OIAN 12

Question 1

Teres major

Answer 1

Origin:
- Lower 1/3rd of the scapula’s lateral border
Insertion:
- Medial lip of the bicipital groove of the humerus
Action:
- Internally rotates the arm
- Extends the arm (from a flexed position)
- Adducts the arm
Nerve:
- Lower subscapular
- C 5,6

Question 2

Subscapularis

Answer 2

Origin:
- Subscapular fossa
Insertion:
- Lesser tubercle of the humerus
- Capsule of the shoulder joint
Action:
-  Internally rotates the arm
Nerve:
- Upper and lower subscapular   
- C5,6

Question 3

Subclavius

Answer 3

Origin:
- First rib
Insertion:
- Inferior surface of clavicle
Action:
- Depresses and stabilizes clavicle
Nerve:
- Nerve to the subclavius
- C5,6

Question 4

Pectoralis major

Answer 4

Origin:
- Medial portion of clavicle
- Sternum and upper 6 costal cartilages
Insertion:
- Lateral lip of the bicipital groove
Action:
-  Adducts the arm
- Internally rotates the arm
- Horizontal Adduction of arm
- Flexes the shoulder (from an extended position)
- Depresses the arm & shoulder
Nerve:
- Clavicular portion: lateral pectoral
- C 5,6,7
- Sternal portion: medial pectoral
- C8, T1

Question 5

Pectoralis minor

Answer 5

Origin:
- Outer and anterior surface of ribs 3-5 near cartilage
Insertion:
- Coracoid process
Action:
-  Depresses the scapula
- Downwardly rotates the scapula
Nerve:
- Medial pectoral
- C8, T1