Ulnar Claw vs Hand of Benediction Flashcards Preview

ESA 2- Musculoskeletal System > Ulnar Claw vs Hand of Benediction > Flashcards

Flashcards in Ulnar Claw vs Hand of Benediction Deck (24):
1

What are the ulnar claw and hand of benediction?

Two characteristic signs of peripheral nerve damage

2

When is the ulnar claw deformity seen?

In long standing ulnar nerve damage at the wrist

3

What does the ulnar claw affect?

The little and ring fingers of the hand

4

What happens to the little and ring fingers of the hand in ulnar claw?

They are hyperextended at the MCP joint, and flexed at both IP joinsts

5

What muscles are affected by an ulnar nerve lesion in the wrist?

Medial two lumbricals 
Interossei 
Hypothenar muscles
Adductor pollicis

6

What do the medial two lumbricals do?

Flexes at the MCP joints and extends the IP joints of the little and ring fingers

7

What do the interossei do?

Abducts and adducts the fingers

8

What do the hypothenar muscles do?

Flexes, abducts, and opposes the little finger

9

What does the adductor pollicis do?

Adducts the thumb

10

What are the important muscles to consider in the ulnar claw?

The medial lumbricals

11

What happens if the medial lumbricals are paralysed?

There is a loss of flexion at the MCP joints, and a loss of extension at the IP joints, leading to an imbalance between the intrinsic and extrinsic muscles of the hand, producing the claw deformity

12

Why are the MCP joints hyperextended in the ulnar claw?

Due to unopposed extension from the long extensor muscles in the posterior compartment of the forearm

13

Why are the IP joints flexed in the ulnar claw?

Due to unopposed flexion from the long flexor muscles in the anterior compartment of the arm. The extensor muscles cannot extend the IP joint, as their energy is dissipated in hyperextending the MCP joints

14

What happens in a high ulnar nerve injury?

Some muscles in the anterior forearm are paralysed, in addition to the hand muscles

15

What muscles in the anterior forearm are paralysed in a high ulnar nerve injury?

Medial half of the flexor digitorum profundus 
Flexor carpi ulnaris

16

What does the medial half of the flexor digitorum profundus do?

Flexes at the distal IP joints of the ring and little fingers

17

What does the flexor carpi ulnaris do?

Flexes and adducts the risk

18

How does the ulnar claw differ when there is a high ulnar nerve injury?

There will not be any flexion at the distal IP joints of the ring and little fingers, because the flexor digitorum profundus is paralysde, and so the ulnar claw only consists of hyperextension at the MCP joints and flexion at the proximal IP joints, producing a much less evident hand claw

19

Why is the effect of a high ulnar nerve injury known as the ulnar paradox?

Because you would expect a more debilitating injury to produce a more pronounced deformity, but actually the opposite occurs

20

Why does the hand of benediction occur?

As a result of median nerve damage at the elbow

21

How does the hand of benediction differ from the ulnar claw?

It is only apparent if the patient is asked to make a fist, whereas the ulnar claw is produced spontaneously

22

What muscles are affected if the median nerve is lesioned at the elbow?

Long flexors in the anterior compartment of the (except the medial half of the flexor digitorum profundus and the flexor carpi ulnaris) 
Lateral two lumbricals

23

What do the lateral two lumbricals do?

Flexes at the MCP joints and extends at the IP joints of the index and middle fingers

24

What happens if a patient with median nerve damage is asked to make a fist?

They will be able to flex the little and ring fingers, as this action is performed by the medial half of the flexor digitorum profundus and medial two lumbricals, but they will not be able to flex the index and middle fingers.