Muscles Of The Neck Flashcards
What are the 2 main muscles moving the head?
SCM and trapezius
Action of the SCM
Unilaterally - laterally flexes the head (ispilaterally) and rotates head to opposite side
Bilaterally - flexes the head anteriorly
Nerve supply of the SCM
Accessory nerve CNXI (roots C2-3)
Origins of the SCM
2 origins:
One on anterior surface of manubrium of sternum, one on the medial third of the clavicle
Insertion of the SCM
Mastoid process (and superior nuchal line of occiput)
Innervation of trapezius
Accessory nerve (roots C3-4)
Action of trapezius
Unilaterally - flexes the head ipsilaterally
Bilaterally - 2 muscles raise the head together with vertebral column
Origins of trapezius
Arises from the occipital protuberance, superior nuchal line, ligamentum nuchae, C7 spinous process and T1-T12 spinous processes
From the origins, there are superior, middle and inferior fibres that insert. What are their insertions?
Superior fibres insert into posterior border of lateral third of clavicle
Middle fibres insert into medial margin of the acromion
Inferior fibres insert into an aponeurosis which insert on the scapular spine more medially
Action of superior middle inferior fibres?
A lot
What fascia envelopes the SCM and trapezius?
Investing layer of fascia
Where does the ligamentum nuchae break down after and what does it allow?
It breaks down after C7, allowing the vertebral arteries to enter the transverse foramen.
What does the anterior triangle of the neck split into?
Muscular, carotid, submandibular (digastric), submental
What does the posterior border of the neck divide into?
Occipital, subclavian
What is the action of the suprahyoid muscles and what are they?
Elevate the hyoid and larynx during swallowing. Form part of the floor of the mouth.
Mylohyoid, stylohyoid, geniohyoid, digastric
