Flashcards in The Back Deck (16):
What are the superficial, extrinsic muscles of the back?
Trapezius and latissimus dorsi
What are the deep extrinsic muscles of the back?
Levator scapulae and rhomboid
What are the scapulo-humeral muscles in the back?
Deltoid, teres major and the four rotator cuff muscles
What affixes the trapezius to the spine?
What are the three bundles of fibres in the trapezius and what is their function?
Superior - clavicle (elevates)
Middle - inner lip of the acromium (retracts)
Inferior - spine of the scapula (pulls inferiorly)
Innervation of the trapezius
Accessory nerve (cranial nerve XI)
Function of the trapezius
Superior and inferior bundles act together to rotate the scapula upwards so the glenoid cavity can move up and out.
The arm can be abducted to 90 degrees before the trapezius is required.
Describe how you would clinically test the accessory nerve
Get the patient to shrug their shoulders against resistance.
Function of latissimus dorsi
Adduction of the arm, extends at the shoulder joint.
Medial rotation (arm inwards)
Innervation of latissimus dorsi
Thoracodorsal nerve from the posterior cord of the brachial plexus
Function of the rhomboid
Retraction and rotation of the scapula inferiorly so the glenoid cavity points upwards.
Innervation of the rhomboid
Dorsal scapular nerve from the C5 root of the brachial plexus
Function of the levator scapulae
Elevates and rotates the scapula
Innervation of the levator scapulae
Dorsal scapular nerve and cervical nerves
Function of the teres major
Adduction and medial rotation of the arm