OIAN 13

Question 1

Coracobrachialis

Answer 1

Origin:
- Coracoid process
Insertion:
- Medial shaft of humerus about midway down
Action:
- Flexes the shoulder
- Assists to adduct the humerus
Nerve:
- Musculocutaneous 
- C5,6,(some 7)

Question 2

Biceps brachii

Answer 2

Origin:
- Long head: supraglenoid tubercle and glenohumeral labrum
- Short head: coracoid process
Insertion:
- Radial tuberosity
- Bicipital aponeurosis
Action:
- Flexes the elbow (more when supinated)
- Supinates the forearm from neutral
- Flexes shoulder (when palm facing up)
Nerve:
- Musculocutaneous 
- C5,6,(some 7)

Question 3

Brachialis

Answer 3

Origin:
- Lower half of anterior humerus
Insertion:
- Ulnar tuberosity
- Coronoid process of ulna slightly
Action:
- Flexes the elbow
Nerve:
- Musculocutaneous 
- C5,6,(some 7)

Question 4

Triceps brachii

Answer 4

Origin:
- Long head:  infraglenoid tubercle
- Lateral head:  upper half of the posterior humerus
- Medial head:  lower 1/4th of posterior humerus
Insertion:
- Olecranon process
Action:
- Long head:  extends the elbow, adducts the shoulder, may assist in shoulder extension  from a flexed position
- Lateral head: elbow extension
- Medial head: elbow extension
Nerve:
- Radial
- C7,8

Question 5

Anconeus

Answer 5

Origin:
- Lateral epicondyle of the humerus
Insertion:
- Lateral surface of the olecranon process
Action:
- Elbow extension
- Supports the elbow when in full extension
Nerve:
- Radial
- C7,8