OCCIPITAL BONE

Question 1

Occipital bone

Situated

Answer 1

On the Nucheal wall
Encloses the FOR. magnum
For. Magnum:
- links the cranial cavity with the vertebral canal

Question 2

Consist of:

Answer 2

1. SQUAMOS PART
 (fossa crani caudale)
2. LATERAL PART
3. BASAL PART
 (fossa crani medi)

Question 3

Occipital bone

Pars SQUAMOSA

Answer 3

1. Crista Nuchea
   In ca, Eq
2. Crista Saggitalis ext
   Runs on a rostral direction
   In ca, eq
3. Linea Nuchea
   In bo
   Nucheal crest correspond to the Linea Nuchea
4. Protuberantia Occipitalis Externa
   Lies btw the Nucheal crest or line
   In ca, eq, bo
   Directed toward the foremen magnum as CRISTA OCCIPITALiS ext

PARS LATERALIS
- the lateral limits of the foramen magnum

1. Condyli occipitalis
   Forms the atlantooccipital joint
2. Processus Paracondylaris
   Lateral from condylus occipitalis
   Known earlier as the jugular process
3. FOSSA CONDYLARIS Ventralis
   - btw the condyle and paracondylar process
   - depression ventral to the condylus occipitalis
4. FOSSA CONDYLARIS Dorsalis
   - depressesion Dorsal to the condylus occipitalis.
5. Canalis N. hypoglossi
   - passage of hypoglossal n.
6. Canalis CONDYLARIS
   In ca, bo
   Canal for the sinus CONDYLARIS
   Inner surface:
7. Fossa Cerebellaris
   For cerebellum
8. Protuberantia occipitalis int
   In bo
9. Processus Tentorius
   In eq, ca
   Part of tentorium cerebelli osseum
10. impressio Vermialis
    Impression by vermis cerebelli
11. Sinus frontals caudalis
    In bo
    Septum sinuum frontalium

Question 4

Occipital bone

- pars BASILARIS

Answer 4

• Forms the posterior part of the base of the skull
• in front of the foramen MAGNUM
• Articulates with the sphenoid through synchobdrosis sphenoidalis

OUTER surface

1. Tuberculum muscular
   - paramedian tubercle one the ventral surface
   - attachment for musculus longus capitis
2. Tuberculum Pharyngeum
   In car
   Median tubercle
   On the ventral surface

INNER surface
1.  Fossa Crani caudalis
Subdivides into:
Rostral
A. Impressio PONTICA - IMp for the pons
B. impressio medularis - IMp for MO

THE side of the Pars BASILARIS
Bears 
1. For. Jugulare
Btw occipital and petrosal bones
2. FISSURA Petroocipitalis
In car, sis

Question 5

INTERSPECIAL differences

Answer 5

Pars BASILARIS
- Tuberculum Pharyngeum
In CA ONLY

OPENINGS:

1. Foramen JUGULARE 
= passage for IX, X, XI (vagus group) 
in ca: A.carotica interna 
In CAR, RU
In EQ, SU: caudal end of FOR.LACERUM

2. Canalis N.Hypoglossi
   = Passage for XII & A/V CONDYLARIS
   In CAR,RU (ox:doubled)
   In EQ: For. N.Hypoglossi
3. Canalis CONDYLARIS
   = Passage for A/V CONDYLARIS
   In CA, BO
4. Foramen MAGNUM
   = Passage for MO of spinal chord

Question 6

Interspecial differences

Köning

Answer 6

BASILAR PART

1. Fissura Petrooccipitalis - eq+sus
2. Foramen Lacerum - eq+sus
3. Linea Nuchea - Ru
   (CRISTA nuchea is reduced to the prominent nucheal line)
4. CRISTA saggitalis Externa arrive from the CRISTA nuchea in Car+eq
5. CRISTA occipitalis poorly defined, Extends from ext.occ. Protuberance —> for.magnum
6. Processus Tentoricus —> additional process in Car+eq = Tentorium Cerebelli osseum (together with same named process of Pariettal and interpariettal bone)

LATERAL PART
1. Processus Paracondylaris (m. Attachment)
Pig = elongated
Ruminants and horse = shorter
Carnivores = Bulb shaped
—> Rudimentary transverse process of cervical vert.