2 Muscles of the shoulder Flashcards
What is the resting function of the rotator cuff muscles?
To pull head of humerus into glenoid cavity
What are the four rotator cuff muscles?
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
What movemenys of the glenohumeral jiont are generated by the rotator cuff muscles?
Abduction adduction
Lateral medial rotation
Where does subscapularis attach?
Subscapularis fossa on scapula to lesser tubercle of humerus
What is the innervation of the subscapularis?
Upper and lower subscapular nerves
What is the function of subscapularis?
To medially rotate the arm
Where does the supraspinatus attach?
Supraspinous fossa of scapula to greater tubercle of humerus
What is the innervation of supraspinatus?
Suprascapular nerve
What is the function of the supraspinatus?
Abduct arm from 0-15°
Assists deltoid in abduction from 15-90°
Where does the infraspinatus attach?
Infraspinous fossa of scapula to greater tubercle of humerus
What is the innervation of infraspinatus?
Suprascapular nerve
What is the function of the infraspinatus?
Lateral rotation of arm
Where does teres minor attach?
Posterior surface of scapula adjacent to lateral border to greater tubercle of humerus
What is the innervation of teres minor?
Axillary nerve
What is the function of teres minor?
Laterally rotate arm
What are the three divisions of the deltoid?
Anterior middle posterior
Where does the deltoid attach?
Scapula and clavicle to deltoid tuberosity of humerus
What is the innervation of the deltoid?
Axillary nerve
What is the function of the deltoid?
Anterior - flexion of arm at shoulder
Middle - abduction of arm 15-90°
Posterior - extension of arm at shoulder
Where does teres major attach?
Posterior surface of inferior angle of scapula to intertubercular groove of humerus
What is the innervation of teres major?
Lower subscapular nerve
What is the function of teres major?
Adducts the shoulder
Medially rotates the arm
What are the intrinsic muscles of the shoulder?
Muscles that originate from scapula and/or clavicle and attch to humerus
What are the six intrinsic muscles of the shoulder?
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
Deltoid
Teres major
What is the common injury which results in trapped axillary nerve?
Fracture of surgical necj of humerus
Skin over shoulder (officers badge) would have loss of sensation
What are extrinsic muscles of the shoulder?
Muscles that originate from torso and attach to bones of the shoulder
Also known as superficial back muscles
What are the layers of extrinsic muscles of the shoulder?
Superficial - trapezius, latissimus dorsi
Deep - levator scapulae, rhomboid major, rhomboid minor
