This bone assists in forming the base of the cranium. It is situated immediately below the occipital bone, with which it articulates.

Its middle part or body is somewhat thick, and from it proceed upward two flattened portions, or wings, and downward two narrower and more slender projections (pterygoid processes).

Skull (Posterior Surface).

Fig. 288. - Skull (Posterior Surface).

1 Foramen Magnum. 2 Styloid Process of Occiput. 3 External Auditory Process. 4 Styloid Process of Petrous Temporal Bone. 5 Sphenoid Bone. 6 Pterygoid Process. 7 Superior Maxillary Bone. 8 Palatine Bone. 9 Molar Teeth. I0 Palatine Process of Superior Maxillary Bone. 11 Premaxillary Bone. 12 Incisor Teeth. 13 Foramen Incissivum. 14 Palato-maxillary Foramen. 15 Vomer. 16 Ethmoid Bone. 17 Temporal Condyle. 18 Foramen Lacerum Basis Cranii. 19 Basilar Process of Occiput. 20 Petrous Temporal Bone. 21 Occipital Condyle.