posterior shoulder and rotator cuff muscles Flashcards
parts of deltoid and their function
posterior (spinal) : extends shoulder
middle (acromial) : abduct shoulder (taking over for supraspinatus above 15 degrees)
anterior (clavicular): flex shoulder
what does the trapezius do?
ascending, middle, and descending parts of trapezius: scapular depression, retraction and elevation respectively (ascending and descending parts contracting together produce superior rotation of glenoid fossa)
what does the elevator scapulae do?
elevates scapula and inferior rotation of glenoid fossa
what are the rhomboids?
rhomboid major: retracts scapula and inferior rotation of glenoid fossa
rhomboid minor: retracts scapula and inferior rotation of glenoid fossa
rotator cuff muscles?
supraspinatus: stabilize head of humerus/ first 15 degree abduction at shoulder
infraspinatus: stabilize head of humerus/LATERAL rotation at shoulder
teres minor: stabilize head of humerus in glenoid/LATERAL rotation at shoulder
subscapularis: stabilize head of humorous in glenoid/MEDIAL rotation at shoulder
what does teres major do?
adduction/medial rotation at shoulder
what muscles attach to the pectoral girdle?
pectorals major, minor, and serrates anterior
why is superior rotation of scapula important?
allows us to fully abduct our upper limb, it is required to prevent the greater tubercle of humerus from impinging on the acromion of scapula
where do the rotator cuff muscles attach?
scapula proximally and tubercles of head of humerus distally (all but subscapularis: greater tubercle, subscapularis: lesser tubercle)
what do the distal tendons of the rotator cuff do?
blend with and reinforce fibrous capsule of shoulder joint
innervation of rotator cuff?
brachial plexus
what is painful arc syndrome?
impingement of supraspinatus tendon between the humerus and the acromion process, pain during 50-130 of abduction
