Spin structure of nucleon

The quark spin content of the nucleons is subjected to constraints implied by sum rules due to global approximate chiral symmetries and perturbativeqcd effects. The model, so obtained, has a large polarisation residing in the flavour singlet constituents of hadron. Predictions for the expected longitudinal and transverse spin asymmetries in deep inelastic lepton-nucleon scattering are made on the basis of the standard form of the electromagnetic and charged weak currents.