Posterior Forearm, Dorsum of Hand, Joints - Severson

Question 1

What makes up the anatomical snuffbox?

What artery runs through the snuffbox?

Answer 1

Extensor pollicis longus
Extensor pollicis brevis
Abductor pollicis longus

The radial artery runs through it

Question 2

What is the structure that goes around the top of the wrist like a bracelet?

Answer 2

The extensor retinaculum

Question 3

What extensors make up the 4th compartment?

Answer 3

Extensor digitorum

Question 4

What extensors make up the 1st compartment?

Answer 4

Abductor policis longus

Extensor policis brevis

Question 5

What extensors make up the 6th compartment?

Answer 5

Extensor carpi ulnaris

Question 6

What extensors make up the 5th compartment?

Answer 6

Extensor digiti minimi

Question 7

What extensors make up the 3rd compartment?

Answer 7

Extensor policis longus

Question 8

What extensors make up the 2nd compartment?

Answer 8

extensor carpi radialis brevis

extensor carpi radialis longus

Question 9

Which muscles serve to abduct the 2nd 3rd and 4th digits from the midline?

Answer 9

The dorsal interossei! (there are 4, 1 between all 5 digits)

Question 10

What do the lumbricals and interossei do mechanically to the finger?

Answer 10

Both the Lumbricals and the Interossei flex the MP joint and extend the distal phalanges through the PIP and DIP joints

(They insert on the extensor hood)

Question 11

Signs and symptoms of proximal median nerve palsy:

Answer 11

Hand of Benediction
Atrophy of thenar eminence
Thumb is laterally rotated and adducted
Loss of thumb flexion
Loss of flexion at 2nd and 3rd PIP and DIP joints
Weakened flexion at 2nd and 3rd MP joints

Question 12

Signs and symptoms of distal median nerve palsy:

Answer 12

*Carpal Tunnel Syndrome*
Paresthesia in lateral 3.5 fingers
Abnormal sensation in palm
Loss of coordination/strength in thumb
Difficult in thumb gripping
Weakened flexion of 2nd and 3rd MP joints
Phalen test positive

Question 13

Signs and symptoms of proximal ulnar nerve palsy:

Answer 13

Loss of flexion at 4th and 5th DIP joints
Loss of flexion at 4th and 5th MP joint (hyperextension of joint)
Inability to extend the IP joints when attempting to straighten the fingers
Hypoesthesia and paresthesia in little finger and ulnar half of ring finger
Atrophy of the interossei muscles
Weakness of thumb adduction

Question 14

Signs and symptoms of distal ulnar nerve palsy:

Answer 14

Guyon Canal Syndrome
No loss of flexion at 4th and 5th DIP joints
Loss of flexion at 4th and 5th MP joint (hyperextension of joint)
Inability to extend the IP joints when attempting to straighten the fingers
Hypoesthesia and paresthesia in little finger and ulnar half of ring finger
Atrophy of the interossei muscles
Weakness of thumb adduction
Ability to flex unaffected; no radial deviation of hand

Question 15

Radial Nerve Injury will cause what symptoms?

Answer 15

Inability to extend the wrist and fingers at the MP joint

Wrist partially flexed

Question 16

Why should you worry about swinging children by their arms?

Answer 16

You can pull the head of the radius out of the anular ligament - disclocating or subluxing the radial head

Nursemaid’s elbow