Mandibular Splint vs Botox Injection in Lateral Pterygoid on Cervical Muscle Activity in Patients With Temporomandibular Disorders

Inclusion Criteria: * Age from 18-40 years old. * Both sexes. * Duration of the disease is more than 3 months. * Anterior mandibular disc displacement with reduction will be included. * Unilateral anterior mandibular displacement with reduction grade 2\&3 (Wilkes) will be included. * Patients with cervical muscles spasm and trigger points (upper trapezius\& sternocleidomastoid) will be included. * Patients with sufficient cognitive abilities that enables them to understand and follow instructions. Exclusion Criteria: * Neurological or musculoskeletal diseases that affect cervical spine other than mandibular disc displacement (eg: cervical spondylosis, spondylolisthesis, and cervical disc injuries) * Bilateral anterior mandibular disc displacement patients. * Musculoskeletal disorders such as severe arthritis, cervical spine surgery or contractures of fixed deformity, leg length discrepancy. * women during pregnancy and lactation. * Patients with known hypersensitivity to any component of the drug (especially hypersensitivity to human albumin). * Patients with infection or inflammation of the area where the toxin injections are planned, in patients with musculoskeletal conduction disorders, in primary muscular disorders (muscular dystrophy, neuromyopathy, congenital myopathies, myotonic disorders, mitochondrial myopathy and unspecified or other primary muscle disorders). * Patients being treated with aminoglycoside antibiotics, ciclosporin, D-penicillamine, tubocurarine, pancuronium, gallamine, succinylcholine, chloroquine, or hydroxychloroquine. * History of cervical spine surgery. * History of trauma or fractures in cervical spine. * Signs of cervical radiculopathy or myelopathy. * Vascular syndrome such as vertebrobasilar insufficiency. * Signs of serious pathology ( e.g., malignancy, inflammatory disorders, infection).