Extrinsic Back Muscles Flashcards
What are the origins of trapezius?
Medial 1/3 of nuchal line
EOP
Ligamentum nuchae
Spinous processes of C7 - T12
How are the fibers of trapezius classified? And what are their insertion attachments?
Descending fibers (Superior) : insert on lateral 1/3 of clavicle.
Middle fibers : insert on spine and acromion process of scapula.
Ascending fibers (inferior ): base of the spine of the scapula.
What are the actions of the descending middle and inferior fibers of trapezius?
What are the bilateral and unilateral actions of trapezius?
Descending fibers: lift shoulder
Middle fibers: moves scapula towards midline. Retract scapula.
Inferior fibers: move scapula down. Depressed scapula.
Bilateral action: extend head to look back/up
Unilateral action: lateral flexion, bend head to one side
What is the innervation of trapezius ?
Motor and Sensory
Motor: Cranial nerve 11 (CNXI)
Sensory : c3 and c4 ventral Rami
Where does cranial nerve 11 run?
Exits the brain stem through the jugular foramen of the skull.
Runs deep to the sternocleidomastoid muscle.
Runs obliquely from mastoid process and forms part of subtrapezial plexus.
What is a plexus?
A network of nerves
What artery supplies blood to the superior fibers of trapezius ?
The occipital artery
Where does the occipital artery Branch from and where does it run?
Branches from the external carotid artery.
Runs in occipital groove (medial to mastoid notch)
Ascends and runs along occipital bone.
What is the first branch from the subclavian artery and where does it run?
Bonus: what is the risk here?
The vertebral artery.
Runs in the transverse foramina of the cervical vertebrae.
Potential risk of dissection during adjustment.
Where does the thyroservical trunk Branch from? In what section?
The thyrocervical trunk branches from the first section of the subclavian artery medial to the anterior scalene muscle.
What artery branches from thyrocervical trunk?
The transverse cervical artery
What artery supplies blood to the middle fibers of trapezius?
The transverse cervical artery
What trunk branches from the subclavian artery deep to the anterior scalene muscle?
The costocervical trunk
What artery branches from the subclavian lateral to anterior scalene and median to rib 1?
Dorsal scapular artery
What artery provides blood supply to ascending (inferior) fibers of trapezius?
Dorsal scapular artery