Association between cervical lordotic curvature and cervical muscle cross-sectional area in patients with loss of cervical lordosis.

Disruption of the cervical lordotic curve can cause undesirable symptoms such as neck pain, and cord compression. The purpose of this study was to investigate the biomechanics of loss of cervical lordosis by measuring the cross-sectional area (CSA) of the cervical muscles using magnetic resonance imaging (MRI), and to determine the relationship between cervical lordosis angle and cervical muscle status. The cervical lordosis angle was measured on standing lateral plain radiography using the posterior tangent technique in patients who complained of neck pain. The CSAs of the cervical flexor muscles including the longus cervicis and longus capitis, the cervical extensor muscles including the splenius capitis and semispinalis capitis, and the sternocleidomastoid muscle, were measured at the maximum levels by axial T1-weighted MRI. We compared neck muscle CSAs between the two groups, the correlation with cervical lordosis angle, and muscle status including CSA and imbalance. The CSA of the semispinalis capitis was significantly lower in the loss of cervical lordosis group, and the ratio of cervical flexor to extensor was significantly different between the two groups (P < 0.05). Partial correlation analysis revealed that the cervical lordotic angle was significantly positively correlated with the ratio of flexor to extensor muscle CSAs (P < 0.05). There is a significant relationship between cervical muscle imbalance, including extensor muscle weakness, and loss of cervical lordosis. An exercise program focusing on cervical extensor muscle strengthening and restoring the balance of flexor and extensor muscles is recommended for patients with loss of cervical lordosis. Clin. Anat. 31:710-715, 2018.