dr. b ch 06_lecture_presentation

© 2012 Pearson Education, Inc.

6The Skeletal System: Axial Division

PowerPoint® Lecture Presentations prepared bySteven BassettSoutheast Community College Lincoln, Nebraska


Introduction

• The axial skeleton:• Composed of bones along the central axis of

the body• Divided into three regions:

• Skull• Vertebral column• Thoracic cage


Figure 6.1b The Axial Skeleton (Part 1 of 2)

Anterior (left) and posterior (right) views of the bones of the axial skeleton

Skull

Ribs

Lumbarvertebrae

Sacrum

Coccyx

Sternum


Introduction

• Functional anatomy of the axial skeleton: • Framework that supports and protects organs in the

dorsal and ventral body cavities• Protects special sense organs for taste, smell,

hearing, balance, and vision• Attachment sites for muscles that:

• Adjust the posture of the head, neck, and trunk• Move the thoracic cage for respiration• Stabilize the appendicular skeleton• The connection between axial and appendicular skeleton in

the upper body is sternum-clavicle.


Figure 6.1a The Axial SkeletonSKELETAL SYSTEM

APPENDICULAR SKELETON

(see Figure 7.1)

AXIAL SKELETON 80

Skull andassociated

bones

Thoraciccage

Vertebralcolumn

Skull

Associatedbones

Auditoryossicles

Cranium

Face

Hyoid

Sternum

Ribs

Vertebrae

Sacrum

Coccyx

29

25

26

14

24

24

8

6

1

1

1

1

Anterior view of the skeletonhighlighting components of theaxial skeleton; the flowchartindicates relationships amongthe axial components.

126

206


Figure 6.2 Cranial and Facial Subdivisions of the Skull (Part 1 of 2)

SKULL

ASSOCIATED BONES

Hyoid bone 1

7

6

Auditory ossiclesenclosed in

temporal bones(detailed inChapter 18)

FACE CRANIUM14 8

2

2

2

2

2

2

1

1

2

1

2

1

1

Maxillae

Palatine bones

Nasal bones

Inferior nasalconchae

Zygomatic bones

Lacrimal bones

Vomer

Mandible

Occipital bone

Parietal bones

Frontal bone

Temporal bones

Sphenoid

Ethmoid

1


Figure 6.2 Cranial and Facial Subdivisions of the Skull (Part 2 of 2)

Facial Bones Cranial Bones

Nasal bone

Zygomaticbone

Maxilla

Lacrimalbone

Vomer

Mandible

Frontalbone

Sphenoid

Ethmoid

Parietal bone

Temporalbone

Occipitalbone


Bones of the Cranium The cranial cavity is a fluid-filled chamber that supports and

protects the brain. It is made up of the Occipital: foramen magnum, hypoglossal canal, occipital

condyle. Parietal (2): coronal, lambdoid and sagittal surures. Frontal: supraorbital foramen, supraorbital arch, glabella,

frontal sinus. Temporal (2): squamous portion, petrose portion, mastoid

process, styloid process, external acoustic meatus. Sphenoid: sella turcica, clinoid process, optic groove,

dorsum sellae, pterigoid process. Ethmoid: perforating panel, crista galli, perpendicular plate,

ethmoid sinuses, superior portion of nasal septum.

The Skull and Associated Bones


Figure 6.3a The Adult Skull

Posterior view of the bones of the adult skullMandible

External occipitalprotuberance

Occipital condyle

Styloid process

Mastoid process

Temporal bone

Squamoussuture

Lambdoidsuture

Sagittal suture

Left parietalbone

Right parietalbone

Occipitalbone

Sagittal suture

Lambdoid suture

Squamous suture

Temporal bone

External occipitalprotuberance

Mastoid process

Occipital condyle

Left parietalbone Right parietal

bone

Occipital bone


Figure 6.6a The Occipital and Parietal Bones

Occipital bone, inferior (external) view

Hypoglossalcanal

Foramen magnum

Occipital condyle

Hypoglossal canal

Condyloid fossa

Inferior nuchal line

External occipital crest

Superior nuchal line

External occipital protuberance


Figure 6.3b The Adult Skull

Superior view of the bonesof the adult skull

Nasal bones

Frontalbone

Rightparietal

bone

Leftparietal

bone

Occipitalbone

Occipitalbone

Frontalbone

Rightparietal

bone

Leftparietal

bone

Lambdoidsuture

Sagittalsuture

Coronalsuture

Zygomaticbone


Figure 6.3c The Adult Skull (Part 1 of 2)

Lateral view of the bones of the adult skull

Parietal bone Frontal bone

Temporalbone

Occipital bone

Superior temporal line

Inferior temporal line

Squamous suture

Lambdoid suture

External acousticmeatus

Mastoid process

Zygomaticarch

Styloid process

Zygomatic process of temporal bone

Temporal process of zygomatic bone

Mandible

Coronal suture

Sphenoid

Supra-orbital foramen

Frontonasal suture

Nasal bone

Lacrimal groove of lacrimal bone

Ethmoid

Infra-orbital foramen

Maxilla

Zygomatic bone

Mental foramenMental protuberance


Figure 6.3d The Adult Skull (Part 1 of 2)

Anterior view of the bones of the adult skull

Parietal bone

Supra-orbital foramen

Sphenoid

Temporal bone

Ethmoid

Palatine bone

Lacrimal bone

Zygomaticofacialforamen

Zygomatic bone

Nasal bone

Maxilla

Inferior nasal concha

Vomer

Mandible

Frontal bone

Coronal suture

Frontonasal suture

Optic canal

Superior orbital fissure

Inferior orbital fissure

Temporal process ofzygomatic bone


Middle nasal concha

Perpendicular plateof ethmoid

Mental foramen

Mental protuberance


Figure 6.3e The Adult Skull (Part 1 of 2)

Inferior view of the adult skull, mandible removed

Greater palatine foramen

Frontal bone

Lesser palatine foramen

Zygomatic bone

Vomer

Sphenoid

Foramen ovale

Styloid processMandibular fossa

Temporal squama

Externalacoustic meatus

Jugular foramen

Condyloid fossa

Lambdoid suture

Occipital bone

External occipital protuberance

Incisive fossa

Palatal process of maxilla

Maxilla

Internal nares

Palatine bone

Zygomatic arch

Medial and lateralpterygoid processes

Foramen lacerum

Carotid canalTemporal bone

Mastoid process

Stylomastoid foramen

Occipitomastoid suture

Occipital condyle

Foramen magnum

Superior nuchal line


Figure 6.4 Sectional Anatomy of the Skull, Part I (Part 1 of 2)

Frontal bone

Ethmoid

Sphenoid

Temporal boneCarotid canal

Mastoid foramen

Parietal bone

Occipital bone

Crista galliCribriform plate

Sella turcicaForamen rotundumForamen lacerumForamen ovaleForamen spinosum

Internalacoustic meatus

Jugular foramen

Hypoglossal canal

Foramenmagnum

Horizontal section


Figure 6.5 Sectional Anatomy of the Skull, Part I (Part 1 of 2)

Sagittal section

Coronal suture

Frontal bone

Sphenoid

Sphenoidal sinus (right)

Frontal sinus

Crista galli

Nasal bone

Perpendicular plate of ethmoid

Vomer

Palatine bone

Maxilla

Mandible Styloid process

Hypoglossal canal

Occipital bone

Internal acoustic meatus

Hypophyseal fossaof sella turcica

Lambdoid suture

Temporal bone

Squamous suture

Parietal bone


Figure 6.9a The Sphenoid

Superior surface

Tuberculumsellae

Foramenrotundum

Superiororbitalfissure

Opticcanal

Opticgroove

Anteriorclinoid

processLesserwing

Greaterwing

Foramenovale

Posteriorclinoid process

Foramenspinosum

Sellaturcica

Dorsumsellae

Sphenoidalspine

Foramenrotundum

Anteriorclinoid

process

Opticgroove

Tuberculumsellae Lesser

wingGreater

wingTemporal

bone

Foramenovale

Foramenspinosum

Sphenoidalspine

Sellaturcica

Dorsum sellae

Posterior clinoidprocess

Middle clinoidprocess

To opticcanal


Figure 6.10b The Ethmoid

Anterior view

Ethmoidallabyrinth

containinglateral

masses

Cribriformplate

Cristagalli

Middlenasal

concha

Perpendicularplate


Figure 6.11a The Cranial Fossae

A sagittal section through the skull showingthe relative positions of the cranial fossae

Optic groove

Crista galli

Frontal sinus

Sphenopalatine foramen

Sphenoidal sinus

Nasal conchae(superior, middle,

and inferior)

Anteriorcranialfossa

Middlecranialfossa

Posteriorcranialfossa

Sellaturcica

Hypoglossalcanal

Jugular foramenInternal acousticmeatus


Figure 6.11b The Cranial Fossae

Horizontal sections, superior view. The superior portion ofthe brain has been removed, but portions of the brain stemand associated nerves and blood vessels remain.

Sella turcica

Entrance tooptic canal

Anterior clinoidprocess

Superior orbitalfissure

Foramenrotundum

Posteriorclinoid

process

Foramenovale

Foramenspinosum

Foramenlacerum

Petrous part oftemporal bone

Internal acousticmeatus

Jugular foramen

Hypoglossal canal


Middlecranialfossa


Foramenmagnum

Crista galli of ethmoid

Cribriform plate

Crista galliOlfactory tract

Optic nerve

Optic chiasm

Cerebralarterial circle

Midbrain


Middlecranialfossa



Bones of the Face The skull contains 14 total facial bones.

The facial bones included the paired bones named the Maxillae: alveolar process, maxillary sinus (the largest

paranasal sinus), infraorbital foramen, front part of hard palate. Palatine: dorsal part of hard palate. Nasal Zygomatic: cheek bones Lacrimal Inferior nasal conchae

Single bones of the face are the Vomer: makes the inferior portion of nasal septum. Mandible: Alveolar process, ramus, condylar process, coronoid

process.



Figure 6.12ac The Maxillae

Right maxilla, anteriorand lateral surfaces

Body

Zygomaticprocess

Frontal process

Lacrimal groove

Orbital surface


Anterior nasal spine

Alveolarprocess

Superior view of a horizontal sectionthrough both maxillae and palatinebones showing the orientation of themaxillary sinuses and the structureof the hard palate

Alveolar process

Maxillary sinuses

Palatine bone(horizontalplate)

Incisivecanals

Palatal processof right maxilla


Figure 6.14a The Mandible

Superior and lateral surfaces

Head

Teeth (molar)

Mylohyoid line

Coronoidprocess

Condylarprocess

Mandibularnotch

Ramus

Angle

Body

Mentalforamen

Mentalprotuberance

Alveolarpart


Figure 6.15 The Orbital Complex

Sphenoid


Inferior orbitalfissure

Zygomaticbone

Infra-orbitalgroove

Infra-orbitalforamen

Frontal bone

Supra-orbitalnotch

Opticcanal

Palatinebone

Ethmoid

Lacrimalbone

Lacrimalgroove

Nasolacrimalcanal

Maxillarybone

Supra-orbitalnotch

Frontalbone

Sphenoid

Optic canal


Ethmoid

Inferior orbitalfissure

Infra-orbitalgroove

Zygomaticbone

Maxillarybone

Infra-orbitalforamen

Nasolacrimalcanal


The Nasal Complex Paranasal sinuses are the interconnected

hollow spaces inside the frontal, ethmoid, sphenoid, and maxillary bones.

These spaces reduce the weight of the skull, produce mucus, and allow air to resonate for voice production.

These paranasal sinuses are called the frontal sinus, maxillary sinus, sphenoidal sinus, and the ethmoidal air cells.



Figure 6.16b The Nasal Complex, Part I

Diagrammatic sagittal section with the nasal septum removed toshow major features of the wall of the right nasal cavity

Nasal bone

Ethmoid

Frontal sinuses

Frontal bone

Maxilla(hard palate)

Sphenoidalsinuses

Sphenoid

Superior

MiddleInferior

Nasalconchae

Horizontal plateof palatine bone


Figure 6.7c The Frontal Bone

Posterior view

Margin ofcoronal suture

Squamous part

Frontal crest

Orbital part

Notch for ethmoid


Figure 6.18a The Hyoid Bone

Anterior view showing the relationship of the hyoid boneto the skull, the larynx, and selected skeletal muscles

Digastric muscle (anterior belly)

Greater horn

Lesser horn

Thyrohyoid ligament Thyroidcartilage

Digastric muscle(posterior belly)

Stylohyoid muscle

Stylohyoid ligament

Mandible

Masatoid process(temporal bone)

Styloid process(temporal bone)


• There are 22 bones of the skull• Facial bones

• Maxillae – 2• Palatine bones – 2• Nasal bones – 2• Inferior nasal conchae – 2• Zygomatic bones – 2• Lacrimal bones – 2• Vomer – 1• Mandible – 1

Review of the Skull


• There are 22 bones of the skull• Cranial bones

• Occipital bone – 1• Parietal bones – 2• Frontal bone – 1• Temporal bones – 2• Sphenoid bone – 1• Ethmoid bone – 1

Review of the Skull (continued)


• There are 7 associated bones of the skull• Associated bones

• Auditory ossicles – 6• Hyoid bone – 1

Review of the Skull (continued)


• Major features of the infant skull• 4 major fontanel areas• Membranous areas where sutures will

eventually form• Anterior fontanel (baby’s “soft spot”)• Posterior fontanel• Sphenoidal fontanels• Mastoid fontanels

The Skull of Infants


Figure 6.19a The Skull of an Infant

Lateral view

Maxilla Mandible Temporalbone

Mastoidfontanel

Occipitalbone

Lambdoidsuture

Squamoussuture

Parietalbone

Frontalbone

Coronalsuture

Sphenoidalfontanel

Greater wingof sphenoid

Nasalbone


Figure 6.19c The Skull of an Infant

Superior view

Coronal suture

Coronal suturePosterior fontanel

Lambdoidsuture

Occipital bone

Frontalbone

Frontalbone

Parietalbone

Parietalbone

Frontalsuture

Anteriorfontanel

Sagittal suture


Figure 6.19d The Skull of an Infant

Posterior view

Sagittal suture

Parietal bone

Posterior fontanel

Lambdoid suture

Occipital bone


• The adult vertebral column is made up of 26 bones:

• 24 vertebrae• 7 cervical vertebrae• 12 thoracic vertebrae• 5 lumbar vertebrae

• 1 sacrum (5 fused vertebrae)• 1 coccyx (3 to 5 fused vertebrae)

The Vertebral Column



• Functional anatomy of the vertebral column• Encloses and protects the spinal cord• Supports the skull• Supports the weight of the head, neck, and trunk• Transfers weight to the lower limbs• Helps maintain the upright position of the body


Figure 6.20a The Vertebral Column

The major divisions of thevertebral column, showingthe four adult spinal curves

Sacral

Lumbar

Thoracic

CervicalCervical

Sacral

Lumbar

Thoracic

Coccygeal

C1

C2

C3

C4

C5C6

C7T1

T2T3

T4

T5

T6

T7

T8

T9

T10

T11

T12

L1

L2

L3

L4

L5

SPINAL CURVES VERTEBRAL REGIONS



Spinal CurvesPrimary curves/accommodation curves are the posteriorly sweeping curves of the thoracic and sacral regions.

These curves develop before birth to allow the abdominopelvic viscera more room.

Secondary curves/compensation curves develop in the infant and toddler as anteriorly sweeping curves of the cervical and lumbar regions.

These curves develop as the infant learns to hold up his or her head (cervical) and begins to walk (lumbar).


Figure 6.20d The Vertebral Column

The development of spinal curves

Cervical

Thoracic

Lumbar

Sacral

2 fetalmonths

6 fetalmonths

Newborn 4-year-old

13-year-old

Adult



• Abnormal curvatures of the vertebral column

• Scoliosis• Abnormal lateral curvature

• Kyphosis• Exaggerated posterior curvature of the thoracic

region

• Lordosis• Exaggerated anterior curvature of the lumbar

region


Spinal curve deformities



• Vertebral Processes (Cervical Vertebrae)• Vertebral body• Vertebral foramen• Spinous process• Transverse process

• Transverse foramen

• Lamina• Pedicle



Cervical Vertebrae

7 total cervical vertebrae are the smallest, most superior vertebrae.

The spinous processes are relatively stumpy and may be split, resulting in a bifid process.

Costal processes are extra extensions of bone from the ventrolateral body that attach to the transverse processes.

Transverse foramina result from the hole between the costal process and the transverse process.


Figure 6.22c Cervical Vertebrae

Superior view of the same vertebra. Note thecharacteristic features listed in Table 6.3.

Vertebralarch

Vertebralforamen

Pedicle

Transverseprocess

Costalprocess

Bifid tip ofspinous process

Spinous process

Lamina

Superior articularprocess

Superior articularfacet

Transverseforamen

Vertebral body



The Atlas (C1)The atlas has no body and articulates cranially with the occipital condyles.

The articulations with the occipital condyles allow one to shake his or her head “yes.”

The atlas has two arches—the anterior and posterior vertebral arches.Superior and inferior articular facets do not extend beyond the arches.


Figure 6.23e Atlas and Axis

The articulated atlas and axis, insuperior and posterior view

Articular facet fordens of axis

Dens

Atlas (C1)

Axis (C2)



The Axis (C2)The body of the atlas fuses with the body of the axis during development to form the dens (odontoid process).

Because of the dens, there is no intervertebral disc.

The articulation between the atlas and axis allows one to shake his or her head “no.”


Figure 6.23f Atlas and Axis

Articular facet fordens of axis

Dens

Atlas (C1)

Axis (C2)

The articulated atlas (C1) and axis (C2) showing thetransverse ligament that holds the dens of the axisin position at the articular facet of the atlas

Transverseligament


The vertebral column

Vertebra Prominens (C7) The last cervical vertebrae, and therefore

resembles the thoracic vertebra in structure This vertebra has a long, slender spinous

process, and enlarged transverse processes that may or may not contain a transverse foramen.

An elastic ligament called the ligamentum nuchae extends from the spinous process cranially to the occipital crest.


Vertebral column

Thoracic Vertebrae 12 total thoracic vertebrae make up the posterior of

the rib cage. The bodies of the thoracic vertebrae have a heart

shape. The spinous process is long and slender and points

on a posterocaudal angle. The transverse processes point dorsolateral. The thoracic vertebrae articulate with ribs and

therefore contain extra facets.


Figure 6.24c Thoracic Vertebrae

A representative thoracic vertebra,superior view

Transverse costalfacet for tubercle

of rib

Superiorcostal facet

Spinous process

Lamina

Transversecostal facet

Transverse process

Superior articular facet

Superior articular process

Pedicle

Inferior costal facet

Vertebral foramen

Vertebralbody Superior

costalfacet


Vertebral column


Vertebral column

Lumbar Vertebrae 5 total lumbar vertebrae are the largest vertebrae, and they

make up the lower back region. The body of lumbar vertebrae is very thick and oval

shaped. The relatively small vertebral foramen is triangular. The transverse processes point more laterally than the

thoracic vertebrae. The spinous process resembles a tail fin of a fish, stumpy

and flattened.


Figure 6.25b Lumbar Vertebrae

A representative lumbar vertebra,superior view

Vertebralbody

Vertebralbody

Vertebralforamen

Vertebralforamen

Superiorarticular

facet

Superiorarticular

facet

Pedicle

Superior articular process

Transverse process

Lamina

Spinous process


Vertebral column


Figure 6.26a The Sacrum and Coccyx

Posterior view

Articularprocess

Entranceto sacral

canal

Sacralhiatus

Sacraltuberosity

Lateralsacral crest

Mediansacral crest

Sacral cornu

Coccygeal cornu


The Thoracic Cage

The Thoracic cage has two functions: Made of sternum, 12 pairs of ribs and 12 thoracic vertebrae. Sternum is made of:

Manubrium Body Xiphoid process

12 pairs of ribs: 1-7 are true ribs: attach to the sternum by separate cartilaginous extensions. 8-10 are false ribs: attach to the sternum by one shared cartilaginous extension. 11-12 are floating ribs: not attached to the sternum.

Function: It protects the heart, lungs, thymus, and other structures within the cavity. It serves as the attachment site for muscles involved in Respiration Positioning the vertebral column Movements of the pectoral girdle and upper limb


Figure 6.27a The Thoracic Cage

Anterior view of the rib cage and sternum

T11

T12

T1

11

12

10

1

2

3

4

5

6

7

8

9

Jugular notch

Claviculararticulation

Sternum

Manubrium

Body

Xiphoidprocess

Costal cartilages

Floating ribs (ribs 11–12)

Vertebrochondral ribs(ribs 8–10)

True ribs(ribs 1–7)

False ribs(ribs 8–12)


Figure 6.27b The Thoracic Cage

Posterior view of the rib cage

True ribs(ribs 1–7)

False ribs(ribs 8–12) T12

T11

T10

T9

T8

T7

T6

T5

T4

T3

T2

T1

C7

1 12 2

3 3

4 4

5 5

6 6

7 7

8 8

9 9

10 10

11 11

12 12L1


Figure 6.27c The Thoracic Cage

A superior view of the articulationbetween a thoracic vertebra andthe vertebral end of a left rib

Transversecostal facet

Costal facet

Tubercle of rib

Neck

Angle

Head(capitulum)

Vertebralend

dr. b ch 06_lecture_presentation

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pearson education

associated bones bones

bones mandible

inferior view

clinoid process

pterigoid process

rightparietalbonesuperior

frontal sinus