Arm/Shoulder/Forearm Muscles

Alex DayJanuary 2010

Arm/Shoulder MusclesBiceps brachii

Scapula of shoulder girdle

Proximal radius

Flexes elbow and supinates forearm

Brachialis Distal Humerus Proximal Ulna Flexes ElbowDeltoid Scapular spine

and clavicleHumerus (deltoid tuberosity)

Abducts arm

Biceps BrachiiThe biceps has several functions, the most important being to rotate the forearm and to flex the elbow.

The biceps is tri-articulate, meaning that it works across three joints. 1. Proximal radioulnar joint – 2. Humeroulnar joint – (Elbow)3. Glenohumeral joint –

(Shoulder)

BrachialisA muscle in the upper arm that flexes the elbow joint. It lies just deep of the biceps brachii, and is a synergist that assists the biceps brachii in flexing at the elbow.

The brachialis is the strongest flexor of the elbow.

Deltoid-The muscle forming the rounded contour of the shoulder.-An important function of the deltoid in humans is stopping : preventing the dislocation of the humeral head when a person carries heavy loads.

1.The anterior fibers are involved in shoulder abduction when the shoulder is externally rotated.2. The posterior fibers are strongly involved in transverse extension3. The lateral fibers are involved in shoulder abduction when the shoulder is internally rotated, are involved in shoulder flexion when the shoulder is internally rotated, and are involved in shoulder transverse abduction (shoulder externally rotated)

Arm/Forearm MusclesTriceps Brachii Shoulder

girdle and Proximal humerus

Olecranon process of ulna

Extends ulna

Flexor carpi radialis

Distal Humerus 2nd and 3rd metacarpals

Flexes wrist, abducts hand

Flexor Carpi Ulnaris

Distal Humerus and Posterior Ulna

Carpals of wrist and 5th metacarpal

Flexes wrist, abducts hand

Flexor Digitorum Superficialis

Distal Humerus, ulna and radius

Middle phalanges of 2nd to 5th fingers

Flexes wrist and fingers

Extensor carpi radialis

Humerus Base of 2nd and 3rd metacarpals

Extend wrist and abducts hand

Extensor Digitorum

Distal humerus Distal phalanges of 2nd to 5th fingers

Extends fingers and wrist

Triceps BrachiiThe large muscle on the back of the human upper limb. It is the muscle principally responsible for extension of the elbow joint (i.e. straightening of the arm).

1.The three heads have the following names and origins: The "Long head": infraglenoid tubercle of the scapula. 2. The "Lateral head": posterior shaft of the humerus, lateral and superior to the radial (spiral) groove.3. The "Medial head": posterior shaft of the humerus, medial and inferior to the radial (spiral) groove

Flexor Carpi RadialisA muscle of the human forearm that acts to flex and abduct the hand.

Flexor Carpi Ulnaris-A muscle of the human forearm that acts to flex and adduct the hand.-Flexor carpi ulnaris muscle arises by two heads - humeral and ulnar

Flexor Digitorum Superficialis

An extrinsic flexor muscle of the fingers at the proximal interphalangeal joints.-The muscle has two classically described heads - the humeroulnar and radial.

The primary function of flexor digitorum superficialis is flexion of the middle phalanges of the fingers at the proximal interphalangeal joints, however under continued action it also flexes the metacarpophalangeal joints and wrist joint.

Extensor Carpi Radialis

It is one of the five main muscles that control movements at the wrist. This muscle is quite long, starting on the lateral side of the humerus, and attaching to the base of the second metacarpal bone (metacarpal of the index finger).

Extensor Digitoruma muscle of the posterior forearm present in humans and other animals. It extends the medial four digits of the hand.-It divides below into four tendons

-The tendons then diverge on the back of the hand, and are inserted into the middle and distal phalanges