Muscles Of The Glenohumeral Joint

Question 1

Deltoid

Answer 1

Origin- lateral clavicle, acromion process and the spine of the scapula

Insertion- deltoid tuberosity of the humerus

Functions-
Anterior fibres- flexion and medial rotation of the arm at the GH joint
Middle fibres- abduction of the arm at the GH joint
Posterior fibres- extension and lateral rotation of the arm at GH joint

Question 2

Coracobrachialis

Answer 2

Origin- coracoid process of the scapula

Insertion- medial shaft of the humerus

Functions- flexes and adducts the arm at the GH joint

Question 3

Pectoralis major

Answer 3

Origin- medial clavicle, sternum and the costal cartilages of ribs 1-7

Insertion- lateral lip of the bicipital groove of the humerus

Functions- adducts, medial rotates and flexes the arm at GH joint
Extension of the flexed arm

Question 4

Latissimus Dorsi

Answer 4

Origin- spinous process of T7-L5 , posterior sacrum and the posterior iliac crest

Insertion- medial lip of the bicipital groove of the humerus

Functions- medial rotate, adducts and extends the arm at the GH joint

Question 5

Teres major

Answer 5

Origin- inferior angle and inferior lateral border of the scapula

Insertion- medial lip of the bicipital groove of the humerus

Functions- medial rotates, adducts and extends the arm at the GH joint

Question 6

What are the rotator cuff muscles ?

Answer 6

Supraspinatus

Infraspinatus

Teres minor

Subscapularis

Question 7

Supraspinatus

Answer 7

Origin- supraspinous fossa of the scapula

Insertion- greater tubercle of the humerus

Functions- abducts and flexes the arm at the GH joint

Question 8

Infraspinatus

Answer 8

Origin- infraspinous fossa of the scapula

Insertion- greater tubercle of the humerus

Functions- laterally rotates arm at the GH joint

Question 9

Teres minor

Answer 9

Origin- superior lateral border of the scapula

Insertion- greater tubercle of the humerus

Functions- laterally rotates arm at the GH joint

Question 10

Subscapularis

Answer 10

Origin- subscapular fossa of the scapula

Insertion - lesser tubercle of the humerus

Functions- medially rotates the arm at the GH joint