There is a multitude of neuromuscular diseases that are exceptionally difficult to diagnose. In some cases, even extensive clinical examination and laboratory workups fail to reveal a diagnosis. In these cases, a nerve and or a muscle biopsy might be required to secure a diagnosis. Once a definitive diagnosis is obtained, the appropriate prognosis and treatments may be provided.
Essentially any nerve or muscle in the body can be used for biopsy. The majority of biopsies sample muscles and nerves that are surgically accessible with a local anesthetic with a minimum of effort. These procedures are almost invariably tolerated quite easily by awake patients.
Common muscles subjected to biopsy are the following:
- gracilis muscles
Common nerves subjected to biopsy are the following:
- superficial peroneal
- superficial radial sensory
The gracilis nerve is a motor nerve that supplies the gracilis muscle in the thigh. As a motor nerve, it is an extremely useful nerve used in the diagnosis of motor neuron diseases such as amyotrophic lateral sclerosis (ALS).