Injuries

Question 1

Where is weakest part of clavicle?

Answer 1

Weakest part = junction b/t middle and lateral thirds
SCM elevates medial portion
Coracoclavicular l. usually prevents dislocation at AC joint

Question 2

What n. is damaged in a fracture of the humeral surgical neck? What effects occur?

Answer 2

Axillary n (C5-6) Deltoid atrophies. May loose sensation in lateral deltoid area

Question 3

Which n. is at risk in a transverse and spiral fractures of shaft of humerus?

Answer 3

Radial n

Question 4

What n. is at risk during intercondylar fractures of humerus?

Answer 4

Median or ulnar nerves

Question 5

What is the name for the most common fracture of the forearm?
Where does it occur?

Answer 5

Colles fracture - complete transverse fracture of the distal 2 cm of the radius.
Ulnar styloid process is often broken off; posterior angulation happens in forearm just proximal to wrist
* = Dinner fork deformity

Question 6

Which carpal bone is most commonly fractured?

Answer 6

Scaphoid. Results in degenerative joint disease of wrist

Question 7

Which joint is affected in a seperated shoulder?

When is it considered severe?

Answer 7

AC joint. Severe where both AC and coracoclavicular ll. are torn

Question 8

Which n. passes inferior to humeral head, and winds around surgical neck?
How is this nerve damaged?
What is effected?

Answer 8

Axillary n.; Damaged by fracture of surgical neck, dislocation of GH joint, compression from crutches, or intramuscular injections.
Deltoid atrophies; loss of sensation over lateral part of arm (area supplied by superior lateral cutaneous n. = branch of axillary)
ABD of humerus from 15-90 degrees would be affected

Question 9

Which rotator cuff muscle is most commonly injured?

Complete tear would result in?

Answer 9

Supraspinatus = most commonly injured

Results in inability to initiate first 15 degrees of ABD

Question 10

Which nerve is likely damaged during a knife fight when limb is elevated, and Serratus Anterior m. is cut?
What are affects?

Answer 10

Long Thoracic n. (C5-7)
“Winged Scapula” = medial border scapula moves laterally and posteriorly.
Upper limb may not be able to ABD above 90 degrees. *No sensory loss

Question 11

Excessive increased angle b/t neck and shoulder results in (1) upper brachial plexus injury or (2) lower brachial plexus injury?
What nerve roots are stretched or torn from spinal chord?

Answer 11

Upper Brachial Plexus Injury

Roots C5-6

Question 12

Damage to Superior Trunk results in?

Any sensation loss?

Answer 12

Paralysis of muscles of shoulder and arm supplied by C5-6 (deltoid, bicep, brachialis)
= Waiter’s tip position (Erb-Duchenne palsy)
Lateral aspect of arm will loose sensation due to lateral antebrachial cutaneous n.

Question 13

How do lower brachial plexus injuries occur? What is the resulting action? Which nerve is damaged? Loss of sensation?

Answer 13

Occurs when upper limb is suddenly pulled superiorly. C8-T1 = Klumpke palsy or “Claw Hand”
Damage to Dorsal branch of ulnar n. and Palmar branch and palmar digital branches of ulnar n. Loss of sensation to medial part of dorsum of hand and medial 1 1/2 dgits and palmar surface of hand.

Question 14

Injury to musculocutaneous n. affects?

Answer 14

(C5-7) weakened shoulder flexion, weakened flexion of elbow, weakened supination of forearm
Sensory loss may occur on lateral surface of forearm to area supplied by lateral antebrachial cutaneous n. (continuation of musculocutaneous)

Question 15

Rupture tendon of long head of biceps brachia looks like…

Answer 15

“Popeye Deformity”

Question 16

Biceps tendonitis produces…

Answer 16

tenderness/pain and Crepitus (cracling sound)

Question 17

Which nerve is the most commonly injured nerve?

Answer 17

Radial n. C5-8

Question 18

What is the common characteristic of an injury to radial n superior to origin of branching to triceps?

Answer 18

Wrist drop
Damage = paralysis of tricep, brachioradialis, supinator, and extensors of wrist and fingers; unable to extend wrist and fingers at MP joint; Loss of sensation to posterior arm, forearm, dorsum of hand and lateral fingers *Posterior radial cutaneous and superficial radial nerve damage

Question 19

An injury to radial n. in the Radial Groove results in?

Answer 19

Wrist drop
Fracture to humeral shaft. Does not paralyze, only weakens medial head of triceps. Paralyzes all other posterior compartment forearm mm. Loss of sensation to dorsum of hand and lateral fingers from Superficial radial n. damage

Question 20

What is dupuytren Contracture?

Answer 20

Progressive shortening, thickening, and fibrous of palmar aponeurosis

Question 21

PIN innervates which 4 muscles?

Answer 21

Snuff box muscles and extensor indices