1. Norma Basalis Externa
Inferior View of the Skull

3. BONES INVOLVED IN
NORMA BASALIS EXTERNA

4. 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

5. 4. Vomer
5. Medial pterygoid plate
- scaphoid fossa located on the lateral side of the
base: hamulus, at the lower extremity.
6. Lateral pterygoid plate

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

7. 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,

8. 9. Basilar part of occipital bone
- pharyngeal tubercle.
10. Lateral part of occipital bone
- condyles,
- condylar fossa and canal,
- hypoglossal canal

9. 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,

10. FORAMINA PRESENT IN
NORMA BASALIS EXTERNA

11. Name Bone Contents
Incisive canals Palatine process of Nasopalatine n.,
the maxilla 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.

12. Name Bone Contents
Carotid Temporal Int. carotid a.
Carotid plexus
Condyloid Occipital Vein from
transverse sinus
Tympanic Temporal Tympanic br. of
canaliculus IX

13. Name Bone Contents
Mastoid Temporal Auricular br. of X
canaliculus
Tympanomastoid Temporal Auricular br. of X
fissure