The neck and head do not contribute to the generation of pressure, so head and neck posture should be whatever is most comfortable and least stressful. Forward head posture, a common postural distortion imbalance pattern that occurs is caused by a flexion of the head and neck.
Motions of the Cervical Spine
Table 1 shows average healthy ranges of axial motion of the cervical spine (head and neck), from the atlanto-occipital joint through the C7-T1 joint.