Muscles of the posterior compartment of the arm (extensors) JO

Question 1

Name this muscle:
State its Origin(s), Insertion(s), Innervation(s), and Action(s)

Answer 1

Triceps
Origin: Long head: infraglenoid tubercle of scapula; lateral head: posterior-superior surface (laterally) of humerus; medial head: posterior-inferior surface (medially) of humerus
Insertion: Posterior surface of the olecranon and fascia of the forearm
Innervation: Radial nerve (C6, C7, C8)
Action: Extends the elbow joint; long head also extends the shoulder joint

Question 2

Name this muscle:
State its Origin(s), Insertion(s), Innervation(s), and Action(s)

Answer 2

Anconeus
Origin: Posterior surface of lateral epicondyle of humerus
Insertion: Lateral aspect of the olecranon process and superior part of posterior ulna
Innervation: Radial nerve (C7, C8, T1)
Action: Assists triceps in producing elbow extension; plays a small role in forearm pronation