[[Image:Pig skull ventral view.jpg|thumb|right|150px|Pig skull ventral view.jpg]] The sphenoid bone forms the base of the neurocranium and is composed of a body and wings. The bones are separated by cartilage which ossifies with age. The '''presphenoid (os praespenoidale)''' is rostral and has a caudal fossa which is a hollow body with sphenoid sinuses located inside. Within the sinuses are the '''optic chiasma''' and '''optic canal'''. The '''basisphenoid (os basispenoidalis)''' is caudal and has a '''median cranial fossa'''. The wings oppose the temporal bone, maxilla, orbit and the brain. The wings also form the '''oval foramen''' and other foramen (see [[Skull and Facial Muscles - Anatomy & Physiology#Species_Differences|species differences]]) including the '''carotid notch, oval foramen''' and '''spinous notch''' (in the horse). The pterygoid processes are also present. <br> <br> <br> <br>
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[[Image:Pig skull ventral view.jpg|thumb|right|150px]] The sphenoid bone forms the base of the neurocranium and is composed of a body and wings. The bones are separated by cartilage which ossifies with age. The '''presphenoid (os praespenoidale)''' is rostral and has a caudal fossa which is a hollow body with sphenoid sinuses located inside. Within the sinuses are the '''optic chiasma''' and '''optic canal'''. The '''basisphenoid (os basispenoidalis)''' is caudal and has a '''median cranial fossa'''. The wings oppose the temporal bone, maxilla, orbit and the brain. The wings also form the '''oval foramen''' and other foramen (see [[Skull and Facial Muscles - Anatomy & Physiology#Species_Differences|species differences]]) including the '''carotid notch, oval foramen''' and '''spinous notch''' (in the horse). The pterygoid processes are also present. <br> <br> <br> <br> <br>