Posterior compartment of the arm

Question 1

triceps brachii

Answer 1

O: long head: infraglenoid tubercle
lateral head: proximal half of posterior humerus
Medial head: distal posterior humerus
I: olecranon process
A: elbow extension
long head: shoulder adduction and shoulder extension from flexed
I: radial

Question 2

Anconeus

Answer 2

O: lateral epicondyle of humerus, posterior surface
I: olecranon process and shaft of ulna
A: elbow extension
I: radial