The trial is designed as a before-and-after study conducted on asymptomatic subjects. The aim is to assess temporomandibular joint and three perimandibular muscles (temporal, masseter, sternocleidomastoid) by means of rehabilitative ultrasound imaging, carried out by a novice clinician. These evaluations are performed before and after a dry needling treatment directed to the tree studied muscles of one side of the face. The side to be treated is randomly assigned by using a computer-generated randomization process, the other side is used as control.~One month after the treatment sonographic images are taken by the novice clinician and by an expert one. The aim is to assess the reliability of ultrasonography comparing the results of their assessments.
The articular disc of temporomandibular joint and three muscles of the cervico-facial region (temporal, masseter, sternocleidomastoid) are evaluated by means of sonographic images to observe and measure their dimensions' changes after a dry needling intervention. The participants are asymptomatic subjects and will be randomly divided in 2 groups: half of them are treated on the right side of the face, while the other half on the left side. Our hypothesis is that ultrasonography can reveal changes in the structures measured on the treated side.