Extensor-Supinator (Posterior) Muscles of the Forearm

Question 1

Brachioradialis

Answer 1

SUPERFICIAL LAYER
Attachments:

Superior/Proximal: Proximal Supra-Epicondylar Ridge (Humerus)
Inferior/Distal: Lateral Distal Radius

Action:

Weak Flexion of Forearm & Maximal when Forearm is Mid-Pronated

Question 2

Extensor Carpi Radialis Longus

Answer 2

SUPERFICIAL LAYER
Attachments:

Superior/Proximal: Lateral Supra-Epicondylar Ridge (Humerus)
Inferior/Distal: Dorsal Base 2nd Metacarpal

Action:

Active in Fist Clenching & Extend and Abduct Hand at Wrist Joint

Question 3

Extensor Carpi Radialis Brevis

Answer 3

SUPERFICIAL LAYER
Attachments:

Superior/Proximal: Lateral Epicondyle of Humerus
Inferior/Distal: Dorsal Base 3rd Metacarpal

Action:

Extend and Abduct Hand at Wrist Joint

Question 4

Extensor Digitorum

Answer 4

SUPERFICIAL LAYER
Attachments:

Superior/Proximal: Lateral Epicondyle of Humerus
Inferior/Distal: Extensor Expansions of Medial 4 Digits

Action:

Extends Medial 4 Digits at MP Joints then IP Joints

Question 5

Extensor Digiti Minimi

Answer 5

SUPERFICIAL LAYER
Attachments:

Superior/Proximal: Lateral Epicondyle of Humerus
Inferior/Distal: Extensor Expansion of 5th Digit

Action:

Extends 5th Digit at MP Joint then IP Joint

Question 6

Extensor Carpi Ulnaris

Answer 6

SUPERFICIAL LAYER
Attachments:

Superior/Proximal: Lateral Epicondyle of Humerus
Inferior/Distal: Dorsal Base of 5th Metacarpal

Action:

Extends and Adducts Hand at Wrist

Question 7

Supinator

Answer 7

DEEP LAYER
Attachments:

Superior/Proximal: Lateral Epicondyle of Humerus & Supinator Fossa
Inferior/Distal: VERIFY IN BOOK AND EDIT

Action:

Supinates Arm & Rotates Radius to turn Palm when Arm is Flexed

Question 8

Extensor Indicis

Answer 8

DEEP LAYER
Attachments:

Superior/Proximal: Posterior Distal Ulna & Interosseous Membrane
Inferior/Distal: Extensor Expansion 2nd Digit

Action:

Extends 2nd Digit & Assist Extension of Wrist

Question 9

Abductor Pollicis Longus

Answer 9

OUTCROPPING MUSCLES OF DEEP LAYER
Attachments:

Superior/Proximal: Posterior Proximal Ulna, Radius and Interosseous Membrane
Inferior/Distal: Base of 1st Metacarpal

Action:

Abducts and Extends Thumb at CMC Joint

Question 10

Extensor Pollicis Longus

Answer 10

OUTCROPPING MUSCLES OF DEEP LAYER
Attachments:

Superior/Proximal: Posterior Middle Ulna and Interosseous Membrane
Inferior/Distal: Dorsal Base Distal Phalanx of Thumb

Action:

Extends Phalanx at IP Joint, then MC and CMC Joints

Question 11

Extensor Pollicis Brevis

Answer 11

OUTCROPPING MUSCLES OF DEEP LAYER
Attachments:

Superior/Proximal: Posterior Distal Radius and Interosseous Membrane
Inferior/Distal: Dorsal Base Proximal Phalanx of Thumb

Action:

Extends Proximal Phalanx at MC then CMC Joint