Brachial Plexus Quiz
Questions: 16 · 10 minutes
1. A fracture at the surgical neck of the humerus is followed by weak shoulder abduction and numbness over the lateral shoulder. Which nerve is most likely injured?
Suprascapular nerve
Upper subscapular nerve
Musculocutaneous nerve
Axillary nerve
2. Which spinal nerve roots typically form the brachial plexus?
C3 through C7
C5 through T1
C7 through T3
T1 through T5
3. Which terminal nerve arises primarily from the medial cord?
Ulnar nerve
Musculocutaneous nerve
Radial nerve
Axillary nerve
4. After traction between the neck and shoulder, a patient develops the classic pattern associated with Erb palsy. Which part of the plexus is most likely affected?
The medial cord only
The middle trunk, mainly C7 fibers
The lower trunk, mainly C8–T1 fibers
The upper trunk, mainly C5–C6 fibers
5. A posterior cord injury causes marked weakness of elbow, wrist, and finger extension. Dysfunction of which terminal branch best accounts for this pattern?
Median nerve
Musculocutaneous nerve
Ulnar nerve
Radial nerve
6. Which nerve is a terminal branch of the posterior cord?
Musculocutaneous nerve
Median nerve
Axillary nerve
Ulnar nerve
7. A forceful upward pull on an abducted arm injures the lowest portion of the plexus and produces a Klumpke-type pattern. Which structure is most likely involved?
The upper trunk
The lower trunk
The lateral cord
The posterior division of the middle trunk only
8. A posterior cord branch is damaged during axillary surgery, leaving the patient weak when extending and medially rotating the humerus with latissimus dorsi. Which nerve is affected?
Lower subscapular nerve
Dorsal scapular nerve
Lateral pectoral nerve
Thoracodorsal nerve
9. A lesion confined to the lateral cord would most directly threaten which terminal nerve?
Musculocutaneous nerve
Ulnar nerve
Radial nerve
Axillary nerve
10. After an injury near the medial cord, a patient loses sensation along the medial forearm while intrinsic hand strength remains intact. Which branch best matches the sensory deficit?
Lateral antebrachial cutaneous nerve
Medial brachial cutaneous nerve
Medial antebrachial cutaneous nerve
Superficial radial nerve
11. Following axillary surgery, a patient has a winged scapula that becomes prominent when pushing against a wall. Which nerve was most likely injured?
Long thoracic nerve
Suprascapular nerve
Thoracodorsal nerve
Dorsal scapular nerve
12. Immediately distal to the trunks, how is each trunk organized?
Into anterior and posterior divisions
Into superficial and deep branches
Into medial and lateral roots
Into proximal and distal fascicles
13. Which root contribution is typical of the long thoracic nerve?
C5–C6 only
C5–C7
C6–C8
C8–T1
14. Which roots normally unite to form the upper trunk of the brachial plexus?
C4 and C5
C5 and C6
C6 and C7
C8 and T1
15. Which statement correctly describes the formation of the median nerve?
It arises entirely from the posterior cord
It is formed by the union of the radial and ulnar nerves
It is formed by contributions from the lateral and medial cords
It branches directly from the upper and middle trunks
16. The lateral, medial, and posterior cords are named for their positions relative to which structure?
The subclavian vein
The clavicle
The second part of the axillary artery
The first rib