Angular correlations in dense solutions and melts of flexible polymer chains are investigated with respect to the distance r between the bonds by comparing quantitative predictions of perturbation calculations with numerical data obtained by Monte Carlo simulation of the bond-fluctuation model. We consider both monodisperse systems and grand-canonical (Flory-distributed) equilibrium polymers. Density effects are discussed as well as finite chain length corrections. The intrachain bond-bond correlation function P(r) is shown to decay as P(r) similar to I/r(3) for xi << r << r* with xi being the screening length of the density fluctuations and r* similar to N-1/3 a novel length scale increasing slowly with (mean) chain length N.