Anatomy & Physiology I
AXIAL SKELETON: SELECTED BONES AND MARKINGS
Prof. Atsma © 2008
Introduction: Following are tables which describe selected bones and their most important markings.
Find and be able to identify these bones/markings on the bones provided in your laboratory or the ALC.
SKULL
1. FRONTAL - "forehead"
bone extending from the
superior eye sockets to
the top of the skull
Frontal sinus* - located
within the central, anterior
portion area; Internal and
only visible on
cut/disarticulated skulls.
Supraorbital foramen - small holes just above
the eye sockets
2. PARIETAL - two large
bones that make up most of
the top and sides of the skull
3. TEMPORAL - inferior
to the parietals; partially
covered by the ears;
also curves under the
earlobe area; described
as having a squamous
(flat) region and a
petrous (irregular)
region.
Zygomatic process - slender
portion extending anterior
(together with the slender
portion of the zygomatic =
zygomatic arch)
External auditory meatus the canal for the passage of
sound vibrations through each
temporal bone to the middle
ear
Mastoid process - the large,
blunt projections pointing
inferiorly
Styloid process - the
'needle-like' projections on the
underside of the temporal
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3. Temporal (continued)
Mandibular fossa – small depressions
where the mandible attaches
Mastoid sinus – hollow area in the
mastoid portion; Internal and only
visible on cut/disarticulated skulls.
4. OCCIPITAL posterior/inferior part of the
skull/braincase.
Occipital condyles - the two mostly
lateral bumps around the foramen
magnum
Foramen magnum - large hole in the
inferior portion of the occipital for the
passage of the spinal cord
External occipital protuberance and
crest - small posteriorly pointing bump
and ridge; nicknamed the occipital bun
by anthropologists after the old
hairstyle.
5. ZYGOMATIC - the "cheekbones;"
the processes of the zygomatic and
temporal bones meet to form the
"zygomatic arch"
6. MAXILLA - "upper jaw bone;" also
extends upward to form part of the
eye socket and nasal cavities; curves
into the roof of the mouth
Alveoli – small sacs for the roots of
each tooth
Infraorbital foramen – two small
holes under each eye socket
Maxillary sinus – located laterally
within the maxilla; Internal and only
visible on cut/disarticulated skulls.
Palatine (horizontal) process - the
anterior 3/4 of the "hard palate"
7. PALATINE - this small, separate
bone finishes the last 1/4 of the "hard
palate"; really a pair of fused bones,
as are many of the bones of the face.
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8. LACRIMAL - small rectangular
bones barely inside the medial
portion of the eye socket; surrounds
the lacrimal canals (the holes found
medially/inferiorly in the eye socket).
9. MANDIBLE - "lower jaw bone"
Coronoid process – the more pointed projections
anterior to the condyloid processes.
Condyloid process - (A.K.A. mandibular condyle) the
blunt, rounded processes that fit into the mandibular
fossae of the temporal bones.
Body - the horseshoe-shaped, anterior 3/4 of the
mandible where the teeth attach.
Mental foramen - two small holes near the front of the
mandible for the passage of nerves/ blood vessels.
Ramus - the posterior 1/4 of the mandible that curves
upward from the body.
Alveoli - small sacs/sockets for the roots of each tooth.
10. NASAL - two fused bones make up the bony
'bridge' of the nose
11. ETHMOID - very irregular bone that forms the
roof of the nasal cavity and a small part of the floor
of the brain case
Perpendicular plate - plate-like bone making up
the superior part of the nasal septum (attaches to
the vomer to form the bony nasal septum)
Superior and middle conchae - paired curved,
feathery bones inside the nasal cavity (the superior
cannot be seen except in sagittal cuts of the skull)
Cribriform plate - flat upper portion of the ethmoid
making up a small portion of the floor of the
anterior brain case; dotted with small “pin holes”
called olfactory foramina (for olfactory nerve fibers)
Crista galli - small "shark fin-like" projection in the
middle of the cribriform plate; separates the two
olfactory bulbs which send nerve endings through
the olfactory foramina.
Ethmoid sinuses* - the irregular folds of the
ethmoid are mostly hollow and contain the ethmoid
sinuses; visible mainly in damaged “real” bones
and diagrams
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12. INFERIOR CONCHA - paired curved, feathery
bones inside the nasal cavity (the most inferior of
the three pairs of conchae)
13. VOMER - plate-like bone making up the inferior
part of the bony nasal septum
14. SPHENOID - “bat” or "butterfly
shaped" bone that extends through the
skull behind the eyes from temple to
temple
Sella turcica - small depression on the
back of the butterfly in which the pituitary
gland is found (translates to "Turkish
saddle")
Lesser wings - small flat area
immediately anterior to the sella turcica
Greater wings - large lateral projections
that run along the posterior of the eye
sockets and end at the area commonly
referred to as the “temples”
Sphenoidal sinus – located within the
central portion of the sphenoid; Internal
and only visible on cut/disarticulated skulls
Pterygoid process - "legs" of the
bat/butterfly that extend to the
maxilla/palatine bones
15. SUTURES - Jagged, immovable joints
connecting major skull bones.
Frontal (coronal) - along the frontal plane; posterior
border of frontal bone
Sagittal - along the sagittal plane; separates the two
parietal bones
Lambdoidal - horseshoe-shaped posterior suture; forms
most of the border of the occipital bone, largely
separating it from the parietal bones
Squamosal - curves around the upper flat ("squamous")
portion of the temporal bones
16. WORMIAN BONES - (A.K.A. sutural
bones) - small bones trapped within the
sutures
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17. HYOID BONE - Single small bone in the neck; not attached to any other bone; anchors some
muscles of the mouth/throat.
18. EAR OSSICLES - Tiny, specialized bones found between the auditory meatus and the mastoid
sinus: Malleus - “hammer”; Incus - “anvil”; Stapes - “stirrup”.
VERTEBRAL COLUMN
1. "GENERALIZED" VERTEBRA
Spinous process - posterior pointing process; may
be sharp or blunt
Transverse process - slender wings that extend
laterally
Lamina - slender connection between transverse
and spinous processes
Pedicle - slender connection between body and
transverse process
Body - solid, mostly rounded mass
Vertebral foramen - opening encircled by all of the
above leaving space for the spinal cord and its
surrounding tissues
Intervertebral foramina - lateral spaces between
vertebrae for the passage of the spinal nerves
Intervertebral discs - fibrocartilaginous discs
composing amphiarthrotic joints between bodies of
vertebrae
2. CERVICAL - First curved region with 7
vertebrae; proportionally small body.
Atlas ("C-1") – ring-like without a body; "yes
bone"
Axis ("C-2") - has a second body which actually
belongs to the atlas (the dens); "no bone"
Dens (aka odontoid process) - "tooth-like"
projection of the axis
Transverse foramina - small holes in
transverse processes found only in cervical
vertebrae
3. THORACIC - Second curved region with 12
vertebrae; long, thin spinous processes;
proportionally intermediate body
Facets - flat surface (for attachment of ribs) on
body and transverse process; one pair is found on
the transverse processes, the other on the body
near the pedicles.
Axis
Atlas
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4. LUMBAR - Third curved region with 5 vertebrae;
blunt, square spinous processes; proportionally
large body
5. SACRAL (OR "SACRUM") - Slightly
curved, shield-like region of fused
vertebrae that closes the posterior portion
of the pelvis
Sacral canal - equivalent to vertebral
foramina; longitudinal tunnel for the inferior
portion of the spinal cord in the fetus
(contains sacral nerves called the ‘cauda
equina’ in adults)
Sacral foramina - holes for passage of
nerves from in between the fused
vertebrae
6. COCCYX - several very small
vertebrae; vestigial tailbone
OTHER BONES OF THE AXIAL SKELETON
1. STERNUM - long flat bone in the middle
anterior thoracic area
Manubrium - almost square top portion
Body - long middle portion
Xiphoid process - small, sharp inferior
portion
2. RIBS - Twelve pairs of long curved
bones between vertebrae and sternum;
"true ribs" attached to sternum by costal
cartilage; "false ribs" attached to sternum
indirectly by cartilage of rib of it, and
"floating ribs" (last two pair that do not
attach to the sternum)
Head - slightly thicker portion attached to the vertebrae
Neck - below head
Tubercle - bump below neck