Nonspecific neck pain is pain that does not show pathognomonic signs and symptoms,  when the duration of symptoms is greater than 12 weeks of evolution, it acquires the value of chronicity, being denominated non-specific chronic neck pain.  It is a common disorder, which generates a great impact and socio-economic cost.  This impact in personal life, social environment, community, health system and enterprises is high. Although some studies show that among 33% and 65% of subjects recover from an episode of neck pain after a year, most of cases refer that symptomatology remains during life and, thus, recurrence is common . Moreover, psychosocial factors in neck pain are determinants for understanding and management of this condition, not just paying attention to musculoskeletal factors and approaching this condition from a biopsychosocial perspective. [5,6]
In last years, epidemiologic research in relation to neck and shoulder pain has shown the relationship between these anatomic regions. In that sense, a recent study performed in 18 different countries which included 12195 workers shows that it is important to assess the different forms of presentation in relation to neck/shoulder pain and other associated signs and symptoms.  In addition, some authors have developed the regional interdependence model, [8-10] defined by Wainner RS as ”the concept that seemingly unrelated impairments in a remote anatomical region may contribute to, or be associated with, the patient’s primary complaint.”  Meanwhile, Bialosky et al argued that although the regional interdependence model has been focused on musculoskeletal system, underlying mechanisms to patient’s complaints and main signs and symptoms could be more complex, involving other physiological systems including those related to peripheral, spinal cord or supraspinal mechanisms. Any condition or pathology trigger a cascade of reactions that affects not just musculoskeletal system, but also biopsychosocial, somatovisceral and neurophysiological systems. 
Clinical interest in thoracic spine has grown despite the lack of evidence that supports the implication of this region as main source of pain symptomatology , what can be observed in the number of studies investigating and supporting the application of manipulative therapy in thoracic spine for treating cervical signs and symptoms, as disability, pain and range of motion. [13-16] In that sense, Heneghan N. and Rushton A. theorized about how thoracic dysfunction could be involved in triggering and maintenance of pain in other region . In the same way, McDevitt A. et al supported the interventions applied over thoracic spine for the treatment of upper quarter conditions, in line with the interdependence regional model and the neurophysiological effects of spine manipulation.  From the point of view of thoracic mobility, Tanaka R. et al studied the quantitative analysis of rib kinematics through dynamic chest bone images, and they found that bone fractures and vertebral deformities limit respiratory function because of reduction of ribs mobility, what leads to a decrease in vital capacity. Thus, this fact explain the influence of thoracic mobility in pulmonary function and vital capacity . Abnormal movement of rib and chest wall is very common among patients with chronic obstructive pulmonary disease. [23,24] Different studies have tried to prove the influence of manual therapy in respiratory function, although results are highly variable, so no determining conclusions have been found between different authors [25-31].
The aim of the present study is to evaluate the influence of bilateral manipulative technique over first rib, so common in clinical practice, on cervical range of motion and peak expiratory flow in subjects with non-specific neck pain.
To determine if bilateral manipulative technique (HVLA) over first rib in prone position modifies middle cervical range of motion and the spirometric value of maximum expiratory flow at short term in subjects with non-specific neck pain.
Bilateral manipulative technique over first rib in prone position modifies mobility of middle cervical spine in subjects with non-specific neck pain, in flexion, extension, rotation and side bending, as well as the peak expiratory flow.
Randomized, controlled, multicenter, parallel, double-blind, two-arm clinical trial of treatment.