Protein complex forming portion of the radial spoke that is orthogonal to the elongated stalk and which projects towards the central pair of microtubules within the ciliary or flagellum axoneme. [ GOC:krc http://www.ncbi.nlm.nih.gov/pubmed/22754630 GOC:hjd http://www.ncbi.nlm.nih.gov/pubmed/34871179 GOC:cilia ]
Synonyms: radial spokehead