Download SKULL - De Anza College

AXIAL SKELETON
(Note - You will only be tested on bones and bone markers, not additional contextual information)
SKULL
 Sutures
o Coronal, Sagittal, Lambdoidal, Squamous
 Cranial Bones
o Frontal Bone
o
o
Temporal Bones
 Zygomatic process - w/ zygomatic bone forms zygomatic arch or
cheekbone

Mandibular fossa - articulates w/ condyle of mandible to form the
temporomandibular joint (TMJ)

Mastoid process

External auditory meatus - outer ear canal, ends at the tympanic
membrane

Petrous portion - houses the middle and inner ears

Internal auditory meatus - outlet for the cranial nerve carrying sensory
information from the inner ear
Occipital Bone
 Foramen magnum - opening where spinal cord enters cranium

o
o
o
Occipital condyles - articulate w/ first cervical vertebra (C1 or atlas)
Sphenoid Bone
 Greater and Lesser wings

Optic foramina - passage for the optic nerve

Sella turcica - holds the pituitary gland
Ethmoid Bone
 Cribriform plate - forms the roof of the nasal cavity, perforated by the
olfactory foramina to allow passage of olfactory neurons

Crista galli - projection of the cribiform plate into the cranial cavity that
serves as a point of attachment for the meninges

Perpendicular plate – forms the top portion of the external nasal septum
Parietal Bones
 Facial Bones
o Nasal Bones
o
Maxillary Bones
 Palatine process - transverse shelf of bone that forms the anterior 2/3 of
the hard palate (roof of the mouth)
o
Lacrimal Bones
 Lacrimal foramen or sulcus- holds the tear duct
o
Zygomatic Bones - form the anterior portion of the zygomatic arches
(cheekbones)
o
Palatine Bones
 Horizontal plate - forms the posterior portion of the hard palate
o
Vomer - inferior portion of the nasal septum
o
Inferior nasal conchae
o
Mandible
 Mandibular condyles - articulate with the mandibular fossae of the
temporal bones
 STERNUM
o Xiphoid process
 RIBS
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o
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True ribs - Pairs 1-7, attach directly to sternum
False ribs - Pairs 8-10, attach to costal cartilages of the rib above
Floating ribs - Pairs 11-12, no anterior attachment
 VERTEBRAE
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Parts of a Typical Vertebra
 Body
 Vertebral foramen - allows passage of the spinal cord
 Transverse processes
 Spinous process
 Intervertebral foramina - allow passage of spinal nerves
o
Regional Differences in Vertebrae

Cervical Vertebrae (C1-C7)
• C1 or atlas: articulates with the occipital condyles
• C2 or axis:
• dens articulates w/ C1
• Body – small or absent
• Transverse foramina - openings in the transverse processes,
allow passage of arteries and veins
• Spinous processes – bifid (except C1, C7)

Thoracic Vertebrae (T1-T12)
• Body – heart-shaped
• Spinous processes - long, slender and projected downward

Lumbar Vertebrae (L1-L5)
• Body - large and heavy
• Spinous process - square and short

Sacral vertebrae - fused to form the sacrum

Coccygeal vertebrae - fused to form the coccyx