OIAN 16

Question 1

Extensor digitorum

Answer 1

Origin:
- Lateral epicondyle via the CET
Insertion:
- Base of middle phalanx of the four fingers (central band) and base of distal phalanx (lateral bands)
Action:
- Extends the four medial digits
- Extends the wrist (if fingers are flexed)
- Abducts the digits (during extension)
Nerve:
- Radial 
- C6,7,8

Question 2

Extensor digiti minimi

Answer 2

Origin:
- Lateral epicondyle via CET
- Ulnar aspect of extensor digitorum
Insertion:
- Base of middle phalanx of the 5th finger (central band) and base of distal phalanx (lateral bands)
Action:
- Extends the 5th digit
- Abducts the 5th digit
Nerve:
- Radial 
- C6,7,8

Question 3

Extensor indicis

Answer 3

Origin:
- Posterior surface of ulna
- Interosseous membrane
Insertion:
- Base of middle and distal phalanx of index finger
Action:
- Extends the 2nd digit
- Adducts the 2nd digit
- Assists to extend the wrist
- Stabilizes McP joint for flexion of IP solely
Nerve:
- Radial 
- C6,7,8

Question 4

Supinator

Answer 4

Origin:
- Lateral epicondyle
- Supinator crest
- Radial collateral and annular ligament
Insertion:
- Proximal and anterolateral surface of radius
Action:
- Supinates the forearm
Nerve:
- Radial 
- C6,7,8

Question 5

Extensor pollicis longus

Answer 5

Origin:
- Posterior surface of ulna
- Interosseous membrane
Insertion:
- Distal phalanx of thumb
Action:
- Extends distal phalanx of thumb
- Extends proximal phalanx of thumb
- Assists to extend the wrist (if fingers are flexed)
Nerve:
- Radial 
- C6,7,8