Brachial Plexus (Injuries) Flashcards
What would occur if there was an injury to individual roots?
How might an injury occur?
What does C6 root provide sensation for?
These are rare. Root could be cut by gunshot or knife wound but the root is more commonly avulsed (torn from spinal cord) by rapid pulling or stretching due to traumatic injury. Since so many roots contribute to many muscles, it is hard to localize the motor effects of the lesion. Sensory loss (loss of a dermatome) may be more diagnostic. The C6 root provides sensation for the thumb.
How would a wound to long thoracic nerve occur? What would result?
Injury caused by stab wound or during radical mastectomy.
Results in paralysis of the serratus anterior muscle. This muscle rotates the scapula upward, abducts the scapula and elevates it above horizontal.
loss of this muscle function results in inability to raise arm above horizontal plane and a winged scapula.
What would be an upper trunk injury?
What would result?
Erb- Duchenne paralysis or Erb palsy.
Caused by a birth injury during breech delivery or violent displacement of head from shoulder (fall from motorcycle or horse)
Results in loss of abduction, flexion, and lateral rotation of the arm, producing waiter’s tip hand (arm lies in medial rotation resulting from paralysis of lateral rotator muscles)
Can be associated with shoulder dystocia, a trauma which occurs when the infants shoulder gets caught on the mothers pubic bone during delivery
What is a lower trunk injury?
How would it occur?
What results?
Klumpke’s palsy.
Can be caused by difficult breech delivery in which arm is forecully abducted. Or cervical rib or abnormal spasm of anterior and middle scalene muscles or traumatic forceful abduction of the arm due to a fall or accident.
Causes a claw hand.
What would result from injury to posterior cord?
Can result in crutch palsy or saturday nite palsy (drunken fool passes out with arm draped over top of chair)
Results in loss of extensors of arm, forearm, and hand–results in wrist drop
How would injury of axillary nerve occur?
What results?
Caused by a fracture of the surgical neck of the humerus or inferior dislocation of the humerus.
Results in weakness of lateral rotation and abduction of the arm
How would injury to radial nerve occur?
What would result?
Caused by a fracture of the midshaft of the humerus.
Results in loss of function in the extensors of forearm, hand, metacarpals, and phalanges. It also results in loss of wrist extension, leading to wrist drop, and produces a weakness of abduction and adduction of the hand
What does injury to musculocutaneous nerve result in?
weakness of supination (biceps) and flexion (biceps and brachialis) of forearm and loss of sensation on lateral side of forearm.
How does injury to median nerve occur?
What results?
Injury can be caused by supracondylar fracture of the humerus or a compression in the carpal tunnel
Results in loss of pronation, opposition of the thumb, and flexion of the lateral 2 interphalangeal joints and impairment of the medial 2 interphalangeal joints. Wasting of the thenar eminence results in ape hand or Benedictine hand which is similar to claw hand but presents upon attempted flexion of fingers.
How is injury to ulnar nerve caused?
What results?
caused by a fracture of the medial epcondyle and results in claw hand- ring and little fingers are hyperextended at MP joints and flexed at IP joints.
Loss of abduction and adduction of fingers and flexion at the MP joints because of loss of dorsal and palmar interossei and medial 2 lumbricals. Hypothenar eminence is waters and adductor pollicis is lost.
