Anterior Forearm Muscles

Question 1

Superficial compartment
Flexor carpi ulnaris 
- Origin and insertion?
- Innervation?
- Actions?

Answer 1

• Origin: medial epicondyle of humerus, plus long origin on ulna
• Insertion: pisiform carpal bone
• Action: flexion and adduction of the wrist
• Innervation: Ulnar nerve

Question 2

Superficial compartment
Palmaris longus 
- Origin and insertion?
- Innervation?
- Actions?

Answer 2

• Origin: medial epicondyle
• Insertion: flexor retinaculum of wrist
• Action: flexion at wrist
• Innervation: median nerve

Question 3

Superficial compartment 
Flexor carpi radialis
- Origin and insertion?
- Innervation?
- Actions?

Answer 3

• Origin: medial epicondyle of humerus
• Insertion: base of metacarpals 1 and 2
• Action: flexion and abduction of wrist
• Innervation: median nerve

Question 4

Superficial compartment 
Pronator teres
- Origin and insertion?
- Innervation?
- Actions?

Answer 4

• Origin: medial epicondyle of humerus and coronoid process of ulna
• Insertion: mid-shaft of radius
• Actions: pronation of forearm
• Innervation: median nerve

Question 5

Intermediate compartment 
Flexor digitorum superficialis
- Origin and insertion?
- Innervation?
- Actions?

Answer 5

• Origin: medial epicondyle of humerus and radius
• Insertion: splits into four tendons which travel through the carpal tunnel and insert onto middle phalanges of the four fingers
• Actions: flexion of MCP joints and proximal IP joints, flexion at wrist
• Innervation: median nerve

Question 6

Deep compartment
Flexor digitorum profundus
- Origin and insertion?
- Innervation?
- Actions?

Answer 6

• Origin: ulna and interosseus membrane
• Insertion: splits into tendons which pass through carpal tunnel and insert onto distal phalanges of the four fingers
• Actions: flexion of distal IP joints, flexion of MCP joints, flexion of wrist
• Innervation: medial half -ulnar nerve, lateral half -median nerve

Question 7

Deep compartment
Flexor pollicis longus
- Origin and insertion?
- Innervation?
- Actions?

Answer 7

• Origin: anterior surface of radius & interosseus membrane
• Insertion: distal phalanx of thumb
• Actions: flexion of IPJ and MCPJ of thumb
• Innervation: median nerve

Question 8

Deep compartment
Pronator quadratus
- Origin and insertion?
- Innervation?
- Actions?

Answer 8

• Origin: anterior surface of ulna
• Insertion: anterior surface of radius
• Action: pronation of forearm
• Innervation: median nerve