Hand

Question 1

What clinical feature will show up with a nerve palsy to the ulnar nerve (at the wrist)?

Answer 1

CLAW HAND. Inability to extend fingers at the interphalengeal joints. This results in permanant flexion

Question 2

What are the functions of ulnar nerve in the hand?

Answer 2

Abduction and Adduction.

Note that adductor pollicis is innervated by the ulnar nerve as well. Therefore all of adduction will be gone if the ulnar nerve becomes damaged. Conversely, you will still get abduction in the thumb as well as well as opposition and flexion in the thumb becuase the median nerve innervates those structures.

Question 3

What clinical feature will show up with a nerve palsy to the median nerve (at the wrist)?

Answer 3

1. APE HAND

2. HAND OF BENEDICTION (Will see the deformity when trying to make a fist)

Question 4

What clinical feature will show up with a nerve palsy to the radial nerve (at the wrist)?

Answer 4

Loss of sensation. However, proximal to the elbow will be Wrist Drop

Question 5

What would happen if the radial nerve was damaged at the WRIST?

Answer 5

Loss of sensation (Dorsal side, Lateral 3 1/2 fingers) but not motor function because the radial nerve does not provide motor functon at the wrist

Question 6

What muscles do the ulnar nerve supply in the hand?

Answer 6

The ulnar nerve supplies most of the hand except for the lateral 1/2 LOAF which is supplied by the median nerve.

Question 7

What is the normal function of the lumbricals? Where do they originate?

Answer 7

1. Flex the metacarpalphalengeal joints
2. Extend the proximal and distal interphalengeal joints

They originate from the flexor digitorum profundus

This allows us to SALUTE. It allows us to PINCH THE PULP OF THE FINGERS NOT THE TIPS ( The interphalangeal joint must remain extended)

Question 8

What muscle does the median nerve innervate in the hand.

Answer 8

1/2 LOAF. Lateral
1/2 Lumbricals 
Opponens Pollicis
Abductor Pollicis brevis
Flexor Pollicis brevis

Question 9

Extensor Expansion Hood

Answer 9

Common hood which aids in extension of fingers because it receives the extensor digitorum, interossei and the lumbrical tendons.

Question 10

Dorsal Interossei

Answer 10

DABS. Four 2-headed muscles starting at the thumb. They abduct the fingers.

Question 11

Palmer Interossei

Answer 11

PADS. Three single-headed muscles starting at the pinky which adduct the fingers. There is no muscle for the middle because we don’t need it. The middle finger is our reference point.

Question 12

What are the bones of the hand?

Answer 12

List starting from attachment to the radius and swinging back around to the radius.

Scaphoid ( We have a tubercle of scaphoid)
Lunate
Triquetrum
Pisiform
Hamate ( We have a hook of hamate)
Capitate
Trapazoid
Trapezium

Question 13

What are the bones of the hand?

Answer 13

List starting from attachment to the radius and swinging back around to the radius. Considered Proximal Row and then Distal Row.

Scaphoid ( We have a tubercle of scaphoid)
Lunate
Triquetrum
Pisiform
Hamate ( We have a hook of hamate)
Capitate
Trapazoid
Trapezium

Question 14

How does the ulnar nerve and ulnar artery enter the hand?

Answer 14

Through the Canal of Guyon

Question 15

The Carpal Tunnel houses one nerve. Which is it?

Answer 15

Median Nerve

Question 16

Carpal Tunnel contents and boundaries

Answer 16

9 tendons and 1 nerve

1. Tendons of the Flexor Digitorum Superficialis (4 tendons)
2. Tendons of the Flexor Digitorum Profundus (4 tendons)
3. Flexor Pollicis Longus (1 tendon)

Question 17

Carpal Tunnel contents and boundaries

Answer 17

9 tendons and 1 nerve (Median Nerve)

1. Tendons of the Flexor Digitorum Superficialis (4 tendons)
2. Tendons of the Flexor Digitorum Profundus (4 tendons)
3. Flexor Pollicis Longus (1 tendon)

Posterior boundry: Carpal bones
Anterior boundry: Flexor retinaculum

Question 18

Palmar Aponeurosis

Answer 18

Thin over the thenar and hypothenar eminences, but thick in the palm.

Question 19

Blood supply to the hand?

Answer 19

Radial Artery
Continues around the lateral carpi bones (Radial pulse). It then moves dorsally where it can be seen across the floor of the snuff box. It then dives DEEP piercing the FIRST DORSAL INTEROSSEOUS where it continues through the palm to form the DEEP PALMER ARCH.

Note: There is a superficial palmer branch of the radial artery that branches off to anastomose with superficial palmer arch of the ulnar artery.

Other branches are the principes pollicis and the radialis indicis

Ulnar Artery
Enter the hand with the ulnar nerve via the canal of Guyon. The superficial branch becomes the SUPERFICIAL PALMER ARCH. It flows across the palm to the fingers giving off the COMMON PALMER DIGITAL ARTERY which becomes the PROPER PALMER DIGITAL ARTERY

Note: there is a deep branch of the ulnar artery that passes between the ABductor digiti minimi and the flexor digiti minimi to anastomose with the deep palmer arch of the radial artery.

Median Artery
There is no Median artery

Question 20

USRD (Arteris)

Answer 20

Ulnar superficial: Radial Deep

Question 21

Nerve supply

Answer 21

Radial Cutaneous only (called Superficial Branch)
Passes over the anatomical snuff box. Innervates dorsal lateral 2 1/2 digits proximal to the DIP joint (distal interphalangeal joints)

Median Nerve
Enters the hand under the flexor retinaculum throught the carpal tunnel. Innervates:
1/2 LOAF
Recurrent Thenar Branch
Becomes common palmer digital and then proper palmer digital.
Provides cutaneous sensation to the palmer lateral 3 1/2 fingers and the dorsal nail beds of the same fingers (considered distalP

Ulnar Nerve
Pierces every muscle in the hand except the few exceptions 2 1/2 on dorsal side (named dorsal cutaneous branch) and 1 1/2 on palmer side (named palmer cutaneous branch)

Question 22

Claw Hand

Answer 22

Effects your ulnar nerve. We know that the ulnar nerve innervates almost every muscle of the hand but the lumbricals are the most important in this situation.

We know that only the 3 and 4 lumbricals are innervated by the the ulnar nerve so we expect to the the deformity in the pinky and ring finger.

Instead of normal action of the lumbricals we get hyperextension of the 4th and 5th metacarpalphalnegeal joints and flexion of the PIP’s and DIP’s.

Also important in the chracteristic claw hand is due to the unopposed action activity of the extensor digitorum muscle.

USUALLY AT THE WRIST IF AT THE ELBOW WILL SEE TO A LESSER DEGREE

Question 23

Ape Hand

Answer 23

Median Nerve.
Wasting of Thenar muscle. Inability to oppose thumbs. Thumb is pulled posteriorly and lines up with the other digits.
This can happen if the median nerve is injured at the wrist or the elbow

Question 24

Hand of Benediction

Answer 24

Median nerve deformity while trying to make a first. It almost looks like the claw hand but for different reasons. In this case the pinky and ring finger (partially) are completely fine they can flex down but the lateral 3 1/2 fingers cannot.

Question 25

Wrist Drop

Answer 25

Radial nerve usually damaged proximal to the elbow causing a loss of motor innervation to the wrist extensers in the forearm.
There is no opposition to the flexors so the wrist hangs down.