Download Ch6-7

6&7
Bones and Skeletal
Tissues
Axial Skeleton
Pages 123-131, 133-135, 150-179
PowerPoint® Lecture Presentations prepared by
Leslie Hendon
University of Alabama, Birmingham
© 2014 Pearson Education, Inc.
Types of Cartilage
• Hyaline cartilage (glassy)
• Most abundant cartilage
• Provides support through flexibility
• Elastic cartilage—contains many elastic fibers
• Able to tolerate repeated bending
• Fibrocartilage—resists strong compression
and strong tension
• An intermediate between hyaline and elastic
cartilage
© 2014 Pearson Education, Inc.
Function of Bones
• Support—provides hard framework
• Movement—skeletal muscles use bones as
levers
• Protection of underlying organs
• Mineral storage—reservoir for important
minerals
• Blood-cell formation—bone contains red
marrow
• Energy metabolism—osteoblasts secrete
osteocalcin
© 2014 Pearson Education, Inc.
Classification of Bones
• Long bones—longer than wide; a shaft plus
ends
• Short bones—roughly cube-shaped
• Flat bones—thin and flattened, usually curved
• Irregular bones—various shapes, do not fit
into other categories
© 2014 Pearson Education, Inc.
Figure 6.3 Classification of bones.
Flat bone
(sternum)
Long bone
(humerus)
Short bone
(talus)
© 2014 Pearson Education, Inc.
Irregular bone
(vertebra), right
lateral view
Structure of a Typical Long Bone
• Diaphysis—“shaft” of a bone
• Epiphysis—ends of a bone
• Blood vessels—well vascularized
• Medullary cavity—hollow cavity filled with
yellow marrow
• Membranes
• Periosteum, perforating fibers (Sharpey’s fibers),
and endosteum
© 2014 Pearson Education, Inc.
Figure 6.4 The structure of a long bone (humerus).
Articular
cartilage
Proximal
epiphysis
Compact bone
Spongy bone
Endosteum
Epiphyseal
line
Periosteum
Endosteum
Compact bone
Medullary
cavity
(lined by
endosteum)
Diaphysis
Yellow
bone marrow
Compact bone
Periosteum
Perforating
collagen fiber
bundles
Nutrient
arteries
Distal
epiphysis
© 2014 Pearson Education, Inc.
Table 6.1 Bone Markings (1 of 2)
© 2014 Pearson Education, Inc.
Table 6.1 Bone Markings (2 of 2)
© 2014 Pearson Education, Inc.
Bone Tissue
• Bone tissue
• Organic components—cells, fibers, and ground
substance
• Inorganic components—mineral salts that
invade bony matrix
© 2014 Pearson Education, Inc.
Cells
• Three types of cells in bone produces or
maintain bone
• Osteogenic cells—stem cells
• Osteoblasts—actively produce and secrete
bone matrix
• Osteocytes—keep bone matrix healthy
Osteoclasts—responsible for resorption of bone
© 2014 Pearson Education, Inc.
Gross Anatomy of Bones
• Compact bone—dense outer layer of bone
• Spongy (cancellous) bone—internal network of
bone
© 2014 Pearson Education, Inc.
Figure 6.7 Microscopic structure of compact bone.
Compact bone Spongy bone
Perforating
(Volkmann’s) canal
Central
(Haversian) canal
Endosteum lining bony canals
and covering trabeculae
Osteon
(Haversian system)
Circumferential
lamellae
Lamellae
Osteocyte
within lacuna
Nerve
Vein
Artery
Canaliculi
Osteocyte
in a lacuna
© 2014 Pearson Education, Inc.
Perforating collagen fiber bundles
Periosteal blood vessel
Periosteum
Lamellae
Central
canal
Lacunae
Central canal
Interstitial
lamella
Figure 6.9 Spongy bone.
Marrow
space
Trabecula
Osteocytes
Endosteum
Osteoblasts
© 2014 Pearson Education, Inc.
The Skeleton
• Consists of:
• Bones, cartilage, joints, and ligaments
• Composed of 206 named bones grouped into
two divisions
• Axial skeleton (80 bones)
• Appendicular skeleton (126 bones)
© 2014 Pearson Education, Inc.
The Axial Skeleton
Skull
• Formed from 80
named bones
• Consists of skull,
vertebral column,
and bony thorax
Thoracic cage
(ribs and
sternum)
Vertebral
column
Sacrum
Cranium
Facial bones
Clavicle
Scapula
Sternum
Rib
Humerus
Vertebra
Radius
Ulna
Carpals
Phalanges
Metacarpals
Femur
Patella
Tibia
Fibula
(a) Anterior view
© 2014 Pearson Education, Inc.
Tarsals
Metatarsals
Phalanges
Figure 7.1a
The Skull
• Formed by cranial and facial bones
Frontal bone
Parietal bone
Squamous part
of frontal bone
Nasal bone
Sphenoid bone
(greater wing)
Temporal bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Infraorbital foramen
Maxilla
Mandible
Glabella
Frontonasal suture
Supraorbital foramen
(notch)
Supraorbital margin
Superior orbital fissure
Optic canal
Inferior orbital fissure
Middle nasal concha
Ethmoid
Perpendicular plate bone
Inferior nasal concha
Vomer
Mental
foramen
Mental
protuberance
(a) Anterior view of skull
© 2014 Pearson Education, Inc.
Figure 7.6a
The Cranium
• Is the body’s most complex bony structure
• The cranium
• Encloses and protects brain
• Provides attachment for head and neck muscles
© 2014 Pearson Education, Inc.
The Face
• Facial bones serve to
• Form framework of the face
• Form cavities for the sense organs of sight,
taste, and smell
• Provide openings for the passage of air and
food
• Hold the teeth in place
• Anchor muscles of the face
© 2014 Pearson Education, Inc.
Cribriform plate
of ethmoid bone
Sphenoid sinus
Posterior nasal
aperture
Nasopharynx
Pharyngeal tonsil
Opening of
pharyngotympanic
tube
Uvula
Oropharynx
Palatine tonsil
Isthmus of the
fauces
Laryngopharynx
Esophagus
Trachea
(b) Illustration
© 2014 Pearson Education, Inc.
Frontal sinus
Nasal cavity
Nasal conchae
(superior, middle
and inferior)
Nasal meatuses
(superior, middle,
and inferior)
Nasal vestibule
Nostril
Hard palate
Soft palate
Tongue
Larynx
Lingual tonsil
Hyoid bone
Epiglottis
Vestibular fold
Thyroid cartilage
Vocal fold
Cricoid cartilage
Thyroid gland
Figure 22.3b
Cranial Bones
• Formed from eight large bones
• Paired bones include
• Temporal bones
• Parietal bones
• Unpaired bones include
• Frontal bone
• Occipital bone
• Sphenoid bone
• Ethmoid bone
© 2014 Pearson Education, Inc.
Parietal Bones and Sutures
• Parietal bones form superior and lateral parts of
skull
• Four sutures of the cranium
• Coronal suture—runs in the coronal plane
• Located where parietal bones meet the frontal
bone
• Squamous suture—occurs where each parietal
bone meets a temporal bone inferiorly
© 2014 Pearson Education, Inc.
Parietal bone
Frontal bone
Sphenoid bone
(greater wing)
Ethmoid bone
Squamous suture
Lacrimal bone
Lambdoid suture
Lacrimal fossa
Coronal suture
Occipital bone
Nasal bone
Temporal bone
Zygomatic
bone
Maxilla
Zygomatic process
Occipitomastoid suture
External acoustic meatus
Mastoid process
Styloid process
Alveolar
margins
Mandible
Mental
foramen
Mandibular condyle
Mandibular notch
Mandibular ramus
(a) External anatomy of the
right side of the skull
© 2014 Pearson Education, Inc.
Mandibular angle
Coronoid
process
Parietal Bones and Sutures
• Four sutures of the cranium (continued)
• Sagittal suture—occurs where right and left
parietal bones meet superiorly
• Lambdoid suture—occurs where the parietal
bones meet the occipital bone posteriorly
© 2014 Pearson Education, Inc.
The Skull— Posterior View
Sagittal suture
Parietal bone
Sutural bone
Lambdoid
suture
Occipital bone
Superior nuchal line
External occipital
protuberance
Inferior nuchal line
External occipital crest
© 2014 Pearson Education, Inc.
Occipital
condyle
Occipitomastoid
suture
Figure 7.5
Frontal Bone
• Forms the forehead and roofs of orbits
• Supraorbital margin—superior margin of
orbits
• Glabella—smooth part of frontal bone between
superciliary arches
• Frontal sinuses within frontal bone
© 2014 Pearson Education, Inc.
Frontal bone
Parietal bone
Squamous part
of frontal bone
Nasal bone
Sphenoid bone
(greater wing)
Temporal bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Infraorbital foramen
Maxilla
Mandible
Glabella
Frontonasal suture
Supraorbital foramen
(notch)
Supraorbital margin
Superior orbital fissure
Optic canal
Inferior orbital fissure
Middle nasal concha
Ethmoid
Perpendicular plate bone
Inferior nasal concha
Vomer
Mental
foramen
Mental
protuberance
(a) Anterior view of skull
© 2014 Pearson Education, Inc.
Figure 7.6a
Cranial cavity
Frontal
bone
Paranasal
sinuses
Frontal
sinus
Orbit
Orbit
Zygomatic
bone
Ethmoid
sinuses
Ethmoid
bone
Maxillary
sinus
Inferior
nasal
concha
Nasal
cavity
Oral
cavity
Fig. 7.3
© 2014 Pearson Education, Inc.
Maxilla
Vomer
Mandible
Occipital Bone
• Forms the posterior portion of the cranium and
cranial base
• Articulates with the temporal bones and parietal
bones
• Foramen magnum located at its base
© 2014 Pearson Education, Inc.
Parietal bone
Frontal bone
Sphenoid bone
(greater wing)
Ethmoid bone
Squamous suture
Lacrimal bone
Lambdoid suture
Lacrimal fossa
Coronal suture
Occipital bone
Nasal bone
Temporal bone
Zygomatic
bone
Maxilla
Zygomatic process
Occipitomastoid suture
External acoustic meatus
Mastoid process
Styloid process
Alveolar
margins
Mandible
Mental
foramen
Mandibular condyle
Mandibular notch
Mandibular ramus
(a) External anatomy of the
right side of the skull
© 2014 Pearson Education, Inc.
Mandibular angle
Coronoid
process
Inferior Aspect of the Skull
Maxilla
(palatine process)
Hard
palate
Palatine bone
(horizontal plate)
Zygomatic bone
Vomer
Temporal bone
(zygomatic process)
Mandibular fossa
Styloid process
Mastoid process
Temporal bone
(petrous part)
Basilar part of
the occipital bone
Occipital bone
Incisive fossa
Intermaxillary suture
Median palatine suture
Infraorbital foramen
Maxilla
Sphenoid bone
(greater wing)
Pterygoid process
Foramen ovale
Foramen spinosum
Foramen lacerum
Carotid canal
External acoustic meatus
Stylomastoid
foramen
Jugular foramen
Occipital condyle
Inferior nuchal line
Superior nuchal line
External occipital crest
External occipital
protuberance
Foramen magnum
(a) Inferior view of the skull (mandible removed)
© 2014 Pearson Education, Inc.
Figure 7.7a
Temporal Bones
• Lie inferior to parietal bones
• Specific regions of temporal bone
• Squamous, tymphanic, petrous, and mastoid
regions
• The mastoid process
• Site for neck muscle attachment
• Contains air sinuses
© 2014 Pearson Education, Inc.
Lateral Aspect of the Skull
Frontal bone
Sphenoid bone
(greater wing)
Coronal suture
Parietal bone
Ethmoid bone
Lacrimal bone
Squamous suture
Nasal bone
Temporal bone
Lacrimal fossa
Zygomatic
bone
Coronoid
process
Maxilla
Zygomatic process
Lambdoid suture
Occipital bone
External occipital
protuberance
Occipitomastoid
suture
Alveolar
margins
Mandible
Mental foramen
External acoustic
meatus
Mastoid process
Mandibular
condyle
Styloid
process
Mandibular
notch
Mandibular ramus
Mandibular angle
(b) Photograph of right side of skull
© 2014 Pearson Education, Inc.
Figure 7.4b
The Temporal Bone
External acoustic
meatus
Squamous
region
Mastoid
region
Zygomatic
process
Mastoid process
Mandibular
fossa
Styloid process
Tympanic
region
© 2014 Pearson Education, Inc.
Figure 7.8
The Sphenoid Bone
• Spans the width of the
cranial floor
• Resembles a butterfly or
bat
• Consists of a body and
three pairs of processes
Superior view
© 2014 Pearson Education, Inc.
Body of sphenoid
Lesser
wing
Superior
orbital
fissure
Greater
wing
Pterygoid
process
(b) Posterior view
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
The Ethmoid Bone
• Lies between nasal and sphenoid bones
• Forms most of the medial bony region between
the nasal cavity and orbits
• Cribriform plate—superior surface of the
ethmoid bone
• Contain olfactory foramina
• Crista galli—attachment for falx cerebri
• Perpendicular plate—forms superior part of
nasal septum
© 2014 Pearson Education, Inc.
Cranial cavity
Frontal
bone
Paranasal
sinuses
Frontal
sinus
Orbit
Orbit
Zygomatic
bone
Ethmoid
sinuses
Ethmoid
bone
Maxillary
sinus
Inferior
nasal
concha
Nasal
cavity
Oral
cavity
Maxilla
Vomer
Mandible
© 2014 Pearson Education, Inc.
The Ethmoid Bone
Crista galli
Olfactory
foramina
Orbital
plate
Cribriform
plate
Left
lateral
mass
Ethmoidal
air cells
Perpendicular
plate
© 2014 Pearson Education, Inc.
Middle
nasal concha
Figure 7.12
Facial Bones
• Unpaired bones
• Mandible and vomer
• Paired bones
• Maxillae
• Zygomatic bones
• Nasal bones
• Lacrimal bones
• Palatine bones
• Inferior nasal conchae
© 2014 Pearson Education, Inc.
Facial Bones
Frontal bone
Parietal bone
Squamous part
of frontal bone
Nasal bone
Sphenoid bone
(greater wing)
Temporal bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Infraorbital foramen
Maxilla
Mandible
Glabella
Frontonasal suture
Supraorbital foramen
(notch)
Supraorbital margin
Superior orbital fissure
Optic canal
Inferior orbital fissure
Middle nasal concha
Ethmoid
Perpendicular plate bone
Inferior nasal concha
Vomer
Mental
foramen
Mental
protuberance
(a) Anterior view of skull
© 2014 Pearson Education, Inc.
Figure 7.6a
Mandible
• The lower jawbone is the largest and strongest
facial bone
• Composed of two main parts
• Horizontal body
• Two upright rami
© 2014 Pearson Education, Inc.
Mandible
Temporomandibular
joint
Mandibular notch
Mandibular fossa
of temporal bone
Coronoid
process
Mandibular
condyle
Mandibular foramen
Alveolar
margin
Mental
foramen
Ramus
of
mandible
Mandibular
angle
Body of mandible
(a) Mandible, right lateral view
© 2014 Pearson Education, Inc.
Figure 7.13a
Maxillary Bones
• Articulate with all other facial bones except the
mandible
• Contain maxillary sinuses—largest paranasal
sinuses
• Forms part of the inferior orbital fissure
• Are the “keystone” bones of the face
© 2014 Pearson Education, Inc.
Maxillary Bones
Articulates with
frontal bone
Frontal process
Orbital surface
Zygomatic
process
(cut)
Infraorbital
foramen
Anterior nasal
spine
Alveolar
margin
(b) Maxilla, right lateral view
© 2014 Pearson Education, Inc.
Figure 7.13b
Cranial cavity
Frontal
bone
Paranasal
sinuses
Frontal
sinus
Orbit
Orbit
Zygomatic
bone
Ethmoid
sinuses
Ethmoid
bone
Maxillary
sinus
Inferior
nasal
concha
Nasal
cavity
Oral
cavity
Maxilla
Vomer
Mandible
© 2014 Pearson Education, Inc.
Inferior Aspect of the Skull
Maxilla
(palatine process)
Hard
palate
Palatine bone
(horizontal plate)
Zygomatic bone
Vomer
Temporal bone
(zygomatic process)
Mandibular fossa
Styloid process
Mastoid process
Temporal bone
(petrous part)
Basilar part of
the occipital bone
Occipital bone
Incisive fossa
Intermaxillary suture
Median palatine suture
Infraorbital foramen
Maxilla
Sphenoid bone
(greater wing)
Pterygoid process
Foramen ovale
Foramen spinosum
Foramen lacerum
Carotid canal
External acoustic meatus
Stylomastoid
foramen
Jugular foramen
Occipital condyle
Inferior nuchal line
Superior nuchal line
External occipital crest
External occipital
protuberance
Foramen magnum
(a) Inferior view of the skull (mandible removed)
© 2014 Pearson Education, Inc.
Figure 7.7a
Other Bones of the Face
• Zygomatic bones
• Form lateral wall of orbits
• Nasal bones
• Form bridge of nose
• Lacrimal bones
• Located in the medial orbital walls
• Palatine bones
• Complete the posterior part of the hard palate
© 2014 Pearson Education, Inc.
Frontal bone
Parietal bone
Squamous part
of frontal bone
Nasal bone
Sphenoid bone
(greater wing)
Temporal bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Infraorbital foramen
Maxilla
Mandible
Glabella
Frontonasal suture
Supraorbital foramen
(notch)
Supraorbital margin
Superior orbital fissure
Optic canal
Inferior orbital fissure
Middle nasal concha
Ethmoid
Perpendicular plate bone
Inferior nasal concha
Vomer
Mental
foramen
Mental
protuberance
(a) Anterior view of skull
© 2014 Pearson Education, Inc.
Figure 7.6a
Other Bones of the Face
• Vomer
• Forms the inferior part of the nasal septum
• Inferior nasal conchae
• Thin, curved bones that project medially form
the lateral walls of the nasal cavity
© 2014 Pearson Education, Inc.
Nasal Cavity
Frontal sinus
Superior, middle, and
inferior meatus
Superior
nasal concha
Middle
nasal concha
Ethmoid
bone
Inferior nasal concha
Nasal bone
Anterior nasal spine
Sphenoid
bone
Maxillary bone
(palatine process)
Sphenoid
sinus
Pterygoid
process
Palatine bone
(perpendicular
plate)
Palatine bone
(horizontal plate)
(a) Bones forming the left lateral wall of the nasal cavity
(nasal septum removed)
© 2014 Pearson Education, Inc.
Figure 7.14a
Nasal Septum
Ethmoid
bone
Sella turcica
Sphenoid sinus
Crista galli
Cribriform
plate
Frontal sinus
Nasal bone
Perpendicular
plate of
ethmoid bone
Septal
cartilage
Palatine bone
Hard
Palatine process
palate of maxilla
Vomer
Alveolar margin
of maxilla
(b) Nasal cavity with septum in place showing the contributions of the
ethmoid bone, the vomer, and septal cartilage
© 2014 Pearson Education, Inc.
Figure 7.14b
Paranasal Sinuses
• Air-filled sinuses are
located within
• Frontal bone
• Ethmoid bone
• Sphenoid bone
• Maxillary bones
• Lined with mucous
membrane
• Lighten the skull
© 2014 Pearson Education, Inc.
The Hyoid Bone
• Lies inferior to the
mandible
• The only bone with
no direct
articulation with
any other bone
• Acts as a movable
base for the
tongue
© 2014 Pearson Education, Inc.
Greater horn
Lesser horn
Body
Figure 7.17
The Vertebral Column
• Formed from 26 bones in the adult
• Transmits weight of trunk to the lower limbs
• Surrounds and protects the spinal cord
• Serves as attachment sites for muscles of the
neck and back
• Held in place by ligaments
• Anterior and posterior longitudinal ligaments
• Ligamentum flavum
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
The Vertebral Column
C1
2
3
4
5
6
7
T1
2
3
4
5
6
7
8
9
10
11
12
L1
2
3
4
5
© 2014 Pearson Education, Inc.
Anterior view
Cervical curvature
(concave)
7 vertebrae, C1 – C7
Spinous
process
Transverse
processes
Thoracic
curvature
(convex)
12 vertebrae,
T1 – T12
Intervertebral
discs
Intervertebral
foramen
Lumbar
curvature
(concave)
5 vertebrae, L1 – L5
Sacral
curvature
(convex) 5 fused
vertebrae sacrum
Coccyx
4 fused vertebrae
Right lateral view
Figure 7.18
Regions
• The Vertebral column has five major regions
• 7 cervical vertebrae of the neck region
• 12 thoracic vertebrae
• 5 lumbar vertebrae
• Sacrum—five fused bones
• Inferior to lumbar vertebrae
• Coccyx—inferior to sacrum
© 2014 Pearson Education, Inc.
Intervertebral Discs
• Are cushion-like pads
between vertebrae
• Composed of
• Nucleus pulposus
• Anulus fibrosus
© 2014 Pearson Education, Inc.
General Structure of Vertebrae
• Common structures to all
regions
• Body
• Vertebral arch
• Vertebral foramen
• Spinous process
• Transverse process
• Superior and inferior
articular processes
© 2014 Pearson Education, Inc.
Cervical Vertebrae
• Seven cervical vertebrae (C1–C7)—
smallest and lightest vertebrae
• C3–C7 are typical cervical vertebrae
• Body is wider laterally
• Spinous processes are short and
bifid (except C7)
• Vertebral foramen are large and
triangular
• Transverse processes contain
transverse foramina
© 2014 Pearson Education, Inc.
Cervical Vertebrae
Dens of axis
Transverse ligament
of atlas
C1 (atlas)
C2 (axis)
C3
Inferior articular
process
Bifid spinous
process
Transverse processes
C7 (vertebra
prominens)
(a) Cervical vertebrae
© 2014 Pearson Education, Inc.
Figure 7.21a
The Atlas
• C1 is termed the atlas
• Lacks a body and spinous process
• Supports the skull
• Superior articular facets receive the occipital
condyles
• Allows flexion and extension of neck
• Nodding the head “yes”
© 2014 Pearson Education, Inc.
The Axis
• Has a body and spinous process
• Dens (odontoid process) projects superiorly
• Formed from fusion of the body of the atlas
with the axis
• Acts as a pivot for rotation of the atlas and
skull
• Participates in rotating the head from side to
side to indicate ‘no’
© 2014 Pearson Education, Inc.
Thoracic Vertebrae (T1—T12)
• All articulate with ribs
• Have heart-shaped bodies
from the superior view
• Spinous processes are long
and point inferiorly
• Vertebral foramen are
circular
• Transverse processes
articulate with tubercles of
ribs
© 2014 Pearson Education, Inc.
Lumbar Vertebrae (L1—L5)
• Bodies are thick and
robust
• Transverse processes are
thin and tapered
• Spinous processes are
thick, blunt, and point
posteriorly
• Vertebral foramina are
triangular
© 2014 Pearson Education, Inc.
Sacrum (S1—S5)
• Shapes the posterior wall of pelvis
• Formed from 5 fused vertebrae
• Superior surface articulates with L5
• Inferiorly articulates with coccyx
Coccyx
• Is the “tailbone”
• Formed from 3—5 fused vertebrae
• Offers only slight support to pelvic organs
© 2014 Pearson Education, Inc.
Sacrum
Body
Sacral promontory
Ala
Sacral
canal
Body of
first
sacral
vertebra
Facet of superior
articular process
Auricular
surface
Transverse
ridges (sites
of vertebral
fusion)
Apex
Median
sacral
crest
Anterior
Posterior
sacral
sacral
foramina
foramina
Coccyx
(a) Anterior view
© 2014 Pearson Education, Inc.
Coccyx
Lateral
sacral
crest
Sacral
hiatus
(b) Posterior view
Figure 7.23
The Thoracic Cage
• Forms the framework of the chest
• Components
• Thoracic vertebrae—posteriorly
• Ribs—laterally
• Sternum and costal cartilage—anteriorly
• Protects thoracic organs
• Supports shoulder girdle and upper limbs
• Provides attachment sites for muscles
© 2014 Pearson Education, Inc.
The Thoracic Cage
Jugular notch
Clavicular notch
Manubrium
Sternal angle
Body
Xiphisternal
joint
Xiphoid
process
True
ribs
(1–7
Sternum
False
ribs
(8–12)
Intercostal
spaces
L1
Vertebra
Floating ribs (11, 12)
(a) Skeleton of the thoracic cage, anterior view
© 2014 Pearson Education, Inc.
Costal cartilage
Costal margin
Figure 7.24a
Sternum
• Formed from three sections
• Manubrium—superior section
• Articulates with medial end of clavicles
• Body—bulk of sternum
• Sides are notched at articulations for costal
cartilage of ribs 2–7
• Xiphoid process—inferior end of sternum
© 2014 Pearson Education, Inc.
Ribs
• All ribs attach to vertebral column posteriorly
• True ribs - superior seven pairs of ribs
• Attach to sternum by costal cartilage
• False ribs—inferior five pairs of ribs
• Ribs 11–12 are known as floating ribs
© 2014 Pearson Education, Inc.