Muscles of the Upper Arm

Question 1

Brachialis

Answer 1

Anterior

Origin: distal half of anterior surface of humerus and inter muscular septa

Insertion: ulnar tuberosity and joint capsule

Action: flexor of elbow joints, slight retroversion at shoulder joint

Question 2

Biceps Brachii

Answer 2

Anterior

Long head origin: supraglenoid tubercle

Short head origin: coracoid process

Insertion: radial tuberosity and ante brachial fascia on ulnar side

Action: abducts arm and rotates it medially, short head of adductor, ante version of shoulder joint, supinator of elbow joint

Question 3

Triceps Brachii

Answer 3

Posterior

Long head origin: infraglenoid tubercle of scapula

Short head origin: distally from groove for radial nerve (posterior humerus)

Lateral head origin: posterior surface of humerus, lateral and proximal to groove for radial nerve

Insertion: olecranon of ulna and posterior wall of capsule

Action: extensor of elbow joint, retroversion/adduction of the arm

Question 4

Anconeous

Answer 4

Posterior

Origin: posterior surface of lateral epicondyle and radial collateral ligament

Insertion: proximal fourth of posterior ulna

Action: produces extension, tenses capsule of elbow joint