Rotator cuff pathology is defined as the degeneration or tear of one or more of the muscles or tendons of the rotator cuff, namely the supraspinatus, infraspinatus, teres minor, and subscapularis. Shoulder girdle biomechanics are not solely comprised of the glenohumeral joint but are built upon a kinetic chain involving the synchronized movement of the scapula, clavicle, and thoracic spine. In this context, the concept described in the literature as the "Regional Dependence" model argues that functional impairment in a distal segment like the shoulder may stem from or exacerbate limitations in a more proximal region like the thoracic spine. Conventional treatment approaches that focus solely on the shoulder joint may have limited clinical outcomes due to neglecting the fundamental link in the kinetic chain. Maintained natural apophyseal glides (SNAGs), a cornerstone of Mulligan's Concept in spinal rehabilitation, are a dynamic manual therapy technique aimed at correcting microscopic misalignments in facet joints during active movement. The aim of this randomized controlled trial is to investigate the effects of thoracic mobilization added to the Mulligan movement shoulder mobilization technique on pain intensity, range of motion, proprioception, and upper extremity functionality in individuals with rotator cuff pathology, and to evaluate the superiority of this combined approach over shoulder mobilization alone. Assessments will be performed before treatment and at the end of the 3-week intervention. Rest and activity pain intensity will be assessed using the Pain Numerical Rating Scale (PMR), shoulder range of motion using a digital goniometer, thoracic kyphosis degrees using a smartphone with the 'Angle Meter' software installed and calibrated gyroscope and accelerometer sensors, functionality using the Shoulder Pain and Disability Index (SPAI), and proprioception using a laser pointer and target device. The obtained data will be compared using appropriate statistical analysis methods. This study is expected to provide scientific evidence regarding the clinical effectiveness of thoracic mobilization technique added to shoulder mobilization technique applied in conjunction with conventional treatment in individuals with rotator cuff pathology, and to contribute to filling the methodological gap mentioned in the literature.

Inclusion Criteria:

• Having been diagnosed with unilateral rotator cuff pathology (impingement syndrome, tendinopathy, or partial tear) by a specialist physician through clinical examination and/or radiological imaging (USG/MR);
• Being between 18 and 65 years of age;
• Having shoulder pain that has persisted for at least 3 months;
• Having a positive result on at least two of the Neer, Hawkins-Kennedy, and Empty Can tests;
• Having a pain intensity of at least 3/10 on the Pain Numerical Rating Scale (NPRS) during rest or activity;
• Having sufficient cognitive ability to follow simple instructions and administer the tests;
• Having a Mini Mental State Test score ≥24;
• Having the ability to provide signed informed consent and agreeing to participate in the study voluntarily.

Exclusion Criteria:

• Having undergone previous surgery on the shoulder or thoracic region;
• Having full-thickness rotator cuff tears requiring surgical indication;
• Having adhesive capsulitis, shoulder instability, labrum tears, or calcific tendinitis;
• Having cervical radiculopathy or neurological diseases affecting the upper extremity;
• Having uncontrolled diabetes, inflammatory rheumatic diseases (rheumatoid arthritis, etc.), or malignancy;
• Having severe osteoporosis, unstable vertebral fractures, or active infection in the thoracic region;

having received steroid (cortisone) or PRP injections to the shoulder region within the last 3 months.