Norma Basalis Externa

Inferior View of the Skull

BONES INVOLVED IN NORMA BASALIS EXTERNA

1. Palatine process of the maxilla- Incisive fossa and foramen

2. Horizontal plate of palatine bone- located here are the greater and lesser

palatine foramina

4. Vomer5. Medial pterygoid plate

- scaphoid fossa located on the lateral side of the base: hamulus, at the lower extremity.

6. Lateral pterygoid plate

6. Greater wing of sphenoid- contains foramina ovale, and spinosum; angular spine; and groove for auditory tube.

8. Temporal bone- Mandibular fossa, - Petrotympanic fissure- styloid process; - stylomastoid foramen, - mastoid process with mastoid notch and occipital

groove, - carotid canal, - Jugular fossa- foramen lacerum,

9. Basilar part of occipital bone- pharyngeal tubercle.

10. Lateral part of occipital bone- condyles, - condylar fossa and canal,

- hypoglossal canal

11. Squamous part of occipital bone- external occipital protruberance with the superior nuchal line, - external occipital crest with the inferior nuchal line running laterally from its middle,

FORAMINA PRESENT IN NORMA BASALIS EXTERNA

Name Bone Contents

Incisive canals Palatine process of the maxilla

Nasopalatine n.,Ant. Brs. Descending palatine a. and v.

Greater palatine Palatine Greater palatine N.Descending palatine vessels

Lesser palatine Palatine Lesser palatine n and aa.

Stylomastoid Temporal Facial n., stylomastoid a.

Name Bone Contents

Carotid Temporal Int. carotid a.Carotid plexus

Condyloid Occipital Vein from transverse sinus

Tympanic canaliculus

Temporal Tympanic br. of IX

Name Bone Contents

Mastoid canaliculus

Temporal Auricular br. of X

Tympanomastoid fissure

Temporal Auricular br. of X