The document presents a study investigating discrete quartic spline interpolation over non-uniform meshes. It begins with background on discrete splines and defines deficient splines. The paper then develops a new function for deficient quartic spline interpolation and obtains existence, uniqueness, and convergence properties of the deficient discrete quartic spline interpolation matching given function values at two interior points and first differences at midpoints, with boundary conditions on the function. It presents the analysis that leads to a system of equations and proves that for any mesh spacing h>0, there exists a unique deficient discrete quartic spline satisfying the given conditions.