Notes on Upper Extremity Nerves

Overview

• Focus on learning upper extremity nerves (nerves of the arm)
• Important for exams like USMLE and COMLEX
• Utilize mnemonic: ARM YOU to remember nerve injuries
• Correlate nerves with corresponding injuries

Axillary Nerve

• Mnemonic: A in ARM YOU
• Origin: C5-C6
• Injury: Surgical neck fracture of the humerus
  • Mnemonic: A in ARM YOU corresponds with N in NAME SOME (surgical Neck fracture)
• Clinical Finding: Problems with abduction of the shoulder

Radial Nerve

• Mnemonic: R in ARM YOU
• Origin: C5-T1
• Injuries:
  • Axillary compression (e.g., Saturday night palsy or crutch palsy)
  • Mid-shaft fracture of the humerus
  • Mnemonic: R in ARM YOU correlates with A and M in NAME SOME (Axillary and Mid-shaft fracture)
• Clinical Finding: Wrist drop (R for Radial nerve)

Median Nerve

• Mnemonic: M in ARM YOU
• Origin: C5-T1
• Injury: Supracondylar fracture
  • Mnemonic: M in ARM YOU corresponds with S in NAME SOME
• Clinical Finding: Ape hand (Monkey hand) affecting thumb opposition and finger positioning

Ulnar Nerve

• Mnemonic: U in ARM YOU
• Origin: C8-T1
• Injuries:
  • Outstretched fall injuring the hook of the hamate
  • Medial epicondylar fracture
  • Mnemonic: U in ARM YOU correlates with O, M, and E in NAME SOME (Outstretched fall, Medial Epicondylar fracture)
• Clinical Finding: Ulnar claw

Conclusion

• Use the mnemonic ARM YOU to easily recall nerve injuries and clinical manifestations
• Important to correlate nerve origins, injury locations, and clinical findings
• High-yield topic for exams; understanding these correlations can provide easy points on test day.

Study Tip: Pair the letters in ARM YOU with the corresponding injury and clinical finding for easier recall.