The higher self, the awakened Christ within, is dressed in a mockery of its own sovereignty before the crowd of lower thoughts can take it seriously. Thorns ring the head because the crown of illumination, the true light meant to shine from the crown center at the top of the skull, has been twisted into pain by a mind that only feels pressure where it should feel radiance. The reed placed in the right hand is a hollow, bending scepter: real spiritual authority, the power of the active side of the self, is handed a weak substitute that snaps under any weight.
The bent knee and the shouted title are worship that does not mean it. A person can salute the divinity in themselves with words while inwardly jeering at it, and that split is the whole state pictured here. The king is real; the honor given him is empty, and the empty honor is what keeps the true reign from taking hold.
Crown of thorns: the light of the crown center at the top of the head turned into pressure and pain by a mind that cannot yet bear illumination
Reed: a hollow, bending scepter, the counterfeit of true inner authority that gives way under any real weight
Right hand: the active, outgoing power of the self, here made to hold a false emblem of rule