Table 2.

Appearance rate of the sphenoid elements.

CS	Lateral cartilage								Prechordal cartilage		Hypophyseal cartilage
	Orbitosphenoid		Ali sphenoid				Medial pterygoid process		Presphenoid	Mesethmoid	Basisphenoid
			Alar process		Ala temporalis
	Left	Right	Left	Right	Left	Right	Left	Right
Histological section
17	10/12	9/12	0	0	0	0	0	0	0	0	7/12
18	10/10	10/10	2/10	2/10	7/10	7/10	0	0	8/10	0	10/10
19	10/10	10/10	9/10	9/10	6/10	6/10	0	0	10/10	7/10	10/10
20	10/10	10/10	10/10	10/10	10/10	10/10	0	0	10/10	9/10	10/10
21	10/10	10/10	10/10	10/10	10/10	10/10	2/10	2/10	10/10	10/10	10/10
22	9/9	9/9	9/9	9/9	9/9	9/9	3/9	3/9	9/9	9/9	9/9
23	4/4	4/4	4/4	4/4	4/4	4/4	3/3*	3/3*	4/4	4/4	4/4
Phase-contrast CT
17	2/7	2/7	0	0	0	0	0	0	0	0	0
18	6/8	5/8	1/8	1/8	0	0	0	0	1/8	0	2/8
19	10/12	9/12	9/12	9/12	6/12	6/12	0	0	10/12	8/12	11/12
20	10/10	10/10	10/10	10/10	10/10	10/10	0	0	10/10	9/10	10/10
21	7/7	7/7	7/7	7/7	7/7	7/7	3/7	1/7	7/7	7/7	7/7
22	6/6	6/6	6/6	6/6	6/6	6/6	3/6	2/6	6/6	6/6	6/6
23	7/7	7/7	7/7	7/7	7/7	7/7	7/7	7/7	7/7	7/7	7/7

*In one specimen of CS 23 (#2530), several slices around the medial pterygoid process were missing.