Fig. 2From: Incidence and risk factors of axial symptoms after cervical disc arthroplasty: a minimum 5-year follow-up studyThe functional spinal unit angle (α) was examined on lateral radiographs and was formed by lines drawn at the superior end plate of the cephalad vertebral body and at the inferior end plate of the caudal body. Disc height was defined based on the average values of the anterior disc height (a) and the posterior disc height (b)Back to article page