Table 2. Newly proposed cervical spine sagittal parameters which allow us to better understand the cervical spine in segments, as well as its relationship with gaze direction and whole body balance.

Parameter	Description
Upper cervical spine angle	Angle between gaze direction and line tangential to inferior end plate of C2
Middle cervical spine angle	Angle between lines tangential to inferior end plate of C2 and superior end plate of C4
Lower cervical spine angle	Angle between lines tangential to inferior end plate of C4 to superior end plate of C7 or T1
EAM-C7 sagittal vertical axis	Horizontal distance between vertical line from the external auditory meatus and the posterosuperior corner of C7
Gaze direction	(Discussed later in article)