Anatomical Sciences

Question 1

Specific nerve pathways & how Sx map to their areas of innervation

What are the characteristic patterns of nerve pathology and how do they present in terms of dermatomes, myotomes, and peripheral nerve injuries?

Answer 1

1. Dermatomes: Each spinal nerve innervates a specific skin region. Pathology often results in sensory deficits in a mapped area.
   
   • Example: An issue with the C5 nerve root could cause numbness in the lateral arm.
   2. Myotomes: Specific spinal nerves also control certain muscle groups, so motor deficits align with these zones.
      * Example: C5-C6 innervates the biceps, so injury here could result in weakened elbow flexion.
   3. Peripheral Nerves: Unique deficits arise based on where a peripheral nerve is damaged.
      * Example: Median nerve compression in carpal tunnel syndrome leads to numbness in the thumb, index, and middle fingers.

Note: Pathologies can also cause distinctive gaits (like Trendelenburg gait due to superior gluteal nerve issues) or postures, which aid in diagnosis.