MSK 4

Question 1

Intermediate and deep flexors in anterior forearm

• where do they arise from
• nerve with roots
• actions

Answer 1

Arise at medial epicondyle and radius
Median nerve (C6-T1) for:
FDS - Flexion of wrist, medial 4 digits @ MCPJ and Flexion at prox IPJ
FPL - Flexion of thumb at MCPJ and IPJ
PQ - pronates forearm
FDP (lateral half) - flexion of index and middle finger at wrist, MCPJ and distal IPJ

Medial half of FDP (ulnar nerve, C8-T1)
- Flexion of wrist, Flexion of ring and little finger at MCPJ and distal IPJ

Question 2

Superficial extensors in posterior forearm

• where do they arise from
• nerve with roots
• actions

Answer 2

Arise from lateral epicondyle
All radial nerve innervated (C5-T1)
ED - extension of digits 2-5 at MCPJ and IPJ
EDM - extension of little finger
ECRB/L - extension and abduction of the wrist
Brachioradialis - flexor however radial nerve innervated
ECU - extension of wrist and adduction
Anconeus - involved in pronation and extension of elbow

Question 3

Deep extensors in posterior forearm

• where do they arise from
• nerve with roots
• actions

Answer 3

All radial nerve innervated (C5-T1) 
Supinator - supinates forearm 
EI - extension of index feel independently to others
APL - abducts the thumb
EPB/L - extension of the thumb p

Question 4

What is lateral epicondylitis more commonly known as, and what is its cause?

Answer 4

Commonly known as tennis elbow.
Occurs due to repeated use of the extensors in the forearm, and there is inflammation of the periosteum of the lateral epicondyle.
The repeated use causes straining of the tendinous attachment.

Question 5

What nerve is damaged in wrist drop, 2 common causes and explain the presentation of wrist drop.

Answer 5

Radial nerve damage, commonly occurring in mid humeral shaft fractures (as the radial nerve travels in the radial groove which is mid humeral) and a dislocation of the humerus.
Damage to the radial nerve can cause unopposed Flexion of the wrist as the radial nerve, which innervates the extensors in the forearm, is damaged.

Question 6

Boundaries of anatomical snuff box.

Answer 6

Lateral - extensor pollicis brevis and abductor pollicis longus
Medial - extensor pollicis longus
Proximal - styloid process of the radius
Floor - scaphoid and trapezium
Roof - skin

Question 7

Contents of the anatomical snuff box

Answer 7

Radial artery, branch of radial nerve and Cephalic vein.

Question 8

A patient presents to your department after a fall. She is in severe pain and she points to the posterior aspect of the hand, just at the base of the thumb. What are your concerns regarding the location of her pain?

Answer 8

Could be fracture of the scaphoid, possibility of avascular necrosis.

Question 9

What are the bones that articulate at the wrist joint ?

Answer 9

Radius and the scaphoid, lunate and triquetral.

Question 10

If a patient suffers from avascular necrosis of the scaphoid, what is the likely problem they will suffer from in the future ?

Answer 10

Patient can end up with arthritis

Question 11

Describe the appearance of the classical dinner fork deformity seen in a Colles fracture.

Answer 11

Falling on an out stretched hand. 
Radius fracture
Distal fragment displaced posteriorly
Radial shortening. 
Ulna styloid process can become avulsed.

Question 12

What is seen in a smiths fracture

Answer 12

Distal fragment of radius is pushed anteriorly.

Question 13

Superficial flexors in anterior forearm

• where do they arise from
• nerve with roots
• actions

Answer 13

All arise from the medial epicondyle

• median ( C6-T1) nerve for:
  
  • pronator teres - pronates the forearm
  • FCR - flexes the wrist and also abduction of wrist
  • palmaris longus - Flexion at the wrist
• ulnar nerve (C8-T1) for:
  
  • FCU - Flexion at the wrist and adduction of wrist