Bony spaces of the head

What are the 2 broad categories of the bony spaces of the head

intra-cranial

extra-cranial

What makes up the boundaries of the intracranial space

the cranial vault/ skull cap

Contents of the cranial vault

brain

associated nerves

vasculature

cerebrospinal fluid

meninges

What is the largest bony space of the head

the main vestibule of the cranial vault

What are some of the smaller spaces within the cranial vault

tympanic cavity

epitympanic recess

facial canal

mastoid air cells

pituitary fossa

How is the cranial vault divided into compartments?

-divided into 2 continuous compartments by inward folds of the meningeal layer of dura mater

What is the tentorium cerebelli and what does it do

tent shaped fold of dura mater

divides the intracranial cavity into supratentorial and infratentorial compartments

What are the posterior, lateral and anterior attachements of the tentorium cerebelli

posterior- internal occipital protuberance and transverse sulci

lateral- superior border of the petrous part of the temporal bone

anteriorly- anterior and posterior clinoid processes

What divides the supratentorial compartment

divided by the falx cerebri into the left and right supratentorial space which can communicate with each other and with the infratentorial space

What is the falx cerebri

vertical fold of the dura mater located in the longitudinal fissure that separates the left and right cerebral hemispheres

Anterior, superior and posterior attachements of the falx cerebri

anterior- crista galli

posterior- internal occipital protuberance

superior- internal surface of calvaria along the sagittal suture

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What are the 3 main extra-cranial spaces of the head

temporal fossa

infra-temporal fossa

pterygopalatine fossa

What is the temporal fossa

shallow depression on the side of the skull bounded by temporal lines

terminates below the level of the zygomatic arch

Superior and posterior borders of the temporal fossa

superior temporal line (origin of the deep temporal fascia)

Inferior border of the temporal fossa

runs along the zygomatic arch

Anterior border of the temporal fossa

posterior surface of frontal process of the zygomatic bone and the zygomatic process of the frontal bone

Medial borders of the temporal fossa

frontal, parietal, temporal and sphenoid bone

Lateral border of the temporal fossa

temporal fascial

Which muscle is the temporal fossa the site of origin for

temporalis muscle

What is the insertion point of the temporalis muscle

under the zygomatic arch, to the coronoid process of the mandible

Which blood vessels are found in the temporal fossa

superficial temporal artery- which is a terminal branch of the external carotid artery

Which nerves are found in the temporal fossa

-mandibular nerve

-anterior and posterior branches of the deep temporal nerve

-auricotemporal nerve

-zygomaticotemporal nerve (NCV2)

-temporal branches of the facial nerve

Location of the infratemporal fossa in relation to other structures

-below the middle cranial fossa

-medial and deep to the zygomatic arch

-behind the maxilla

How does the infratemporal fossa communicate with the temporal fossa

through the interval between the zygomatic arch and cranial bones

What is the basilar process of the infratemporal fossa

irregularly shaped cavity of anatomical and clinical importance

Superior border of the infratemporal fossa

infratemporal surface greater wing of the sphenoid

Anterior border of the infratemporal fossa

posterior surface of the maxilla

Medial border of the infratemporal fossa

lateral pterygoid plate

Posterior border of infratemporal fossa

styloid and mastoid processes

Lateral border of the infratemporal fossa

ramus of the mandible

Muscular contents of the infratemporal fossa

-lower part of the medial pterygoid

-lower part of the lateral pterygoid

-lower part of the temporalis msucle

Nerve contents of the infratemporal fossa

mandibular nerve and its branches:

inferior alveolar nerve

buccal nerve

lingual nerve

(nerves to msucles of mastication)

Clinical importance of the infratemporal fossa

-it is a potential anatomical space and pathologies within this region can evolve without detection

Deep arteries of the infratemporal fossa

maxillary artery and middle meningeal artery

Superficial arteries of the infratemporal fossa

superficial temporal artery

Veins of the infratemporal fossa

maxillary vein

middle meningeal vein

pterygoid venous plexus

Label 1 to 5

1- superior ophthalmic vein

2- anterior intercavernous sinus

3- inferior ophthalmic vein

4- pterygoid venous plexus

5- middle meningeal vein

Openings of the infratemporal fossa

foramen ovale

foramen spinosum

alveolar canal

inferior orbital fissure

pterygomaxillary fissure

What is inferior alveolar nerve block

anaesthetic injected around the mandibular foramen which blocks the inferior alveolar nerve

What is mandibular nerve block

anaesthetic injected adjacent to the nerve as it enters the infratemporal fossa

Which nerves are affected by mandibular nerve block

inferior alveolar, lingual, buccal and auriculotemporal

Location of the pterygopalatine fossa

small space behind and below the orbit

betweent the viscerocranium and neurocranium

Anterior boundary of the pterygopalatine fossa

posterior surface of the maxilla

Posterior boundary of the ptg fossa

pterygoid process

Medial boundary of the pterygopalatine fossa

perpendicular plate of palatine bone

Lateral boundaries of the pterygopalatine fossa

pterygomaxillary fissure

Superior and inferior boundary of the pterygopalatine fossa

superior- greater wing and body of sphenoid

inferior- pyramidal process of palatine bone

Why is the pterygopalatine fossa of clinical importance

-communicates with many other sites

-can be a major route of spread of infections and metastases (spread of cancer)

How does the pterygopalatine fossa communicate with the infratemporal fossa

via the pterygomaxillary fissure

How does the ptg fossa communicate with the middle cranial fossa

via the foramen rotundum

How does the ptg fossa communicate witht he nasal cavity

via the sphenopalatine foramen

How does the ptg fossa communicate with the orbital cavity

via inferiororbital fissure

How does the ptg fossa communicate with the palate

via the palatine canal

How does the ptg fossa communicate with the nasopharynx

via the pharyngeal and pterygoid canals