Appendicular Muscles: Brachium Region

Vocabulary flashcards covering the appendicular muscles of the brachium (upper arm) region, including their origins, insertions, actions, and key joint movements.

Direction of Muscle Pull

The rule that muscles never push; they only pull the bone at their insertion toward their origin.

Adduction

Movement toward the body or toward the midline.

Abduction

Movement away from the body or away from the midline.

Coracobrachialis

A deep brachium muscle (model #15) originating on the coracoid process of the scapula and inserting on the medial aspect of the humeral shaft; acts to flex the arm and assist in shoulder adduction.

Brachialis

A muscle located deep to the biceps brachii (model #14) originating on the anterior surface of the distal half of the humerus and inserting on the coronoid process and tuberosity of the ulna; acts as the prime mover of elbow flexion.

Prime Mover of Elbow Flexion

The brachialis muscle, which does the bulk of work during elbow flexion as opposed to the biceps brachii.

Biceps brachii

A two-headed muscle (model #11) covering the coracobrachialis and brachialis; originates on the superior margin of the glenoid cavity (long head) and coracoid process of the scapula (short head), and inserts on the tuberosity of the radius and fascia of the forearm.

Supination

Forearm position or movement characterized by holding the hand as if holding a bowl of soup.

Pronation

Forearm movement characterized by dumping out a bowl of soup held in the hand.

Triceps brachii

A three-headed muscle on the posterior brachium (model #16); originates on the inferior margin of the glenoid cavity (long head) and the posterior surface of the proximal end of the humerus (lateral head), and inserts onto the olecranon or fascia of the forearm.

Actions of Triceps brachii

Extends the elbow joint, while its long head specifically extends and adducts the humerus.

Elbow Flexor Muscles

The group of muscles that flex the elbow joint, consisting of the biceps brachii, the brachialis, and the brachioradialis.

Brachioradialis

An elbow flexor muscle in the brachial region that crosses over the elbow joint and runs down into the forearm along the radius.

Anconeus

A deep muscle on the forearm involved in extension of the elbow joint alongside the triceps brachii.