Bones Of The Skull

Front 1

Cranium

Back 1

consists of two parts

1. neurocranium-bony covering (case) of the brain and its membranous coverings (meninges)
-has a dome like roof called cavaria and floor or cranial base(basicranium)

2. Viserocranium- made up of facial bones
- 15 irregular bones

Front 2

Bones of the neurocranium

Back 2

frontal

ethmoid

sphenoid

occipital

temporal (paired))

parietal (paired)

Front 3

bones of the viserocranium

Back 3

mandible (singular)

ethmoid (singular)

vomer (singular)

maxilla

inferior nasal concha

zygomatic

palatine

nasal

lacrimal

Front 4

Frontal Bone

Back 4

forms skeleton of forehead

articulates wiht nasal zygomatic lacrimal ehtmoid an sphenoid bones

Front 5

nasion

Back 5

intersection of frontal and nasal bones

Front 6

supra-orbital margin

Back 6

angular boundary between squamous (flat) and orbital parts frontal

has superorbital foramen or notch

Front 7

superciliary arch

Back 7

just superior to supra-orbital margin is this ridge

Front 8

Glabella

Back 8

remenent of developmental frontal suture (metopic suture)

smooth area between the superciliary arches

Front 9

zygomatic bones

Back 9

prominance of cheeks, lie of inferolateral sides orbits, and rest on checks

zygomaticofacial foramen pierces lateral aspect each bone

Front 10

piriform aperture

Back 10

inferior to nasal bone

anterior nasal opening of the cranium

Front 11

nasal septum

Back 11

divides nasal cavity into right and left parts

Front 12

nasal conchae

Back 12

on lateral wall of each nasal cavity

Front 13

maxillae

Back 13

form upper jaw and united at intermaxillary suture

alveolar processes incule tooth sockets and constitute the supporting bone for the maxillary teeth

surround the piriform aperture and infraorbital margins

contain infra-orbital foramen

Front 14

mandible

Back 14

U shaped bone forming jaw

has alveolarprocesses fro the mandibular teeth

horizontal part=body

vertical part= ramus

Front 15

mental foramina

Back 15

inferior to the second premolar teeth

Front 16

mental protuberance

Back 16

forms prominance of chin

Front 17

mandibular symphysis

Back 17

region where halves of the infantile mandible fuse

Front 18

within orbits

Back 18

superior and inferior orbital fissures and optic canals

Front 19

temporal fossa

Back 19

bounded superiorly and posteriorly by superior and inferior temporal lines, anteriorly by frontal and zygomatic bones and inferiorly by zygomatic arch

Front 20

zygomatic arch

Back 20

formed by union of temporal process of zygomatic bone and zygomatic process of temporal bone

infratemporal fossa is irregular space deep to the zygomatic arch and mandible and posterior to axilla

Front 21

pterion

Back 21

indicated by H-shaped formation of sutures that unite the frontal, parietal, sphenoid (greater wing), and temporal bones

Front 22

external acoustic opening

Back 22

entrance to the external acoustic meatus (ear canal) which leads to the tympanic membrane

Front 23

mastoid process

Back 23

lies posteroinferior to external acoustic meatus

anteriomedial=styloid process

Front 24

external occipital protuberance

Back 24

easily palpable

superior nuchal line- superior limit of the neck

inferior less distinct

Front 25

lambda

Back 25

indicates junction of sagittal and lambdoid sutures

sometimes felt as depression

Front 26

bregma

Back 26

intersection of sagittal and coronal sutures

Front 27

hard plate

Back 27

formed by palatine process of the maxillae and horizontal planes of palatine bones anteriorly

Front 28

incissive fossa

Back 28

posterior to central incisor teath

Front 29

greater and lesser palatine foramina

Back 29

posteriolaterally

Front 30

choannae

Back 30

posterior edge of the palate forms inferior boundrary of the chanae (posterior nasal apertures)

seperated from each other by vomer

Front 31

vomer

Back 31

thin flat bone that forms part of bony nasal septum

Front 32

sphenoid

Back 32

three pairs of processes
1. greater wings
2. lesser wings
3. pterygoid processes

pterygoid processes have medial and lateral pterygoid plates
-extend inferiorly on each side of the sphenoid from the junction of the body and greater wings

Front 33

pharyngotympanic (auditory tube)

Back 33

opening of tube and the sulcus for the cartilaginous part of the tube lies medial to the spine of the sphenoid, inferior to the junction of fthe greater wing of the sphenoid and the petrous

Front 34

petrous

Back 34

(L. rock like) part of the temporal bone

wedged between occipital and sphenoid bones on base of skull

Front 35

mandibular fossae

Back 35

depressions in the sqamous part of the temporal bone

accommodate the heads of the mandible when the mouth is closed

Front 36

ocipital bone

Back 36

articulates with the sphenoid anteriorly

encircle the foramen magnum

lateral to foramen magnum are the occipital condyles which articulate with the vertebral column

Front 37

jugular foramen

Back 37

between occipital bone and petrous part of temporal bone

CN IX, X, and XI exit through

just anterior is external opening of the carotid canal which is where internal carotid artery enters

Front 38

stylomastoid foramen

Back 38

lies posterior to base of the styloid process

Front 39

Foramen Cecum

Back 39

nasal emissary vein

Front 40

cribiform plate

Back 40

axons of olfactory cells in olfactory epithelium

form olfactory nerve CN I

Front 41

optic canal

Back 41

optic nerve and artery

Front 42

superior orbital fissure

Back 42

opthalamic veins, opthalamic nerve (CN V1)

CN III, IV, VI adn sympathetic fibers

Front 43

Foramen rotundum

Back 43

Maxillary nerve (CN V2)

Front 44

Foramen ovale

Back 44

Mandibular nerve (CN V3) and accessory meningeal artery

Front 45

Foramen spinosum

Back 45

Middle meningeal artery and vein and meningeal branch of CN V3

Front 46

Foramen lacerum

Back 46

internal carotid artery and accompanying sympthetic and venous plexuses

Front 47

Groove or hiatus of greater petrosal nerve

Back 47

greater petrosal nerveand petrosal branch of middle meningeal artery

Front 48

Foramen Mangnum

Back 48

medulla and meninges

vertebral arteries

CN XI

dural veins

anterior and posterior spinal arteries

Front 49

Hypoglossal Canal

Back 49

Hypoglossal nerve

Front 50

Condylar Canal

Back 50

emissary vein that passes from sigmoid sinus to vertebral veins in neck

Front 51

Mastoid foramen

Back 51

mastoid emissary vein from sigmoid sinus and meningeal branch of occipital artery

Front 52

anterior cranial fosssa

Back 52

formed by frontal bone anteriorly, ethmoid bone centrally, and body and less wings fo the sphenoid posteriorly

Front 53

Frontal crest

Back 53

medial bony extension of frontal bone

at its base is foramen cecum which gives passage to vessels during fetal development

Front 54

crista galli

Back 54

median ridge of bone that projects superiorly from the ethmoid

cribiform plate on either side

Front 55

sella turcica

Back 55

surrounded by the anterior and posterior clinoid processes

3 parts:
1. tuberculum sellae (horn of the saddle) slight elevation anteriorly on the body of the sphenoid

2. hypophysial fossa (pituitary fossa)- saddle-like depression for the pituitary gland in the middle

3. dorsum sellae (back of the saddle)- posteriorly formed by a square plate of bone on the body of the spheniod
-prominant and superiolateral angles are teh posterior clinoid processes

Front 56

sphenoidal crests

Back 56

sharp posterior margins of the lesser wings of the sphenoid bones which overhang the lateral parts of the fossae anteriorly

end medially as anterior clinoid processes

Front 57

prechiasmatic sulcus

Back 57

extends between the right and left optic canals

Front 58

foramen lacerum

Back 58

posterolateral to the hypophysial fossa

in life closed by cartilage plate

Front 59

clivus

Back 59

from dorsum sellae there is a marked incline which leads to the foramen magnum

Front 60

internal occipital crest

Back 60

landmark that divides the posterior part of the fossae into 2 cerebellar fossae

ends superiorly in the interal occipital protuberance

Front 61

Broad grooves

Back 61

formed by transverse and sigmoid sinuses

Front 62

SCALP

Back 62

Skin

Connective Tissue

Aponeurosis

Loose Connective Tissue

Pericranium

Front 63

Skin

Back 63

thin except in occipital region

contains many sweat and sebaceous glands and hair follicles

abundant arterial supply and good venous and lymphatic drainage

Front 64

Connective tissue

Back 64

thick dense, richly vascularized, subcutaneous layer

well supplied with cutaneous nerves

Front 65

Aponeurosis

Back 65

epicranial aponeurosis

stong tendinous sheet that covers the calvaria

attachment for frontal and occipital bellies of the occipitofrontalis muscle and the superior auricular muscle

collectively these structuresform the msuculoaponeurotic epicranius

Front 66

Loose connective tissue

Back 66

sponge-like layer

has potential spaces that may distend with fluid as result of injury or infection

allows free mvmt of scalp proper (first three layers) over the underlying calvaria

Front 67

pericranium

Back 67

dense layer CT forms external periosteum of neurocranium

firmly attached but can be stripped faily easily from the calvaria except where the pericranium is continuous wiht the fibrous tissue in the cranial sutures

Front 68

basilar fracture

Back 68

bones forming cranial base (occipital bone, temporal, and sphenoid)

result:
-leakage of CSF into nasal cavity or ear
-cranial nerve and blood vessel injury may also occur

Front 69

pterion fracture

Back 69

can be life threatening because overlies branches of the frontal anterior branches of the middle minengial artery

-lie in the groove of the internal aspect of the lateral wall of the calvaria

-hard blow to the side of the head can fracture pterion and rupture frontal branch of the middle meningeal

-resulting hemotoma puts pressure on the cortex=DEATH IF UNTREATED