cavernous sinus: either of a pair of large venous sinuses in the cranial cavity
venous sinus: a wide channel containing blood; does not have the coating of an ordinary blood vessel
starch: a complex carbohydrate found chiefly in seeds, fruits, tubers, roots and stem pith of plants, notably in corn, potatoes, wheat, and rice; an important foodstuff and used otherwise especially in adhesives and as fillers and stiffeners for paper and textiles