Parkinson's disease (PD) is the second most common neurodegenerative disease, characterized pathologically by the progressive loss of dopaminergic neurons in the substantia nigra and clinically by the presence of motor symptoms such as bradykinesia, resting tremor, and/or rigidity.Patients with Parkinson's disease (pwPD) often exhibit poor manual dexterity and decreased strength. Fine motor deficits seen in PD include an inability to control cognitive power/force, poor manual dexterity, and motor dysfunction, which includes difficulties achieving the angles, speed, and coordination required for basic movements. Anatomical strength, as detailed in activities of daily living (ADL), is an important indicator of motor characteristics and vitality.Studies have shown a strong relationship between postural control and fine motor functions. For high-quality distal movement, better proximal stabilization is necessary. During upper extremity functions, the body's center of gravity must shift with arm movements, allowing adaptation to changing gravity. Good trunk control is essential in this dynamic process of maintaining balance. Studies examining this link between trunk control, balance, and hand functions are available in the literature. Among these studies conducted in diverse populations, studies involving PD are very few. Investigating parameters such as grip strength, upper extremity dexterity, and reaction time in PD will fill the gap in the literature. Meta-analysis studies have shown that muscle strength and strength in individuals with PD are lower than in healthy individuals. Furthermore, muscle strength in PD has been shown to be related to functional capacity and disease severity. In light of all this information, our study was designed to investigate the relationship between upper body muscle strength, particularly proximal and distal, and manual dexterity in PD. In this direction, the aim of this study is to determine the relationship between proximal and distal muscle strength and upper extremity functional abilities in PD.