13.Muscles of Arm: Posterior View

Question 1

Identify

Answer 1

1. Triceps brachii muscle
2. Anconeus muscle

Question 2

Identify 1. O & I

Answer 2

1. Triceps brachii muscle

Origin (proximal): The long head of the triceps arises from the infraglenoid tubercle of the scapula. The lateral head arises from the posterior surface of the humerus. The medial head arises from the posterior surface of the humerus inferior to the radial groove.

Insertion (distal): All 3 heads of the triceps insert by a common tendon into the posterior portion of the proximal olecranon of the ulna.

Question 3

1. Triceps brachii muscle

Origin (proximal):

• The long head of the triceps arises from ___
• The lateral head arises from ___
• The medial head arises from ___

Answer 3

• the infraglenoid tubercle of the scapula.
• the posterior surface of the humerus.
• the posterior surface of the humerus inferior to the radial groove.

Question 4

Identify 1. Action?

Answer 4

1. Triceps brachii muscle

Action

• All 3 heads extend the forearm at the elbow.
• The long head of the triceps, arising from the scapula, also can extend the humerus (arm) at the shoulder joint.

Question 5

Identify 1. Innervation?

Answer 5

1. Triceps brachii muscle

Innervation: The triceps and anconeus are supplied by the radial nerve (C7 and C8).

Question 6

The triceps receives its blood supply from ___

Answer 6

1. the deep brachial artery and the superior ulnar collateral artery, which arises from the brachial artery.

Question 7

Identify 2. O & I

Answer 7

2. Anconeus muscle

Origin (proximal): Arises from the lateral epicondyle of the humerus.

Insertion (distal): The lateral aspect of the olecranon and into the upper dorsal surface of the body of the ulna.

Question 8

Identify 2. Action

Answer 8

2. Anconeus muscle

• The anconeus muscle and all 3 heads of the triceps extend the forearm at the elbow.
• The anconeus also abducts the ulna during pronation.

Question 9

Identify 2. Innervation

Answer 9

2. Anconeus muscle

Innervation: The triceps and anconeus are supplied by the radial nerve (C7 and C8).