Surgical Landmark of Mandible Angle in the Identification of Cervical Spinal Level.

Mandible angle is considered to be a consistently palpable external landmark for the identification of cervical spinal level by a radiographic study. But this anatomical study aimed to determine the positional relationship between mandible angle and cervical spinal level in cadavers. In this study, the cervical spine of 10 adult cadavers with intact head and neck structure, including 6 males and 4 females, was dissected, and the position of mandible angle (MA) relative to the corresponding cervical spinal level was measured when the head was fixed in the flexion, anatomy position, and extension. The difference between the genders and the sides was analyzed. On the basis of the study of the corpse samples, the reference level of cervical spine was approximated to C2/3 intervertebral disc. The result has confirmed MA as a consistent and convenient landmark in the identification of cervical spinal level. Given some external landmarks do not consistently correspond to the exact level of the cervical spine, MA provides the relatively consistent reference point: C2/3 intervertebral disc. The authors hold that MA is a superior external landmark, which can help surgeons to localize the skin incision before anterior cervical spine surgery.