Comparison of Neck Muscle Thickness via Ultrasound in Patients with Ankylosing Spondylitis and Healthy Controls

Neck pain and limited neck mobility are common symptoms in patients with ankylosing spondylitis (AS). This study aimed to quantify neck muscle thickness in individuals with AS using ultrasonography and to compare these findings with measurements obtained from healthy volunteers.

A total of 30 individuals diagnosed with AS and 30 healthy participants were enrolled in this case-control study. The anteroposterior dimension, lateral dimension, cross-sectional area (CSA) of the longus colli (LC), cervical multifidus (CM), and anteroposterior dimension of the sternocleidomastoid were measured via ultrasound. Individuals diagnosed with AS were asked to complete the Neck Disability Index (NDI), the Ankylosing Spondylitis Quality of Life questionnaire (ASQoL), the Bath Ankylosing Spondylitis Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI), and the Bath Ankylosing Spondylitis Metrology Index (BASMI).

In the AS group, the anteroposterior thickness (P = .025) and CSA (P = .021) of the right LC were markedly reduced compared with the control group. Similarly, the left LC exhibited significantly smaller anteroposterior measurements (P = .023) and CSA values (P = .012) in patients with AS. Additionally, the lateral dimension of the CM was significantly decreased on both the right (P = .001) and left (P = .002) sides relative to healthy controls. In patients with AS, LC thickness correlated negatively with NDI, ASQoL, BASDAI, BASFI, and BASMI, and positively with cervical extension and lateral flexion. In multivariate regression analyses adjusted for age and body mass index, LC thickness was independently associated with disability, functional impairment, and spinal mobility limitation.

Neck muscle thickness is reduced in AS patients, and atrophy of the LC shows significant correlations with greater disability, poorer quality of life, higher disease activity, impaired functional status, and limited spinal mobility. Cite this article as: Karacif D, Karacif O, Cagliyan Turk A. Comparison of neck muscle thickness via ultrasound in patients with ankylosing spondylitis and healthy controls. ArchRheumatol. 2026;41(3):212-222.