sphenoid bone morphology trait pterygoid process morphology trait Trait.ontology Any measurable or observable characteristic related to the shape, structure, color or pattern of the process projecting downward from either side of the sphenoid bone, in vertebrates divided into two plates, an inner and an outer (sometimes called the lateral and medial); the posterior nares pass through the space, called the pterygoid fossa, between the processes. VT:0004452