Temporomandibular dysfunction and dysphonia (TMD).

Freedom of the manducatory apparatus is critical to economical and accurate vocal production. Two types of dysfunction will be discussed: global muscular hypertonia of the muscular manducatory system and dysfunction of the temporomandibular joint (TMJ). Hypertonia occurs in a high number of dysphonic patients. It impairs mandibular mobility and also induces chronic hypertonia of the tongue muscles, hyoid apparatus and occipitocervical joint through the neuromuscular facilitation process. TMJ can be a major source of mandibular kinetics impairment. Its pathogenic effects are most deeply felt in singers, who often have their mouths wide open, especially when singing notes in the upper register. Affected singers generally use an avoidance or compensation strategy which is detrimental to optimal use of resonance cavities and vocal sound articulation. It is consequently vital to understand TMJ pathophysiology and to include an examination of the manducatory apparatus in any clinical evaluation of dysphonia.