Muscles of the Arm and Elbow120.105.184.250/lwcheng/anatomy/e_books/Muscles_of_the... · 2013. 11....

Muscles of the Arm and Elbow

Actions of the Arm at the Elbow

• Flexion: bending at the elbow

• Extension: straightening at the elbow

• Pronation: moving the arm in a palms

down position

• Supination: moving the arm in a palms up

position

Muscles that act to Flex at the

elbow

• Most of these muscles are located on the

anterior side of the upper arm.

• Biceps brachii (prime mover)

• Brachialis

• Brachioradialis

Biceps Brachii

• Origin:

– Long head: supraglenoid tubercle of scapula

– Short head: coracoid process of the scapula

• Insertion:

– Radial tuberosity (radius)

• Actions:

– Flexion at the elbow

– Supination at the elbow

– Assists in flexion at the shoulder

Brachialis

• Origin:

– Humerus

• Insertion:

– Coronoid process of the

ulna

• Action:

– Flexion at the elbow

Brachioradialis

• Origin:

– Humerus

• Insertion:

– Styloid process of the

radius

• Actions:

– Flexion at the elbow,

some pronation and

supination at the elbow

Muscles that act to Extend at the

elbow

• These muscles are located on the posterior

side of the upper arm

• Triceps brachii (prime mover)

• Anconeus:

– Major function is to stabilize elbow joint and

allow for maximal ROM during extension.

Triceps Brachii

• Origin:

– Long head: infraglenoid tubercle of the scapula

– Medial head: humerus

– Lateral head: humerus

• Insertion:

– Olecranon process of the ulna

• Actions:

– Extension at the elbow

– Long head: extension and adduction of the shoulder

Anconeus

• Origin:

– Lateral condyle of the

humerus

• Insertion:

– Olecranon process of the

ulna

• Action:

– Extension of the elbow

Muscles that act to Pronate the

arm

• Pronator teres

• Pronator quadratus

• Brachioradialis

Pronator Teres

• Origin:

– Medial supracondylar

ridge of humerus, ulna

• Insertion:

– Radius

• Actions:

– Pronation, assists with

flexion at the elbow

Pronator Quadratus

• Origin:

– Ulna

• Insertion:

– Radius

• Action:

– Pronation at the wrist

Muscles that act to supinate at the

elbow

• Supinator

• Biceps brachii

• Brachioradialis

Supinator

• Origin:

– Lateral epicondyle

of the humerus,

ulna

• Insertion:

– Radius

• Action:

– Supination