Execution
- 1Screen for neurological signs and perform the test only when it is clinically necessary and safe.
- 2Position the patient sitting with the cervical spine slightly flexed.
- 3Stabilize the spinous process of C2 with one hand.
- 4Place the other hand on the patient's forehead.
- 5Gently press posteriorly through the forehead while maintaining C2 stabilization.
Positive outcome
A clunk, slide, reduction sensation, or reduction of neurological symptoms is positive and suggests anterior atlantoaxial instability from transverse ligament insufficiency. Pain, apprehension, or neurological symptoms require immediate caution. A negative test does not rule out instability.
Studies
| Study | Reliability | Sn | Sp | LR+ | LR− |
|---|---|---|---|---|---|
| Hutting et al. (2013) | systematic review | 19-69 | 71-98 | NA | NA |
| Mansfield et al. (2020) | systematic review of SPT reliability, accuracy, and safety | NA | NA | NA | NA |
CommentMagee stresses that Sharp-Purser must be performed with extreme caution. Modern reviews question its reliability and safety as a routine screen, and sensitivity is too low to rule out upper cervical instability. Use history, neurological signs, imaging, and medical referral when suspicion is meaningful.
Low Clinical Value