With words

consummate v’s

spines\spikes\barbels

*what

don’t fucking tell me its a frill, i don’t need to see your fucking terminology especially if its wrong…..goddamn you.

spikes

Spines, fins, spines. Fins are his ears.

Arrows and pencil tool drawings.

Genitalia.

Cool. This info’ll come in hand for RPing on the MUSHs/MUCKs if I ever decide to chargen another dragon.

Hey, look. A meta image gets downvoted to death just because.
 
That’s SO new.

As Background Pony said, Spike calls them “spines” in the first episode.

On Spike’s head and back, speaking herpetology, that is called a “Comb”. The side ear frills could be considered just that.

ignores question  
Everything is so pink!

Spines: “In a zoological context, a spine is a hard, needle-like anatomical structure. Spines are found in a wide range of animals both vertebrate and invertebrate…”
 
Spines don’t require bones at all. They are probably flexible scales with pointy tips.

Okay. Inaccurate, but there we go.

Spike calls them spines in the first episode. “How are my spines, are they straight?”

Crest might also be a good name. The biological term crest usually applies to feathers, but Spike’s whatevers aren’t always erect, and can be raised and lowered.
 
Those things aren’t actually spines, because spines have bones going through them. They are made of erectile tissue rather than bone or horn. While Spike usually keeps them stiff and straight, that seems to be a matter of grooming as he’s bent and flexed them often enough that it’s an actual feature.

Spines and fins.

They’re frills.

spines or spikes and frills

Dorsal spines.

Spines on his head and back, fronds on the side of his head.

I think “ridges” is acceptable terminology. Head ridges and tail ridges.