Coracobrachialis:
- Origin: Coracoid process of the scapula
- Insertion: Middle third of the medial humerus
- Innervation:Musculocutaneous nerve
- Action: Flexion and abduction of the arm at the shoulder joint
Triceps brachii:
- Origin: Long head- infraglenoid tubercle of the scapula, lateral head- posterior surface of the
humerus, above the radial groove, and the medial head- posterior surface of the humerus,
below the radial groove
- Insertion: Olecranon process of the ulna, the capsule of the elbow joint, and the antebrachial
fascia
- Innervation: Radial nerve (C6-C8)
- Action: Main extensor of the elbow joint
Biceps brachii:
- Origin: Long head- supraglenoid tubercle of the scapula and short head- coracoid process of the
scapula
- Insertion: Radial tuberosity of the radius
- Innervation: Musculocutaneous nerve (C5-C6)
- Action: Forearm flexion and supination
Deltoid-anterior, middle, posterior fibers:
- Origin: Anterior- lateral third of the clavicle, middle- acromion process of the scapula, and
posterior- spine of the scapula
- Insertion: Deltoid tuberosity of the humerus (all fibers)
- Innervation: Axillary nerve
- Action: Anterior- flexion and medial at the shoulder, posterior- extension and lateral rotation at
the shoulder, and middle- abduction at the shoulder
Anconeus:
- Origin: Lateral epicondyle of the humerus ( on the back of the humerus)
- Insertion: Olecranon of the ulna and the proximal part of the ulnas posterior surface
- Innervation: Radial nerve ( C7, C8, and T1 nerves)
- Action: Extends the forearm at the elbow joint. Also helps stabilize the elbow and abducts the
ulna when the forearm pronates
Extensor indicis:
- Origin: Posterior surface of the distal ulna and interosseous membrane
- Insertion: Extensor expansion of the index finger
- Innervation: Posterior interosseous nerve (C7, C8)
- Action: Extends the index finger
Palmaris Longus:
- Origin: Medial epicondyle of the humerus
- Insertion: Palmar aponeurosis and flexor
- Innervation: Median nerve
- Action: Wrist flexion
Flexor Carpi Radialis:
- Origin: Medial epicondyle of the humerus
- Insertion: Bases of the second and third metacarpal bones
- Innervation: Median nerves
- Action: Wrist flexion and radial abduction
Flexor Digitorum Superficialis:
- Origin: Medial epicondyle of the humerus (humeroulnar head), proximal half of the anterior
border of the radius (radial head)
- Insertion: Palmar aspects of the middle phalanges of digits 2-5
- Innervation: Median nerve
- Action: Flexion of the middle phalanges at the proximal interphalangeal joints of digits 2-5, also
assists in wrist flexion
Flexor carpi ulnaris:
- Origin: Medial epicondyle of humerus, olecranon and posterior border of ulna
- Insertion: Pisiform bone, hamate bone, base of metacarpal bone 5
- Innervation: By the ulnar nerve (C7-T1)
- Action: Wrist joint: Wrist flexion, wrist adduction
Flexor digitorum profundus:
- Origin: From the upper three-fourths of the velar and medial surfaces of the ulna, interosseous
membrane, and deep forearm fascia
- Insertion: Attach distally to the bases of the distal phalanges of the medial 4 digits
- Innervation: By the anterior interosseous nerve and ulnar nerves
- Action: Flexes the distal phalanges of the medial 4 digits at the DIP joints
Extensor Carpi Radialis Longus:
- Origin: From the lateral supracondylar ridge of humerus (distal third) and anterior aspect of the
lateral intermuscular septum of the arm
- Insertion: On the posterior aspect of the base of the second metacarpal bone
- Innervation: The radial nerve, from spinal roots C6 and C7
- Action: Primarily acts on the wrist joint to extend and abducts the hand
Extensor Carpi Radialis Brevis:
- Origin: From the fascia of the extensor digitorum communis
- Insertion: At the base of the third metacarpal on the radial side of the dorsal surface
- Innervation: Directly by the radial nerve (C5 - C8), or sometimes from its deep branch/posterior
interosseous nerve
- Action: Extend and abduct the hand at the wrist joint
Extensor Carpi Ulnaris:
- Origin: Lateral epicondyle of humerus, posterior border of ulna
- Insertion: Base of metacarpal bone 5
- Innervation: Posterior interosseous nerve (C7, C8)
- Action: Wrist joint: Hand extension and adduction
Extensor Digitorum:
- Origin: Via common extensor tendon that arises from the lateral epicondyle of the humerus
- Insertion: Into the middle and distal phalanges of the index, middle, ring, and little fingers on the
dorsal side
- Innervation: The posterior interosseous nerve, a branch of the radial nerve with root values C7
and C8
- Action: Extends the phalanges, then the wrist, and finally the elbow
Pronator Teres:
- Origin: Humeral head: medial supracondylar ridge of humerus slightly above the medial
epicondyle of humerus (common flexor tendon) Ulnar head:coronoid process of ulna
- Insertion: Middle of the lateral surface of the body of the radius.
- Innervation: By the median nerve and nerve roots C6 and C7
- Action: Pronates the forearm and weakly flexes the elbow
Pronator quadratus:
- Origin: Distal anterior surface of ulna.
- Insertion: Distal anterior surface of radius.
- Innervation: Median nerve (anterior interosseous nerve, C7, C8)
- Action: Radioulnar joints: forearm pronation
Supinator:
- Origin: From the ulna & humerus
- Insertion: The proximal third of the radius, specifically the anterior, lateral, and posterior
surfaces
- Innervation: By the deep branch of the radial nerve
- Action: Rotates the radius laterally at the proximal radioulnar joint, bringing the hand into a
supinated position (palm up)
