The study aims to evaluate the morphological changes of upper trapezius muscle, using B-mode ultrasonography, in patients with oral cancer undergone neck dissection and physiotherapy. It also investigates the relationship between morphological changes and shoulder active range of motion in abduction. Furthermore , the study assesses the potential of B-mode ultrasonography as an objective tool for monitoring outcomes of the rehabilitation in this population.

The study aims to investigate the effect of 8-week physiotherapy on morphological change of upper trapezius muscle in oral cancer patients who have undergone neck dissection. Key outcome measurements include the muscle's thickness and cross-sectional area (CSA), measured via B-mode ultrasonography, as well as the active range of motion (AROM) in shoulder abduction. Neck dissections may result in spinal accessory nerve (CN XI) injury, often leading to shoulder pain, upper trapezius weakness and impaired shoulder mobility. Therefore, understanding the relationship between muscle thickness, CSA, and AROM is important. The study's goal is to explore the correlation between muscle morphological changes and functional outcomes, and further evaluate the role of B-mode ultrasonography as a non-invasive tool in monitoring muscle morphology in shoulder rehabilitation progress with post-surgical oral cancer patients with shoulder dysfunction.

Inclusion Criteria:

• Newly diagnosed oral cancer patients with scapular dyskinesis, who have undergone neck dissections within 3 months
• Able to cooperate with assessments and physical therapy, and capable of understanding and signing the informed consent form.
• Age between 20 and 65 years.

Exclusion Criteria:

• Unable to effectively communicate.
• Diagnosed with conditions affecting motor function.

A total of 10 newly diagnosed oral cancer patients who received neck dissection with scapular dyskinesis