Ahmad Amro Baradee

General view on the skull:

The skull is divided intotwo parts: 1) Cranium 2) Facial skeleton

There are 22 bones forming the skull:

8 Cranial bones: Base: 1-sphenoid 2-ethmoid

Vertex: singular: 3-Frontal 4-Occipital

Pair: 5-6-parietal 7-8-temporal

14 Facial bones: mobile: 1-mandible

Immobile: singular: 2-vomer

Pair:3-4-inferior concha

5-6-maxilla 7-8-lacrimal

9-10-zygomatic 11-12-nasal

13-14-palatine

The Ophthalmic nerve:

Frontal Supraorbital(through supraorbital foramen)

Supratrochlear (through supratrochler notch)

Ophthalmic Lacrimal Infratochlear

Nasociliary anterior ethmoid

Posterior ethmoid

The ophthalmic nerve gives collateral branches (

before the three terminal branches ) these are: recurrent meningeal branch

, and anastomosis branches with the third and fourth cranial nerves and

with the carotid plexus.

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The external carotid artery:

Superior thyroid

Anteroir lingual

facial

External medial: ascending pharyngeal

Carotid

Artery posterior occipital

Posterior auricular

terminal Maxillary

Superficial temporal Transverse facial

Middle temporal

Zygomatico-orbital

Anterior auricular

2 terminal br.: frontal

parietal

The Maxillary Artery:

Classification "1":

We say the maxillary artery gives 14 collateral branches , and they are

classified among their directions into 4 categories:

A. Three ascending branches heading to the cranium:

1) Tympanic artery

2) Middle meningeal artery

3) Accessory meningeal artery

B. Three lateral branches heading to the muscles:

1) Masseteric artery

2) deep posterior temporal artery

3) deep anterior temporal artery

C. Four descending branches heading to masticating system:

1) inferior dental artery

2) pterygoid artery

3) orobuccal artery (oro=mouth )

4) alveolar artery

D. Four deep branches evolve in the pterygopalatine fossa:

1) Infraorbital artery

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2) Vidian artery ( the artery of pterygoid canal )

3) Descending palatine artery

4) Pterygopalatine artery

Classification "2": ( I, myself, prefer this way of classification)

We say the maxillary artery gives 16 branches , and they are classified

into 3 categories:

A. First category: 1) middle meningeal 2) accessory meningeal

3)inferior alveolar 4) deep auricular 5) anterior tympanic

B. Second category: 1) lateral pterygoid 2) medial pterygoid

3)masseter 4) temporal 5) buccinator

C. Third category: 1) posterior superior alveolar 2) Vidian (artery of

pterygoid canal) 3)greater palatine 4)lesser palatine

5)sphenopalatine 6)infraorbital

Temoral bone's fissures:

Squamotympanic f.

Tympanic Squamos

part part

Petrotympanic f. petrosal squamopetrosal f.

prominence

Only the tympanomastoid fissure is left to be pointed out

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The paranasal sinuses (air sinuses):

These sinuses:

1) Reduce the weight of the skull

2) Give the ability to make sounds

3) Give the shape of the face

Opens into: The paranasal sinus

Semilunar hiatus , middle meatus Maxillary

Semilunar hiatus , middle meatus Frontal

Semilunar hiatus , middle meatus Anterior and middle ethmoid

Superior meatus Posterior ethmoid

Sphenoethmoidal recess,above the superior meatus Sphenoid

Don't open.. Mastoid air cells

Remember: the nasolacrimal duct carries tears into the inferior meatus

Note: "meatus" refers to the space under the concha , means: the inferior

meatus is the space under the inferior concha

The venouses sinuses:

Singular:

Superior sagittal

Inferior sagittal

Straight

Occipital

intercavernous

Pair:

superior petrosal

inferior petrosal

transverse

sigmoid

cavernous

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Ends Venouses sinus

Right transverse Superior sagittal

Straight Inferior sagittal

Left transverse Straight

Continues as: the sigmoid Transverse (right or left)

Jugular bulb Sigmoid

Sigmoid Superior petrosal

Jugular bulb Inferior petrosal

The Sphenoid bone:

The anterior aspect of the sphenoid bone we find the sphenoidal

crest , and on each side we see the apertute of the sphenoidal sinus,

and lateral to that aperture we see semi air cells which present the

place of articulation between the ethmoid labyrinth and the

sphenoid bone.

The anterior part of the sphenoidal concha articulates with the

orbital process of the palatine bone.

The posterior part of the orbital process of the palatine bone gives

an opening to connect with the sphenoidal sinus , whereas the

margins of this opening articulates with the sphenoidal concha.

The inferior surface of the sphenoidal concha articulates with the

superior surface of the sphenoidal process of the palatine bone.

We can recognise the following landmarks in an intercranial aspect

of the sphenoid bone: (in this exact order postero-anteriorly):

Dorsum sellae Pituitary gland's fossa Groove for

intercavernous sinus Tuberculum sellae (on each of its sides we find the

middle clinoid process ) Chiasmatic groove Sphenoidal limbus

Sphenoidal jugum ethmoidal process

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The pterygopalatine fossa:

It’s a pyramidal fossa

1) It's boundaries:

Lateral: the internal surface of the ramus of mandible

Anterior: maxillary tuber

Medial: the perpendicular plate of palatine bone (at it's top

end we see the sphenopalatine foramen )

Posterior: the anterior surface of the pterygoid process

Superior: the inferior surface of the greater wing of the

sphenoid bone (the maxillary surface)

and the apex of this pyramidal fossa is at the inferior end (at the place of

meeting: the pterygoid process with the pyramidal process of palatine

bone together with the tuber of maxillary bone)

2) the foramina that open into the fossa:

Foramen rotundom

Foramen ovale

The aperture of the pterygoid canal

The aperture of the Palatovaginal canal

the sphenopalatine foramen (connects the fossa with the

nasal cavity )

the inferior orbital fissure (connects it with the orbit)

the pterygomaxillary (pterygopalatine) fissure (connects it

with the infratemporal fossa)

it connects with the oral cavity through the greater palatine

Canal (the pterygopalatine canal) which has the (Mercedes

sign shape:

the posterior part of the canal is formed by the pterygoid

process , the anterio-medial is formed by the perpendicular

plate of palatine bone (with making a groove on it) , the

anterio-lateral part is formed by the posterior part of the

nasal surface of the maxillary bone (also with making a

groove on it )

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Note: the term (pterygopalatine canal) can refer to one of two

canals:

1) the greater palatine canal

2) OR:the palatovaginal canal

3) It's contents:

The two pterygoid muscles

The maxillary artery and it's branches

The maxillary nerve and it's branches

The mandibular nerve and it's branches

The pterygoid venouses plexus

The pterygopalatine ganglion: lies at the bottom of the fossa

4) The branches of the pterygopalatine ganglion:

Orbital branches(passes through the inferior orbital

fissure)

nasopalatine nerve

posterior superior nasal branches

greater palatine nerve

lesser palatine nerve

Bock's nerve ( the pterygopalatine nerve) (passes through

the palatovaginal canal)

o The vidian nerve (the nerve of pterygoid canal) , and two sturdy

branches of the maxillary nerve: end up at the ganglion.

I hope this was helpful

By: Ahmad Amro Baradee