Gross Anatomy #7 – Brachial Plexus

Question 1

What nerve roots (anterior rami) correspond to the radial nerve?

a) C5-C7
b) C5-T1
c) C6-T1
d) C7-T1
e) C8-T1

Answer 1

b) C5-T1

Question 2

The brachial plexus is leaves the neck:

a) Anterior to the anterior scalene muscle
b) Between the anterior and middle scalene muscles
c) Between the middle and posterior scalene muscles
d) Posterior to the posterior scalene muscles
e) After piercing the middle scalene muscle

Answer 2

b) Between the anterior and middle scalene muscles

Question 3

Which section of the brachial plexus is named based on their location around the
axillary artery?
a) Roots
b) Trunks
c) Divisions
d) Cords
e) Branches

Answer 3

d) Cords

Question 4

Which branch of the brachial plexus pierces the coracobrachialis muscle?

a) Musculocutaneous nerve
b) Axillary nerve
c) Radial nerve
d) Median nerve
e) Ulnar nerve

Answer 4

a) Musculocutaneous nerve

Question 5

A patient with cardiac angina feels referred pain on the medial portion of their

forearm. What nerve root is involved?
a) C5
b) C6
c) C7
d) C8
e) T1

Answer 5

e) T1

Question 6

What nerve root corresponds to the outside deltoid region, also known as the
“regimental patch” region?
a) C5
b) C6
c) C7
d) C8
e) T1

Answer 6

a) C5

Question 7

What nerve accounts for sensation on the top of the hand (posterior aspect) between
the thumb and first two fingers?
a) Musculocutaneous nerve
b) Axillary nerve
c) Radial nerve
d) Median nerve
e) Ulnar nerve

Answer 7

c) Radial nerve

Question 8

A 33-year-old male presents two weeks following a motorcycle crash with a chief
complaint of limited functional use of his right arm. Physical exam reveals a right arm
that is adducted and internally rotated with some flexion of the wrist. History reveals that
during the accident he landed on the upper right shoulder and neck, sustaining significant
skin abrasions to the area of his right lateral neck down to his acromion process. Which
of the following is most likely?
a) Erb-Duchenne Palsy
b) Dejerine-Klumpke Palsy
c) Parsonage-Turner Syndrome
d) Hand of Benediction
e) Thoracic Outlet Syndrome
f) Volkmann Contracture
g) Dupuytren Contracture

Answer 8

a) Erb-Duchenne Palsy

Question 9

A young child presents with history of weakness of the left arm after traumatic birth.
Questioning reveals birth started with the left arm and it was pulled to aid in birth.
Currently, the child shows flexion and supination of the elbow, extension of the wrist,
hyperextension of the metacarpophalangeal joints, and flexion of the interphalangeal
joints with the “claw hand” posture. What nerve roots are likely involved?
a) C5-C6
b) C6-C7
c) C7-C8
d) C8-T1

Answer 9

d) C8-T1