Neuromuscular Anatomy Update: A Useful Tool for Differential Diagnosis between Cervical Spondylosis and Related Disorders

Abstract

Neuromuscular anatomy is the indispensable background for the diagnosis and differential diagnosis of cervical spondylosis (CS), i.e. cervical spondylotic radiculopathy (CSR), cervical spondylotic myelopathy (CSM) and cervical spondylotic amyotrophy (CSA). The spinal cord level is 1.5 segments below the level of the adjacent vertebral body. For instance, lesion at the C5/6 intervertebral foramen causes C6 radiculopathy, whereas the cord compression at the C5/6 level presents segmental signs at C7 level. The dorsal rami of spinal nerve run down several segments from the original intervertebral foramen, which is thought to be the reason why back, especially interscapular pain is often experienced in CS. Multifidus is innervated by the single adjacent root and should be chosen for the needle EMG examination of the paraspinal muscles to document the cervical lesion. Spinal accessory nerve innervating the Trapezius runs upward within the spinal canal and is relatively spared in CS. Dermatome and myotome are the most important knowledge to be mastered. I created an original myotomal chart based on my experiences, some of which have been published. If we evaluate neurological signs with the basis of correct neuroanatomy, we can make 80% correct diagnoses. This is complemented by neuromuscular electrodiagnosis, also based on neuroanatomy.