Intermediate Brachial Plexus Roots and Trunks Quiz

Q1. What is the usual root value of the upper trunk?

• C8-T1
• C6-C7
• C7-C8
• C5-C6

Q2. What is the usual root value of the middle trunk?

• C8-T1
• C5-C6
• C7
• T1-T2

Q3. What is the usual root value of the lower trunk?

• C6-C7
• C7 only
• C8-T1
• C5-C6

Q4. Which two named branches commonly arise from the upper trunk?

• Suprascapular nerve and nerve to subclavius
• Median and ulnar nerves
• Axillary and radial nerves
• Long thoracic and dorsal scapular nerves

Q5. From which parts of the plexus does the long thoracic nerve usually arise?

• C5-C7 roots
• Posterior cord only
• C8-T1 roots only
• Upper and lower trunks only

Q6. Which brachial plexus branch commonly pierces middle scalene?

• Dorsal scapular nerve
• Suprascapular nerve
• Median nerve
• Ulnar nerve

Q7. What structure lies inferior to the brachial plexus trunks as they cross the root of the neck?

• Thyroid isthmus
• Internal carotid artery
• External jugular vein only
• Subclavian artery

Q8. At approximately what region do the brachial plexus trunks divide into anterior and posterior divisions?

• At the carotid bifurcation
• Inside the vertebral canal
• At the angle of the mandible
• Near the lateral border of the first rib

Q9. What is meant by a prefixed brachial plexus?

• A plexus formed only by thoracic nerves
• Greater superior contribution, often C4-C8
• Complete absence of C5
• Greater inferior contribution, often C6-T2

Q10. What is meant by a postfixed brachial plexus?

• A plexus formed only by C5-C7
• Greater superior contribution, often C4-C8
• Fusion of all trunks into one nerve
• Greater inferior contribution, often C6-T2