Posterior Forearm Muscles

Question 1

Aconeus

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 1

Location
Lateral, Posterior Olecranon

• *BLMs**
• Olecranon process
• Lateral epicondyle

ORIGIN

• Lateral epicondyle
• *INSERT**
• Olecranon process
• Posterior, proximal surface of ulna

ACTION
“Extend your elbow”

• EXTEND elbow (HU joint)

NERVE
Radial C7, C8

Question 2

Flexor Carpi Ulnaris

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 2

Location
Superficial on medial forearm

• *BLMs**
• Medial epicondyle
• Shaft of ulna

ORIGIN
HUMERAL HEAD:

• Common flexor tendon from medial epicondyle

ULNAR HEAD:

• Posterior surface of proximal 2/3 of Ulna
• *INSERT**
• Pisiform
• Hook of Hamate
• Base of 5th metacarpal

ACTION
“Flex and/or adduct your wrist”

• FLEX wrist (RC joint)
• *assist to FLEX elbow (HU joint)*
• ADDUCT wrist (R/C joint)

NERVE
Ulnar C7, C8, T1

Question 3

Extensor Carpi Ulnaris

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 3

Location
Superficial on posterior forearm

• *BLMs**
• Lateral epicondyle
• Shaft of ulna

ORIGIN

• Common extensor tendon from lateral epicondyle
• *INSERT**
• Base of 5th metacarpal

ACTION
“Extend and/or adduct your wrist”

• EXTEND wrist (RC joint)
• ADDUCT wrist (R/C joint)

NERVE
Radial C6, C7, C8

Question 4

Extensor Digitorum

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 4

Location
Superficial on posterior forearm

• *BLMs**
• Lateral epicondyle
• Shaft of ulna

ORIGIN

• Common extensor tendon from lateral epicondyle
• *INSERT**
• Base of #2-#5, middle and distal phalanges

ACTION
“Extend your fingers”

• EXTEND 2-5 fingers (MC and IP joints)
  *assist to EXTEND wrist (RC joint)

NERVE
Radial C6, C7, C8

Question 5

Extensor Indicis

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 5

Location
*Interosseous membrane

BLMs
*Interosseous membrane

ORIGIN

• Posterior surface of radius and ulna
• Interosseous membrane
• *INSERT**
• Tendon of extensor digitorum at level of 2nd MC

ACTION
“Extend and/or adduct index finger, extend the wrist”

• EXTEND index (MCP joint)
• *assist EXTEND wrist (RC joint)*
• ADDUCT index (MCP joint)

NERVE
Radial C6, C7, C8

Question 6

Extensor Pollicis Longus

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 6

Location
*Interosseous membrane

BLMs
*Interosseous membrane

ORIGIN

• Posterior surface of radius and ulna
• Interosseous membrane
• *INSERT**
• Base of distal phalanx, 1st metacarpal

ACTION
“Extend thumb, abduct wrist”

• EXTEND thumb (CM, MCP, IP joint)
• ABDUCT wrist (RC joint)

NERVE
Radial C6, C7, C8

Question 7

Extensor Pollicis Brevis

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 7

• *Location**
• **Interosseous membrane**

BLMs
*Interosseous membrane

ORIGIN

• Posterior surface of radius and ulna
• Interosseous membrane
• *INSERT**
• Base of proximal phalanx, 1st metacarpal

ACTION
“Extend thumb, Abduct wrist”

• EXTEND thumb (CM, MCP, IP joint)
• ABDUCT wrist (RC joint)

NERVE
Radial C6, C7, C8

Question 8

Abductor Pollicis Longus

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 8

Location
*Interosseous membrane

BLMs
*Interosseous membrane

ORIGIN

• Posterior surface of radius and ulna
• Interosseous membrane
• *INSERT**
• Base of 1st metacarpal

ACTION
“Abduct thumb and/or wrist, extend thumb”

• EXTEND thumb (CM joint)
• ABDUCT thumb (CM joint)
• ABDUCT wrist (RC joint)

NERVE
Radial C6, C7, C8

Question 9

Extensor Carpi Radialis Brevis

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 9

Location
Superficial on lateral, posterior forearm

• *BLMs**
• Lateral epicondyle
• Shaft of ulna

ORIGIN

• Common extensor tendon from lateral epicondyle
• *INSERT**
• Base of 3rd MC

ACTION
“Extend and/or abduct your wrist”

• EXTEND wrist (RC joint)
• ABDUCT wrist (RC joint)

*assist FLEX eblow (HU joint)

NERVE
Radial C6, C7, C8

Question 10

Extensor Carpi Radialis Longus

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 10

Location
Superficial on lateral, posterior forearm

• *BLMs**
• Lateral epicondyle
• Shaft of ulna

ORIGIN

• Distal 1/3 lateral supracondylar ridge of humerus
• *INSERT**
• Base of 2nd MC

ACTION
“Extend and/or abduct your wrist”

• EXTEND wrist (RC joint)
• ABDUCT wrist (RC joint)

*assist FLEX eblow (HU joint)

NERVE
Radial C5, C6, C7, C8

Question 11

Supinator

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 11

Location
Deep to forearm extensors

• *BLMs**
• Lateral epicondyle
• Shaft of radius

ORIGIN

• Lateral epicondyle
• Radial collateral ligament
• Annular ligament
• Supinator crest of the ulna
• *INSERT**
• Anterior, lateral of proximal 1/3 of radial shaft

ACTION
“Supinate your forearm against my resistance”

• SUPINATE forearm (RU joint)

NERVE
Radial C5, C6, (C7)

Question 12

Brachioradialis

• Location
• BLMs
• ORIGIN
• INSERTION
• ACTION
• Innervate

Answer 12

Location
Superficial

• *BLMs**
• Lateral epicondyle
• Styloid process of radius

ORIGIN

• Proximal 2/3 lateral supracondylar ridge of humerus
• *INSERT**
• Styloid process of radius

ACTION
“Flex elbow against my resistance”

• FLEX elbow (HU joint)
• *assist PRONATE and SUPINATE arm against resistance*

NERVE
Radial C5, C6