The hand

Question 1

What can the hand be used for

Answer 1

The hand can be used for both power and precision functions

Question 2

where does the power of the hand come from

Answer 2

The power comes from the forearm muscles

Question 3

where does the precision of the hand come from

Answer 3

the precision is produced by the intrinsic muscles of the hand

Question 4

what are the two main muscle masses in the hand

Answer 4

There are two main muscle masses in the hand, the thenar muscles at the base of the thumb, and the hypothenar muscles

Question 5

what innervates the thenar muscle

Answer 5

median

Question 6

what innervates the hypothenar muscle

Answer 6

ulnar

Question 7

what does the radial nerve do

Answer 7

The radial nerve supplies a small area of skin at the base of the dorsal thumb.

Question 8

what is the main contributor to the superficial palmer arches

Answer 8

ulnar artery

Question 9

what is the Amin contributor to the deep palmar arches

Answer 9

radial artery

Question 10

where can a patient that has both hypothenar and thenar muscle weakness have a lesion

Answer 10

A patient with both hypothenar and thenar muscle weakness could have a lesion in the brachial plexus at T1
this is because Both the ulnar and median nerve supply to the muscles in the hand comes from the motor neurons in the spinal cord at the T1 level.

Question 11

what can a patient have if they have muscle weakness in the hypothenar and thenar muscles

Answer 11

Patients who come in complaining of loss of manual dexterity and muscle weakness in the hypothenar and thenar muscles may have a tumor of the apex of the lung (Pancoast’s tumor), which compresses the T1 nerve root.

Question 12

what is dupuytren contracture

Answer 12

Dupuytren’s contracture is a thickening and shortening of the palmar aponeurosis, which then results in a flexion of the MCP joints usually beginning with the ring finger.

Question 13

what patients is dupuytrens contracture come in

Answer 13

liver disease

Question 14

describe the anatomical snuff box tenderness test

Answer 14

1. Identify the “anatomical snuffbox” between the
   extensor pollicis longus and brevis. (Extending the thumb makes these structures more prominent.) 2. Press firmly straight down with your index finger or thumb.
2. Any tenderness in this area is highly suggestive of scaphoid fracture.
   In this situation, your clinical exam is actually more
   sensitive than a x-ray. Snuffbox tenderness should be treated as a fracture even if the x-ray is normal! An x-ray a few weeks later will reveal the
   resorption of bone along the fracture.

Question 15

describe the Allen test

Answer 15

1. Have the patient place their hand with the palmar aspect facing up.
2. Have the patient make a fist. This should close off the superficial and deep palmar arterial arches. 3. Compress both the ulnar and radial arteries until the hand blanches (Compress the radial artery against the anterior surface of the radius, the ulnar artery lateral to the pisiform bone)
3. Have the patient open the hand.
4. Release the pressure on either the ulnar side or the radial side releasing the arteries and see if the colour returns within 5 seconds.
5. If colour does not return in 5 min, this indicates possible occlusion or narrowing of the tested artery.

Question 16

describe median nerve test

Answer 16

1. . Hold the patient’s wrist’s in acute flexion for 60 secs.
2. Alternatively ask the patient to press the backs of both hands together to form right angles for 60 secs.
3. If they experience paraesthesia in their hands then the test is positive

Question 17

describe tingles sign

Answer 17

1. With your finger, percuss lightly over the course of the median nerve in the carpal tunnel at the spot indicated by the arrow.
2. Tingling or electric sensations in the distribution of the median nerve constitute a positive test, suggesting carpal tunnel syndrome.

Question 18

describe thumb abduction

Answer 18

1. Ask the patient to raise the thumb perpendicular to the palm as you apply downward pressure on the distal phalanx.
2. This manoeuvre reliably tests the strength of the abductor pollicis brevis, which is innervated only by the median nerve

Question 19

describe rotator cuff tests

Answer 19

To test for degenerative tendonitis which is often found in older people or a person whose job involves a lot of overhead work the following test is useful.

Question 20

describe drop arm test

Answer 20

1. Start with the patient’s arm abducted to 90°.
2. Ask the patient to slowly lower the arm.
3. If the rotator cuff (especially the supraspinatus) is torn, the patient will be unable to lower the arm slowly and smoothly.

Question 21

what is the most common torn part of the rotator cuff

Answer 21

the supraspinatus tendon is the most commonly torn part of the rotator cuff because it is relatively avascular and during abduction of the shoulder joint the supraspinatus tendon is exposed to friction from the acromion as it passes through the gap between the acromion and the glenoid cavity.

Question 22

why is abduction painful

Answer 22

The tendon of supraspinatus is separated from the coracoacromial ligament, acromion and deltoid by the subacromial bursa. When this Becomes inflamed, (bursitis), abduction of the arm is extremely painful during the arc of 50 to 130 degrees (painful arc syndrome

Question 23

How do you do the impingement sign test

Answer 23

1. Start with the patient’s arm relaxed and the shoulder in neutral rotation.
2. Abduct the arm to 90°.
3. Significant shoulder pain as the arm is raised suggests an impingement of the rotator
   cuff against the acromion.
   If the patient can perform the drop arm test but experiences pain in the shoulder this suggests that the rotator cuff is injured but not torn. Chronic rotator cuff injury leads to an impingement syndrome with significant pain in the shoulder and arm.

Question 24

how do you do the flexor digitorum superficilicasi test

Answer 24

1. Hold the fingers in extension except the finger being tested.
2. Ask the patient to flex the finger at the proximal interphalangeal joint.
3. If the patient cannot flex the finger, the flexor digitorum superficialis tendon is cut or
   non-functional.

Question 25

How do you do the flexor digitorum profundus test

Answer 25

1. Hold the metacarpophalangeal and proximal interphalangeal joints of the finger being tested in extension.
2. Ask the patient to flex the finger at the distal interphalangeal joint.
3. If the patient cannot flex the finger, the flexor digitorum profundus tendon is cut or
   non-functional.

Question 26

why is the musculocutaneous nerve only injured rarely

Answer 26

This nerve is injured only rarely because it is well protected by the biceps brachii.