Temporomandibular disorders (TMD) are a musculoskeletal disorder affecting the masticatory muscles, the temporomandibular joint (TMJ), and associated structures. Evidence suggests that TMD are commonly associated with other conditions of the head and neck region, including cervical spine disorders and headache. Presence of neck pain was shown to be associated with TMD 70% of the time [1, 2]. Neuroanatomical and functional connections between masticatory and cervical regions are discussed as explanations for concomitant jaw and neck symptoms [3, 4]. The presence of pain in the masticatory system, especially related to myogenic TMD, could be caused by dysfunctions in the cervical column, or vice versa, showing the intrinsic relationship between the different structures [1, 5].Although the association of cervical spine disorders and TMD has been studied by different authors, it is far from being exhaustively explained [6, 7]. Most of the studies agree that symptoms from the cervical spine can be referred to the stomatognathic region through the trigeminocervical nucleus. Several studies have examined the presence of signs and symptoms in the cervical region of patients suffering with TMD and that the presence of tender points in the cervical area of these patients is very common [8–13]. de Laat et al. [11] found that, on palpation, 23–67% of the patients with TMD had neck muscle tenderness in the sternocleidomastoid and upper trapezius as well as other cervical and shoulder muscles, which was only rarely present in the control group. Recently, Greenspan et al. [14] measured pressure pain threshold (PPT) in the center of the temporalis, masseter, and trapezius muscles in subjects with and without TMD. They showed that patients with TMD were more sensitive to a wide range of mechanical and thermal pain tests than control subjects, including not only the orofacial area, but also the trapezius muscle.Muscle tenderness in the cervical spine and jaw was shown to be associated with increased levels of jaw and neck disability. For example, one study by our team revealed a strong relationship between neck disability and jaw disability (). A subject with a high level of TMD disability (grade IV) had an increase of about 19 points in the NDI when compared with a person without TMD disability [15]. Disability associated with jaw and neck pain interferes greatly with daily activities and can affect the patient’s lifestyle which declines the individual’s ability to work and interact in a social environment [6, 8].Muscle tenderness is the most common sign [8, 16–18] and muscle pain is the most common symptom [19] found in patients with TMD, and their evaluation is still one of the most important methods of establishing a clinical diagnosis of TMD [17, 20], being of particular interest to clinicians treating orofacial pain. Treatment strategies such as exercises, manual therapy, stretching, and education can be targeted to painful and sensitive muscles in order to reduce pain in the orofacial region [8, 20–22].Although several studies have evaluated neck tenderness in subjects with TMD, none of these studies have evaluated the relationship between the level of tenderness and jaw dysfunction. Moreover, most studies that investigated muscle tenderness in subjects with TMD used palpation techniques, which are difficult to quantify and standardize [10, 11].There is a great interest on the knowledge for further relationship between stomatognathic system and cervical spine. If further relationship is established, new clinical strategies that target both regions should be considered and, therefore, the need of a multidisciplinary approach should be reinforced in the management of patients with alterations of the stomatognathic system, including TMD patients. In order to further investigate this relationship, the objective of this study was to determine the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with chronic TMD. We hypothesized that the higher the level of neck disability, the higher the level of jaw dysfunction and the higher the level of muscle tenderness.