Disorders of the arm

Question 1

Supracondylar Fracture of the Distal Humerus cause

Answer 1

Supracondylar fractures of the distal humerus are usually caused by a fall onto an outstretched hand (FOOSH) with a hyperextended elbow.

Question 2

supracondylar fracture of the distal humerus usually occur in

Answer 2

They occur most commonly in children and make up around 75% of ‘elbow’ injuries. The distal fragment is usually displaced posteriorly.

Question 3

presentation of supracondylar fracture of the distal humerus

Answer 3

this condition presents with pain, deformity and reduced function of the elbow joint.

Question 4

Complications of a supracondylar fracture of the distal humerus include:

Answer 4

Damage to ulnar, radial or median nerves (all described later in this article) - the ulnar nerve is most commonly damaged.

• ‘Gunstock deformity’ - where malunion of the fragments results in cubitus varus, an abnormality when an extended elbow has a lateral deviation.
• Volkmann’s ischaemic contracture -

Question 5

Volkmann’s ischaemic contracture

Answer 5

• where damage to the brachial artery causes compartment syndrome, which leads to infarction resulting in fibrotic repair.

Question 6

volkmanns ischaemic contracture presents with

Answer 6

with elbow flexion, forearm pronation, wrist flexion, metacarpal-phalangeal joint extension and interphalangeal joint flexion.

Question 7

volkmanns is diagnosed by

Answer 7

This condition is diagnosed with an x-ray.

Question 8

The treatment of volkmanns

Answer 8

involves a cast or splint to promote natural healing for a less severe fracture, or surgery (usually a closed reduction) for a more severe fracture.

Question 9

High Radial Nerve Injury

Question 10

high radial nerve injury usually presents with

Answer 10

It presents with:

• Flexion of the wrists.
• Flexion at the metacarpal-phalangeal joints.
• Paraesthesia of the dorsal aspect of the 1st, 2nd and 3rd digits (excluding the fingertips).
• Elbow extension is spared in the majority of high radial injuries, due to the branch that innervates triceps brachii being given off proximal to the site of injury

Question 11

Treatment of a high radial nerve injury typically

Answer 11

involves restriction of movement with a splint, so that the nerve has time to heal, or it may require surgery. Complete recovery can take anywhere from a few weeks to six months, or recovery may not be possible at all.

Question 12

High Ulnar Nerve Injury also known as

Answer 12

ulnar claw

Question 13

high ulnar nerve injury occurs due to

Answer 13

A high injury to the ulnar nerve usually occurs due to a medial epicondyle fracture.

Question 14

high ulnar nerve injury presents with

Answer 14

It presents with:

• A ‘high ulnar claw’ when asked to extend all the fingers:
  
  • Hyperextensionof the 4th and 5th digits at the metacarpal-phalangeal joints.
  • Flexionof the 4th and 5th digits at the proximal interphalangeal joints but not at the distal interphalangeal joints due to flexor digitorum profundus being paralysed.
  • Paraesthesia of the 4th and 5th digits and medial border of the hand.

Question 16

treatment of high ulnar nerve injury

Answer 16

Treatment typically involves restriction of movement with a splint, so that the nerve has time to heal, or it may require surgery. Complete recovery can take anywhere from a few weeks to six months, or recovery may not be possible at all.

Question 17

It is important to distinguish between the appearance of the high ulnar claw, and

Answer 17

the low ulnar claw that is described in the article Conditions of the Wrist.

Unexpectedly, the appearance of the low ulnar claw is more severe than the appearance of the high ulnar claw. This is because with a high ulnar nerve injury, the innervation to flexor digitorum profundus is destroyed, meaning the fingers cannot flex as much as they can in a low ulnar nerve injury, when this muscle is spared. This is called the ‘Ulnar paradox’.

Question 18

High Median Nerve Injury also known as

Answer 18

Hand of Benediction

Question 20

high median nerve injury due to

Answer 20

A high injury to the median nerve usually occurs due to a supracondylar humeral fracture.

Question 21

high median nerve injury presentation

Answer 21

It presents with:

• Forearm supination
• The ‘Hand of Benediction’ when asked to form a fist:
  
  • Flexion of 4th and 5th digits.
  • Extension of 2nd and 3rd digits.
  • Extension and adduction of the 1st digit.
  • Paraesthesia of the palmar aspect of the lateral hand and 1st, 2nd and 3rd digits.

Question 22

difference between ulnar claw and hand of benediction presentation

Answer 22

ulnar claw present on rest and hand of benediction occurs when asked to form fist