid Veins (Superior, Middle, and Inferior)
What is the viscera of the Muscular Triangle?
Thyroid Gland Parathyroid Gland Larynx Trachea Esophagus
What nerves lie within the Muscular Triangle?
Ansa Cervicalis
External Laryngeal N.
Recurrent Laryngeal N.
The Left Recurrent Laryngeal N. branches off the Left Vagus N. and wraps around the ______ ______, while the Right Recurrent Laryngeal N. branches off the Right Vagus N. and wraps around the _______ _______.
Aortic Arch
Subclavian A.
***Remember, you HAVE to specify Left or Right Recurrent Laryngeal N. because they are anatomically different.
If this nerve is damaged, it can result in hoarseness or loss of your voice. It is very important to watch out for when performing surgeries on the Trachea.
Recurrent Laryngeal N.
This subdivision of the Anterior Triangle has the Superior Belly of Omohyoid, Posterior Belly of Digastric, and SCM for its borders.
Carotid Triangle
What makes up the floor of the Carotid Triangle?
Thyrohyoid
Hyoglossus
Middle and Inferior Constrictor Muscles of the Pharynx
What are the contents of the Carotid Triangle?
Carotid Sheath (and its contents) Branches of External Carotid A. Internal and External Laryngeal Ns. Hypoglossal N. Spinal Accessory N. (CN XI) Ansa Cervicalis
This branch of the External Carotid A. gives rise to the Superior Laryngeal A. and supplies the Thyroid.
Superior Thyroid A.
This branch of the External Carotid A. is the only lateral branch, and lies medially to the Internal Carotid A.
Ascending Pharyngeal A.
This branch of the External Carotid A. is anterior to the Middle Pharyngeal Constrictor, deep to the Hypoglossal N., Stylohyoid M., and the Posterior Belly of Digastric. It then disappears deep to the Hyoglossus M.
Lingual N.
This branch of the External Carotid A. gives rise to the Ascending Palatine A. and Tonsillar A., and is found deep to the Submandibular Gland and angle of the Mandible (pulse point).
Facial N.
This branch of the External Carotid A. passes superficial to the Internal Carotid A. and Hypoglossal N.
Occipital N.
This branch of the External Carotid A. ascends between the External Acoustic Meatus and the Mastoid Process.
Posterior Auricular A.
Which nerve branches off the Glossopharyngeal N. (CN IX) and supplies the Carotid Body and Carotid Sinus?
Carotid Sinus N.
The Vagus N. branches into what?
Pharyngeal branch
Superior Laryngeal (Internal branch and External branch)
Carotid body branch
Besides the Vagus N., what other two Cranial Nerves lie within the Carotid Triangle?
Spinal Accessory N. (CN XI)
Hypoglossal N. (CN XII)
The Hypoglossal N. (CN XII) wraps around what artery?
Occipital A.
The Superior Laryngeal N. branches into the Internal Laryngeal N. and the External Laryngeal N. What do these nerves innervate?
Internal Laryngeal N. – Sensory to Larynx
External Laryngeal N. – Motor to Cricothyroid M.
Where do cranial nerves IX, X, and XI exit the skull?
Jugular Foramen
Explain the path of travel of the Spinal Accessory N. (CN XI).
It exits the skull via the Jugular Foramen, then runs deep to the SCM. It is then exposed for a short time (common point of injury) then runs deep into the Trapezium M.
Explain the path of travel of the Hypoglossal N. (CN XII).
It exits the skull via the Hypoglossal Canal, then wraps around the Occipital A. and dives deeps to the Posterior Belly of Digastric and Stylohyoid Ms. Then it goes superficial to the Hyoglossus M. and finishes at the tongue muscles for motor innervation.
