Your arm is divided into the upper arm and lower arm. The upper arm consists of 1 bone, the humerus, whereas the forearm consists of 2 bones, the radius, and ulna.
The elbow is a pivot joint formed at the junction of the humerus, radius, and ulna. Couple movements occur at the elbow joint: flexion and extension. While elbow flexion, the forearm moves toward the upper arm. During extension, the forearm moves away from the upper arm. The movement also takes place in the forearm when the radius rotates around the ulna. Supination (palm up) and pronation (palm down) take place between the radioulnar joints.
The wrist joint is the junction between the lower end of the forearm bones and the small bones in the hand.
As its name suggests, the biceps brachii muscle has two heads. The short head joins to the coracoid process, and the long head arises from above the glenoid of the shoulder joint.
The 2 headed muscle passes down alongside the humerus and attaches about 4 cm below the elbow joint onto a tuberosity on the inside of the radius bone. The biceps brachii effects flexion at the elbow joint, such
as when raising the hand toward the face. The biceps brachii also causes supination of the forearm, such as when rotating the hand so that the palm faces up. In addition to the biceps brachii, 2 other muscles bend the elbow: the brachialis and brachioradialis. The brachialis muscle lies deep beneath the biceps brachii, arising from the lower half of the humerus and attaching to the ulna bone just below the elbow joint.
The brachialis lifts the ulna at the same time that the biceps brachii lifts the radius. The brachioradialis muscle arises from the outer aspect of the lower end of the humerus and then travels down the forearm to attach to the radius just above the wrist joint.
The triceps brachii muscle has three heads or sections. The long head arises from beneath the glenoid fossa of the shoulder joint, the lateral (outer) head arises from the outer surface of the humerus, and the medial (inner) head arises from the medial and rear surfaces of the humerus.
All 3 heads join at their lower ends to form a single tendon that attaches behind the elbow joint onto the olecranon process of the ulna bone. The triceps brachii causes extension at the elbow, such as when moving the hand away from the face. The triceps brachii is the only muscle that straightens the elbow joint, whereas three muscles (biceps brachii, brachialis, and brachioradialis) bend the elbow. All three heads of the triceps muscle cross the elbow joint, but the long head also crosses beneath the shoulder joint.
The forearm is a mass of 20 muscles. It has two separate muscle compartments:
One flexor group on the palm side and the extensor group on the opposite side.
The chubby muscle portions of almost all these muscles are located in the upper two-thirds of the forearm.
The muscles of the forearm are about equally distributed between those that cause movements at the wrist and those that move the fingers and thumb.
The wrist flexors and extensors are superficial (under the skin), whereas the finger flexors and extensors are deep (close to the bone). The superficial group of wrist flexors and extensors cross both the wrist and elbow joints, so, therefore, have a greater stretch when wrist curls are performed with the elbow joint straight.
The wrist flexors are the palmaris longus, flexor carpi radialis, and flexor carpi ulnaris. The wrist extensors are extensor carpi radialis longus, extensor carpi radialis brevis, and extensor carpi ulnaris.
The finger flexors are the flexor digitorum superficialis, flexor digitorum profundus, and flexor pollicis longus. The finger extensors are the extensor digitorum, extensor pollicis longus, extensor pollicis brevis, and extensor indicis. Supination, or rotating the hand so the palm faces up, is performed by the supinator and biceps brachii muscles.
Pronation, or rotating the hand so the palm faces down, is performed by the pronator teres and pronator quadratus.
The elbow is a pivot joint formed at the junction of the humerus, radius, and ulna. Couple movements occur at the elbow joint: flexion and extension. While elbow flexion, the forearm moves toward the upper arm. During extension, the forearm moves away from the upper arm. The movement also takes place in the forearm when the radius rotates around the ulna. Supination (palm up) and pronation (palm down) take place between the radioulnar joints.
The wrist joint is the junction between the lower end of the forearm bones and the small bones in the hand.
Biceps Brachii
The 2 headed muscle passes down alongside the humerus and attaches about 4 cm below the elbow joint onto a tuberosity on the inside of the radius bone. The biceps brachii effects flexion at the elbow joint, such
as when raising the hand toward the face. The biceps brachii also causes supination of the forearm, such as when rotating the hand so that the palm faces up. In addition to the biceps brachii, 2 other muscles bend the elbow: the brachialis and brachioradialis. The brachialis muscle lies deep beneath the biceps brachii, arising from the lower half of the humerus and attaching to the ulna bone just below the elbow joint.
The brachialis lifts the ulna at the same time that the biceps brachii lifts the radius. The brachioradialis muscle arises from the outer aspect of the lower end of the humerus and then travels down the forearm to attach to the radius just above the wrist joint.
Triceps Brachii
All 3 heads join at their lower ends to form a single tendon that attaches behind the elbow joint onto the olecranon process of the ulna bone. The triceps brachii causes extension at the elbow, such as when moving the hand away from the face. The triceps brachii is the only muscle that straightens the elbow joint, whereas three muscles (biceps brachii, brachialis, and brachioradialis) bend the elbow. All three heads of the triceps muscle cross the elbow joint, but the long head also crosses beneath the shoulder joint.
Forearm
The forearm is a mass of 20 muscles. It has two separate muscle compartments:
One flexor group on the palm side and the extensor group on the opposite side.
The chubby muscle portions of almost all these muscles are located in the upper two-thirds of the forearm.
The muscles of the forearm are about equally distributed between those that cause movements at the wrist and those that move the fingers and thumb.
The wrist flexors and extensors are superficial (under the skin), whereas the finger flexors and extensors are deep (close to the bone). The superficial group of wrist flexors and extensors cross both the wrist and elbow joints, so, therefore, have a greater stretch when wrist curls are performed with the elbow joint straight.
The wrist flexors are the palmaris longus, flexor carpi radialis, and flexor carpi ulnaris. The wrist extensors are extensor carpi radialis longus, extensor carpi radialis brevis, and extensor carpi ulnaris.
The finger flexors are the flexor digitorum superficialis, flexor digitorum profundus, and flexor pollicis longus. The finger extensors are the extensor digitorum, extensor pollicis longus, extensor pollicis brevis, and extensor indicis. Supination, or rotating the hand so the palm faces up, is performed by the supinator and biceps brachii muscles.
Pronation, or rotating the hand so the palm faces down, is performed by the pronator teres and pronator quadratus.
Arms
Reviewed by HealthFighter
on
February 28, 2020
Rating:
Reviewed by HealthFighter
on
February 28, 2020
Rating:
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