Hand and Wrist

Question 1

What is special about the pisiform carpal bone?

Answer 1

The pisiform carpal bone can be found in the tendon of flexor carpi Ulnaris, and articulates with the triquetrum.

Question 2

Which bones do each carpal bone articulate with?

Answer 2

Trapezium articulates with digit 1, trapezoid with digit 2, capitate with digit 3 and hamate with digits 4 and 5. Scaphoid and lunate articulate with the radius to form the wrist joint.

Question 3

What is the carpal tunnel

Answer 3

The carpals form an arch called the carpal tunnel through which many tendons and the median nerve travel, they are encased here by the flexor retinaculum which stops the tendons form bowing.

Question 4

How does the surface of the carpals fit into the radius.

Answer 4

The carpals at the wrist form a convex surface which fits into the concave surface of the radius and articulating disc of the ulna.

Question 5

Describe the ligaments of the wrist

Answer 5

Ligaments of the wrist include: palmer and dorsal radiocarpal and the ulna and radial collateral ligaments.

Question 6

What is special about the 1st carpo-metacarpal joint

Answer 6

Joint between the 1st metacarpal and trapezium is a saddle joint allowing for much more movement than the rest of the digits.

Question 7

Describe the Metacarpophalangeal joints

Answer 7

Metacarpophalangeal joints are condylar and are reinforced by palmer ligaments and medial and lateral collateral ligaments.

Question 8

What is the purpose of the deep transverse metacarpal ligament

Answer 8

The deep transverse metacarpal ligament on the palmer side connects the 2nd and 5th metacarpal unifying the skeletal framework of the palm.

Question 9

What is the palmer aponeurosis

Answer 9

The palmer aponeurosis is a deep fascia that is continuous with the tendon of palmaris longus. It’s purpose is to protect the underlying ligaments and to increase grip of the hand.

Question 10

How are all the tendons passing through the hand protected and prevented from bowing?

Answer 10

All other tendons entering the hand are covered in a synovial sheath including those in the carpal tunnel. Upon reaching the fingers these tendons enter a fibrous sheath.

Question 11

What is the anatomical snuff box?

Answer 11

Anatomical snuff bow – indent formed, when the thumb abducts, by 3 tendons: abductor pollicis longus and extensor pollicis brevis laterally and extensor pollicis brevis medially. The floor is formed from the scaphoid and the trapezium and the radial artery runs across it.

Question 12

What is the most common fracture in the wrist from falling on outstretched hands?

Answer 12

The most common fracture of the wrist is that of the scaphoid when you fall on outstretched hands. It is very hard to see if the scaphoid is fractured until a few weeks after the injury. On top of this the scaphoid receives its blood from only the radial artery which enters the scaphoid distally in 10% of people and so a fracture across the waist of the scaphoid could result in avascular necrosis of the proximal portion in this situation. Pain will be felt over the scaphoid anteriorly and in the anatomical snuff box.

Question 13

What is carpal tunnel syndrome and what causes it?

Answer 13

Carpel tunnel syndrome – median nerve becomes irritated due to inflammation of tendons, rheumatoid arthritis, or cysts. Pins and needles of affected skin and atrophy of Thenar muscles.

TRAMPD
Trauma, Rheumatoid Arthritis, Myxedema (hypothyroidism), pregnancy and diabetes.

Question 14

What is the Ulna claw?

Answer 14

Ulna Claw due to damaged ulnar nerve appears when hand is relaxed due to loss of 3rd and 4th lumbricals. If damage is more proximal, then loss of flexor Digitorum Profundus will cause ulnar paradox.

Question 15

What is the hand of benediction?

Answer 15

Hand of benediction – damage to the median nerve and occurs when attempting to clench into a fist. Due to loss of most flexors and lateral 2 lumbricals.

Question 16

Describe the locations damage can occur to the radial nerve and the pathology they cause.

Answer 16

Radial nerve damage at the axilla – complete paralysis of all posterior arm muscles and skin innervated by the radial nerve (wrist drop); damage at radial groove – similar put still some function of triceps; damage at the elbow – loss of posterior forearm muscles except supinator and extensor carpi Radialis longus (no wrist drop) and damage at the wrist – superficial radial nerve so sensory loss of lateral 3 fingers.