Lecture 12

Question 1

What are the proximal bones of the wrist?

Answer 1

• Scaphoid (articulates with radius, floor of anatomical snuff box)
• Lunate (articulates with radius)
• Triquetral (articulates with ulna via ulnar disc)
• Pisiform (forms in tendon of flexor carpi ulnaris)

Question 2

What is the most common fractured bone in the wrist?

Answer 2

Scaphoid

Question 3

What are the distal bones of the wrist?

Answer 3

Trapezium, trapezoid, capitate, hamate

- articulations are plane joints - permit sliding/gliding motion

Question 4

Radiocarpal joint

1) Type
2) Degrees of freedom
3) Articulates with
4) Action
5) blood supply
6) innervation

Answer 4

1) Condyloid, synovial joint
2) 2
3) Scaphoid, lunate, distal radius, (and triquetral with extreme ulnar deviation)
4) Flexion and extension, ulnar deviation (adduction)
5) Dorsal and palmar arch
6) Anterior interosseous (median n), posterior interosseous (radial n) and ulnar n

Question 5

Midcarpal joint

1) Articulates with
2) Action
3) blood supply
4) innervation

Answer 5

1) Proximal and distal carpals - made up of intercarpal joints
2) Some flexion and extension; primarily Radial deviation (abduction)
3) Dorsal and palmar arch
4) Anterior interosseous (median n), posterior interosseous (radial n) and ulnar n

Question 6

1) What joint provides the most flexion? 2) Most extension?

3) Radial and ulnar deviation?

Answer 6

1) Midcarpal joint
2) Radiocarpal joint
3) Midcarpal joint

Question 7

What forms the floor of the anatomical snuff box and what is the artery most at risk in the floor?

Answer 7

Scaphoid

Radial a

Question 8

What muscles form the borders of the anatomical snuff box?

Answer 8

Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus

Question 9

What is the blood supply and innervation of ALL 3 m? (Abductor pollicis longus, Extensor pollicis brevis, Extensor pollicis longus)

Answer 9

Posterior interosseous artery and posterior interosseous n