Download Skull Bones - Obsessed With Skulls

Objectives
AXIAL SKELETON
SKULL
CRANIAL BONES
(8 total flat bones w/ 2 paired)
1. On a skull or diagram, identify and name
the bones of the skull
2. Identify the structure and function of the
bones of the skull
3. Describe how a fetal skull differs from the
adult skull
4. Explain the function of the fontanels.
1. Frontal Bone
• forms forehead &
upper portion of
eyesocket (orbital)
2. Parietal Bones
• paired bones;
form superior
& lateral walls
of cranium
3. Temporal Bones
• paired bones; inferior
to parietal bones
A. External auditory
meatus – canal
leading to eardrum &
middle ear
B. Styloid process –
sharp projection
below meatus;
attachment of neck &
tongue muscles
1
C. Zygomatic
process – bridge of
bone that joins with
cheekbone
D. Mastoid process –
rough projection
inferior & posterior to
meatus (feel behind
ears); attachment of
neck muscles
E. Jugular foramen
– found at junction
of occipital &
temporal bones;
opening for jugular
vein
F. Carotid canal –
superior to jugular
foramen; passage
for carotid artery
4. Occipital Bone
• most posterior bone;
forms base of skull
A. Foramen magnum
– large opening for
passage of spinal
cord
B. Occipital condyles
– lateral to foramen
magnum; projections
that rest on 1st
cervical vertebrae
5. Sphenoid Bone
• butterfly
shaped;
spans
entire
width of
skull
SPHENOID
2
A. Sella turcica – “Turk’s saddle”;
depression that holds the pituitary gland
B. Foramen ovale – large oval opening at
posterior end of sella turcica; passage of
cranial nerves that control chewing
Sella turcica
Foramen ovale
6. Ethmoid Bone
• irregular bone anterior to sphenoid
• Forms roof of nasal cavity & part of medial
walls of orbitals
A. Cristi galli – “cock’s comb”; projection
on superior surface to which outermost
brain attaches
B. Cribiform plates – holey areas on each
side of cristi galli; passage of olfactory
nerves
Bone of the Orbit
1. Frontal bone
2. Ethmoid bone
3. Sphenoid bone
4. Zygomatic bone
5. Lacrimal bone
6. Maxillary bone
3
SUTURES OF SKULL
(immovable joints of skull bones)
1. Coronal – between frontal & parietal
bones
2. Sagittal – between paired parietal bones
3. Lamboidal – between parietal & occipital
bones
4. Squamosal – between parietal &
temporal bones
1 – Coronal
5 – Squamosal
9 – lamboidal
15 - sagittal
FETAL SKULL
• Contains cartilage filled spaces called fontanels
that allow for brain growth & compression during
birth
• Face is smaller in comparison to cranium
• Adult’s cranium 1/8 of total body length
• Infant’s cranium ¼ of total body length
• Frontal bones split
• Temporal bone is a ring of bone
• Conical projections present – growth areas
FONTANELS
1. Frontal (anterior) –
between parietal &
frontal bones;
diamond shaped;
largest; closes within
18 – 24 months
2. Occipital (posterior)
– between parietal &
occipital bones;
closes within 2
months
3. Sphenoidal
(anterolateral) –
paired; at the junction
of the frontal, parietal,
temporal & sphenoid
bones ; closes within
3 months
4. Mastoid (posterolateral); at the
junction of parietal,
occipital & temporal
bones
4
FACIAL BONES
(14 bones w/ 2 being paired)
1. Maxillae – 2 bones
that fuse to form the
upper jaw
• All facial bones
except mandible join
to maxillae
A. Alveolar margin
(process) – holds
teeth
B. Palantine process
– anterior hard
palate
2. Palatine Bones –
posterior to
palatine processes
of maxillae
• If not fused cleft
palate results
3. Zygomatic Bones
– cheekbones
4. Lacrimal Bones –
smallest facial
bone; forms most
of the medial walls
of the orbits
5
1. Frontal bone
2. Ethmoid bone
3. sphenoid bone
4. Zygomatic bone
5. Nasal Bones – form the bridge of the
nose
6. Vomer Bone – “plow shaped”; single
bone in the median of nasal cavity
7. Conchae – “scroll shaped”; form lateral
walls of nasal cavity
5. Lacrimal bone
6. Maxillary bone
8. Mandible – lower jaw; only free moving joint of
skull
Nasal bones
A. Body – horizontal;
chin
conchae
vomer
B. Rami –
perpendicular
uprights
C. Angle – where body
meets rami
D. Coronoid process –
spine like process;
anterior
E. Condylar process –
knob like process;
posterior; forms
temporal
mandibular joint
F. Mandibular notch –
depression between
processes
G. Mandibular
foramen – opening
on inner surface of
rami
H. Mental foramen –
opening on body
HYOID BONE
• U shaped
• Only bone that doesn’t directly articulate
with any other bone in body
• Located above the larynx ; suspended
from styloid process
• 3 parts:
– Greater cornua – superior
– Lesser cornua – inferior
– Body – anterior
6
OSSICLES
Greater cornua
Lesser cornua
•
•
•
•
Bones of inner ear
Incus – anvil
Malleus – hammer
Stapes - stirrup
7