What do I need to add to rotate the arm not from the middle but closer to top's surface?

game:GetService'RunService'.RenderStepped:Connect(function()
    character.Torso["Right Shoulder"].C1 = CFrame.new()
    character.Torso["Right Shoulder"].C0 = CFrame.new(1, 0.5, -0.5) * CFrame.Angles(math.asin((mouse.Hit.p - mouse.Origin.p).unit.y) + math.rad(90), 0, 0)
end)

https://gyazo.com/28c5285180c153679a71b9f46c644d33

http://gyazo.com/ddcbbeff73f2f173773589753b638cfa

help pl0x