Muscles

Question 1

Biceps brachii

Answer 1

Origin: long head: supraglenoid tubercle
: short head: apex of coracoid process
Insertion: Radial tuberosity + bicipital aponeurosis to fascia of forearm
Action: assists flexion of shoulder
: flexes elbow
: supinates forearm
Innervation: Musculocutaneous nerve C5-6

Question 2

Brachialis

Answer 2

Origin: distal half of shaft of humerus
Insertion: Ulna tuberosity + coronoid process
Action: flexes elbow
Innervation: musculocutaneous nerve C5-6

Question 3

Brachioradialis

Answer 3

Position: superficial layer of muscles on lateral aspect extending from elbow to almost wrist
Origin: Lateral supracondylar ridge of humerus
Insertion: lateral surface of radius (proximal to radial styloid process)
Action: flexes elbow in neutral
: returns supinated/pronated forearm to neutral
Innervation: Radial nerve C5-6

Question 4

Triceps Brachii

Answer 4

Position: posterior aspect of upper arm - making up muscle bulk in this region
Origin: long head: infraglenoid tubercle
lateral head: upper posterior humerus
medial head: lower posterior humerus (radial/spiral groove separates the attachments)
Insertion: posterior surface of the olecranon
Action: extends elbow
: long head: assists shoulder extension
: assists shoulder adduction
Innervation: Radial nerve C6-8

Question 5

Anconeus

Answer 5

Origin: Lateral epicondyle of humerus
Insertion: Olecranon and upper ulnar shaft
Action: extends elbow
Innervation: Radial nerve C7-8

Question 6

Supinator

Answer 6

Origin: Lateral epicondyle of humerus
: Supinator fossa + crest of ulna (inferior to radial notch) + radial collateral + annular ligaments
- radial nerve passes between two heads
Insertion: posterior, lateral and anterior surfaces of proximal 1/3 of radius
Action: Supinates forearm
Innervation: deep branch of Radial nerve C5-6

Question 7

Pronator Teres

Answer 7

Origin: Medial epicondyle of humerus
: Coronoid process of ulna
Insertion: middle of lateral surface of radius
Action: pronates forearm
: assists elbow flexion
Innervation: Median nerve C6-7 (passes between two heads)

Question 8

Pronator Quadratus

Answer 8

Origin: Distal anterior surface of ulna shaft
Insertion: distal anterior surface of radial shaft
Action: Pronates forearm
: Stabilises bones in weightbearing
Innervation: Anterior Interosseous Nerve C8-T1