V1
1: This is the scalpula draconis, it suports the wing.
2: there are 4 fingers, the inner most one is like a thumb.
3: the enlongated arm of the wing.
4: there are different wing structures for different dragons. the most common have 4 long fingers that support most of the wing surface. there is also a thumb.
5: some dragons have spines or frills.
V2
1: the alar pectoral is the main flight muscule, used in th downstroke
2: the alar lattisimus dorsai draws the wing up and back
3:the alar deltoid and cleidomastoid draw the wing up and forward
4: the alar tricep and bicep fold the and unfold the wings
5: the alar carpi ulnaris and carpi radialus allow the wing to twist
6: the tail and neck muscules are good for crushing and bashing people
V4
1: the horns of the dragon can be any shape size texture or colour
2: the belly scales can be large plates or leathery skin, the colour is usually a shade lighter than the dragon
3: the body scales can be plates, spikes, pebbled, or whatever you can think of. the colour is up to you.
4: the skin covering the wings and frill is just skin, no scales.

my compliments to the Draconomicon for this lesson.