Anatomy- Posterior Shoulder and Rotator cuff Flashcards
what are the axio-appendicular muscles
(originate from the torso) trapezius, rhomboid minor and major, serratus anterior, subclavius, latissimus dorsi levator scapulae
what nerve innervates the levator scapulae
dorsal scapula nerve
what are the 4 rotator cuff muscles
supraspinatus
infraspinatus
teres minor
subscapularis
where do the rotator cuff muscles insert
teres minor and supra and infraspinatus insert onto the greater tuberosity
subscapularis inserts into the lesser tuberosity
what are the roles of the rotator cuffs
hold head of humerus in the glenoid fossa
first 15 degrees of abduction of arm done by supraspinatus
infraspinatus and teres minor are lateral rotators
subscapularis is a medial rotator
how much of humeral head is in contact with the glenoid fossa at any time
1/3rd
what is the muscle of the posterior compartment of the arm
triceps brachii
what nerve innervates the triceps brachii
radial
what are the actions of the triceps brachii
extension of arm and forearm
what is the proximal attachment of the trapezius
medial third of superior nuchal line, external occipital protuberance, nuchal ligament, spinous processes of C7-T12 vertebrae
what is the distal attachment of the trapezius
lateral third of clavicle, acromion and spine of scapula
what innervates the trapexius
spinal accessory nerve (CN XI motor fibres), C3,C4 spinal nerves (pain and proprioceptive fibres)
what is the muscle action of the trapezius
descending part elevates
ascending part depresses
middle parts (all parts together) retracts the scapula
descending and ascending parts act together to rotate glenoid cavity superiorly
what is the proximal attachment of the latissimus dorsi
spinous processes pf inferior 6 thoracic vertebrae, thoracolumbar fascia, iliac crest, inferior 3/4 ribs
what is the distal attachment of the latissimus dorsi
floor of intertubercular sulcus of humerus
what innervates the latissimus dorsi
thoracodorsal nerve (C6,7,8)
what is the muscle action of the latissimus dorsi
extends, adducts and medially rotates humerus
raises body towards arms during climbing
what is the proximal attachment of the levator scapulae
posterior tubercles of transverse processes of C1-C4 vertebrae
what is the distal attachment of the levator scapulae
medial border of scapula superior to root of scapula spine