**4.6 Cervical pain disorders**

Cervical pain disorders represent a very common group of musculoskeletal conditions that can greatly influence the head structures. We can divide it in two groups: those that primarily originate in the muscles and those that predominantly originate in the cervical spine. These structures very commonly refer pain to the orofacial region [44, 56].

### **4.7 Extracranial and systemic causes of orofacial pain**

There are also some associated structures that can cause orofacial pain such as the eyes, ears, the nasal-paranasal sinus complex, the salivary glands, and the throat. In these cases, the orofacial pain is a heterotopic pain. At the same time, systemic diseases like oromandibular dystonia, multiple sclerosis, and Lyme disease, often have orofacial manifestations. The importance of an accurate differential diagnosis is obviously tremendous.
