Shoulder Joint Muscles

Question 1

Teres Major

Answer 1

Origin-Posterior surface of scapula
Insertion-lesser tubercle on anterior humerus: insertion tendon fused with that of lat dorsi
Action-extends, medially rotates and adducts the arm

Question 2

Latissimus Dorsi

Answer 2

Origin-indirect attachment into spines of lower 6 thoracic vertebrae, lower vertebrae, lower 3-4 ribs and iliac crest
Insertion-Spirals around teres major to insert in floor of intertubercular sulcus of humerus
Action-Prime mover of arm extension

Question 3

Deltoid

Answer 3

Origin-Lateral 3rd of clavicle
Insertion-Deltoid tuberosity of humerus
Action-prime mover of arm abduction

Question 4

Pectoralis Major

Answer 4

Origin-sternal end of clavicle, sternum, cartilage of ribs 1-6, and aponeurosis of external oblique muscle
Insertion-fibers coverge to insert by a short tendon into greater tubercle of humerus
Action-Prime mover of arm flexion

Question 5

Coracobrachialis

Answer 5

Origin-Coracoid process of scapula
Insertion-Medial surface of humerus shaft
Action-Flexion and abduction of arm

Question 6

Teres Minor

Answer 6

Origin-lateral border of dorsal scapular surface
Insertion-greater tubercle of humerus
Action-Laterally rotates arm

Question 7

Subscalpularis

Answer 7

Origin-Subscapular fossa of scapula
Insertion-lesser tubercle of humerus
Action-Medially rotates arm

Question 8

Infraspinatus

Answer 8

Origin- Infraspinous fossa of scapula
Insertion-Greater tubercle of humerus
Action-Laterally rotates arm

Question 9

Supraspinatus

Answer 9

Origin-Supraspinous fossa of scapula
Insertion-Greater tubercle of humerus
Action-initiates abduction of arm