A computed tomography (CT) examination with an analytical cross-section was conducted. For a study, the researchers sought to determine the relationship between upper quadrant pain and disability and the cross-sectional area (CSA) and density of neck muscles (sternocleidomastoid, upper trapezius, levator scapulae, anterior scalene, longus coli, and longus capitis). About 230 people with neck pain were referred for CT scans, and 124 out of 230 met the inclusion and exclusion criteria. The CSA and muscle density values were retrieved from the scans after interviewing the subjects. Muscles linked with temporary disability of the arms, shoulders, and hand questionnaire (QDASH) were the posterior lateral group LPG CSA C3–C4 on the right side (beta=–0.31, P=0.029); the sternocleidomastoid (SCM) CSA C3–C4 on the left side (beta=0.29, P=0.031); the LPG CSA C3–C4 on the right side (beta=–0.49, P=0.000); the LCM CSA C5–C6 on the right side (beta=–0.19, P=0.049); the LPG CSA C5–C6 on the right side (beta=–0.36, P=0.012); and the LPG CSA C5–C6 on the left side (beta=–0.42, P=0.002). Further outlines, including radiculopathy as an augmenting/enhancing variable (moderator), revealed a more robust model (r2=0.25) and a better prediction of pain and disability. Muscle measures did not predict neck disability index (NDI) scores. Researchers discovered a link between the CSA of the deep and superficial neck muscles and discomfort and impairment in the upper extremities by employing precise measuring equipment. The shoulders and neck muscles were put under a lot of strain when doing manual labor. Future research should have looked at the effectiveness of exercise-type intervention programs to strengthen the muscles of the deep neck and upper extremities and prevent muscle fatigue.