Chapter 6

Chapter 1
6 Lecture
Fifth Edition
Chapter 6
The Skeletal System:
Axial Division
Frederic Martini
Michael Timmons
Robert Tallitsch
Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings
• The axial skeleton:
– skull
– Vertebral column
– Rib cage
• Sternum
• ribs
Figure 6.1a The Axial Skeleton
The Skull and Associated Bone
Figure 6.2 Cranial and Facial Subdivisions of the Skull
Figure 6.3a The Adult Skull
Figure 6.3b The Adult Skull
Figure 6.3c The Adult Skull
The Skulls of Infants - Fontanels
Figure 6.18 The Skulls of Infants
The Cranium
• The cranial cavity is a chamber that
supports and protects the brain.
• Bones of the cranium are the:
– Occipital
– Parietal (2)
– Frontal
– Temporal (2)
– Sphenoid
– Ethmoid
Occipital Bone
Figure 6.6a,b The Occipital Bone
Occipital Bone
Figure 6.3e Inferior View of Skull
Frontal Bone
Figure 6.7 The Frontal Bone
Parietal Bone
Figure 6.6c The Parietal Bone
Temporal Bone
Figure 6.8 The Temporal Bone
Temporal Bone
Figure 6.3e Inferior View of the Skull
Sphenoid Bone
Figure 6.9 The Sphenoid Bone
Ethmoid Bone
Figure 6.10 The Ethmoid
Ethmoid in Skull
The Cranial Fossae
Figure 6.11a The Cranial Fossae
The Cranial Fossae
Figure 6.11b The Cranial Fossae
The Facial Bones
• The skull contains 14 total facial bones:
– Paired bones:
Inferior nasal conchae
– Single bones:
• Vomer
• Mandible
Maxillary Bones
Figure 6.12a,b The Maxillae
The Palatine Bones
Figure 6.13 The Palatine Bones
The orbital complex
Figure 6.15 The Orbital Complex
The Orbital and Nasal Complexes
Figure 6.15 The Orbital Complex
The Inferior Nasal Conchae
Figure 6.16a,b The Nasal Complex
The Inferior Nasal Conchae
Figure 6.16c,d The Nasal Complex
The Vomer
Figure 6.5 Sectional View of the Skull
The Mandible
Figure 6.14 The Mandible
The Orbital and Nasal Complexes
Figure 6.16a The Nasal Complex
Paranasal Sinuses
• Are the interconnected hollow spaces
inside the frontal, ethmoid, sphenoid, and
maxillary bones.
• These spaces reduce the weight of the
skull, produce mucus, and allow air to
resonate for voice production.
• Frontal sinus, maxillary sinus, sphenoidal
sinus, and the ethmoidal air cells
Paranasal Sinues
The Hyoid Bone
Figure 6.17 The Hyoid Bone
Review of the Skull
• 22 Bones of the Skull:
– 8 form the cranium:
– 14 total facial bones:
• Paired bones:
Parietal (2)
Temporal (2)
Inferior nasal conchae
• Single bones:
– Vomer
– Mandible
The Skull
The Vertebral Column
• The adult vertebral column has ~33 bones:
– Vertebra (24), sacrum ( 5 fused into 1), and
coccyx (3 – 5 fused into1)
• Performs several functions:
– Encloses and protects the spinal cord
– Supports the skull
– Supports the weight of the head, neck, and
– Transfers weight to the lower limbs
– Helps maintain the upright position of the body
The Vertebral Column
• Divided into regions from superior to
– Cervical (7)
– Thoracic (12)
– Lumbar (5)
– Sacral (1); 5 fused vertebrae
– Coccygeal (1); 3–5 fused vertebrae
Spinal Curves
• Spinal curves are weight transferring
anterior and posterior curves.
– The spinal curves are named for the region of
the vertebral column they occur in:
Cervical curve
Thoracic curve
Lumbar curve
Sacral curve
Vertebral Column
Vertebral Anatomy
Figure 6.20a,b,c Vertebral Anatomy
Vertebral Anatomy
Figure 6.20d,e Vertebral Anatomy
Intervertebral disk
Cervical Vertebrae
• There are seven total; they are the smallest, most superior vertebrae.
• The spinous processes: relatively stumpy; may be split, resulting in a bifid
• Have Transverse foramina
• Superior articular facet faces up
• Inferior articular facet faces down
• No rib facets
• C1 and C2 special – Atlas and Axis
The Atlas (C1)
• The atlas has no body and articulates
cranially with the occipital condyles.
– The articulations with the occipital condyles
allow one to shake their head “yes”.
• The atlas has two arches, the anterior and
posterior vertebral arches.
• Superior and inferior articular facets do not
extend beyond the arches.
The Atlas (C1)
Figure 6.22a,b The Atlas and Axis
The Axis (C2)
• The body of the atlas fuses with the body
of the axis during development to form the
dens (odontoid process).
– There is no intervertebral disc because of the
• The articulation between the atlas and axis
allow one to shake their head “no”.
The Axis (C2)
Figure 6.22c–f The Atlas and Axis
Cervical Vertebrae
• Bifid spinous
• Transverse foramen
• Superior articular
facet faces superiorly
Thoracic Vertebrae
• There are 12 total; make up the posterior
of the rib cage.
• The bodies of the thoracic vertebrae have
a heart shape.
• The spinous process is long and slender
and points on a posterocaudal angle.
• The transverse processes point
• Articulates with ribs and therefore contain
extra facets.
Typical Thoracic Vertebrae
Thoracic Vertebrae
• Facets for ribs
Lumbar Vertebrae
• There are 5 total; the largest vertebrae,
and make up the lower back region.
• The body of lumbar vertebrae is very thick
and oval shaped.
• The relatively small vertebral foramen is
Lumbar Vertebrae
• The transverse processes point more
laterally than the thoracic vertebrae.
• The spinous process resembles a tail fin of
a fish; stumpy and flattened.
Typical Lumbar Vertebrae
Sacrum and Coccyx
Figure 6.25 The Sacrum and Coccyx
Sacrum and coccyx
The Thoracic Cage
• Has two functions:
– Protects the heart, lungs, thymus, and other
structures within the cavity.
– Serves as the attachment site for muscles
involved in:
• Respiration
• Positioning the vertebral column
• Movements of the pectoral girdle and upper limb
Axial Skeleton

similar documents