The diagnosis and treatment of a patient with suspected neuromuscular disease requires an integrated approach that utilizes clinical, electrodiagnostic, pathologic and genetic data. Ultrasound complements the clinical and electrophysiology exam by showing the degree of abnormalities in myopathies, as well as spontaneous muscle activities in motor neuron diseases and other disorders. US is particularly well suited for evaluation of neuromuscular disorders as it can be performed at the bedside, has no need for sedation, can rapidly evaluate multiple body regions, and is well tolerated by both children and adults including patients in wheelchairs or those who cannot lay flat or still. Muscle ultrasound can be used as a biomarker for Duchenne and FSH muscular dystrophy and spinal muscular atrophy, and the combination of electromyography and ultrasound increases the diagnostic certainty of amyotrophic lateral sclerosis. Qualitative visual analysis of muscle can be graded using the Heckmatt scale, based on the degree of echogenicity and visualization of the deep boney structures. Quantification of the gray scale levels can be performed by importing the ultrasound image into an image analysis software program such as ImageJ, selecting a region of interest within the muscle belly, and measuring the mean gray scale pixel values within the region of interest. Quantitative analysis allows for more sensitive and specific determinations of muscle pathology than qualitative analysis, with reported sensitivities for neuromuscular pathology around 95%. A drawback of quantitative muscle ultrasound is that it requires that imaging settings be held constant and that normative values have been obtained using identical imaging parameters. A strong advantage of ultrasound over other imaging modalities is that evaluation in real time permits the identification of pathologic muscle movement, particularly fasciculations.