Brachial Plexus

Question 1

Cause & effect of true claw:

Answer 1

Cause: Damage to lower roots –> damage to median, radial, and ulnar nerves
Effect: Inability to extend digits

Question 2

Cause & effect of ulnar claw:

Answer 2

Cause: Distal ulnar nerve injury
Effect: Paralysis of the 2 medial lumbricals. May cause thenar wasting due to loss of adductor pollicis.

Question 3

Cause & effect of Pope’s blessing or Benedictine sign:

Answer 3

Cause: Median nerve injury
Effect: Paralyzes the lateral 2 lumbricals and weakens the flexor digitorum superficialis and deep.
Appears the same as ulnar claw but only upon attempting to make a fist.

Question 4

Klumpke’s palsy: what is it? How can it come about?

Answer 4

• Damage to the lower roots affects the ulnar, median, and radial nerves–affecting all lumbricals and weakening extension of the digits.
• Can occur thru sudden jerking of a child’s arm or grabbing branch while falling from a tree.

Question 5

Erb’s palsy: what is it? How can it come about?

Answer 5

• A result of upper root damage and affects the suprascapular, musculocutaneous, and axillary nerves. The deltoid, brachialis, biceps, supraspinatus, and infraspinatus muscles may be affected contributing to the “waiter’s tip” sign.

Question 6

Dystocia definition. Which palsy’s can it lead to?

Answer 6

• Difficult birth, typically caused by a large or awkwardly positioned fetus, by smallness of the maternal pelvis, or by failure of the uterus and cervix to contract and expand normally.
• Can lead to Klumpke’s or Erb’s palsy.

Question 7

Dermatome (simple definition)

Answer 7

Sensory band served by 1 dorsal root

Question 8

Cutaneous nerves (simple definition)

Answer 8

May come from several dorsal roots; innervate larger patch of skin than dermatome