MSS Week 9 Posterior Compartment of the Hand

Question 1

Extensor Carpi Radialis Longus

Origin
Insertion
Innervation
Action

Answer 1

Origin: Supracondylar ridge of humerus

Insertion: metacarpals bones 2 and 3

Innervation: Radial Nerve

Action: Extension and Abduction of the wrist

Question 2

Extensor Carpi Radialis Brevis

Origin
Insertion
Innervation
Action

Answer 2

Origin: Lateral epicondyle

Insertion: metacarpal bones 2 and 3

Innervation: Deep Branch of Radial Nerve

Action: Extension and Abduction of the wrist

Question 3

Extensor Digitorum

Origin
Insertion
Innervation
Action

Answer 3

Origin: Lateral epicondyle

Insertion: Extensor hood of each finger

Innervation: Radial Nerve

Action: Extension of the medial four fingers at the MCP and IP joints

Question 4

Extensor Digiti Minimi

Origin
Insertion
Innervation
Action

Answer 4

Origin: Lateral epicondyle of the humerus

Insertion: Extensor hood of the little finger

Innervation: Radial Nerve

Action: Extension of the little finger and wrist

Question 5

Extensor Carpi Ulnaris

Origin
Insertion
Innervation
Action

Answer 5

Origin: Lateral epicondyle of the humerus

Insertion: Base of the metacarpal 5

Innervation: Ulnar Nerve

Action: Extension and Adduction of the wrist

Question 6

Supinator

Origin
Insertion
Innervation
Action

Answer 6

Origin: Lateral head of the epicondyle of the humerus, posterior surface of the ulna

Insertion: Posterior surface of the radius

Innervation: Radial Nerve

Action: Supination of the Forearm

Question 7

Extensor Pollicis Longus

Origin
Insertion
Innervation
Action

Answer 7

Origin: Posterior surface of the ulna and interosseous membrane

Insertion: distal phalanx of the thumb

Innervation: Radial Nerve

Action: Extension of the joints of the thumb

Question 8

Extensor Pollicis Brevis

Origin
Insertion
Innervation
Action

Answer 8

Origin: Posterior surface of the radius and interosseous membrane

Insertion: Base of the proximal phalanx of the thumb

Innervation: Radial Nerve

Action: Extension of the metacarpophalangeal and carpometacarpal joints of the thumb

Question 9

Abductor pollicis longus

Origin
Insertion
Innervation
Action

Answer 9

Origin: Interosseous membrane and the adjacent posterior surface of the radius and ulna

Insertion: Lateral side of the base of metacarpal

Innervation: Radial Nerve

Action: Abduction of the thumb

Question 10

Extensor Indicis

Origin
Insertion
Innervation
Action

Answer 10

Origin: posterior surface of the ulna and interossesous membrane

Insertion: Extensor hood of the index finger

Innervation: Radial Nerve

Action: Extension of the index finger