ANATOMY- Neck Musculature
What does the brachial plexus supply?
All motor and sensory to your upper limbs
What innervates the infrahyoid muscles (specifically the omohyoid and sternohyoid)?
Ansa cervicalis (C1-C3) Note that in this loop, you have a superior and inferior root
Name the parts of the cervical plexus
Ansa cervicalis (C1-C3), lesser occipital (C2), greater auricular (C2-C3), transverse cervical (C2-C3), supraclavicular (C3-C4), phrenic nerve (C3-C5)
What form the scalene hiatus?
Anterior and Middle scalenes
Name your suprahyoid muscles of your anterior cervical triangles.
Anterior and Posterior belly of your digastric, stylohoid, mylohyoid, and geniohyoid
What are the boundaries of your posterior cervical triangle?
Anterior border: SCM Posterior border: Upper trapezius Base: clavicle
What structure comes out of the scalene hiatus?
Brachial plexus
What CN innervates the geniohyoid?
C1 via the hypoglossal nerve (CN XII)
What CN innervates the anterior belly of the digastric?
CN V- Trigeminal
What CN innervates the mylohyoid?
CN V- Trigeminal
What CN innervates the stylohyoid?
CN VII
What CN innervates the posterior belly of the diagastric?
CN VII- Facial
What happens if you had a tumor on your parathyroid?
Calcium levels start secreting a lot of PTH and levels get really high- one way to recognize a tumor
What happens if your parathyroid gland stops working?
Calcium levels will drop, tetany
What are the contents of your carotid triangle?
Carotid sheath (common carotid artery and bifurcation, vagus nerve and IJ)
What are the total content of nerves found in the occipital triangle?
Cervical plexus nerves, brachial plexus (5 Rami and 3 trunks), spinal accessory nerve CN XI
What does the zygomatic bone form?
Cheek
In order to test the function of the trapezius muscle, what can you tell the patient to do?
Elevate (or shrug) shoulders
Where are your parathyroid glands located?
Embedded in your thyroid gland
What vein cross the sternocleidomastoid?
External jugular
What CN innervates the platysma?
Facial Nerve CN VII
The intermediate tendon of the anterior and posterior bellies of the digastric are fastened down to the hyoid by the ____ ____.
Fascial sling
Your ____ ____ is how the hyoid can be lifted by the digastric muscles.
Fascial sling
Where do the anterior and middle scalene muscle attach?
First rib
What does the frontal bone form?
Forehead
What innervates the thyrohyoid?
Hypoglossus CN XII via C1
What tendon connects the anterior and posterior bellies of the digastric?
Intermediate tendon
What is a good reference point to find your ansa cervicalis?
Internal Jugular vein- the ansa cervicalis overlies the IJ laterally **Remember Dr. Thomas was super jazzed about the ansa cervicalis on the cadaver!**
What nerves originate in the occipital triangle?
Lesser occipital nerve, auricular nerve, transverse cervical nerve, and supraclavicular nerve - All these nerves originate in the occipital triangle
What blood vessel is in the occipital portion of the posterior cervical triangle?
Lower 1/3 of the External Jugular Vein (then enters the subclavian triangle where it terminates in the subclavian vein)
What are the boundaries of your submandibular triangle?
Mandible, anterior belly of digastric, posterior belly of digastric/stylohyoid
Erb's Point marks the emergence of the _____ plexus nerves, and the point where ____ and ____ emerge.
Marks location of emergence of all cervical plexus nerves, and marks the point where C5 and C6 VPR emerge
With your _____ trapezius, fibers are running horizontally so can allow to retract scapula
Middle
What divides the 2 anterior cervical triangles?
Midline of neck
Where does your platysma originate and insert?
O: skin of clavicle I: skin of jaw
In the upper trapezius muscle, what is the origin and insertion?
O: superior nuchal line of the skull I: spine of scapula and acromion
In the middle and lower trapezius muscle, what is the origin and insertion?
O: thoracic vertebrae I: spine of scapula, acromion, and lateral clavicle
What are the two triangles that the omohyoid muscle creates?
Occipital triangle and Subvlavian (Omoclavicular) triangle
If you were to damage your brachial plexus in a neck injury, what would happen?
Paralysis to upper limbs
What is meant by the ORIGIN of a muscle?
Part that is stable or not moving
What is meant by the INSERTION point of a muscle?
Part that's moving
What muscle is known as your "grimacing" muscle?
Platysma
What 2 veins branch off the external jugular vein?
Retromandibular (in front of ear) and posterior auricular vein (behind ear)
When you turn your head to the left, your (right/left) SCM is working.
Right
How does the omohyoid muscle get to the posterior cervical triangle?
Runs up from scapula, passes deep to the SCM, then attaches into hyoid.
What is the difference in location of the subclavian artery and the subclavian vein?
SCA goes through the scalene hiatus and exits through the scalene hiatus SCV does not go through the scalene hiatus; it is anterior to the scalene hiatus
What muscle divides the anterior and posterior cervical triangles?
SCM
What are the boundaries of the anterior cervical triangles?
SCM, Body of Mandible, Midline of the neck (line down the midline of the neck connecting the mental protuberance and the suprasternal jugular notch
Where does the posterior scalene muscle attach?
Second rib
What CN innervates the trapezius and SCM?
Spinal Accessory Nerve XI ; all the XI does is innervate these 2!
Where does the brachial plexus originate?
Spinal cord segments
Which artery supplies blood to the entire upper limbs?
Subclavian artery
What are the contents of the subclavian (omoclavicular) triangle?
Subclavian artery, subclavian vein, distal branches of supraclavicular nerve, and termination of the external jugular vein (in subclavian vein)
What is the relationship between the lingual nerve and the submandibular duct?
Submandibular duct goes OVER the lingual nerve
What is the relationship between the mylohyoid and the submandibular gland?
Submandibular gland hooks around mylohyoid
What are your 4 anterior cervical smaller triangles?
Submandibular triangle, submental triangle, carotid triangle, muscular triangle
What are your superficial infrahyoid muscles?
Superior belly of the omohyoid and the sternohyoid
What two points does the the sternocleidomastoid run from?
The sternocleidomastoid muscle runs obliquely from the mastoid process to the sternum and clavicle
In the anterior cervical triangle, what is the suprahyoid muscles main function?
To elevate the hyoid and help you swallow
Which spinal cord segments does the brachial plexus specifically come off from?
Upper trunk: C5 and C6 Middle trunk: c7 Lower trunk: C8-T1
Explain how babies form their mastoid process
When babies are born, their mastoid process is smooth. As they continue to develop and start to lift their head using their sternocleidomastoid muscle, this muscle puts stress on the bone and causes the mastoid process to be pointy.
Explain how the suprahyoid muscles help you swallow?
When the suprahyoid muscles are contracted, they lift the hyoid up, epiglottis falls and covers nasopharynx. Once the muscles are relaxed, the hyoid bone comes back down and epiglottis comes open again
What process runs lateral to the spine of the scapula and helps form the shoulder?
acromion process
Where are your deep cervical nodes located?
along your SCM
What does the transverse cervical nerve innervate?
anterolateral side of your neck
What are the contents of your submandibular triangle?
apex of parotid gland, facial artery and vein, submandibular gland
What does the greater auricular nerve innervate?
around ear and parotid gland
What are the boundaries of your muscular triangle?
artifical line, superior omohyoid, SCM
What are the boundaries of your submental triangle?
artificial line, hyoid bone, anterior belly of digastric
What does the nasal bone form?
bridge of your nose
In the sternocleidomastoid muscle, the fibers that run laterally and attach to the clavicle are known as _____.
clavicular fibers of the sternocleidomastoid muscle
The SCM is (superficial/deep) to the external jugular.
deep
The external jugular is (superficial/deep) to the platysma.
deep
What covers (or makes the "roof") of the anterior cervical triangles?
deep cervical investing fascia
What is covering the posterior cervical triangle?
deep cervical investing fascia
The anterior jugular vein terminates at the ____ _____ ____.
external jugular vein
You can always differentiate the mylohyoid from other muscles by this feature
fibers running crossways and flat muscle
What does the supraclavical nerve innervate?
general sensation around your clavicle
What other muscle is also innervated by CN XII via C1?
geniohyoid
Where are the anterior cervical triangles located?
in front of the SCM
Which branch of the Trigeminal specifically innervates the mylohyoid and anterior belly of the digastric?
inferior alveolar branch
What muscle divides the posterior cervical triangle into 2 more triangles?
inferior belly of the omohyoid
What are the contents of your muscular triangle?
infrahyoid muscles (except omohyoid because it is a boundary), larynx and associated structures (intrinsic muscles and membranes), thyroid gland, and trachea-cervical portion
What are the visceral structures seen in your anterior cervical triangle?
larynx, common carotid artery, IJ, trachea (cervical portion and pre-tracheal fascia), thyroid gland-isthmus and lateral lobes, vagus nerve, submandibular gland
What nerves make up the cervical plexus?
lesser occipital nerve (C2), greater auricular nerve (C2-C3), transverse cervical nerve (C2-C3), and supraclavicular nerve (C3-C4)
What 2 muscles make up the "floor" of the posterior cervical triangle?
levator scapulae and splenius capitis
What does the lesser occipital nerve innervate?
lower portion of head behind ear
What is the bump on your chin or the "chin" of the jaw?
mental protuberance
Where are your anterior cervical nodes located?
midline of neck
What is the most superficial part of your anterior cervical triangles that covers everything?
platysma
What is the most superficial structure on both anterior cervical triangles?
platysma
The upper trapezius muscle is the part that physically covers the _____ aspect of your neck
posterior
What are the boundaries of your carotid triangle?
posterior belly of digastric/stylohyoid, superior omohyoid, SCM
Where is your posterior cervical triangle located?
space that exists right behind SCM
What runs in transverse fashion to the scapula?
spine of the scapula
In the sternocleidomastoid muscle, the fibers that run medially and attach into the sternum portion are known as ____.
sternal portion of the sternocleidomastoid muscle
The ______ runs medially to the superior belly of the omohyoid.
sternohyoid
What vein does the external jugular vein eventually drain in to?
subclavian vein
What are the contents of your submental triangle?
submental lymph nodes, mylohyoid (floor), geniohyoid, anterior jugular vein
What is the deep muscle of the infrahyoid?
thyrohyoid
What is the function of the parathyroid glands?
to secrete PTH (parathyroid hormone) and regulate calcium levels
Where do all 3 scalenes originate from?
transverse process of cervical vertebrae
What are your infrahyoid muscles responsible for?
when they contract, these muscles pull hyoid back down to starting position in the swallowing process
What kind of injury can affect the infrahyoid muscles?
whip-lash injury
