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7
The Axial Skeleton
PowerPoint® Lecture Presentations prepared by
Jason LaPres
Lone Star College—North Harris
© 2012 Pearson Education, Inc.
An Introduction to the Axial Skeleton
• Structures of Bones
• Articulations
• Contacts with other bones
• Landmarks (bone markings; marks)
• Areas of muscle and ligament attachment
• Foramina
• Openings for nerves and blood vessels
© 2012 Pearson Education, Inc.
7-1 The Axial Skeleton
• The Axial Skeleton
• Forms the longitudinal axis of the body
• Has 80 bones
• The skull
• 8 cranial bones
• 14 facial bones
• Bones associated with the skull
• 6 auditory ossicles
• The hyoid bone
© 2012 Pearson Education, Inc.
7-1 The Axial Skeleton
• The Axial Skeleton
• The vertebral column
• 24 vertebrae (singular = vertebra)
• The sacrum
• The coccyx
• The thoracic cage
• 24 ribs
• The sternum
© 2012 Pearson Education, Inc.
Figure 7-1a The Axial Skeleton
SKELETAL SYSTEM
206
APPENDICULAR SKELETON
AXIAL SKELETON
(see Figure 8–1)
8
Cranium
14
Face
6
Auditory
ossicles
1
Hyoid
1
Sternum
Skull
24
Associated
bones
Skull and
29 associated
bones
25
Thoracic
cage
26
Vertebral
column
Ribs
24 Vertebrae
1
Sacrum
1
Coccyx
An anterior view of the entire skeleton, with the axial components highlighted.
The numbers in the boxes indicate the number of bones in the adult skeleton.
© 2012 Pearson Education, Inc.
80
Figure 7-1b The Axial Skeleton
Skull
Cervical
vertebrae
Sternum
Ribs
Thoracic
vertebrae
Costal
cartilages
Lumbar
vertebrae
Sacrum
Coccyx
Anterior (left) and posterior (right) views of the axial skeleton.
The individual bones associated with the skull are not visible.
© 2012 Pearson Education, Inc.
7-1 The Axial Skeleton
• Functions of the Axial Skeleton
• Supports and protects organs in body cavities
1. Attaches to muscles of head, neck, and trunk
2. Performs respiratory movements
3. Stabilizes parts of appendicular skeleton
© 2012 Pearson Education, Inc.
7-2 The Skull
• The Skull
• Protects:
• The brain
• Entrances to respiratory system
• Entrance to digestive system
• Contains:
• 22 bones
• 8 cranial bones
• Form the braincase or cranium
• 14 facial bones
• Protect and support entrances to digestive and
respiratory tracts
© 2012 Pearson Education, Inc.
Figure 7-2 Cranial and Facial Subdivisions of the Skull
SKULL
CRANIUM
FACE
14
Maxillary bones
2
Occipital bone 1
Palatine bones
2
Parietal bones
2
Nasal bones
2
Frontal bone
1
Inferior nasal
conchae
2
Zygomatic bones 2
Lacrimal bones
2
Vomer
1
Mandible
1
© 2012 Pearson Education, Inc.
8
Temporal bones 2
Sphenoid
1
Ethmoid
1
ASSOCIATED BONES 7
Hyoid bone 1 Auditory ossicles
enclosed in
temporal bones 6
(detailed in
Chapter 17)
Figure 7-2 Cranial and Facial Subdivisions of the Skull
FRONTAL
BONE
SPHENOID
ETHMOID
PARIETAL BONE
TEMPORAL
BONE
OCCIPITAL
BONE
LACRIMAL
BONE
NASAL
BONE
Cranial bones
VOMER
ZYGOMATIC
BONE
MAXILLA
MANDIBLE
Facial bones
© 2012 Pearson Education, Inc.
7-2 The Skull
• Cranial Bones
• Enclose the cranial cavity
• Which contains the brain
• And its fluids, blood vessels, nerves, and
membranes
© 2012 Pearson Education, Inc.
7-2 The Skull
• Facial Bones
• Superficial facial bones
• For muscle attachment
• Deep facial bones
• Separate the oral and nasal cavities
• Form the nasal septum
© 2012 Pearson Education, Inc.
Figure 7-3a The Adult Skull
Sagittal suture
PARIETAL
BONE
(left)
PARIETAL
BONE
(right)
Lambdoid
suture
OCCIPITAL
BONE
Squamous
suture
TEMPORAL BONE
Mastoid process
Styloid process
Occipital condyle
External occipital
protuberance
MANDIBLE
Posterior view
© 2012 Pearson Education, Inc.
Figure 7-3b The Adult Skull
OCCIPITAL BONE
Lambdoid
suture
PARIETAL
BONE
(right)
PARIETAL
BONE
(left)
Sagittal
suture
Coronal
suture
FRONTAL BONE
ZYGOMATIC
BONE
NASAL BONES
Superior view
© 2012 Pearson Education, Inc.
Figure 7-3c The Adult Skull
Coronal suture
FRONTAL
BONE
PARIETAL
BONE
SPHENOID
Supra-orbital foramen
Squamous suture
TEMPORAL
BONE
NASAL BONE
LACRIMAL BONE
Squamous part of
temporal bone
Lambdoid suture
External acoustic
meatus
ETHMOID
Infra-orbital foramen
MAXILLA
ZYGOMATIC BONE
OCCIPITAL
BONE
Mastoid process
Zygomatic
arch
Styloid process
Zygomatic process
of temporal bone
Temporal process
of zygomatic bone
MANDIBLE
Lateral view
© 2012 Pearson Education, Inc.
Mental foramen
Mental protuberance
Figure 7-3d The Adult Skull
Coronal suture
PARIETAL BONE
FRONTAL BONE
SPHENOID
TEMPORAL BONE
Supra-orbital foramen
ETHMOID
PALATINE BONE
Optic canal
Superior orbital fissure
LACRIMAL BONE
Inferior orbital fissure
Temporal process of
zygomatic bone
ZYGOMATIC BONE
Mastoid process of
temporal bone
Infra-orbital foramen
NASAL BONE
Middle nasal concha
(part of ethmoid)
Perpendicular plate
of ethmoid
Bony nasal
VOMER
septum
MAXILLA
INFERIOR
NASAL CONCHA
MANDIBLE
Mental foramen
© 2012 Pearson Education, Inc.
Mental protuberance
Anterior view
Figure 7-3e The Adult Skull
FRONTAL BONE
MAXILLA
ZYGOMATIC BONE
VOMER
SPHENOID
PALATINE BONE
Foreman ovale
Zygomatic arch
Medial and lateral
pterygoid processes
Styloid process
Mandibular fossa
Foramen lacerum
Carotid canal
TEMPORAL BONE
External
acoustic meatus
Mastoid process
Jugular foramen
Stylomastoid foramen
Lambdoid suture
Occipital condyle
OCCIPITAL BONE
External occipital
protuberance
Foramen magnum
Inferior view
© 2012 Pearson Education, Inc.
Figure 7-4a The Sectional Anatomy of the Skull
Coronal suture
PARIETAL BONE
FRONTAL BONE
SPHENOID
Squamous suture
Sphenoidal sinus (right)
Frontal sinus
Crista galli
NASAL BONE
ETHMOID
TEMPORAL BONE
Lambdoid suture
Hypophyseal fossa
of sella turcica
Internal acoustic meatus
VOMER
PALATINE BONE
OCCIPITAL BONE
Hypoglossal canal
Styloid process
MAXILLA
MANDIBLE
Medial view of a sagittal section through the skull.
© 2012 Pearson Education, Inc.
Figure 7-4b The Sectional Anatomy of the Skull
FRONTAL BONE
Crista galli
Cribriform plate
ETHMOID
Sella turcica
Foramen rotundum
Foramen lacerum
SPHENOID
Foramen ovale
Foramen spinosum
TEMPORAL BONE
Carotid canal
PARIETAL BONE
Internal occipital crest
Foramen
magnum
Internal
acoustic meatus
Jugular foramen
Hypoglossal canal
OCCIPITAL BONE
Superior view of a horizontal section through the skull, showing the
floor of the cranial cavity. Compare with part (a) and with Figure 7–3e.
© 2012 Pearson Education, Inc.
7-2 The Skull
• Superficial Facial Bones
• Maxillae = maxillary bones
• Lacrimal
• Nasal
• Zygomatic
• Mandible
• Deep Facial Bones
• Palatine
• Inferior nasal conchae
• Vomer
© 2012 Pearson Education, Inc.
7-2 The Skull
• Sinuses
• Cavities that decrease the weight of the skull
1. Lined with mucous membranes
2. Protect the entrances of the respiratory system
© 2012 Pearson Education, Inc.
7-2 The Skull
• Sutures
• The immovable joints of the skull
• The four major sutures
1. Lambdoid suture
2. Coronal suture
3. Sagittal suture
4. Squamous suture
© 2012 Pearson Education, Inc.
7-2 The Skull
•
Lambdoid Suture
• Separates occipital from parietal bones
• May contain sutural (Wormian) bones
•
Coronal Suture
• Attaches frontal bone to parietal bones
• The calvaria (skullcap)
• Consists of occipital, parietal, and frontal bones
© 2012 Pearson Education, Inc.
7-2 The Skull
• Sagittal Suture
• Between the parietal bones
• From lambdoid suture to coronal suture
• Squamous Sutures
• Form boundaries between temporal bones and
parietal bones
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Cranial Bones
• Occipital bone
• Parietal bones
• Frontal bone
• Temporal bones
• Sphenoid
• Ethmoid
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Occipital Bone
• Functions of the occipital bone
• Forms the posterior and inferior surfaces of the
cranium
• Articulations of the occipital bone
• Parietal bones
• Temporal bones
• Sphenoid
• First cervical vertebra (atlas)
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Occipital Bone
• Marks of the occipital bone
• External occipital protuberance
• External occipital crest
• Occipital condyles articulate with neck
• Inferior and superior nuchal lines: attachment site
of muscles and ligaments
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Occipital Bone
• Foramina of the occipital bone
• Foramen magnum connects cranial and spinal
cavities
• Jugular foramen for jugular vein
• Hypoglossal canals for hypoglossal nerves
© 2012 Pearson Education, Inc.
Figure 7-5a The Occipital and Parietal Bones
Hypoglossal
canal
Occipital
condyle
Foramen
magnum
Inferior
nuchal line
External
occipital
protuberance
External
occipital
crest
Superior
nuchal
line
Occipital bone, inferior view
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Parietal Bones
• Functions of the parietal bones
• Form part of the superior and lateral surfaces of the cranium
• Articulations of the parietal bones
• Other parietal bone
• Occipital bone
• Temporal bone
• Frontal bone
• Sphenoid
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Parietal Bones
• Marks of the parietal bones
• Superior and inferior temporal lines
• To attach temporalis muscle
• Grooves for cranial blood vessels
© 2012 Pearson Education, Inc.
Figure 7-5b The Occipital and Parietal Bones
Superior
temporal line
Inferior
temporal line
Right parietal bone, lateral view
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Frontal Bone
• Functions of the frontal bone
• Forms the anterior cranium and upper eye sockets
• Contains frontal sinuses
• Articulations of the frontal bone
• Parietal bone
• Maxillary
• Metopic suture
• Ethmoid
• Lacrimal bone
• Zygomatic bone
• Sphenoid
• Nasal bone
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Frontal Bone
• Marks of the frontal bone
• Frontal squama (forehead)
• Supra-orbital margin (protects eye)
• Lacrimal fossa (for tear ducts)
• Frontal sinuses
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Frontal Bone
• Foramina of the frontal bone
• Supra-orbital foramen
• For blood vessels of eyebrows, eyelids, and frontal
sinuses
• Supra-orbital notch
• An incomplete supra-orbital foramen
© 2012 Pearson Education, Inc.
Figure 7-6a The Frontal Bone
Frontal
(metopic)
suture
Frontal squama
Superior
temporal line
Supra-orbital
margin
© 2012 Pearson Education, Inc.
Supra-orbital
notch
Anterior surface
7-3 The Cranial Bones of the Skull
• The Temporal Bones
• Functions of the temporal bones
1. Part of lateral walls of cranium and zygomatic
arches
2. Articulate with mandible
3. Surround and protect inner ear
4. Attach muscles of jaws and head
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Temporal Bones
• Articulations of the temporal bones
• Zygomatic bone
• Sphenoid
• Parietal bone
• Occipital bone
• Mandible
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Temporal Bones
• Marks of the temporal bones
• Squamous part
• Zygomatic process
• Mandibular fossa
• Mastoid process
• Styloid process
• Petrous part
• Auditory ossicles
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• Squamous Part
• Borders the squamous suture
• Zygomatic Process
• Inferior to the squamous portion
• Articulates with temporal process of zygomatic bone
• Forms zygomatic arch (cheekbone)
• Mandibular Fossa
• Articulates with the mandible
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• Mastoid Process
• For muscle attachment
• Contains mastoid air cells connected to middle ear
• Styloid Process
• To attach tendons and ligaments of the hyoid, tongue,
and pharynx
• Petrous Part
• Encloses structures of the inner ear
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• Auditory Ossicles
• Three tiny bones in tympanic cavity (middle ear)
• Transfer sound from tympanic membrane (eardrum) to
inner ear
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Temporal Bones
• Foramina of the temporal bones
• Carotid canal for internal carotid artery
• Foramen lacerum
• For carotid and small arteries
• Hyaline cartilage
• Auditory tube
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Temporal Bones
• Foramina of the temporal bones
• External acoustic meatus (canal) ends at tympanic
membrane
• Stylomastoid foramen for facial nerve
• Internal acoustic meatus (canal)
• For blood vessels and nerves of the inner ear
• Facial nerve
© 2012 Pearson Education, Inc.
Figure 7-7a The Temporal Bones
Petrous
part
Squamous
part
Internal
acoustic meatus
Mastoid
process
Zygomatic
process
© 2012 Pearson Education, Inc.
Styloid process
Medial view of the
right temporal bone
Figure 7-7b The Temporal Bones
Squamous
part
External
acoustic meatus
Styloid process
Mastoid process
Lateral view of the
right temporal bone
© 2012 Pearson Education, Inc.
Mandibular
fossa
Zygomatic
process
Figure 7-7c The Temporal Bones
External acoustic
meatus
Mastoid process,
cut to show
mastoid air cells
A cutaway view
of the mastoid
air cells
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Sphenoid
• Functions of the sphenoid
• Part of the floor of the cranium
• Unites cranial and facial bones
• Strengthens sides of the skull
• Contains sphenoidal sinuses
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Sphenoid
• Articulations of the sphenoid
• Ethmoid
• Frontal bone
• Occipital bone
• Parietal bone
• Temporal bone
• Palatine bones
• Zygomatic bones
• Maxillae
• Vomer
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Sphenoid
• Marks of the sphenoid
•
•
•
•
•
•
•
Sphenoid body
Sella turcica
Hypophyseal fossa
Sphenoidal sinuses
Lesser wings
Greater wings
Pterygoid processes
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• Sphenoid Body
• At the central axis of the sphenoid
• Sella Turcica
• Saddle-shaped enclosure
• On the superior surface of the body
• Hypophyseal Fossa
• A depression within the sella turcica
• Holds the pituitary gland
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• Sphenoidal Sinuses
• On either side of the body
• Inferior to the sella turcica
• Lesser Wings
• Anterior to the sella turcica
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• Greater Wings
• Form part of the cranial floor
• Sphenoidal spine
• Posterior wall of the orbit
• Pterygoid Processes
• Form pterygoid plates
• To attach muscles of the lower jaw and soft palate
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Sphenoid
• Foramina of the sphenoid
• Optic canals for optic nerves
• Superior orbital fissure for blood vessels and nerves of
the orbit
• Foramen rotundum for blood vessels and nerves of the
face
• Foramen ovale for blood vessels and nerves of the face
• Foramen spinosum for blood vessels and nerves of the
jaws
© 2012 Pearson Education, Inc.
Figure 7-8a The Sphenoid
Optic Optic
Foramen
rotundum groove canal
Lesser
wing
Foramen
ovale
Foramen
spinosum
Greater wing
Sella turcica
Superior surface
© 2012 Pearson Education, Inc.
Sphenoidal
spine
Figure 7-8b The Sphenoid
Superior Sphenoidal
sinus
orbital fissure
Greater
wing
Orbital
surface
Lesser
wing
Body
Foramen
rotundum
Pterygoid
process
Pterygoid
plates
Anterior surface
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Ethmoid
• Functions of the ethmoid
• Forms anteromedial floor of the cranium
• Roof of the nasal cavity
• Part of the nasal septum and medial orbital wall
• Contains ethmoidal air cells (network of sinuses)
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Ethmoid
• Articulations of the ethmoid
• Frontal bone
• Sphenoid
• Nasal bone
• Lacrimal bone
• Palatine bone
• Maxillary bones
• Inferior nasal conchae
• Vomer
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Ethmoid
• Three parts of the ethmoid
1. The cribriform plate
2. The two lateral masses
3. The perpendicular plate
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Cribriform Plate
• Floor of the cranium
• Roof of the nasal cavity
• Contains the crista galli
• The Two Lateral Masses
• Ethmoidal labyrinth (ethmoidal air cells)
• Superior nasal conchae
• Middle nasal conchae
• The Perpendicular Plate
• Part of the nasal septum
© 2012 Pearson Education, Inc.
7-3 The Cranial Bones of the Skull
• The Ethmoid
• Foramina of the ethmoid
• Olfactory foramina
• In the cribriform plate
• For olfactory nerves
© 2012 Pearson Education, Inc.
Figure 7-9a The Ethmoid
Lateral mass
containing
ethmoidal
labyrinth
Olfactory
foramina
Cribriform
plate
Crista galli
Perpendicular
plate
© 2012 Pearson Education, Inc.
Superior surface
Figure 7-9b The Ethmoid
Crista galli
Superior
nasal
concha
Middle nasal
concha
Perpendicular
plate
Posterior surface
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Facial Bones
• Maxillae (maxillary bones)
• Palatine bones
• Nasal bones
• Vomer
• Inferior nasal conchae
• Zygomatic bones
• Lacrimal bones
• Mandible
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Maxillae
• Functions of the maxillae
• Support upper teeth
• Form inferior orbital rim
• Form lateral margins of external nares
• Form upper jaw and hard palate
• Contain maxillary sinuses (largest sinuses)
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Maxillae
• Articulations of the maxillae
• Frontal bones
• Ethmoid
• With one another
• All other facial bones except the mandible
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Maxillae
• Marks of the maxillae
• Orbital rim protects eye and orbit
• Anterior nasal spine attaches cartilaginous anterior nasal
septum
• Alveolar processes border the mouth and support upper
teeth
• Palatine processes form the hard palate (roof of mouth)
• Maxillary sinuses lighten bone
• Nasolacrimal canal protects lacrimal sac and
nasolacrimal duct
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Maxillae
• Foramina of the maxillae
• Infra-orbital foramen
• For sensory nerve to brain (via foramen rotundum
of sphenoid)
• Inferior orbital fissure
• For cranial nerves and blood vessels
© 2012 Pearson Education, Inc.
Figure 7-10a The Maxillae and Palatine Bones
Orbital
rim
Infra-orbital
foramen
Alveolar
process
Zygomatic
process
An anterolateral view of the
right maxilla.
© 2012 Pearson Education, Inc.
Anterior
nasal
spine
7-3 The Facial Bones of the Skull
• The Palatine Bones
• Functions of the palatine bones
• Form the posterior portion of the hard palate
• Contribute to the floors of the orbits
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Palatine Bones
• Articulations of the palatine bones
• With other palatine bone
• Maxillae
• Sphenoid
• Ethmoid
• Inferior nasal conchae
• Vomer
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Palatine Bones
• Divisions of the palatine bones
• Horizontal plate: posterior part of hard palate
• Perpendicular plate from horizontal plate to orbital process
of orbit floor
• Foramina of the palatine bones
• Many in the lateral portion of the horizontal plate
• For small blood vessels and nerves of the roof of the mouth
© 2012 Pearson Education, Inc.
Figure 7-10b The Maxillae and Palatine Bones
Palatine bone
(horizontal plate)
Palatine
process
Alveolar
process
Maxillary
sinus
Superior view of a horizontal
section through right maxilla and
palatine bone; note the size and
orientation of the maxillary sinus.
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Nasal Bones
• Functions of the nasal bones
• Support the bridge of the nose
• Connect to cartilages of the distal part of the nose
(external nares)
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Nasal Bones
• Articulations of the nasal bones
• With other nasal bones
• Ethmoid
• Frontal bones
• Maxillae
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Vomer
• Functions of the vomer
• Forms the inferior portion of the bony nasal septum
• Articulations of the vomer
• Sphenoid
• Ethmoid
• Palatine bones
• Maxillae
• Cartilaginous part of the nasal septum
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Inferior Nasal Conchae
• Functions of the inferior nasal conchae
• To create air turbulence in the nasal cavity
• To increase the epithelial surface area
• To warm and humidify inhaled air
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Inferior Nasal Conchae
• Articulations of the inferior nasal conchae
• Ethmoid
• Maxillae
• Palatine bones
• Lacrimal bones
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Zygomatic Bones
• Functions of the zygomatic bones
• Contribute to the rim and lateral wall of the orbit
• Form part of the zygomatic arch
• Articulations of the zygomatic bones
• Sphenoid
• Frontal bone
• Temporal bones
• Maxillae
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Zygomatic Bones
• Marks of the zygomatic bones
• Temporal process
• Meets the zygomatic process of the temporal bone
• Foramina of the zygomatic bones
• Zygomaticofacial foramen
• For sensory nerves of cheeks
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Lacrimal Bones
• Functions of the lacrimal bones
• The smallest facial bones
• Form part of the medial wall of the orbit
• Articulations of the lacrimal bones
• Frontal bone
• Maxillae
• Ethmoid
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Lacrimal Bones
• Marks of the lacrimal bones
• Lacrimal sulcus
• Location of the lacrimal sac
• Leads to the nasolacrimal canal (between orbit and
nasal cavity)
© 2012 Pearson Education, Inc.
Figure 7-11 The Smaller Bones of the Face
Supra-orbital foramen
NASAL BONE
SPHENOID
TEMPORAL BONE
Zygomaticofacial
foramen
ZYGOMATIC BONE
Infra-orbital foramen
MAXILLA
Perpendicular plate VOMER
of ethmoid
Bony nasal septum
© 2012 Pearson Education, Inc.
Figure 7-11 The Smaller Bones of the Face
Lacrimal sulcus
Optic canal
Superior orbital
fissure
LACRIMAL BONE
Middle nasal
concha
INFERIOR NASAL CONCHA
Temporal process of
zygomatic bone
Mastoid process
Perpendicular plate VOMER
of ethmoid
Bony nasal septum
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Mandible
• Functions of the mandible
• Forms the lower jaw
• Articulations of the mandible
• Mandibular fossae of the temporal bones
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Mandible
• Marks of the mandible
• Body of the mandible horizontal portion
• Alveolar processes support the lower teeth
• Mental protuberance attaches facial muscles
• A depression on the medial surface for submandibular
salivary gland
• Mylohyoid line for insertion of the mylohyoid muscle (floor of
mouth)
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Mandible
• Marks of the mandible
• Ramus ascending from the mandibular angle on either side
• Condylar process articulates with temporal bone at
temporomandibular joint
• Coronoid process: insertion point for temporalis muscle
(closes the jaws)
• Mandibular notch separates condylar and coronoid
processes
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Mandible
• Foramina of the mandible
• Mental foramina
• For sensory nerves of lips and chin
• Mandibular foramen
• Entrance to the mandibular canal
• For blood vessels and nerves of lower teeth
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Hyoid Bone
• Functions of the hyoid bone
• Supports the larynx
• Attaches muscles of the larynx, pharynx, and tongue
• Articulations of the hyoid bone
• Connects lesser horns to styloid processes of temporal
bones
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Hyoid Bone
• Marks of the hyoid bone
• Body of the hyoid
• Attaches muscles of larynx, tongue, and
pharynx
© 2012 Pearson Education, Inc.
7-3 The Facial Bones of the Skull
• The Hyoid Bone
• Marks of the hyoid bone
• Greater horns (greater cornua)
• Support larynx
• Attach muscles of the tongue
• Lesser horns (lesser cornua)
• Attach stylohyoid ligaments
• Support hyoid and larynx
© 2012 Pearson Education, Inc.
Figure 7-12a The Mandible and Hyoid Bone
Articular surface for
temporomandibular
joint
Coronoid process
Teeth
Mandibular
notch
Alveolar process
Head
Ramus
Condylar process
Body
Angle
A lateral and slightly superior
view of the mandible
© 2012 Pearson Education, Inc.
Mental
protuberance
Mental foramen
Figure 7-12b The Mandible and Hyoid Bone
Articular surface
Alveolar
process
Condylar process
Coronoid process
Mandibular foramen
Mylohyoid line
Depression for submandibular
salivary gland
A medial view of the right mandible
© 2012 Pearson Education, Inc.
Figure 7-12c The Mandible and Hyoid Bone
Greater horn
Lesser horn
Body
An anterior view of the hyoid bone
© 2012 Pearson Education, Inc.
7-4 The Orbital and Nasal Complexes
• The Eye Sockets (Orbits)
• Frontal bone (roof)
• Maxilla (floor)
• Maxillary, lacrimal, and ethmoid bones (orbital rim
and medial wall)
• Sphenoid and palatine bones
© 2012 Pearson Education, Inc.
Figure 7-13 The Orbital Complex
FRONTAL
BONE
SPHENOID
Supra-orbital
notch
Optic canal
ETHMOID
Superior
orbital
fissure
LACRIMAL
BONE
Lacrimal
sulcus
Nasolacrimal
canal
PALATINE
BONE
Inferior orbital
fissure
ZYGOMATIC
BONE
Infra-orbital Infra-orbital MAXILLA
groove
foramen
© 2012 Pearson Education, Inc.
Figure 7-13 The Orbital Complex
Supra-orbital notch
FRONTAL BONE
SPHENOID
Optic canal
Superior orbital
fissure
ETHMOID
Nasolacrimal canal
Inferior orbital
fissure
Infra-orbital
groove
ZYGOMATIC BONE
MAXILLA Infra-orbital
foramen
© 2012 Pearson Education, Inc.
7-4 The Orbital and Nasal Complexes
• Bones of the Nasal Cavities and Paranasal
Sinuses Make Up the Nasal Complex
• Frontal bone, sphenoid, and ethmoid
• Superior wall of nasal cavities
• Maxillae, lacrimal bones, ethmoid, and inferior nasal
conchae
• Lateral walls of nasal cavities
• Maxillae and nasal bones
• Bridge of nose
© 2012 Pearson Education, Inc.
Figure 7-14a The Nasal Complex
FRONTAL BONE
Frontal sinuses
ETHMOID
NASAL BONE
PALATINE BONE
(bony palate)
MAXILLA
(bony palate)
© 2012 Pearson Education, Inc.
Sphenoidal
sinuses
SPHENOID
Superior
Middle
INFERIOR
NASAL
CONCHA
A sagittal section through the skull,
with the nasal septum removed to
show major features of the wall of
the right nasal cavity. The
sphenoidal sinuses are visible.
Nasal
conchae
of ethmoid
Figure 7-14b The Nasal Complex
FRONTAL
BONE
Cranial cavity
Ethmoidal air cell
Perpendicular
plate of ethmoid
Maxillary
sinus
VOMER
Frontal sinus
Right orbit
Superior
nasal concha
Middle nasal
concha
ZYGOMATIC
BONE
INFERIOR NASAL
CONCHA
MAXILLA
(bony palate)
Tongue
MANDIBLE
© 2012 Pearson Education, Inc.
A frontal section through the
ethmoidal air cells and maxillary
sinuses, part of the paranasal sinuses.
7-4 The Orbital and Nasal Complexes
• Paranasal Sinuses
• Air-filled chambers connected to the nasal cavities
• Lighten skull bones
• Provide mucous epithelium (flushes nasal cavities)
© 2012 Pearson Education, Inc.
7-5 Fontanelles
• The Infant Skull
• Grows rapidly
• Is large compared to the body
• Has many ossification centers
© 2012 Pearson Education, Inc.
7-5 Fontanelles
• The Infant Skull
• Fusion is not complete at birth
• Two frontal bones
• Four occipital bones
• Several sphenoidal and temporal elements
© 2012 Pearson Education, Inc.
7-5 Fontanelles
• Fontanelles
• Are areas of fibrous connective tissue (soft spots)
• Cover unfused sutures in the infant skull
• Allow the skull to flex during birth
© 2012 Pearson Education, Inc.
7-5 Fontanelles
• Anterior Fontanelle
• Frontal, sagittal, and coronal sutures
• Occipital Fontanelle
• Lambdoid and sagittal sutures
• Sphenoidal Fontanelles
• Squamous and coronal sutures
• Mastoid Fontanelles
• Squamous and lambdoid sutures
© 2012 Pearson Education, Inc.
Figure 7-15a The Skull of an Infant
Coronal
suture
FRONTAL
BONE
PARIETAL
BONE
Sphenoidal
fontanelle
NASAL BONE
Squamous suture
Lambdoid suture
MAXILLA
OCCIPITAL BONE
SPHENOID
MANDIBLE TEMPORAL
BONE
Lateral view
© 2012 Pearson Education, Inc.
Mastoid
fontanelle
Figure 7-15b The Skull of an Infant
PARIETAL
BONE
FRONTAL
BONE
Coronal
suture
Frontal suture Anterior Sagittal suture
fontanelle
FRONTAL
BONE
Superior view
© 2012 Pearson Education, Inc.
PARIETAL
BONE
Occipital
fontanelle
Lambdoid
suture
OCCIPITAL
BONE
7-6 The Vertebral Column
• The Vertebral Column (Spine)
• Protects the spinal cord
• Supports the head and body
• 26 bones
• 24 vertebrae, the sacrum, and the coccyx
© 2012 Pearson Education, Inc.
Figure 7-16 The Vertebral Column
Spinal Curves
Vertebral Regions
Primary curves develop
before birth, and secondary
curves after birth.
Regions are defined
by anatomical
characteristics of
individual vertebrae.
The cervical curve, a
secondary curve, develops as
the infant learns to balance the
weight of the head on the
vertebrae of the neck.
The thoracic curve, a
primary curve,
accommodates the
thoracic organs.
The lumbar curve, a
secondary curve, balances
the weight of the trunk over
the lower limbs; it develops
with the ability to stand.
The sacral curve, a
primary curve,
accommodates the
abdominopelvic organs.
© 2012 Pearson Education, Inc.
Cervical
(7 vertebrae)
Thoracic
(12 vertebrae)
Lumbar
(5 vertebrae)
Sacral
Coccygeal
7-6 The Vertebral Column
• Vertebrae
• The neck
• Seven cervical vertebrae
• The upper back
• 12 thoracic vertebrae
• Each articulates with one or more pair of ribs
• The lower back
• Five lumbar vertebrae
© 2012 Pearson Education, Inc.
7-6 The Vertebral Column
• The Sacrum and Coccyx
• The fifth lumbar vertebra articulates with the sacrum
• The sacrum articulates with the coccyx
© 2012 Pearson Education, Inc.
7-6 The Vertebral Column
• Four Spinal Curves
1. Cervical curve
2. Thoracic curve
3. Lumbar curve
4. Sacral curve
© 2012 Pearson Education, Inc.
7-6 The Vertebral Column
• Thoracic and Sacral Curves
• Are called primary curves (present during fetal
development)
• Or accommodation curves (accommodate internal
organs)
• Lumbar and Cervical Curves
• Are called secondary curves (appear after birth)
• Or compensation curves (shift body weight for
upright posture)
© 2012 Pearson Education, Inc.
Figure 7-17a Abnormal Curvatures of the Spine
Kyphosis
© 2012 Pearson Education, Inc.
Figure 7-17b Abnormal Curvatures of the Spine
© 2012 Pearson Education, Inc.
Lordosis
Figure 7-17c Abnormal Curvatures of the Spine
Scoliosis
© 2012 Pearson Education, Inc.
7-6 The Vertebral Column
• Vertebral Anatomy
• The vertebral body (centrum)
• Transfers weight along the spine
• The vertebral arch
• Posterior margin of vertebral foramen
• The articular processes
• Lateral projections between laminae and pedicles
© 2012 Pearson Education, Inc.
Figure 7-18a Vertebral Anatomy
Articular processes
Vertebral arch
Vertebral body
The major components of
a typical vertebra
© 2012 Pearson Education, Inc.
7-6 The Vertebral Column
• Vertebral Anatomy
• The vertebral arch
• Pedicles
• Walls of the vertebral arch
• Laminae
• Roof of the vertebral arch
© 2012 Pearson Education, Inc.
7-6 The Vertebral Column
• Vertebral Anatomy
• The vertebral arch
• Spinous process
• Projection where vertebral laminae fuse
• Transverse process
• Projection where laminae join pedicles
© 2012 Pearson Education, Inc.
7-6 The Vertebral Column
• Vertebral Anatomy
• The articular processes
• Superior articular process
• Inferior articular process
• Have articular facets on articular faces
© 2012 Pearson Education, Inc.
Figure 7-18b Vertebral Anatomy
Superior articular
process
Pedicle
Transverse
process
Vertebral body
Spinous
process
Inferior articular
facet
Inferior articular
process
Arrow passing
through vertebral
foramen
A lateral and slightly inferior
view of a vertebra
© 2012 Pearson Education, Inc.
Figure 7-18c Vertebral Anatomy
Spinous
process
Superior
articular
process
Inferior
articular
process
Transverse
process
Pedicle
Inferior
articular
facet
Vertebral
foramen
Vertebral
body
An inferior view of a
vertebra
© 2012 Pearson Education, Inc.
7-6 The Vertebral Column
• Vertebral Foramina
• Intervertebral foramina
• Gaps between pedicles of adjacent vertebrae
• For nerve connections to spinal cord
• Vertebral canal
• Formed by vertebral foramina
• Encloses the spinal cord
© 2012 Pearson Education, Inc.
7-6 The Vertebral Column
• Intervertebral Discs
• Are pads of fibrocartilage
• Separate the vertebral bodies
• Absorb shocks
© 2012 Pearson Education, Inc.
Figure 7-18d Vertebral Anatomy
Superior articular facets
Superior articular process
Lamina of
vertebral arch
Spinous process
Intervertebral
disc
Transverse process
Vertebral body
An posterior view
of three articulated
vertebrae
© 2012 Pearson Education, Inc.
Inferior
articular
process
Figure 7-18e Vertebral Anatomy
Superior articular facets
Lamina of
vertebral arch
Intervertebral
foramen
Intervertebral
disc
Spinous process
Transverse process
Vertebral body
Inferior
articular
facet
© 2012 Pearson Education, Inc.
Arrow passing
through vertebral
canal
A lateral and sectional view
of three articulated
vertebrae
7-7 Vertebral Regions
• Vertebral Regions
• Vertebrae are numbered
• By region, from top (superior) to bottom (inferior)
• C1 articulates with skull, L5 with sacrum
• Vertebrae of each region
• Have characteristics determined by functions
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• Regions of the Vertebral Column
• Cervical (C)
• Thoracic (T)
• Lumbar (L)
• Sacral (S)
• Coccygeal (Co)
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• The Cervical Vertebrae
• Small body (support only head)
• Large vertebral foramen (largest part of spinal cord)
• Concave superior surface
• Slope posterior to anterior
• C1 (atlas) has no spinous process
• All others have short spinous processes
• Tip of each spinous process is notched (bifid)
© 2012 Pearson Education, Inc.
Figure 7-19a The Cervical Vertebrae
C1
C2
C3
C4
C5
Spinous
process of
vertebra
prominens
C6
C7
A lateral view of the
cervical vertebrae,
C1–C7
© 2012 Pearson Education, Inc.
Figure 7-19b The Cervical Vertebrae
Vertebral
arch
Spinous process
Lamina
Superior articular
process
Vertebral
foramen
Pedicle
Vertebral body
Transverse
process
Costal process
Superior
Transverse articular
facet
foramen
A superior view of a representative
cervical vertebra showing
characteristics of C3–C6. Notice the
typical features listed in Table 7–2.
© 2012 Pearson Education, Inc.
Figure 7-19c The Cervical Vertebrae
Superior articular
process
Transverse process
Inferior articular
process
Spinous process
Bifid tip of
spinous process
Location of
transverse
foramen
Inferior articular
facet
Vertebral
body
A lateral view of the same vertebra
as in b.
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• The Cervical Vertebrae
• Transverse processes
• Are fused to costal processes
• Which encircle transverse foramina (protect arteries
and veins)
• Atlas (C1)
• Articulates with occipital condyles of skull
• Has no body or spinous process
• Has a large, round foramen within anterior and
posterior arches
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• The Cervical Vertebrae
• Axis (C2)
• Supports the atlas
• Has heavy spinous process
• To attach muscles of head and neck
• Axis and atlas bodies fuse during development to
form the dens
© 2012 Pearson Education, Inc.
Figure 7-19d The Cervical Vertebrae
Anterior
arch
Transverse
ligament
Dens of
axis
Atlas (C1)
Posterior
arch
Axis (C2)
The atlas (C1) and axis (C2).
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• The Cervical Vertebrae
• Vertebra prominens (C7)
• Transitions to thoracic vertebrae
• Has a long spinous process with a broad tubercle
• Has large transverse processes
• Ligamentum nuchae (elastic ligament) extends from
C7 to skull
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• Thoracic Vertebrae (T1–T12)
• Have heart-shaped bodies
• Larger bodies than in C1–C7
• Smaller vertebral foramen than in C1–C7
• Long, slender spinous processes
• Dorsolateral surfaces of body have costal facets
• Which articulate with heads of ribs
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• Thoracic Vertebrae (T1–T12)
• T1–T10
• Have transverse costal facets
• On thick transverse processes for rib articulation
• Ribs at T1–T10
• Contact costal and transverse costal facets
• T1–T8 articulate with two pairs of ribs
• At superior and inferior costal facets
• T9–T11 articulate with one pair of ribs
• T10–T12 transition to lumbar vertebrae
© 2012 Pearson Education, Inc.
Figure 7-20a The Thoracic Vertebrae
T1
T2
T3
Intervertebral
foramen
T4
T5
T6
Thoracic
vertebrae
(T1–T12)
T7
T8
T9
T10
T11
T12
© 2012 Pearson Education, Inc.
A lateral view of the thoracic region of
the vertebral column. The vertebra
prominems (C7) resembles T1, but lacks
facets for rib articulation. Vertebra T12
resembles the first lumbar vertebra (L1)
but has a facet for rib articulation.
Figure 7-20b The Thoracic Vertebrae
Spinous
process
Transverse
process
Lamina
Transverse
costal facet
Superior
articular
facet
Vertebral
foramen
Superior
costal facet
Vertebral
body
Thoracic vertebra, superior view.
© 2012 Pearson Education, Inc.
Figure 7-20c The Thoracic Vertebrae
Superior
articular facet
Transverse costal
facet for tubercle
of superior rib
Transverse
process
Superior costal facet
for head of superior rib
Vertebral
body
Spinous
process
Inferior costal facet
for head of inferior rib
Thoracic vertebra, lateral view.
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
•
Lumbar Vertebrae (L1–L5)
•
Largest vertebrae
•
Oval-shaped bodies
•
Thicker bodies than T1–T12
•
No costal or transverse costal facets
•
Triangular vertebral foramen
•
Superior articular processes
•
•
Face up and in
Inferior articular processes
•
Face down and out
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• Lumbar Vertebrae (L1–L5)
• Transverse processes
• Slender
• Project dorsolaterally
• Spinous process
• Short, heavy
• For attachment of lower back muscles
© 2012 Pearson Education, Inc.
Figure 7-21a The Lumbar Vertebrae
L1
L2
L3
L4
L5
Sacrum
Coccyx
A lateral view of the lumbar
vertebrae and sacrum
© 2012 Pearson Education, Inc.
Figure 7-21b The Lumbar Vertebrae
Superior articular
process
Pedicle
Transverse process
Spinous
process
Vertebral
body
Inferior articular process
Inferior articular facet
A lateral view of a typical lumbar vertebra
© 2012 Pearson Education, Inc.
Figure 7-21c The Lumbar Vertebrae
Spinous process
Superior articular facet
Lamina
Superior articular
process
Transverse
process
Transverse process
Vertebral
foramen
Pedicle
Vertebral
body
A superior view of the same
vertebra shown in part b
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• The Sacrum
• Is curved, more in males than in females
• Protects reproductive, urinary, and digestive organs
• Attaches:
• The axial skeleton to pelvic girdle of appendicular
skeleton
• Broad muscles that move the thigh
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• The Sacrum
• The adult sacrum
• Consists of five fused sacral vertebrae
• Fuses between puberty and ages 25–30
• Leaving transverse lines
• Sacral canal
• Replaces the vertebral canal
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• The Sacrum
• Sacral cornua
• Horn shaped
• Formed by laminae of the fifth sacral vertebra
• Which do not meet at midline
• Sacral hiatus
• Opening at the inferior end of the sacral canal
• Formed by ridges of sacral cornua
• Covered by connective tissues
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• The Sacrum
• Median sacral crest
• Fused spinous processes
• Four pairs of sacral foramina open to either side
• Lateral sacral crest
• Fused transverse processes
• Attach to muscles of lower back and hip
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• The Sacrum
• Auricular surface
• Thick, flattened area
• Articulates with pelvic girdle (forming sacroiliac joint)
• Sacral tuberosity
• Rough area
• Attaches ligaments of the sacroiliac joint
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• The Sacrum
• Base
• The broad superior surface
• Ala
• Wings at either side of the base
• To attach muscles
• Sacral promontory
• At the center of the base
• Apex
• The narrow inferior portion
• Articulates with the coccyx
© 2012 Pearson Education, Inc.
7-7 Vertebral Regions
• The Coccyx
• Attaches ligaments and a constricting muscle of the
anus
• Mature coccyx
• Consists of three to five fused coccygeal vertebrae
• First two coccygeal vertebrae
• Have transverse processes
• Have unfused vertebral arches
• Coccygeal cornua
• Formed by laminae of first coccygeal vertebra
© 2012 Pearson Education, Inc.
Figure 7-22a The Sacrum and Coccyx
Articular Entrance to
process sacral canal
Sacral
tuberosity
Lateral
sacral crest
Median
sacral crest
Sacral
hiatus
Sacral cornu
Coccygeal cornu
© 2012 Pearson Education, Inc.
A posterior view
Figure 7-22b The Sacrum and Coccyx
Sacral
promontory
Auricular
surface
Lateral
sacral crest
Median
sacral crest
Sacral cornu
Coccygeal cornu
Sacral curve
Coccyx
A lateral view from the right side
© 2012 Pearson Education, Inc.
Figure 7-22c The Sacrum and Coccyx
Base
Sacral
promontory
Sacral
foramina
Ala
Ala
Transverse
lines
Apex
Coccyx
An anterior view
© 2012 Pearson Education, Inc.
7-8 The Thoracic Cage
• The Thoracic Cage
• The skeleton of the chest
• Supports the thoracic cavity
• Consists of:
• Thoracic vertebrae
• Ribs
• Sternum (breastbone)
• The Rib Cage
• Formed of ribs and sternum
© 2012 Pearson Education, Inc.
Figure 7-23a The Thoracic Cage
Jugular notch
T1
Clavicular articulation
1
Manubrium
Sternum
2
3
Body
4
Xiphoid
process
Costal
cartilages
5
10
T11
T12
Vertebrochondral
ribs
(ribs 8–10)
Floating ribs
(ribs 11–12)
© 2012 Pearson Education, Inc.
True ribs
(ribs 1–7)
11
12
6
7
8
9
An anterior view, showing the
costal cartilages and the sternum
False ribs
(ribs 8–12)
Figure 7-23b The Thoracic Cage
C7
1
T1
2
T2
3
1
2
3
T3
4
4
T4
5
T5
5
T6
6
7
T7
7
8
T8
6
True ribs
(ribs 1–7)
8
T9
9
10
11
12
T10
9
T11
10
11
T12
L1
False ribs
(ribs 8–12)
12
A posterior view, showing the
articulations of the ribs and vertebrae
© 2012 Pearson Education, Inc.
7-8 The Thoracic Cage
• Functions of the Thoracic Cage
1. Protects organs of the thoracic cavity
• Heart, lungs, and thymus
2. Attaches muscles
1. For respiration
2. Of the vertebral column
3. Of the pectoral girdle and the upper limbs
© 2012 Pearson Education, Inc.
Figure 7-24c The Ribs
Sternum
Ribs
The effect of rib
movement on the
thoracic cavity is similar
to the movement of a
bucket handle. Elevation
of curved ribs increases
the volume of the
thoracic cavity.
© 2012 Pearson Education, Inc.
7-8 The Thoracic Cage
• Ribs (Costae)
• Are 12 pairs of long, curved, flat bones
• Extending from the thoracic vertebrae
• Ribs are divided into two types
1. True ribs
2. False ribs
© 2012 Pearson Education, Inc.
7-8 The Thoracic Cage
• Ribs 1–7 (True Ribs)
• Vertebrosternal ribs
• Connected to the sternum by costal cartilages
© 2012 Pearson Education, Inc.
7-8 The Thoracic Cage
• Ribs 8–12 (False Ribs)
• Do not attach directly to the sternum
• Vertebrochondral ribs (ribs 8–10)
• Fuse together
• Merge with cartilage before reaching the sternum
• Floating or vertebral ribs (ribs 11–12)
• Connect only to the vertebrae and back muscles
• Have no connection with the sternum
© 2012 Pearson Education, Inc.
Figure 7-23a The Thoracic Cage
Jugular notch
T1
Clavicular articulation
1
Manubrium
Sternum
2
3
Body
4
Xiphoid
process
Costal
cartilages
5
10
T11
T12
Vertebrochondral
ribs
(ribs 8–10)
Floating ribs
(ribs 11–12)
© 2012 Pearson Education, Inc.
True ribs
(ribs 1–7)
11
12
6
7
8
9
An anterior view, showing the
costal cartilages and the sternum
False ribs
(ribs 8–12)
7-8 The Thoracic Cage
• Structures of the Ribs
• The head (capitulum)
• At the vertebral end of the rib
• Has superior and inferior articular facets
• The neck
• The short area between the head and the tubercle
© 2012 Pearson Education, Inc.
7-8 The Thoracic Cage
• Structures of the Ribs
• The tubercle (tuberculum)
• A small dorsal elevation
• Has an auricular facet that contacts the facet of its
thoracic vertebra (at T1–T10 only)
• The tubular body (shaft)
• Attaches muscles of the pectoral girdle and trunk
• Attaches to the intercostal muscles that move the ribs
© 2012 Pearson Education, Inc.
Figure 7-24a The Ribs
Transverse
costal
facet
Tubercle
of rib
Angle
Neck
Demifacet
Head
(capitulum)
Vertebral
end
A superior view of the details of rib
structure and the articulations between
the ribs and thoracic vertebrae.
© 2012 Pearson Education, Inc.
Figure 7-24b The Ribs
Head
Neck
Attachment to
costal cartilage
(sternal end)
Articular facets
Tubercle
Body
Angle
Costal groove
A posterior view of the head of a
representative rib from the right side (ribs 2–9).
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7-8 The Thoracic Cage
• The Sternum
• A flat bone
• In the midline of the thoracic wall
• Three parts of the sternum
1. The manubrium
2. The sternal body
3. The xiphoid process
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7-8 The Thoracic Cage
•
Manubrium
• The superior portion of sternum
• Broad, triangular shape
• Articulates with clavicles (collarbones)
• Articulates with cartilages of first rib pair
• Has a jugular notch, a shallow indentation between
clavicular articulations
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7-8 The Thoracic Cage
•
The Sternal Body
• Is tongue-shaped
• Attaches to the manubrium
• Attaches to costal cartilages of ribs 2–7
•
The Xiphoid Process
• Is the smallest part of the sternum
• Attaches to the sternal body
• Attaches to diaphragm and rectus abdominis muscles
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Figure 7-23a The Thoracic Cage
Jugular notch
T1
Clavicular articulation
1
Manubrium
Sternum
2
3
Body
4
Xiphoid
process
Costal
cartilages
5
10
T11
T12
Vertebrochondral
ribs
(ribs 8–10)
Floating ribs
(ribs 11–12)
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True ribs
(ribs 1–7)
11
12
6
7
8
9
An anterior view, showing the
costal cartilages and the sternum
False ribs
(ribs 8–12)
7-8 The Thoracic Cage
• Development of the Sternum
• The developing sternal body
• Consists of four unfused bones
• Completes fusion about age 25
• Leaving transverse lines
• The xiphoid process
• Is the last part of sternum to fuse
• Can easily be broken away
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