Lateral Shear test is a cervical spine examination procedure that tests for odontoid dysplasia or aplasia.
Patient should be awake and cooperative while a Lateral Shear test is done.
- Patient should be in a supine lying position with the head supported
- The examiner places his hand (2nd MCP) against the transverse process of C1 (atlas). His other hand (2nd MCP) is placed against the opposite transverse process of C2 (axis).
- The examiner proceeds to approximate hands; he applies shearing force between C1-C2.
- The examiner checks for a soft end feel, nystagmus and muscle spasm. He asks the patient for dizziness and nausea.
Positive Lateral Shear Test
There is positive Lateral Shear test when there is observed soft end feel, muscle spasm, dizziness, nystagmus or nausea. These signs could indicate the presence of odontoid dysplasia or aplasia.
Examiners should have a clear knowledge and understanding of the cervical vascular structures along the area since these are compressed during the application of various hand positions. A positive Lateral Shear test should be followed with diagnostic imaging.