Abstract
The clinical features, differential diagnosis and treatment of unilateral spasms of the jaw and masticatory muscles are discussed and illustrated by eight cases of unilateral jaw spasms of various aetiologies. These include focal dystonia of the jaw, hemimasticatory spasm with and without facial hemiatrophy, paroxysmal events in multiple sclerosis and tetany. Attention is particularly drawn to four cases of unilateral dystonia of the jaw which has not been described before.