UPPER LIMB INJURIES

Question 1

Describe what occurs in nerve regeneration.

Answer 1

After a nerve is severely compressed or cut, it takes 2 weeks for regeneration to begin. The ends grow at 1 mm/day as they attempt to re-establish continuity of the PNS connective tissue.

Question 2

Describe the causes, muscle(s) affected and symptoms of a:

Long Thoracic Nerve injury.

Answer 2

Caused by downward trauma on the scapula or a surgical trauma. Affects the serratus anterior leading to “Winged Scapula”. Results in limited motion in abduction of flexion at the shoulder.

Question 3

Describe the causes, muscle(s) affected and symptoms of a:

Axillary Nerve Injury

Answer 3

Caused by a glenohumeral joint (shoulder) dislocation or surgical fracture at the neck of the humerus. Affects Teres minor and deltoid muscles potentially leading to “Deltoid Atrophy”

Question 4

Describe the causes, muscle(s) affected and symptoms of a:

Radial Nerve injury

Answer 4

Caused by a midshaft fracture of the humerus or cut/compression at the lateral wrist site more distally. Tissues affected include the Posterior forearm, lateral wrist Extensors and lateral part of the posterior hand (for cutaneous sensation). Results in limited motion in extension of the hand.

Question 5

Define the Wrist Drop test.

Answer 5

A test where a patient holds out his upper limbs in front and attempts to keep his or her wrists up. If the wrists drop, there may be a radial nerve injury.

Question 6

List out the mechanisms (known causes) of a radial nerve injury.

Answer 6

Upward pressure of the Axilla floor via Saturday night palsy or from a crutch injury. A dislocation of the GHJ and midshaft fracture of the Humerus are other proximal causes. More distal mechanisms include radial head dislocation or cuts/compression of the dorsal wrist leading to cutaneous sensory loss.

Question 7

Describe the causes and muscle(s) affected:

Median Nerve injury

Answer 7

Caused by an elbow dislocation, supracondylar fracture, lunate dislocation, protonator teres entrapment, carpal tunnel syndrome or a wrist lacteration. Affects the lateral FDP, digits 2-5 of FDS and FPL + FPB.

Question 8

Describe the signs and symptoms of a median nerve injury.

Answer 8

Median Claw hand - loss of flexion of DIP at 2nd and 3rd digits
Sign of Benediction - Loss of FDP of 2nd and 3rd digits + loss of FPL and FPB
Thenar atrophy - prolonged loss of 2LOAF innervation
Loss of Cutaneous sensation along dorsal digits 1-3.5 and medial thumb
Loss of Opposition - tested by “OK sign”

Question 9

Median Nerve injury

Answer 9

If a patient cannot perform the “OK sign”, he or she may have sustained a _____ _____ ____.

Question 10

Describe the causes, muscle(s) affected and symptoms of an:

Ulnar Nerve injury

Answer 10

Caused by an impinged ulnar nerve under medial epicondyle, hitting the “funny bone”. Leads to loss of cutaneous sensation along digits 4 and 5, Ulnar claw hand and wasting of interosseus.

Question 11

Describe the causes, muscle(s) affected and symptoms of a:

Upper trunk injury

Answer 11

Caused by pulling the head and shoulder in opposite directions such as from falling or faulty birthing process (pulling head at shoulder). Can lead to upper limb being adducted, internally rotated and protonated. This is known as “Erb’s Palsy” or the “Waiter’s Tip Sign”

Question 12

Describe the causes, muscle(s) affected and symptoms of a:

Lower trunk injury

Answer 12

Caused by compression from an extra cervical rib or a faulty birthing process (pulling at the infant’s arm). Can lead to limited movement of the intrinsic hand muscles (lumbricals, hypothenar and thenar muscles). Clawing at digits 2-5 is known as “Klumpske’s Palsy”

Question 13

Define Horner’s Syndrome.

Answer 13

A lower trunk injury at T1 area can lead to abnormal sympathetic symptoms such as drooping of the eyelid, pupil constricting or sweating at the affected side. This is because the sympathetic chain are located from T1-L2.

Question 14

List some common FOOSH injuries.

Answer 14

Falling on Outstretched hand injuries can occur anywhere along the bones or joints of the upper limb. They include:
Colles Fracture, Scaphoid Fracture, Lunate Fracture, Midshaft fracture, surgical neck fracture, clavicular midshaft fracture or ACJ shoulder separation.

Question 15

Explain the meaning of “Overriding of Antagonists”.

Answer 15

A phenomenom where the paralysis of one muscle causes a pull on a joint opposite to that muscle. Commonly seen in claw hands in the Waiter’s Tip sign of an upper trunk injury.

Question 16

Explain the significant danger of a Supracondylar Fracture.

Answer 16

The median nerve can be compressed or the brachial artery can be cut (a lethal occurrence) potentially leading to the loss of radial and ulnar pulse as well as the sensory loss of the lateral palm and 1-3.5 digits.

Question 17

Describe what occurs in a Median Claw Hand

Answer 17

DIP joints of digits 2 and 3 are ineffective due to loss of innervation to lateral FDP;
Caused by median nerve injury

Question 18

Describe the what occurs and the cause of the Sign of Benediction.

Answer 18

Loss of FDS of digits 2-5, Loss of FDP in digits 2 and 3, Loss of FPL and FPB,
Caused by median nerve injury

Question 19

OK Sign Test

Answer 19

The loss of opposition in the hand can be tested by…

Question 20

A motorcyclist collides with an incoming car and sustains trauma on his right neck. What type of injury did he get and what are the signs?

Answer 20

Upper trunk injury presented as Erb’s Palsy (Waiter’s Tip Sign).This involves loss of sensory innervation to the lateral side of the upper limb (C5-C7)

Question 21

What are some causes of an upper trunk injury and how would they present in a patient?

Answer 21

Hyperabduction of the arm would present as an inability to abduct digits 2-5 (Dorsal interossei via deep ulnar nerve)and oppose the thumb (via recurrent median nerve)

Question 22

A radial nerve injury would be caused by what 3 events?

Answer 22

Fracture of the shaft of the humerus; dislocation of the head of the radius; humeral head dislocation