Muscle Chart: Extensor Group - Superficial Layer

Question 1

Brachioradialis

Origin, Insertion, Innervation, Blood Supply

Answer 1

Origin: Proximal 2/3 of lateral supracondylar ridge of humerus

Insertion: Lateral surface of the distal end of the radius, proximal to the radial styloid process

Innervation: Radial nerve (C5, C6, C7)

Blood Supply: Recurrent branch of radial artery

Question 2

Brachioradialis Movement

Answer 2

Elbow flexion when forearm is in neutral pronation/supination

Question 3

Extensor Carpi Radialis Longus (ECRL)

Origin, Insertion, Innervation, Blood Supply

Answer 3

Origin: Distal 1/3 of lateral supracondylar ridge

Insertion: Dorsal aspect of the base of 2nd metacarpal

Innervation: Radial nerve (C6, C7)

Blood Supply: Radial artery

Question 4

Extensor Carpi Radialis Longus (ECRL) Movements

Answer 4

Extend and radially deviate the hand; assist with elbow flexion

Question 5

Extensor Carpi Radialis Brevis (ECRB)

Origin, Insertion, Innervation, Blood Supply

Answer 5

Origin: Lateral epicondyle of the humerus (common extensor origin)

Insertion: Dorsal aspect of the base of 3rd metacarpal

Innervation: Deep branch of the radial nerve (C6, C7)

Blood Supply: Radial artery

Question 6

Extensor Carpi Radialis Brevis (ECRB) Movements

Answer 6

Extend and radially deviate hand; assist with elbow flexion

Question 7

Extensor Digitorum (ED)

Origin, Insertion, Innervation, Blood Supply

Answer 7

Origin: Lateral epicondyle of the humerus (common extensor origin)

Insertion: Base of distal phalanges of digits 2-5

Innervation: Deep branch of the radial nerve (same as ECRB)

Blood Supply: Common interosseous from the middle collateral artery

Question 8

Extensor Digitorum (ED) Movements

Answer 8

Extends digits 2-5 at MCP and IP joints; extends the hand at the wrist

Question 9

Extensor Digiti Minimi (EDM)

Origin, Insertion, Innervation, Blood Supply

Answer 9

Origin: Lateral epicondyle of the humerus (common extensor origin)

Insertion: Extensor expansion of the digit 5

Innervation: Deep branch of radial nerve (same as ECRB and ED) (C7, C8)

Blood Supply: Common interosseous from middle collateral artery (same as ED)

Question 10

Extensor Digiti Minimi (EDM) Movements

Answer 10

Extends digit 5 at the MCP and IP joints

Question 11

Extensor Carpi Ulnaris (ECU)

Origin, Insertion, Innervation, Blood Supply

Answer 11

Origin: Lateral epicondyle of the humerus and posterior border of ulna

Insertion: Dorsal aspect of the base of metacarpal 5

Innervation: Deep branch of the radial nerve (C7, C8)

Blood Supply: Ulnar artery

Question 12

Extensor Carpi Ulnaris (ECU) Movements

Answer 12

Extends and ulnarly deviates the wrist