Muscle Biopsy

#The Neurology
Question: What is the most appropriate site for muscle biopsy?

A. Atrophic muscle
B. Recent EMG site
C. Power MRC grade 4/5
D. Power MRC grade 3/5

(Source: The Neurology: Self-Assessment & Review By Dr. Sunil Kumar,

Reference: Bradley's Neurology in Clinical Practice, 6th ed. Page 2066


Preferred site for Muscle Biopsy
  • Moderately weak muscle
  • Avoid sites for Muscle Biopsy
  • Muscle with no weakness
  • Muscle with severe weakness
  • Recent EMG site
  • Recent intramuscular injections site
  • Recent muscle trauma site
  • Previous muscle surgery site
Avoid muscle biopsy from severely weak and atrophic muscle, because in end-stage muscle disease, loss of myofibers is severe, and they are replaced by fibrovascular and adipose tissue.

Biopsy from minimally involved muscle may lack diagnostic histological features.

Take muscle biopsy from muscle belly and not from tendon insertion site, as it will show central nuclei, variation in fibre size and endomysial fibrosis mimicking myopathy.

[Answer: C. Power MRC grade 4/5]


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