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Chapter 8
*Lecture PowerPoint
The Skeletal System
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Introduction
• Many organs are named for their relationships to nearby
bones
• Understanding muscle movements also depends on
knowledge of skeletal anatomy
• Positions, shapes, and processes of bones can serve as
landmarks for clinicians
7-2
Overview of the Skeleton
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Skull
Pectoral
girdle
• Axial skeleton is
colored tan
Parietal bone
Frontal bone
Occipital bone
Maxilla
Mandible
Mandible
Clavicle
Clavicle
Scapula
Scapula
– Forms central
supporting axis of the
body
– Skull, vertebrae,
sternum, ribs,
sacrum, and hyoid
Sternum
Humerus
Thoracic Ribs
cage
Costal cartilages
Vertebral column
Pelvis
Hip bone
Sacrum
Ulna
Radius
Coccyx
• Appendicular
skeleton is colored
green
Carpus
Metacarpal
bones
Phalanges
–
–
–
–
Femur
Patella
Fibula
Tibia
Pectoral girdle
Upper extremity
Pelvic girdle
Lower extremity
Metatarsal bones
Tarsus
Phalanges
Figure 8.1
(a) Anterior view
8-3
(b) Posterior view
Bones of the Skeletal System
• Number of bones
– 206 in typical adult skeleton
• Varies with development of sesamoid bones (patella)
– Bones that form within some tendons in response to stress
• Varies with presence of sutural (wormian) bones in skull
– Extra bones that develop in skull suture lines
– 270 bones at birth, decreases with fusion
• Surface markings
– Ridges, spines, bumps, depressions, canals, pores, slits,
cavities, and articular surfaces
8-4
Anatomical Features of Bones
• Bone markings—ridges, spines, bumps,
depressions, canals, pores, slits, cavities, and
articular surfaces
• Ways to study bones
– Articulated skeleton: held together by wire
and rods, show spatial relationship to each
other
– Disarticulated bones: bones taken apart so
their surface features can be studied in more
detail
8-5
Anatomical Features of Bones
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Lines
Crest
Sinuses
Foramen
Fovea
Head
Meatus
Crest
Trochanters
Process
Condyle
Spine
Head
Tubercle
Alveolus
Foramen
Tuberosity
(a) Skull (lateral view)
Line
Process
Fossae
Spine
Epicondyles
Fossae
Condyles
(b) Scapula (posterior view)
Figure 8.2
(c) Femur
(posterior view)
(d) Humerus
(anterior view)
8-6
The Skull
• Expected Learning Outcomes
– Distinguish between cranial and facial bones.
– Name the bones of the skull and the anatomical
features.
– Identify the cavities in the skull and in some of its
individual bones.
– Name the principal sutures that join the bones of the
skull.
– Describe some bones that are closely associated with
the skull.
– Describe the development of the skull from infancy
through childhood.
8-7
The Skull
• Skull—the most complex part of the skeleton
• 22 bones joined together by sutures (immovable
joints)
• 8 cranial bones surround cranial cavity which
encloses the brain
• Other cavities—orbits, nasal cavity, oral (buccal)
cavity, middle- and inner-ear cavities, and paranasal
sinuses
8-8
The Skull
• Paranasal sinuses—frontal, sphenoid, ethmoid,
and maxillary
– Lined by mucous membrane and air-filled
– Lighten the anterior portion of the skull
– Act as chambers that add resonance to the voice
• Foramina—holes that allow passage for nerves and
blood vessels
• 14 facial bones support teeth, facial, and jaw
muscles
8-9
The Skull
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Cranial cavity
Ethmoid
air cells
Frontal bone
Ethmoid bone
Orbit
Superior
Nasal
conchae
Middle
Zygomatic
bone
Inferior
Maxilla
Maxillary
sinus
Vomer
Nasal cavity
Oral
cavity
Mandible
Figure 8.7
8-10
Cranial Bones
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Frontal lobe
Anterior cranial
fossa
Temporal lobe
Middle cranial
fossa
Cerebellum
Posterior cranial
fossa
Posterior cranial fossa
Middle cranial fossa
Figure 8.9
Anterior cranial fossa
(a) Superior view
(b) Lateral view
• Cranium (braincase)—protects the brain and associated sense organs
– Meninges separates brain from direct contact with bones—that is,
dura mater
– Swelling of the brain inside the rigid cranium may force tissue through
foramen magnum (large hole, exit for spinal cord) resulting in death
– Consists of two parts: calvaria (skullcap) and cranial base
8-11
Cranial Bones
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Figure 8.9
Frontal lobe
Anterior cranial
fossa
Temporal lobe
Middle cranial
fossa
Cerebellum
Posterior cranial
fossa
Posterior cranial fossa
Middle cranial fossa
Anterior cranial fossa
(a) Superior view
(b) Lateral view
• Base is divided into three basins that comprise the cranial floor
– Anterior cranial fossa holds the frontal lobe of the brain
– Middle cranial fossa holds the temporal lobes of the brain
– Posterior cranial fossa contains the cerebellum
• 8 cranial bones: 1 frontal, 2 parietal, 2 temporal, 1 occipital, 1
sphenoid, 1 ethmoid
8-12
The Frontal Bone
• Forms forehead and part of
the roof of the cranium
• Coronal suture—posterior
boundary of frontal bone
• Supraorbital margin forms
roof of the orbit
• Supraorbital foramen
provides passage for nerve,
artery, and vein
• Glabella—smooth area
above root of the nose
• Contains frontal sinus
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Frontal bone
Supraorbital
foramen
Glabella
Parietal bone
Coronal suture
Supraorbital
margin
Squamous suture
Temporal bone
Sphenoid bone
Lacrimal bone
Ethmoid bone
Nasal bone
Middle nasal
concha
Zygomatic bone
Inferior nasal
concha
Infraorbital foramen
Maxilla
Vomer
Mandible
Mental foramen
Mental protuberance
Figure 8.3
8-13
The Parietal Bones
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Coronal suture
Frontal bone
Parietal bone
Temporal lines
Lambdoid suture
Ethmoid bone
• Form most of cranial roof and
part of its lateral walls
Sphenoid bone
Nasal bone
Occipital bone
Lacrimal bone
Squamous suture
Zygomaticofacial foramen
Temporal bone
Infraorbital foramen
Zygomatic process
External acoustic meatus
Zygomatic bone
Maxilla
Mastoid process
Temporal process
Styloid process
Mandible
Mandibular condyle
Mental foramen
(a) Right lateral view
Figure 8.4a
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Anterior
Frontal bone
Coronal suture
• Bordered by four sutures
– Sagittal: between parietal
bones
– Coronal: at anterior margin
– Lambdoid: at posterior
margin
– Squamous: at lateral border
• Two temporal lines serve as
attachment of the temporalis
muscle
Parietal bone
Sagittal suture
Sutural bone
Parietal foramen
Lambdoid suture
Occipital bone
Posterior
Figure 8.6
8-14
The Temporal Bones
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Coronal suture
Frontal bone
Parietal bone
Temporal lines
Lambdoid suture
Ethmoid bone
• Lateral wall and part of floor
of cranial cavity
– Squamous part
Sphenoid bone
Nasal bone
Occipital bone
Lacrimal bone
Squamous suture
Zygomaticofacial foramen
Temporal bone
Infraorbital foramen
Zygomatic process
External acoustic meatus
Zygomatic bone
Maxilla
Mastoid process
• Encircled by squamous
suture
• Zygomatic process
• Mandibular fossa
Temporal process
Styloid process
Mandible
Mandibular condyle
Mental foramen
(a) Right lateral view
Figure 8.4a
– Tympanic part
• External auditory meatus
• Styloid process
8-15
The Temporal Bones
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Coronal suture
Frontal bone
Parietal bone
Temporal lines
Lambdoid suture
Ethmoid bone
Sphenoid bone
Nasal bone
Occipital bone
Lacrimal bone
Squamous suture
Zygomaticofacial foramen
Temporal bone
Infraorbital foramen
Zygomatic process
External acoustic meatus
Zygomatic bone
Maxilla
Mastoid process
Temporal process
Styloid process
Mandible
Mandibular condyle
Mental foramen
– Mastoid part
• Mastoid process
– Mastoiditis from ear
infection
• Mastoid notch
• Stylomastoid foramen
• Mastoid foramen
(a) Right lateral view
Figure 8.4a
8-16
The Temporal Bones
– Petrous part
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Diploe (spongy bone)
Frontal bone
Crista galli
Cribriform plate
of ethmoid bone
Cribriform foramina
Sphenoid bone
Optic foramen
Sella turcica
Foramen rotundum
Foramen ovale
Temporal bone
Foramen spinosum
Internal acoustic
meatus
Petrous part of
temporal bone
Jugular foramen
Parietal bone
Groove for
venous sinus
Foramen magnum
Occipital bone
Hypoglossal canal
(b) Superior view of cranial floor
Figure 8.5b
• Part of cranial floor
• Separates middle from
posterior cranial fossa
• Houses middle- and innerear cavities
• Receptors for hearing and
sense of balance
• Internal auditory
meatus—opening for CN
VII (vestibulocochlear
nerve)
• Carotid canal
• Jugular foramen
8-17
The Temporal Bones
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Squamous suture
Squamous part
Mastoid part
Zygomatic process
Mandibular fossa
Mastoid notch
Mastoid process
Styloid process
External acoustic
meatus
Tympanic part
(a) Lateral surface
Squamous suture
Squamous part
Petrous part
Zygomatic
process
Internal acoustic
meatus
Mastoid process
Styloid process
(b) Medial surface
Figure 8.10
8-18
The Occipital Bone
• Rear and base of skull
• Foramen magnum holds spinal
cord
• Basilar part, thick median plate
• Skull rests on atlas at occipital
condyles
– Condylar canal, posterior to
each occipital condyle
• Hypoglossal canal transmits
hypoglossal nerve (CN XII)
supplying tongue muscles
• External occipital
protuberance for nuchal
ligament
• Superior and inferior nuchal
lines mark neck muscles
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Incisive foramen
Palatine process
of maxilla
Intermaxillary suture
Zygomatic bone
Palatine bone
Zygomatic arch
Greater palatine foramen
Posterior nasal
aperture
Medial pterygoid plate
Lateral pterygoid plate
Vomer
Sphenoid bone
Foramen ovale
Mandibular fossa
Foramen spinosum
Foramen lacerum
Basilar part of
occipital bone
Carotid canal
Styloid process
External acoustic meatus
Occipital condyle
Stylomastoid foramen
Mastoid process
Mastoid notch
Temporal bone
Jugular foramen
Foramen magnum
Condylar canal
Mastoid foramen
Parietal bone
Lambdoid suture
Inferior nuchal line
External occipital
protuberance
Superior nuchal line
Occipital bone
(a) Inferior view
Figure 8.5a
8-19
The Sphenoid Bone
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Lesser wing
Dorsum sellae
Greater wing
Superior orbital
fissure
Foramen
rotundum
Body
Foramen ovale
Lateral pterygoid plate
Medial pterygoid plate
Pterygoid processes
(b) Posterior view
Figure 8.11b
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Diploe (spongy bone)
Frontal bone
Cribriform plate
of ethmoid bone
Crista galli
Cribriform foramina
• Body
• Greater wing
• Lesser wing
• Optic foramen
Sphenoid bone
Optic foramen
Foramen rotundum
Foramen ovale
Foramen spinosum
Internal acoustic
meatus
Jugular foramen
Sella turcica
Temporal bone
Petrous part of
temporal bone
Parietal bone
Foramen magnum
Groove for
venous sinus
Hypoglossal canal
Occipital bone
(b) Superior view of cranial floor
Figure 8.5b
• Anterior clinoid
processes
• Superior orbital
fissure
8-20
The Sphenoid Bone
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Optic foramen
Hypophyseal fossa
Lesser wing
Greater wing
Foramen rotundum
Sella turcica
Anterior clinoid
process
Foramen ovale
Foramen spinosum
Dorsum sellae
• Foramen
rotundum
• Foramen ovale
(a) Superior view
Figure 8.11a
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Diploe (spongy bone)
Frontal bone
Cribriform plate
of ethmoid bone
Crista galli
Cribriform foramina
Sphenoid bone
Optic foramen
Foramen rotundum
Foramen ovale
Foramen spinosum
Internal acoustic
meatus
Jugular foramen
Sella turcica
Temporal bone
Petrous part of
temporal bone
Parietal bone
Foramen magnum
Groove for
venous sinus
Hypoglossal canal
Occipital bone
Figure 8.5b
• Foramen lacerum
• Posterior nasal
apertures or
choanae
• Medial pterygoid
plate
• Lateral pterygoid
plate
• Sphenoid sinus
(b) Superior view of cranial floor
8-21
The Sphenoid Bone
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Coronal suture
Frontal bone
Incisive foramen
Parietal bone
Palatine process
of maxilla
Sphenoid sinus
Squamous suture
Frontal sinus
Intermaxillary suture
Zygomatic bone
Crista galli
Palatine bone
Zygomatic arch
Cribriform plate of
ethmoid bone
Posterior nasal
aperture
Perpendicular plate
of ethmoid bone
Vomer
Occipital bone
Temporal bone
Sella turcica
Lambdoid suture
Internal acoustic meatus
Jugular foramen
Hypoglossal canal
Styloid process
Mandibular foramen
Greater palatine foramen
Medial pterygoid plate
Lateral pterygoid plate
Nasal bone
Sphenoid bone
Foramen ovale
Vomer
Mandibular fossa
Palatine process
of maxilla
Styloid process
Foramen spinosum
Foramen lacerum
Basilar part of
occipital bone
Carotid canal
Maxilla
External acoustic meatus
Occipital condyle
(b) Median section
Stylomastoid foramen
Palatine bone
Mandible
Mastoid process
Mastoid notch
Mental spines
Temporal bone
Jugular foramen
Foramen magnum
Condylar canal
Mastoid foramen
Parietal bone
Lambdoid suture
Inferior nuchal line
Figure 8.4b
External occipital
protuberance
Superior nuchal line
Occipital bone
(a) Inferior view
Figure 8.5a
Sphenoid sinus
8-22
The Ethmoid Bone
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Supraorbital foramen
Roof of
orbit
Medial
wall
Orbital plate of frontal bone
Lesser wing of sphenoid bone
Zygomatic process
of frontal bone
Optic foramen
Greater wing of
sphenoid bone
Orbital plate of ethmoid bone
Orbital surface of
zygomatic bone
Lacrimal bone
Superior orbital fissure
Frontal process of maxilla
Inferior orbital
fissure
Orbital process of
palatine bone
Floor of
orbit
Lateral wall
of orbit
Infraorbital
foramen
Orbital surface of
maxilla
Figure 8.14
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Cribriform
plate
Cribriform
foramina
Orbital plate
Ethmoidal
cells
Perpendicular
plate
Crista galli
Superior
nasal concha
Middle
nasal concha
• Anterior cranial bones
located between the
eyes
• Contributes to medial
wall of orbit
• Lateral walls and roof of
nasal cavity, and nasal
septum
• Three major portions of
this porous, delicate
bone
• Perpendicular plate
forms superior two-thirds
of nasal septum
Figure 8.12
8-23
The Ethmoid Bone
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Coronal suture
Frontal bone
Crista galli
Parietal bone
Frontal bone
Cribriform plate
Sphenoid sinus
Frontal sinus
Cribriform foramina
Squamous suture
Frontal sinus
Nasal bone
Sella turcica
Crista galli
Nasal conchae:
Occipital bone
Temporal bone
Sella turcica
Lambdoid suture
Internal acoustic meatus
Jugular foramen
Hypoglossal canal
Cribriform plate of
ethmoid bone
Superior
Perpendicular plate Sphenoid sinus
of ethmoid bone
Inferior
Nasal bone
Middle
Nasal cartilages
Occipital bone
Vomer
Palatine process
of maxilla
Styloid process
Mandibular foramen
Maxilla
Palatine bone
Mandible
Figure 8.4b
Mental spines
Sphenoid bone
Anterior nasal spine
Palatine bone
Incisive foramen
Lacrimal bone
Lip
Maxilla
Incisor
(b) Median section
Figure 8.13
• Cribriform plate—forms roof of nasal cavity
– Crista galli: attachment point for meninges
– Cribriform (olfactory) foramina
• Labyrinth—large mass on each side of perpendicular plate
– Ethmoidal cells make up the ethmoid sinus
– Orbital plate
8-24
The Ethmoid Bone
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Coronal suture
Frontal bone
Crista galli
Parietal bone
Frontal bone
Cribriform plate
Sphenoid sinus
Frontal sinus
Squamous suture
Cribriform foramina
Frontal sinus
Nasal bone
Sella turcica
Crista galli
Nasal conchae:
Occipital bone
Temporal bone
Sella turcica
Lambdoid suture
Internal acoustic meatus
Jugular foramen
Hypoglossal canal
Cribriform plate of
ethmoid bone
Superior
Perpendicular plate Sphenoid sinus
of ethmoid bone
Inferior
Styloid process
Palatine process
of maxilla
Nasal bone
Middle
Nasal cartilages
Occipital bone
Vomer
Mandibular foramen
Maxilla
Palatine bone
Mandible
Mental spines
(b) Median section
Figure 8.4b
Sphenoid bone
Anterior nasal spine
Palatine bone
Incisive foramen
Lacrimal bone
Lip
Maxilla
Incisor
Figure 8.13
• Superior and middle nasal conchae—scroll-like plates project
into the nasal fossa
• Inferior nasal concha—separate bone
• Three chonchae occupy most of the nasal cavity, create
turbulence of airflow, humidify air before it reaches the lungs 8-25
Facial Bones
• Facial bones (14)—those that have no direct contact with
the brain or meninges
–
–
–
–
Support the teeth
Give shape and individuality to the face
Form part of the orbital and nasal cavities
Provide attachments for muscles of facial expression and
mastication
2 maxillae
2 palatine bones
2 zygomatic bones
2 lacrimal bones
2 nasal bones
2 inferior nasal conchae
1 vomer
1 mandible
8-26
The Maxillae
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Frontal bone
Supraorbital
foramen
Glabella
Parietal bone
Coronal suture
Supraorbital
margin
Squamous suture
• Largest facial bones
• Forms upper jaw and meets at
median intermaxillary suture
– Alveolar processes: bony points
between teeth
– Alveolus: sockets that hold teeth
Temporal bone
Sphenoid bone
Lacrimal bone
Ethmoid bone
Nasal bone
Middle nasal
concha
Zygomatic bone
Inferior nasal
concha
Infraorbital foramen
Maxilla
Vomer
Figure 8.3
Mandible
Mental foramen
Mental protuberance
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Incisive foramen
Palatine process
of maxilla
Zygomatic bone
Intermaxillary suture
Zygomatic arch
Palatine bone
Greater palatine foramen
Medial pterygoid plate
Lateral pterygoid plate
Posterior nasal
aperture
Vomer
Sphenoid bone
Mandibular fossa
Foramen ovale
Foramen spinosum
Foramen lacerum
Basilar part of
occipital bone
Carotid canal
Stylomastoid foramen
Jugular foramen
Foramen magnum
Mastoid foramen
Styloid process
External acoustic meatus
Occipital condyle
Mastoid process
Mastoid notch
Temporal bone
Condylar canal
Parietal bone
Lambdoid suture
Inferior nuchal line
External occipital
protuberance
Superior nuchal line
Occipital bone
Figure 8.5a
(a) Inferior view
8-27
The Maxillae
Cont.
• Forms inferomedial wall of orbit
– Infraorbital foramen
– Inferior orbital fissure
• Forms most of the hard palate
–
–
–
–
–
Palatine process
Palate: forms roof of mouth and floor of nasal cavity
Incisive foramen
Palate allows us to chew while breathing
Cleft palate and cleft lip
8-28
The Maxillae
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Sphenoid
sinus
Frontal
sinus
Ethmoid
sinus
Maxillary
sinus
Figure 8.8
Figure 8.8
• Maxillary sinus fills maxillae bone
• Larger in volume than frontal, sphenoid,
and ethmoid sinuses
8-29
The Palatine Bones
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• L-shaped bone
Crista galli
• Form the posterior
portion of the hard
palate
Frontal sinus
Cribriform foramina
Nasal bone
Sella turcica
Nasal conchae:
Superior
Middle
Sphenoid sinus
Inferior
Nasal cartilages
Occipital bone
Sphenoid bone
• Part of lateral nasal
cavity wall
• Part of the orbital
floor
Frontal bone
Cribriform plate
Anterior nasal spine
Palatine bone
Incisive foramen
Lacrimal bone
Lip
Maxilla
Incisor
Figure 8.13
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Supraorbital foramen
Roof of
orbit
Orbital plate of frontal bone
Lesser wing of sphenoid bone
Zygomatic process
of frontal bone
Greater wing of
sphenoid bone
Optic foramen
• Greater palatine
foramina
Orbital surface of
zygomatic bone
Orbital plate of ethmoid bone
Medial
wall
Lacrimal bone
Superior orbital fissure
Frontal process of maxilla
Inferior orbital
fissure
Orbital process of
palatine bone
Floor of
orbit
Lateral wall
of orbit
Infraorbital
foramen
Orbital surface of
maxilla
Figure 8.14
8-30
The Zygomatic Bones
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Coronal suture
• Forms angles of the
cheekbones and part of
lateral orbital wall
Frontal bone
Parietal bone
Temporal lines
Lambdoid suture
Ethmoid bone
Sphenoid bone
Nasal bone
Occipital bone
• Zygomaticofacial
foramen
Lacrimal bone
Squamous suture
Zygomaticofacial foramen
Temporal bone
Infraorbital foramen
Zygomatic process
External acoustic meatus
Zygomatic bone
Maxilla
Mastoid process
Temporal process
Styloid process
Mandible
Mandibular condyle
Mental foramen
(a) Right lateral view
Figure 8.4a
• Zygomatic arch is
formed from temporal
process of zygomatic
bone and zygomatic
process of temporal
bone
8-31
The Lacrimal Bones
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• Form part of medial
wall of each orbit
Coronal suture
Frontal bone
Parietal bone
Temporal lines
Lambdoid suture
Ethmoid bone
Sphenoid bone
Nasal bone
Occipital bone
Lacrimal bone
Squamous suture
Zygomaticofacial foramen
Temporal bone
Infraorbital foramen
Zygomatic process
External acoustic meatus
Zygomatic bone
Maxilla
Mastoid process
Temporal process
Styloid process
Mandible
Mandibular condyle
Mental foramen
(a) Right lateral view
Figure 8.4a
• Smallest bone of skull
• Lacrimal fossa
houses lacrimal sac
in life
– Tears collect in
lacrimal sac and drain
into nasal cavity
8-32
The Nasal Bones
• Forms bridge of nose
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Frontal bone
• Supports cartilages
that shape lower
portion of the nose
• Often fractured by
blow to the nose
Supraorbital
foramen
Glabella
Parietal bone
Coronal suture
Supraorbital
margin
Squamous suture
Temporal bone
Sphenoid bone
Lacrimal bone
Ethmoid bone
Nasal bone
Middle nasal
concha
Zygomatic bone
Inferior nasal
concha
Infraorbital foramen
Maxilla
Vomer
Mandible
Mental foramen
Mental protuberance
Figure 8.3
8-33
The Inferior Nasal Conchae
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Three conchae in the
nasal cavity
– Superior and middle are
part of the ethmoid
bone
Crista galli
Frontal bone
Cribriform plate
Frontal sinus
Cribriform foramina
Nasal bone
Sella turcica
Nasal conchae:
Superior
Middle
Sphenoid sinus
Inferior
Nasal cartilages
Occipital bone
Sphenoid bone
Anterior nasal spine
• Inferior nasal concha
is a separate bone
Palatine bone
Incisive foramen
Lacrimal bone
Lip
Maxilla
Incisor
Figure 8.13
– Largest of the three
8-34
The Vomer
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Coronal suture
Frontal bone
Parietal bone
Sphenoid sinus
Squamous suture
Frontal sinus
Crista galli
Occipital bone
Cribriform plate of
ethmoid bone
Temporal bone
Sella turcica
Lambdoid suture
Internal acoustic meatus
Jugular foramen
Hypoglossal canal
Perpendicular plate
of ethmoid bone
Nasal bone
Vomer
Palatine process
of maxilla
Styloid process
Mandibular foramen
Maxilla
Palatine bone
Mandible
Mental spines
(b) Median section
Figure 8.4b
• Inferior half of the
nasal septum
– Superior half formed
by perpendicular
plate of ethmoid
• Supports cartilage
that forms the
anterior part of the
nasal septum
8-35
The Mandible
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Strongest bone of the skull
– Only bone of skull that moves
noticeably
– Supports lower teeth
• Provides attachments for
muscles of facial expression
and mastication
Figure 8.5a
Incisive foramen
Palatine process
of maxilla
Intermaxillary suture
Zygomatic bone
Palatine bone
Zygomatic arch
Greater palatine foramen
Posterior nasal
aperture
Medial pterygoid plate
Lateral pterygoid plate
Vomer
Sphenoid bone
Foramen ovale
Mandibular fossa
Foramen spinosum
Foramen lacerum
Basilar part of
occipital bone
Carotid canal
Styloid process
External acoustic meatus
Occipital condyle
Stylomastoid foramen
Mastoid process
Mastoid notch
Temporal bone
Jugular foramen
Foramen magnum
Condylar canal
Mastoid foramen
Parietal bone
Lambdoid suture
Inferior nuchal line
External occipital
protuberance
Superior nuchal line
• Mental symphysis—
median cartilaginous joint in
fetus
– Develops as two separate
bones in fetus
– Ossifies in early childhood
Occipital bone
(a) Inferior view
Mandibular condyles
Condylar process
Coronoid process
Mandibular notch
Mandibular foramen
Ramus
Alveolar process
Mental foramen
Mental protuberance
Figure 8.15
Angle
Body
8-36
The Mandible
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Mental protuberance—
point of chin
• Two major parts on each
side
– Body: supports teeth
– Ramus: articulates with
cranium
• Angle—where body and
ramus meet
• Alveolar processes
between teeth
• Mental foramen—permits
passage of nerves and BVs
• Mental spines
Figure 8.5a
Incisive foramen
Palatine process
of maxilla
Intermaxillary suture
Zygomatic bone
Palatine bone
Zygomatic arch
Greater palatine foramen
Posterior nasal
aperture
Medial pterygoid plate
Lateral pterygoid plate
Vomer
Sphenoid bone
Foramen ovale
Mandibular fossa
Foramen spinosum
Foramen lacerum
Basilar part of
occipital bone
Carotid canal
Styloid process
External acoustic meatus
Occipital condyle
Stylomastoid foramen
Mastoid process
Mastoid notch
Temporal bone
Jugular foramen
Foramen magnum
Condylar canal
Mastoid foramen
Parietal bone
Lambdoid suture
Inferior nuchal line
External occipital
protuberance
Superior nuchal line
Occipital bone
(a) Inferior view
Mandibular condyles
Condylar process
Coronoid process
Mandibular notch
Mandibular foramen
Ramus
Alveolar process
Mental foramen
Mental protuberance
Figure 8.15
Angle
Body
8-37
The Mandible
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Mandibular condyles
Condylar process
Coronoid process
Mandibular notch
Mandibular foramen
Ramus
Alveolar process
Mental foramen
• Condylar process bears the
mandibular condyle—oval
knob that articulates with the
mandibular fossa of the
temporal bone forming the
hinge temporomandibular
joint (TMJ)
• Coronoid process—point of
insertion of temporalis muscle
Mental protuberance
Angle
Body
Figure 8.15
• Mandibular notch
• Mandibular foramen—BVs,
nerves supply lower teeth
8-38
Bones Associated with the Skull
• Auditory ossicles
– Three in each middle-ear cavity
– Malleus, incus, and stapes
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Hyoid bone
– Slender U-shaped bone
between the chin and larynx
– Does not articulate with any
other bone
– Suspended from styloid
process of skull by muscle and
ligament
– Body and greater and lesser
horns (cornua)
– Fractured hyoid bone is
evidence of strangulation
Styloid process
Stylohyoid muscle
Hyoid
Larynx
Lesser horn
Greater horn
Body
Figure 8.16
8-39
The Skull in Infancy and Childhood
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Coronal
suture
Frontal
bone
Parietal bone
• Fontanels—spaces between
unfused bones
– Filled with fibrous membrane
– Allow shifting of bones during
birth and growth of brain
– Anterior, posterior,
sphenoid (anterolateral), and
mastoid (posterolateral)
fontanels
Sphenoid
fontanel
Lambdoid
suture
Nasal
bone
Squamous
suture
Maxilla
Occipital bone
Zygomatic
bone
Mastoid
fontanel
Temporal bone
Mandible
Sphenoid
bone
(a) Lateral view
Frontal bone
• Two frontal bones fuse by age
6 (metopic suture)
Anterior fontanel
Sagittal suture
Parietal
bone
• Skull reaches adult size by 8
or 9 years of age
Posterior fontanel
(b) Superior view
Figure 8.17
8-40
The Vertebral Column
and Thoracic Cage
• Expected Learning Outcomes
– Describe the general features of the vertebral column
and those of a typical vertebra.
– Describe the structure of the intervertebral discs and
their relationship to the vertebrae.
– Describe the special features of vertebrae in different
regions of the vertebral column, and discuss the
functional significance of the regional differences.
– Describe the anatomy of the sternum and ribs and
how the ribs articulate with the thoracic vertebrae.
8-41
General Features of the
Vertebral Column
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Anterior view
• Functions
–
–
–
–
Supports the skull and trunk
Allows for their movement
Protects the spinal cord
Absorbs stress of walking,
running, and lifting
– Provides attachments for
limbs, thoracic cage, and
postural muscles
Posterior view
Atlas (C1)
Axis (C2)
Cervical vertebrae
C7
T1
Thoracic vertebrae
T12
L1
• 33 vertebrae with
intervertebral discs of
fibrocartilage between
most of them
Lumbar vertebrae
L5
S1
Sacrum
S5
Coccyx
Figure 8.18
Coccyx
8-42
General Features of
the Vertebral Column
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Anterior view
• Adult vertebral column
averages 71 cm (28 in.)
long
– Intervertebral discs
account for about onequarter of its length
– Person is 1% shorter when
in bed
– Compression squeezes
water out during the day
and absorbs water when
compression is removed
during sleep
Posterior view
Atlas (C1)
Axis (C2)
Cervical vertebrae
C7
T1
Thoracic vertebrae
T12
L1
Lumbar vertebrae
L5
S1
Sacrum
S5
Coccyx
Figure 8.18
Coccyx
8-43
General Features of
the Vertebral Column
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Anterior view
• Five vertebral groups
–
–
–
–
7 cervical in the neck
12 thoracic in the chest
5 lumbar in lower back
5 fused sacral at base
of spine
– 4 fused coccygeal
• Variations in number of
lumbar and sacral
vertebrae occur in 1 in
20 people
Posterior view
Atlas (C1)
Axis (C2)
Cervical vertebrae
C7
T1
Thoracic vertebrae
T12
L1
Lumbar vertebrae
L5
S1
Sacrum
S5
Coccyx
Figure 8.18
Coccyx
8-44
General Features of
the Vertebral Column
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Spine exhibits one
continuous C-shaped
curve at birth
• Known as primary
curvature
Figure 8.20
© The McGraw-Hill Companies, Inc./Bob Coyle, photographer
8-45
General Features of
the Vertebral Column
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
C1
Cervical curvature
C7
T1
Thoracic curvature
T12
L1
• S-shaped vertebral column
with four normal
curvatures
– Cervical
– Thoracic
– Lumbar
– Pelvic
Lumbar curvature
L5
S1
Pelvic curvature
Figure 8.19
8-46
General Features of
the Vertebral Column
• Primary curvatures—present at birth
– Thoracic and pelvic
• Secondary curvatures—develop later
– Cervical and lumbar
– Lifting head as it begins to crawl develops cervical
curvature
– Walking upright develops lumbar curvature
8-47
Abnormal Spinal Curvatures
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• From disease, paralysis of trunk
muscles, poor posture,
pregnancy, or congenital defect
• Scoliosis—abnormal lateral
curvature
(a) Scoliosis
Key
(b) Kyphosis
(“hunchback”)
Normal
Pathological
Figure 8.21
(c) Lordosis
(“hunchback”)
–
–
–
–
Most common
Usually in thoracic region
Particularly of adolescent girls
Developmental abnormality in
which the body and arch fail to
develop on one side of the
vertebrae
8-48
Abnormal Spinal Curvatures
• Kyphosis (hunchback)—exaggerated thoracic
curvature
– Usually from osteoporosis, also osteomalacia or spinal
tuberculosis, or wrestling or weight lifting in young boys
• Lordosis (swayback)—exaggerated lumbar
curvature
– From pregnancy or obesity
8-49
General Structure of Vertebra
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Posterior
• Body (centrum)
– Mass of spongy bone that
contains red bone marrow
– Covered with thin shell of
compact bone
– Weight-bearing portion
– Rough superior and inferior
surfaces provide firm
attachment for
intervertebral discs
• Vertebral foramina
– Collectively form vertebral
canal for spinal cord
Spinous process
Lamina
Superior articular
facet
Vertebral
arch
Transverse
process
Pedicle
Vertebral foramen
Body
Anterior
(a) 2nd lumbar vertebra (L2)
Nucleus pulposus
Anulus fibrosus
(b) Intervertebral disc
Figure 8.22a,b
8-50
General Structure of Vertebra
• Vertebral arch
– Composed of two parts on each side
– Pedicle: pillarlike and lamina: platelike
• Spinous process
– Projection extending from the apex of arch
– Extends posteriorly and downward
• Transverse process
– Extends laterally from point where pedicel and lamina
meet
• Superior articular processes
– Project upward from one vertebra and meets inferior
articular processes from the vertebra above
• Facets
– Flat articular surfaces covered with hyaline cartilage
8-51
General Structure of Vertebra
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Intervertebral foramen
Superior articular
process of L1
Inferior vertebral
notch of L1
L1
Intervertebral
foramen
Superior vertebral
notch of L2
L2
Spinous process
Intervertebral disc
L3
Inferior articular
process of L3
(b) Left lateral view
Figure 8.23b
– When two vertebrae are
joined they exhibit an
opening between their
pedicles
– Passageway for spinal
nerves
– Inferior vertebral notch
in the pedicle of the
upper vertebra
– Superior vertebral
notch in the pedicle of
the lower vertebra
8-52
General Structure of Vertebra
• Intervertebral discs (23)
– First one between C2 and C3
– Last one between L5 and sacrum
– Pad consisting of:
• Nucleus pulposus—inner gelatinous mass
• Anulus fibrosus—outer ring of fibrocartilage
–
–
–
–
Bind vertebrae together
Support weight of the body
Absorb shock
Herniated disc (“ruptured” or “slipped” disc) puts painful
pressure on spinal nerve or spinal cord
8-53
The Cervical Vertebrae
• Cervical vertebrae—atlas (C1)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Transverse
process
L2
Body (centrum)
Intervertebral disc
Inferior articular
process of L2
Superior articular
process of L3
L3
Lamina
(a) Posterior (dorsal) view
Figure 8.23a
– Supports the head
– Has no body
– Delicate ring surrounding a
large vertebral foramen
– Lateral masses with superior
articular facets
• Articulates with occipital
condyles
• Allows nodding motion of
skull gesturing “yes”
– Inferior articular facets
articulate with C2
– Anterior and posterior arches
– Anterior and posterior
tubercles
8-54
The Cervical Vertebrae
• Cervical vertebrae—axis (C2)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Dens (odontoid process)
Superior articular facet
Transverse foramen
Transverse process
Inferior articular process
Lamina
Spinous process
(b) Axis
Figure 8.24b
– Allows rotation of the head
gesturing “no”
– Dens or odontoid process—
prominent knob on its
anterosuperior side
Body
• Forms as an independent
ossification center during
first year of life
• Fuses with axis by age 3 to 6
Pedicle
years
• Projects into vertebral
foramen of the atlas
• Held in place by a
transverse ligament
– Atlanto–occipital joint:
between atlas and cranium
– Atlantoaxial joint: between
atlas and axis
8-55
Atlas and Axis Articulation
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Axis of rotation
Dens
Atlas
Transverse
ligament
Axis
Figure 8.24c
(c) Atlantoaxial joint
8-56
The Cervical Vertebrae
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Superior views
Lateral views
Spinous process
Lamina
Superior articular facet
Transverse foramen
Transverse process
Body
Figure 8.25a
Spinous process
(a) Cervical vertebrae
Inferior articular process
•
•
•
•
C1 to C7 are smallest and lightest vertebrae, other than the coccygeals
Bifid or forked spinous processes in C2 to C6
Small body and larger vertebral foramen
Transverse foramen in each short transverse process
– Provides passage and protection for vertebral arteries (supply blood to
brain) and vertebral veins (drain blood from various neck structures)
– Transverse foramen only found in cervical vertebrae
• C7 vertebra prominens—spinous process not bifid and especially long
– Prominent bump on lower back of neck; convenient landmark for
counting vertebrae
8-57
The Thoracic Vertebrae
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Spinous process
Lamina
Transverse costal facet
Superior articular facet
Transverse process
Superior costal facet
Figure 8.25b
Transverse costal facet
Inferior costal facet
Body
Inferior articular facet
(b) Thoracic vertebrae
Spinous process
• 12 thoracic vertebrae (T1–T12)
– Corresponds to the 12 pairs of ribs attached to them
• Spinous processes pointed and angled sharply downward
• Larger body than cervical, but smaller than lumbar
• Costal facets for attachment of ribs
– On body as small, smooth, slightly concave spots
• Transverse costal facets at end of each transverse process T1–T10
– Provide second point of articulation for ribs 1–10
• Inferior and superior costal facets on vertebral body
– In most cases, ribs insert between the two vertebra
8-58
The Lumbar Vertebrae
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Spinous process
Superior articular facet
Superior articular process
Figure 8.25c
Transverse process
Pedicle
Body
Spinous process
(c) Lumbar vertebrae
Inferior articular facet
• Five lumbar vertebrae (L1–L5)
• Thick, stout body
• Blunt, squarish spinous process
• Superior articular processes face medially
– Lumbar region resistant to twisting movements
8-59
The Sacrum
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Superior articular
process
Sacral
promontory
Ala
S1
S2
Transverse lines
S3
Anterior sacral
foramina
S4
S5
Coccyx
Co2 Co1
Co3
Co4
(a) Anterior view
Figure 8.26a
• Sacrum—bony plate that forms
posterior wall of pelvic cavity
• Once considered seat of the
soul
• In children, five separate sacral
vertebrae (S1–S5)
• Begin fusion around age 16
and complete fusion by age 26
• Anterior surface
– Smooth and concave
– Four transverse lines indicate
line of fusion of vertebrae
– Four pairs of large anterior
sacral (pelvic) foramina
• Allow for passage of nerves
and arteries into pelvic
organs
• Sacral promontory on S1
supports L5
8-60
•
•
The Sacrum
Posterior surface very rough
Median sacral crest
–
•
Lateral sacral crest
–
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Superior articular
process
–
Sacral canal
•
Auricular
surface
•
Lateral sacral
crest
Posterior sacral
foramina
Sacral hiatus
Horn
Transverse
process
Coccyx
(b) Posterior view
Figure 8.26b
•
•
Four pairs of openings for spinal
nerves that supply gluteal region and
lower limbs
Sacral canal runs through
sacrum and ends as sacral
hiatus
–
•
Less prominent, and on either side of
median sacral crest
Formed from the fusion of the
transverse processes
Posterior sacral foramina
–
Median
sacral crest
Formed from fusion of spinous
processes
Contains spinal nerve roots
Auricular surface is part of
sacroiliac (SI) joint formed with
hip bone
Superior articular processes on
S1; articulates with L5
Alae—pair of large, rough,
winglike extensions lateral to the
superior articular processes
8-61
The Coccyx
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Superior articular
process
Sacral canal
Median
sacral crest
Auricular
surface
Lateral sacral
crest
Posterior sacral
foramina
Sacral hiatus
Horn
Transverse
process
Coccyx
(b) Posterior view
Figure 8.26b
• Coccyx—usually consists
of four small vertebrae
(Co1–Co4); sometimes five
• Fuse into a single,
triangular bone by age 20 to
30
• Horns (cornua) on Co1
– Serve as attachment points
for ligaments that bind the
coccyx to the sacrum
• Fractured during difficult
childbirth or by hard fall on
buttocks
• Provide attachment for
muscles of the pelvic floor
8-62
The Thoracic Cage
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Sternoclavicular joint
Sternum:
Acromioclavicular joint
T1
1
Pectoral girdle:
Clavicle
Scapula
Suprasternal notch
Clavicular notch
Manubrium
2
Angle
3
Body
4
True ribs (1–7)
5
Xiphoid process
6
7
Costal cartilages
11
8
False ribs (8–12)
Floating ribs
(11–12)
12
9
10
T12
L1
Costal margin
Figure 8.27
• Consists of thoracic
vertebrae, sternum, ribs
• Forms conical enclosure for
lungs and heart
• Provides attachment for
pectoral girdle and upper
limbs
• Broad base and narrower
apex
• Rhythmically expanded by
respiratory muscles to draw
air into lungs
• Costal margin—inferior
border of thoracic cage
formed by downward arc of
ribs
• Protect thoracic organs, but
also spleen, most of liver,
and to some extent the
8-63
kidneys
The Sternum
• Sternum (breastbone)—bony plate anterior to the heart
• Divided into three regions
– Manubrium
•
•
•
•
Broad superior portion
Suprasternal (jugular) notch medially
Clavicular notches—articulate with clavicle
Ribs attach along scalloped lateral margins
– Body (gladiolus)
• Longest part of sternum
• Sternal angle—point where body joins manubrium
• Ribs attach along scalloped lateral margins
– Xiphoid
• Inferior end of sternum
• Attachment for some abdominal muscles
• In cardiopulmonary resuscitation, improperly performed chest
compressions can drive xiphoid process into the liver and cause a
8-64
fatal hemorrhage
The Ribs
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Tubercle
Neck
Head
Superior Inferior
Angle
Articular facet
for transverse
process
Articular facets
for vertebral bodies
Costal groove
Shaft
Figure 8.28b
(b) Ribs 2–10
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Superior
articular
facet
Transverse
costal facet
for rib 6
Tubercle
Superior
costal
facet
for rib 6
Neck
T6
(b) Superior view
Rib 6
Head
Figure 8.29b
• 12 pairs of ribs
– No difference between sexes
– Posterior (proximal) end
attached to vertebral column
– Anterior (distal) ends
mostly attached to the
sternum
– Costal cartilages composed
of hyaline cartilage attach
anterior ends to sternum
• Head—portion of rib that
articulates with thoracic
vertebrae
– Superior articular facet
– Inferior articular facet
8-65
The Ribs
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Tubercle
Neck
Head
Superior Inferior
Angle
Articular facet
for transverse
process
Articular facets
for vertebral bodies
Costal groove
Shaft
Figure 8.28b
(b) Ribs 2–10
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Superior
articular
facet
Transverse
costal facet
for rib 6
Tubercle
Superior
costal
facet
for rib 6
Neck
T6
(b) Superior view
Rib 6
Head
Figure 8.29b
• Neck—narrow portion
distal to the head
• Tubercle—wider rough
area distal to the neck
– Articulates with
transverse costal facet
of vertebra
• Angle—lateral curve of
rib
• Shaft—long, gentle
sloping, bladelike portion
of rib
– Costal groove on inferior
margin of shaft
8-66
The Ribs
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Inferior costal
facet of T5
Vertebral
body T5
Superior articular
facet of rib 6
Vertebral
body T6
Inferior articular
facet of rib 6
Superior costal
facet of T6
Rib 6
(a) Anterior view
Superior
articular
facet
Transverse
costal facet
for rib 6
Tubercle
Figure 8.29
Superior
costal
facet
for rib 6
T6
Neck
Head
Rib 6
8-67
(b) Superior view
The Ribs
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Sternoclavicular joint
Sternum:
Acromioclavicular joint
T1
1
Pectoral girdle:
Clavicle
Scapula
Suprasternal notch
Clavicular notch
Manubrium
2
Angle
3
Body
4
True ribs (1–7)
5
Xiphoid process
6
7
Costal cartilages
11
8
False ribs (8–12)
Floating ribs
(11–12)
12
9
10
T12
L1
Costal margin
Figure 8.27
8-68
The Ribs
• True ribs (ribs 1–7)
– Each has own costal cartilage connecting to sternum
• False ribs (ribs 8–12)
– Lack independent cartilaginous connection to sternum
– Floating ribs (ribs 11–12)
• Articulate with bodies of vertebrae T11 and T12
• Do not have tubercles
• Do not attach to transverse processes of the vertebra
• No cartilaginous connection to the sternum or any of the
higher costal cartilages
8-69
The Pectoral Girdle and
Upper Limb
• Expected Learning Outcome
– Identify and describe the features of the clavicle,
scapula, humerus, radius, ulna, and bones of the
wrist and hand.
8-70
The Pectoral Girdle
• Pectoral girdle (shoulder girdle) supports the arm
• Consists of two bones on each side of the body
– Clavicle (collarbone) and scapula (shoulder blade)
• Clavicle articulates medially to the sternum and
laterally to the scapula
– Sternoclavicular joint
– Acromioclavicular joint
• Scapula articulates with the humerus
– Glenohumeral joint: shoulder joint
– Easily dislocated due to loose attachment
8-71
The Clavicle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Sternal
end
Acromial
end
Conoid tubercle
(a) Superior view
Figure 8.30
Conoid tubercle
Sternal
end
Acromial
end
(b) Inferior view
• Clavicle—S-shaped, somewhat flattened bone
• Inferior—grooves and ridges for muscle attachment
• Sternal end—rounded head
8-72
The Clavicle
• Acromial end—flattened
– Conoid tubercle: roughened tuberosity near
acromial end; ligament attachment
• Braces shoulder, keeping upper limb away from
midline of body
• Most frequently fractured bone in the body
8-73
The Scapula
• Scapula—named for its resemblance to a spade
or shovel
• Triangular plate that posteriorly overlies ribs 2 to 7
– Three sides: superior, medial (vertebral), and lateral
(axillary) borders
– Three angles: superior, inferior, and lateral angles
8-74
The Scapula
• Suprascapular notch—conspicuous notch on
superior border
– Provides passage for a nerve
• Spine—transverse ridge on posterior surface
– Supraspinous fossa: indentation superior to the spine
– Infraspinous fossa: broad surface inferior to the spine
8-75
The Scapula
• Subscapular fossa—concave, anterior surface
of scapula
• Complex lateral angle of scapula has three
main features
– Acromion: platelike extension of the spine
• Forms apex of the shoulder
• Articulates with the clavicle—the sole point of
attachment of the scapula and the upper limb to the rest
of the skeleton
8-76
The Scapula
Cont.
– Coracoid process: shaped like a bent finger
• Provides attachment for tendons of the biceps brachii
and other arm muscles
– Glenoid cavity: shallow socket that articulates with
the head of the humerus
• Forming glenohumeral joint
8-77
The Scapula
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Superior
border
Suprascapular
notch
Superior angle
Acromion
Acromion
Supraspinous
fossa
Coracoid
process
Glenoid
cavity
Lateral
angle
Spine
Subscapular
fossa
Infraspinous
fossa
Lateral
border
Medial
border
Inferior angle
(a) Anterior view
(b) Posterior view
Figure 8.31
8-78
The Upper Limb
• Upper limb is divided into four regions containing
a total of 30 bones per limb
– Brachium (arm proper): extends from shoulder to elbow
• Contains only 1 bone—humerus
– Antebrachium (forearm): extends from elbow to wrist
• Contains 2 bones—radius and ulna
– Carpus (wrist)
• Contains 8 small bones arranged in two rows
– Manus (hand)
• 19 bones in two groups
– 5 metacarpals in palm
– 14 phalanges in fingers
8-79
The Humerus
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Greater
tubercle
Head
Lesser
tubercle
Greater
tubercle
Anatomical
neck
Surgical
neck
Intertubercular
sulcus
Nutrient
foramen
Deltoid
tuberosity
Deltoid
tuberosity
Coronoid
fossa
Radial
fossa
Lateral
epicondyle
Capitulum
Medial
supracondylar
ridge
Medial
epicondyle
Trochlea
(a) Anterior view
Lateral
supracondylar
ridge
Lateral
epicondyle
Olecranon
fossa
(b) Posterior view
• Proximal end
– Hemispherical head
that articulates with
the glenoid cavity of
scapula
– Anatomical neck
– Greater and lesser
tubercles and deltoid
tuberosity
– Intertubercular
sulcus holds biceps
tendon
– Surgical neck
Figure 8.32
8-80
The Humerus
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Greater
tubercle
Head
Lesser
tubercle
Greater
tubercle
Anatomical
neck
• Distal end
Surgical
neck
Intertubercular
sulcus
Nutrient
foramen
Deltoid
tuberosity
Deltoid
tuberosity
Coronoid
fossa
Radial
fossa
Lateral
epicondyle
Capitulum
Medial
supracondylar
ridge
Medial
epicondyle
Trochlea
Figure 8.32
(a) Anterior view
Lateral
supracondylar
ridge
Lateral
epicondyle
Olecranon
fossa
(b) Posterior view
– Rounded capitulum
articulates with head of
radius
– Trochlea articulates
with ulna
– Lateral and medial
epicondyles
– Lateral and medial
supracondylar ridges
– Olecranon fossa holds
olecranon process of
ulna
– Coronoid fossa
– Radial fossa
8-81
The Radius
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Olecranon
Olecranon
Trochlear notch
Radial notch
of ulna
Head of
radius
Neck of
radius
Head of
radius
Coronoid process
Neck of
radius
Ulnar tuberosity
Radial
tuberosity
Ulna
Radius
Interosseous
borders
• Radius
– Head: disc-shaped, allows
for rotation around the
longitudinal axis of the bone
during pronation and
supination of hand
• Superior surface
articulates with capitulum
on humerus
• Side of disc spins on
radial notch on ulna
Interosseous
membrane
Ulnar notch
of radius
Head of ulna
Styloid process
Styloid
process
Styloid
process
Articular facets
(a) Anterior view
(b) Posterior view
Figure 8.33
– Neck
– Radial tuberosity for
biceps muscle
– Styloid process can be
palpated near thumb
8-82
– Ulnar notch
The Ulna
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Olecranon
Olecranon
Trochlear notch
Radial notch
of ulna
Head of
radius
Neck of
radius
Head of
radius
Coronoid process
Neck of
radius
Ulnar tuberosity
Radial
tuberosity
Ulna
Radius
Interosseous
borders
Ulnar notch
of radius
Head of ulna
Styloid process
Styloid
process
Articular facets
(a) Anterior view
– Trochlear notch articulates
with trochlea of humerus
– Olecranon: bony point at
back of elbow
– Coronoid process
– Radial notch holds head of
radius
– Styloid process
• Interosseous membrane
Interosseous
membrane
Styloid
process
• Ulna
– Ligament attaches radius to
ulna along interosseous
margin of each bone
– Enables the two elbow joints
to share the load
(b) Posterior view
Figure 8.33
8-83
The Carpal Bones
• Eight bones form wrist
– Allow movements of flexion, extension, abduction,
and adduction
• Two rows (four bones each)
– Proximal row: scaphoid, lunate, triquetrum, and
pisiform
• Pisiform is a sesamoid developed by age 9 to12 in
tendon of flexor carpi ulnaris muscle
– Distal row: trapezium, trapezoid, capitate, and
hamate
8-84
The Right Wrist and Hand
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Distal phalanx II
Middle phalanx II
Key to carpal bones
Distal row
Proximal row
Proximal phalanx II
IV
Head
Phalanges
Body
III
Distal
phalanx I
II
V
Base
I
Proximal
phalanx I
Head
Metacarpal Body
bones
Base
Carpal
bones
First
metacarpal
Hamulus of hamate
Hamate
Pisiform
Triquetrum
Lunate
(a) Anterior view
Trapezoid
Trapezium
Carpal
Capitate
bones
Scaphoid
Figure 8.34a
8-85
The Metacarpal Bones
and the Phalanges
• Metacarpals—bones of the palm
– Metacarpal I proximal to base of thumb
– Metacarpal V proximal to base of little finger
– Proximal base, body, and distal head
• Phalanges—bones of the fingers
– Thumb or pollex has two phalanges
• Proximal, distal phalanx
– Fingers have three phalanges
• Proximal, middle, distal phalanx
8-86
The Pelvic Girdle and
Lower Limb
• Expected Learning Outcomes
– Identify and describe the features of the pelvic girdle,
femur, patella, tibia, fibula, and bones of the foot.
– Compare the anatomy of the male and female pelvic
girdles and explain the functional significance of the
differences.
8-87
The Pelvic Girdle
• Pelvic girdle—
consists of a complete
ring composed of
three bones
– Two hip (coxal)
bones, also called
ossa coxae or
innominate bones
– Sacrum is also part of
the vertebral column
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Iliac
crest
Iliac
fossa
Base of
sacrum
Ilium
Sacroiliac joint
Anterior
superior
iliac spine
Pelvic surface
of sacrum
Anterior inferior
iliac spine
Pelvic inlet
Spine
Coccyx
Acetabulum
Ischium
Body
Interpubic
disc
Ramus
Pubis
Obturator
foramen
Superior ramus
Inferior ramus
Body
Pubic symphysis
(a) Anterosuperior view
Figure 8.35a
8-88
The Pelvic Girdle
• Pelvis—bowl-shaped structure composed of the
two coxal bones and sacrum as well as their
ligaments and muscles that line the pelvic cavity
and form its floor
– Supports trunk on the lower limbs and protects
viscera, lower colon, urinary bladder, and internal
reproductive organs
• Sacroiliac joint—joins hipbone to the vertebral
column
– Auricular surface of ileum to auricular surface of
sacrum
8-89
The Pelvic Girdle
• Anteriorly, interpubic
disc—pad of
fibrocartilage joins
pubic bones
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Iliac
crest
Iliac
fossa
Base of
sacrum
Ilium
Sacroiliac joint
Anterior
superior
iliac spine
Pelvic surface
of sacrum
Anterior inferior
iliac spine
Pelvic inlet
Spine
Coccyx
Acetabulum
Ischium
Body
• Pubic symphysis—
the interpubic disc and
adjacent regions of the
pubic bone on each
side
Interpubic
disc
Ramus
Pubis
Obturator
foramen
Superior ramus
Inferior ramus
Body
Pubic symphysis
(a) Anterosuperior view
Figure 8.35a
8-90
The Pelvic Girdle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Iliac
crest
Iliac
fossa
Ilium
Anterior
superior
iliac spine
Anterior inferior
iliac spine
Spine
Sacroiliac joint
Pelvic surface
of sacrum
Pelvic brim
Pelvic inlet
Coccyx
Pelvic inlet
Acetabulum
Ischium
Body
Ramus
Pubis
Greater pelvis
Base of
sacrum
Superior ramus
Inferior ramus
Body
Lesser
pelvis
Interpubic
disc
Obturator
foramen
Pubic symphysis
(a) Anterosuperior view
Figure 8.35a
Pelvic outlet
(b) Median section
Figure 8.35b
•
•
•
•
Greater (false) pelvis—between flare of the hips
Lesser (true) pelvis—narrower and below
Pelvic brim—round margin that separates the two
Pelvic inlet—opening circumscribed by brim that infant’s
head must pass during birth
• Pelvic outlet—lower margin of the lesser pelvis
8-91
The Pelvic Girdle
• Three distinct features
of hip bone
– Iliac crest: superior
crest of hip
– Acetabulum: hip socket
– Obturator foramen:
large hole below
acetabulum
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Ilium
Ischium
Pubis
Iliac crest
Anterior gluteal
line
Inferior gluteal
line
Anterior superior
iliac spine
Posterior gluteal
line
Posterior superior
Iliac spine
Posterior inferior
Iliac spine
Anterior
r
inferior
iliac spine
Greater sciatic notch
Body of ilium
Acetabulum
Superior ramus
of pubis
Ischial spine
Body of pubis
Lesser sciatic notch
Body of ischium
Inferior ramus
of pubis
Ischial tuberosity
Obturator foramen
Ramus of ischium
(a) Lateral view
Figure 8.36a
8-92
The Pelvic Girdle
• Each adult hip bone is formed by the fusion of
three childhood bones: illeum, ishchium,
pubis
• Ileum
– Largest
– Extends from the iliac crest to the center of the
acetabulum
– Anterior and posterior superior spine
– Anterior and posterior inferior spines
– Greater sciatic notch and iliac fossa
8-93
The Pelvic Girdle
• Ischium
–
–
–
–
–
Inferioposterior portion of hip
Heavy body with prominent spine
Lesser sciatic notch
Ischial tuberosity
Ramus
• Pubis (pubic bone)
– Most anterior portion of the hip bone
– Body, superior, and inferior ramus
8-94
The Pelvic Girdle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Triangular
pubic body
Rectangular
pubic body
Large, oval
obturator
foramen
Narrow subpubic angle
(a) Male, anterior view
Wide subpubic angle
Triangular
obturator
foramen
(c) Female, anterior view
Preauricular
sulcus
Wide greater
sciatic notch
(b) Male, medial view
Narrow greater
sciatic notch
(d) Female, medial view
(a): © David Hunt/specimens from the National Museum of Natural History, Smithsonian Institution; (b-c): © L. Bassett/Visuals
Unlimited; (d): © David Hunt/specimens from the National Museum of Natural History, Smithsonian Institution
Figure 8.37
• Male—heavier and thicker due to forces exerted by stronger
muscles
• Female—wider and shallower, and adapted to the needs of
pregnancy and childbirth, larger pelvic inlet and outlet for
passage of infant’s head
8-95
The Lower Limb
• Lower limb divided into four regions containing 30
bones per limb
– Femoral region (thigh): extends from hip to knee region
• Contains the femur and patella
– Crural region (leg proper): extends from knee to ankle
• Contains medial tibia and lateral fibula
– Tarsal region (tarsus): ankle—the union of the crural
region with the foot
• Tarsal bones are considered part of the foot
– Pedal region (pes): foot
• Composed of 7 tarsal bones, 5 metatarsals, and 14 phalanges in
the toes
8-96
The Femur
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fovea capitis
Greater trochanter
Greater trochanter
Head
Neck
Intertrochanteric crest
Intertrochanteric line
Lesser trochanter
Spiral line
Gluteal tuberosity
Linea aspera
Shaft
Medial supracondylar line
Lateral supracondylar
line
Popliteal surface
Lateral epicondyle
Medial epicondyle
Lateral epicondyle
Patellar surface
Lateral condyle
Intercondylar fossa
Medial condyle
Base of patella
Articular facets
Apex of patella
(a) Anterior view
Figure 8.38
(b) Posterior view
• Longest and strongest bone
of the body
• Hemispherical head that
articulates with the
acetabulum of the pelvis
– Forms ball-and-socket joint
– Fovea capitis: pit in head of
femur for attachment of a
ligament
• Greater and lesser
trochanters for muscle
attachment
• Intertrochanteric crest—
thick oblique ridge on the
posterior surface that
connects the trochanters
8-97
The Femur
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fovea capitis
Greater trochanter
Greater trochanter
Head
Neck
Intertrochanteric crest
Intertrochanteric line
Lesser trochanter
Spiral line
Gluteal tuberosity
Linea aspera
• Linea aspera—ridge on
posterior of the shaft
• Spiral (pectineal) line and
gluteal tuberosity
Shaft
Medial supracondylar line
Lateral supracondylar
line
Popliteal surface
Lateral epicondyle
• Intertrochanteric line—more
delicate ridge on the anterior
surface that connects
trochanters
Medial epicondyle
Lateral epicondyle
Patellar surface
• Medial and lateral condyles
and epicondyles found
distally
Lateral condyle
Intercondylar fossa
Medial condyle
Base of patella
• Intercondylar fossa
Articular facets
Apex of patella
(a) Anterior view
Figure 8.38
(b) Posterior view
• Patellar and popliteal
surface
8-98
The Patella
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fovea capitis
Greater trochanter
Greater trochanter
Head
Neck
Intertrochanteric crest
Intertrochanteric line
Lesser trochanter
Spiral line
Gluteal tuberosity
Linea aspera
Shaft
Medial supracondylar line
Lateral supracondylar
line
Popliteal surface
Lateral epicondyle
Medial epicondyle
Lateral epicondyle
Patellar surface
Lateral condyle
Intercondylar fossa
Medial condyle
Base of patella
Articular facets
Apex of patella
(a) Anterior view
(b) Posterior view
Figure 8.38
• Patella—triangular
sesamoid bone embedded
in tendon of knee
• Cartilaginous at birth
– Ossifies at age 3 to 6 years
• Base—broad, superior
portion
• Apex—pointed, inferior
portion
• Articular facets—shallow,
posterior portion
• Quadriceps femoris tendon
extends from anterior
muscle of thigh to patella
– Continues as the patellar
ligament from patella to tibia
8-99
Tibia
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Intercondylar eminence
Medial
condyle
Lateral condyle
Apex
Head of fibula
Tibial
tuberosity
Proximal tibiofibular
joint
• Tibia—thick, medial, weightbearing bone
• Fairly flat articular surfaces
• Articulate with condyle of
femur
Interosseous
membrane
Lateral surface
Anterior crest
Tibia
Fibula
Distal tibiofibular joint
Medial
malleolus
Lateral malleolus
(a) Anterior view
– Only weight-bearing bone of
the crural region
– Broad superior head
– Medial and lateral condyles
Lateral malleolus
(b) Posterior view
Figure 8.39
– Intercondylar eminence—
ridge separating condyles
– Tibial tuberosity—
attachment of quadricep
muscles
– Anterior crest—sharp,
angular
– Medial malleolus—bony
knob on inside of ankle
8100
The Fibula
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Intercondylar eminence
Medial
condyle
Lateral condyle
Apex
Head of fibula
Tibial
tuberosity
Proximal tibiofibular
joint
• Does not bear any body
weight
– Spare bone tissue for grafts
Interosseous
membrane
Lateral surface
• Fibula—slender, lateral strut
that helps stabilizes ankle
• Head—proximal end
Anterior crest
• Apex—point of the head
Tibia
Fibula
• Lateral malleolus—distal
expansion, bony knob on
lateral side of ankle
Distal tibiofibular joint
Medial
malleolus
Lateral malleolus
(a) Anterior view
Lateral malleolus
(b) Posterior view
Figure 8.39
• Joined to tibia by
interosseous membrane
8101
The Ankle and Foot
• Tarsal bones—arranged in
proximal and distal groups
– Tarsal bones are shaped and
arranged differently from
carpal bones due to loadbearing role of the ankle
• Calcaneus—largest tarsal
bone
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Distal phalanx I
– Forms heel
– Distal portion is point of
attachment for calcaneal
(Achilles) tendon
Distal
phalanx V
Proximal phalanx I
Middle
phalanx V
Proximal
phalanx V
Metatarsal
I
II
III
IV
• Talus is most superior tarsal
bone
V
Medial cuneiform
Intermediate cuneiform
Lateral cuneiform
Navicular
Cuboid
Talus
Calcaneus
Trochlear surface
of talus
Key to tarsal bones
Distal
group
Tuberosity of calcaneus
(a) Superior (dorsal) view
Figure 8.40a
Proximal group
– Forms ankle joint with tibia
and fibula
– Sits upon calcaneus and
articulates with navicular
• Proximal row of tarsal bones
– Talus, calcaneus, navicular
• Distal row of tarsal bones
– Medial, intermediate, lateral
cuneiforms and cuboid
8-
The Ankle and Foot
• Remaining bones of foot are
similar in name and
arrangement to the hand
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Metatarsals
Distal phalanx I
Distal
phalanx V
Proximal phalanx I
– Metatarsal I is proximal to the
great toe (hallux)
– Metatarsal V is proximal to the
little toe
– Proximal base, intermediate
shaft, and distal head
Middle
phalanx V
Proximal
phalanx V
Metatarsal
I
II
III
IV
V
Medial cuneiform
Intermediate cuneiform
Lateral cuneiform
Navicular
Cuboid
Talus
• Phalanges
Calcaneus
Trochlear surface
of talus
Key to tarsal bones
Distal
group
Tuberosity of calcaneus
(a) Superior (dorsal) view
Figure 8.40a
Proximal group
– Two in great toe
• Proximal and distal phalanx
– Three in all other toes
• Proximal, middle, distal
phalanx
8103
The Ankle and Foot
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Thumb
Future
thumb
Elbow
Knee
Future
great toe
(a) Seven weeks
Great toe
(b) Eight weeks
Figure 8.41
• Rotation of upper and lower limbs in opposite directions
–
–
–
–
Starts seventh week of embryonic development
Largest digit medial in foot and lateral in hand
Each limb rotates about 90° in opposite directions
Rotation also explains why elbow flexes posteriorly and knee flexes
8anteriorly
104
The Ankle and Foot
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Medial
longitudinal arch
Transverse
arch
Lateral
longitudinal
arch
Figure 8.42a
(a) Inferior (plantar) view
• Sole of foot is not flat on ground
• Three springy arches absorb
stress
– Medial longitudinal arch
• From heel to hallux
• Formed from the
calcaneus, talus, navicular,
cuneiforms, and
metatarsals I and III
• Lateral longitudinal arch
– From heel to little toe
– Includes calcaneus, cuboid,
and metatarsals IV and V
8105
The Ankle and Foot
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
• Transverse arch
Medial
longitudinal arch
Transverse
arch
Lateral
longitudinal
arch
Figure 8.42a
(a) Inferior (plantar) view
– Across middle of foot
– Includes the cuboid,
cuneiforms, and proximal
heads of metatarsals
– Arches held together by
short, strong ligaments
• Pes planus (flat feet)—
excessive weight,
repetitious stress, or
congenital weakness
8106
Skeletal Adaptations for Bipedalism
• Humans are only animals habitually bipedal
– 3.6-million-year-old human footprints indicate upright
walking
• Adaptations
– Strong, springy foot arches
– Great toe not opposable
– Femurs angle inward so knees are closer together—
erect posture requires less muscular effort
– Viscera supported in bowl-shaped pelvis
– Insertions of gluteal muscles differ from other
primates
8107
Skeletal Adaptations for Bipedalism
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
(a) Foot
(b) Knee
Chimpanzee
Human
Figure 8.43a,b
Chimpanzee
Human
8108
Skeletal Adaptations for Bipedalism
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
(c) Gluteal muscles
Chimpanzee
(d) Pelvis
(e) Vertebral column
Chimpanzee
Chimpanzee
Human
Human
Figure 8.43c,d,e
Human
8109
Skeletal Adaptations for Bipedalism
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
(f) Skull
Supraorbital
ridge
Pivot
Foramen
magnum
Chimpanzee
Pivot
Figure 8.43f
Foramen
magnum
Human
8110
8111