Muscles- extension

Question 1

Triceps brachii

Answer 1

O: long head–> infraglenoid tubercle
medial head –> lower part of posterior surface of humerus
lateral head –> upper part of posterior surface of humerus
I: posterior surface olecranon of ulna
I: radial nerve C6-C8
A: extension of the elbow
long head also extends and adducts the shoulder joint

Question 2

Anconeus

Answer 2

O: lateral epicondyle of humerus
I: olecranon and upper part of ulnar shaft
I: radial nerve C7,C8
A: extends the elbow