Posterior Forearm and Dorsum of the Hand Muscles Flashcards
Brachioradialis
Origin
-Lateral supracondylar ridge of humerus
Brachioradialis
Insertion
-Lateral surface of distal radius, proximal to styloid
process
Brachioradialis
Innervation
-Radial nerve (C5, C6, C7)
Brachioradialis
Action
-Weak flexion of elbow (maximal when forearm in
midpronated position)
Extensor Carpi Radialis Longus (ECRL)
Origin
-Lateral supracondylar ridge of humerus
Extensor Carpi Radialis Longus (ECRL)
Insertion
-Dorsal aspect of base of 2nd metacarpal
Extensor Carpi Radialis Longus (ECRL)
Innervation
-Radial nerve (C6, C7)
Extensor Carpi Radialis Longus (ECRL)
Action
-Extends and radially deviates wrist (active
during fist clenching)
Extensor Carpi Radialis Brevis (ECRB)
Origin
-Lateral epicondyle of humerus (via common
extensor tendon)
Extensor Carpi Radialis Brevis (ECRB)
Insertion
-Dorsal aspect of base of 3rd metacarpal
Extensor Carpi Radialis Brevis (ECRB)
Innervation
-Deep branch of radial nerve (C7, C8)
Extensor Carpi Radialis Brevis (ECRB)
Action
-Extends and radially deviates wrist (active during fist clenching)
Extensor Digitorum (ED) Origin
-Lateral epicondyle of humerus (via common extensor tendon)
Extensor Digitorum (ED) Insertion
-Extensor expansions of 2nd-5th digits
Extensor Digitorum (ED) Innervation
-Deep branch of radial nerve (C7, C8)
Extensor Digitorum (ED) Action
- -Extends elbow
- extends hand at wrist
- extends 2nd -5th digits (primarily at MCP joint, secondarily at IP joint)
Extensor Digiti Minimi (EDM)
Origin
-Lateral epicondyle of humerus (via common
extensor tendon)
Extensor Digiti Minimi (EDM)
Insertion
-Extensor expansion of 5th digit
Extensor Digiti Minimi (EDM)
Innervation
-Deep branch of radial nerve (C7, C8)
Extensor Digiti Minimi (EDM)
Action
- extends 5th digit (primarily at MCP joint, secondarily at IP joint)
- Weak wrist extension
Extensor Carpi Ulnaris (ECU)
Origin
-Lateral epicondyle of humerus (via common extensor tendon); posterior border of ulna
Extensor Carpi Ulnaris (ECU)
Insertion
-Dorsal aspect of base of 5th metacarpal
Extensor Carpi Ulnaris (ECU)
Innervation
-Deep branch of radial nerve (C7, C8)
Extensor Carpi Ulnaris (ECU)
Action
-Extends and ulnarly deviates wrist (active during fist clenching)
Supinator
Origin
- Lateral epicondyle of humerus (via common extensor tendon)
- radial collateral and anular ligaments
- supinator fossa; crest of ulna
Supinator
Insertion
-Lateral, posterior, and anterior surfaces of proximal third of radius
Supinator
Innervation
-Deep branch of radial nerve (C7, C8)
Supinator
Action
-Supinates forearm
Abductor Pollicis Longus (APL)
Origin
-Posterior surface of proximal halves of ulna, radius, and interosseous membrane
Abductor Pollicis Longus (APL)
Insertion
-Base of 1st metacarpal
Abductor Pollicis Longus (APL)
Innervation
-Posterior interosseous nerve (C7, C8) (a continuation of deep branch of radial nerve)
Abductor Pollicis Longus (APL)
Action
-Abducts and extends thumb at carpometacarpal
(CMC) joint
Extensor Pollicis Brevis (EPB)
Origin
-Posterior surface of distal third of radius and
interosseous membrane
Extensor Pollicis Brevis (EPB)
Insertion
-Dorsal aspect of base of proximal phalanx of thumb
Extensor Pollicis Brevis (EPB)
Innervation
-Posterior interosseous nerve (C7, C8) (a continuation of deep branch of radial nerve)
Extensor Pollicis Brevis (EPB)
Action
- -Extends proximal phalanx of thumb at MCP joint
- extends CMC joint
Extensor Pollicis Longus (EPL)
Origin
- Posterior surface of middle third of ulna and
interosseous membrane
Extensor Pollicis Longus (EPL)
Insertion
-Dorsal aspect of base of distal phalanx of thumb
Extensor Pollicis Longus (EPL)
Innervation
-Posterior interosseous nerve (C7, C8) (a
continuation of deep -branch of radial nerve)
Extensor Pollicis Longus (EPL)
Action
- -Extends distal phalanx of thumb at IP joint
- extends thumb at MCP and CMC joints
Extensor Indicis
Origin
-Posterior surface of distal third of ulna and
interosseous membrane
Extensor Indicis
Inseriton
-Extensor expansion of 2nd digit
Extensor Indicis
Innervation
-Posterior interosseous nerve (C7, C8) (a continuation of deep branch of radial nerve)
Extensor Indicis
Action
-Extends 2nd digit (enabling its independent
extension from other digits)
-weakly extends hand at wrist