Neuromuscular

Neuromuscular describes the medical domain concerned with the interface between the nervous system and skeletal muscles, including the peripheral nerves, neuromuscular junctions, and muscle tissue. The neuromuscular system enables voluntary movement, reflexes, and maintenance of posture, and is distinct from central nervous system control.

The key components are motor neurons in the spinal cord or brainstem, peripheral nerves carrying signals to muscles, the neuromuscular junction where motor neuron terminals release acetylcholine to receptors on the muscle, and the muscle fibers that contract in response. An action potential travels along a motor neuron, triggering acetylcholine release, opening voltage-gated calcium channels, triggering calcium release in muscle fibers, and initiating contraction through the excitation-contraction coupling process.

Disorders span neuromuscular junction diseases such as myasthenia gravis and Lambert-Eaton syndrome; motor neuron diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy; peripheral neuropathies such as diabetic or inflammatory demyelinating polyneuropathies; muscular dystrophies and congenital myopathies affecting muscle structure or metabolism.

Diagnosis relies on history and exam, electromyography and nerve conduction studies, imaging when needed, serological or genetic testing, and muscle biopsy in selected cases. Electrophysiology can distinguish nerve versus muscle or junctional disease.

Management is often multidisciplinary, including symptomatic therapies, immunomodulation for autoimmune disorders, disease-specific treatments, physical and occupational therapy, respiratory support for bulbar or diaphragm weakness, and emerging gene therapies and targeted treatments for select conditions.