Pectoral girdle and shoulder 2: rotator cuff Flashcards
what is the rotator cuff
group of 4 muscles that help keep head of humerus in the glenoid cavity of scapula
the rotator cuff surrounds the joint capsule except where
at most inferior aspect where a small gap remains
what is the most common direction to dislocate the shoulder
towards gap in an antero-inferior direction
what are the 4 muscles of the rotator cuff
subscapularis
supraspinatus
infraspinatus
teres minor
which of the rotator cuff muscles is considered the odd one out
subscapularis
what are the attachments of subscapularis
subscapular fossa on anterior surface of scapula to lesser tubercle of humerus
what is the innervation of subscapularis
upper and lower subscapular nerves (C5,6,7) from posterior cord of brachial plexus
what does subscapularis do
medially rotates arm and reinforces anterior surface of capsule
why is subscapularis the odd one out
- lies on anterior surface (others are posterior)
- attaches to the lesser tubercle (others are greater)
- medially rotates the arm (2 of the others laterally rotate)
what are the attachments of supraspinatus
supraspinous fossa of scapula (posterior) to greater tubercle of humerus (upper facet)
supraspinatus passes over the ____ surface of the joint
lateral
action of supraspinatus
abducts arm first 10-15 degrees
what is the innervation of supraspinatus
suprascapular nerve (C5,6) from superior trunk of brachial plexus
what can happen if the tendon of supraspinatus becomes inflamed
it can become entrapped in small space near humerus that is passes through
what are the attachments of infraspinatus
infraspinous fossa of scapula (posterior) to greater tubercle of humerus (middle facet)
what is the action of infraspinatus
lateral rotation of arm
what is the innervation of infraspinatus
suprascapular nerve (C5,6) from superior trunk of brachial plexus
the suprascapular nerve (C5,6) innervates what muscles of the rotator cuff
infraspinatus
supraspinatus
what muscle attaches to the upper facet of the greater tubercle of the humerus
supraspinatus
what muscle attaches to the middle facet of the greater tubercle of humerus
infraspinatus
what muscle attaches to the lower facet of the greater tubercle of humerus
teres minor
what are the attachments of teres minor
upper 2/3 lateral border of scapula to greater tubercle of humerus (lower faet)
what is the innervation of teres minor
axillary nerve (C5,6) branch of posterior cord of brachial plexus
what is the function of teres minor
lateral rotation of arm
teres minor attaches to the lateral border of the scapula between what 2 muscles
long head triceps and teres major
what 2 muscles of the rotator cuff are lateral rotators of the arm
teres minor and infraspinatus
what is the innervation of the rotator cuff
subscapularis - subscapular nerve
supraspinatus - suprascapular nerve
infraspinatus - suprascapular nerve
teres minor - axillary nerve
