The Skeletal System - Dr. Michael...

8-1

The Skeletal System

• overview of the skeleton

• the skull

• the vertebral column and

thoracic cage

• the pectoral girdle and upper limb

• the pelvic girdle and lower limb

Figure 8.1a

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Skull

Frontal bone

Pectoralgirdle

Clavicle

Maxilla

Parietal bone

Mandible Mandible

Humerus

Femur

Fibula

Ulna

Radius

Scapula

Hip bone

Sacrum

Patella

Carpus

Thoraciccage

Pelvis

Sternum

Ribs

Costal cartilages

Phalanges

Metatarsal bones

Phalanges

Coccyx

Vertebral column

Metacarpalbones

Tarsus

(a) Anterior view

Tibia

8-2

Overview of the Skeleton• two regions of the skeleton

– axial skeleton – forms the central supporting axis of the body

• skull, auditory ossicles, hyoid bone, vertebral column, and thoracic cage (ribs and sternum)

– appendicular skeleton – includes the bones of the upper limb and pectoral girdle, and the bones of the lower limb and pelvic girdle

8-4

Anatomical Features of BonesCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Sinuses

Crest

Foramen

Foramen

Fossae

HeadTubercle

Crest

Tuberosity

Line

Head

Fovea

Trochanters

Fossae

(a) Skull (lateral view)

Epicondyles

Condyles

Alveolus

SpineCondyleProcess

Lines

Meatus

(b) Scapula (posterior view)(c) Femur (posterior view)

(d) Humerus (anterior view)

Process

Spine

Figure 8.2

8-5

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

• 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

8-6

Major Skull Cavities

Figure 8.7


Frontal bone

Ethmoid bone

Middle

Superior

Inferior Maxilla

Nasal cavity

Mandible

Vomer

Orbit

Cranial cavity

Nasalconchae

Oralcavity

Maxillarysinus

Zygomaticbone

Ethmoidair cells

8-7

Cranial Fossa

• cranium (braincase) – protects the brain and associated sense organs– swelling of the brain inside the rigid cranium may force tissue through

foramen magnum resulting in death

• 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


(a) Superior view

Posterior cranial fossa

Middle cranial fossa

Anterior cranial fossa

Cerebellum

Temporal lobe

Frontal lobe

(b) Lateral view

Anterior cranialfossa

Middle cranialfossa

Posterior cranialfossa

Figure 8.9

8-8

Frontal Bone• forms forehead and part of

the roof of the cranium

• coronal suture – posterior boundary of frontal bone

• contains frontal sinus

Figure 8.3


Frontal bone

Coronal suture

Lacrimal bone

Squamous suture

Infraorbital foramen

Vomer

Mandible

Sphenoid bone

Ethmoid bone

Nasal bone

Zygomatic bone

Maxilla

Mental foramen

Temporal bone

Glabella

Mental protuberance

Parietal bone

Middle nasalconcha

Inferior nasalconcha

Supraorbitalmargin

Supraorbitalforamen

8-9

Parietal Bone• form most of cranial roof

and part of its lateral walls

• bordered by 4 sutures– sagittal – between parietal

bones– coronal – at anterior

margin– lambdoid – at posterior

margin– squamous – at lateral

border

Figure 8.4a


Parietal bone

Frontal bone

Lambdoid suture

Sphenoid bone

Temporal bone

Zygomatic process

External acoustic meatus

Mandible

Temporal lines

Coronal suture

Ethmoid bone

Lacrimal bone

Nasal bone


Zygomatic bone

Temporal process

Zygomaticofacial foramen

Maxilla

Mental foramen

Occipital bone

Squamous suture

Mandibular condyle

Styloid process

Mastoid process

(a) Right lateral view


Frontal bone

Coronal suture

Sagittal suture

Sutural bone

Parietal bone

Parietal foramen

Lambdoid suture

Occipital bone

Posterior

Anterior

Figure 8.6

8-10

Temporal Bone

• lateral wall and part of floor of cranial cavity– squamous part

• encircled by squamous suture

• zygomatic process• mandibular fossa

– tympanic part• external auditory meatus• styloid process

– mastoid part• mastoid process

Figure 8.4a


Parietal bone

Frontal bone

Lambdoid suture

Sphenoid bone

Temporal bone

Zygomatic process


Mandible

Temporal lines

Coronal suture

Ethmoid bone

Lacrimal bone

Nasal bone


Zygomatic bone

Temporal process


Maxilla

Mental foramen

Occipital bone

Squamous suture

Mandibular condyle

Styloid process

Mastoid process


8-11

Temporal Bone

– part of cranial floor

• separates middle from posterior cranial fossa

• houses middle and inner ear cavities

• internal auditory meatus


(b) Superior view of cranial floor

Cribriform foramina

Crista galli

Diploe (spongy bone)

Sphenoid bone

Temporal bone

Parietal bone

Occipital bone

Sella turcica

Frontal bone

Optic foramen

Foramen rotundum

Foramen ovale

Foramen spinosum

Foramen magnum

Jugular foramen

Hypoglossal canal

Internal acousticmeatus

Groove forvenous sinus

Petrous part oftemporal bone

Cribriform plateof ethmoid bone

Figure 8.5b

8-12

Occipital Bone• rear and base of skull

• foramen magnum holds spinal cord

• skull rests on atlas at occipital condyles

Figure 8.5a


Zygomatic bone

Lambdoid suture

Foramen magnum

Mastoid foramen

Jugular foramen

Stylomastoid foramen

Carotid canal

Intermaxillary suture

Palatine bone

Greater palatine foramen

Medial pterygoid plate

Lateral pterygoid plate

Foramen ovale

Foramen spinosum

Foramen lacerum

Incisive foramen

Sphenoid bone

Zygomatic arch

Mandibular fossa

Styloid process


Mastoid process

Mastoid notch

Condylar canal

Temporal bone

Superior nuchal line

Inferior nuchal line

Occipital bone

(a) Inferior view

Parietal bone

Occipital condyle

Vomer

Posterior nasalaperture

Palatine processof maxilla

Basilar part ofoccipital bone

External occipitalprotuberance

Sphenoid Bone

• optic foramen

8-13Figure 8.5b


Lesser wing

Greater wing

Foramen ovale

Body


Medial pterygoid plate Pterygoid processes

(b) Posterior view

Dorsum sellae

Foramenrotundum

Superior orbitalfissure



Cribriform foraminaCrista galli


Sphenoid bone

Temporal bone

Parietal bone

Occipital bone

Sella turcica

Frontal bone

Optic foramen

Foramen rotundumForamen ovaleForamen spinosum

Foramen magnum

Jugular foramen

Hypoglossal canal





Figure 8.11b

8-14

Sphenoid Bone

Figure 8.11a


Optic foramen

Lesser wing

Greater wing

Sella turcica

Dorsum sellae

Foramen rotundum

Hypophyseal fossa

Foramen ovaleForamen spinosum

(a) Superior view

Anterior clinoidprocess



Cribriform foraminaCrista galli


Sphenoid bone

Temporal bone

Parietal bone

Occipital bone

Sella turcica

Frontal bone

Optic foramen

Foramen rotundumForamen ovaleForamen spinosum

Foramen magnum

Jugular foramen

Hypoglossal canal





Figure 8.5b

8-15

Sphenoid Bone

sphenoid sinus

Figure 8.4b


Coronal suture

Frontal bone

Sphenoid sinus

Frontal sinus

Crista galli

Parietal bone

Temporal bone

Internal acoustic meatus

Jugular foramen

Hypoglossal canal

Mandibular foramen

Styloid process

Squamous suture

Lambdoid sutureSella turcica

Occipital bone

Vomer

Palatine bone

Maxilla

Mandible

Mental spines

Nasal bone

(b) Median section

Cribriform plate ofethmoid bone

Perpendicular plateof ethmoid bone


Figure 8.5a


Zygomatic bone

Lambdoid suture

Foramen magnum

Mastoid foramen

Jugular foramen


Carotid canal


Palatine bone




Foramen ovale

Foramen spinosum

Foramen lacerum

Incisive foramen

Sphenoid bone

Zygomatic arch

Mandibular fossa

Styloid process


Mastoid process

Mastoid notch

Condylar canal

Temporal bone



Occipital bone

(a) Inferior view

Parietal bone

Occipital condyle

Vomer





8-16

Ethmoid Bone

Figure 8.12

Supraorbital foramen

Orbital plate of ethmoid bone

Lacrimal bone

Optic foramen

Orbital plate of frontal bone

Lesser wing of sphenoid bone

Frontal process of maxillaSuperior orbital fissure

Roof oforbit

Orbital process ofpalatine bone

Orbital surface ofmaxilla

Floor oforbit

Medialwall

Zygomatic processof frontal bone

Greater wing ofsphenoid bone

Orbital surface ofzygomatic bone

Inferior orbitalfissure

Lateral wallof orbit

Infraorbitalforamen


• between the eyes

• contributes to medial wall of orbit

• lateral walls and roof of nasal cavity, and nasal septum

Figure 8.14

Orbital plate

Crista galli

CribriformplateCribriformforamina

Ethmoidalcells

Perpendicularplate

Superiornasal concha

Middlenasal concha


8-17

Ethmoid Bone

superior and middle concha

perpendicular plate of nasal septum


Coronal suture

Frontal bone

Sphenoid sinus

Frontal sinus

Crista galli

Parietal bone

Temporal bone


Jugular foramen

Hypoglossal canal

Mandibular foramen

Styloid process

Squamous suture


Occipital bone

Vomer

Palatine bone

Maxilla

Mandible

Mental spines

Nasal bone

(b) Median section




Frontal sinus

Inferior

Anterior nasal spine

Maxilla

Incisive foramen

Lacrimal bone

Nasal bone

Nasal cartilages

Superior

Middle

Sphenoid sinus

Palatine bone

Sphenoid bone

Crista galli

Sella turcica

Cribriform plate

Cribriform foramina

Occipital bone

Lip

Frontal bone

Incisor

Nasal conchae:


Figure 8.4b Figure 8.13

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 nasal bones

2 palatine bones 2 inferior nasal conchae

2 zygomatic bones 1 vomer

2 lacrimal bones 1 mandible

8-18

8-19

Maxillary Bones

Figure 8.3


Frontal bone

Coronal suture

Lacrimal bone

Squamous suture


Vomer

Mandible

Sphenoid bone

Ethmoid bone

Nasal bone

Zygomatic bone

Maxilla

Mental foramen

Temporal bone

Glabella

Mental protuberance

Parietal bone

Middle nasalconcha


Supraorbitalmargin

Supraorbitalforamen

Figure 8.5a


Lambdoid suture

Foramen magnumMastoid foramen

Jugular foramenStylomastoid foramenCarotid canal


Palatine bone




Foramen ovaleForamen spinosumForamen lacerum

(a) Inferior view




Zygomatic bone

Incisive foramen

Sphenoid bone

Zygomatic arch

Mandibular fossa

Styloid processExternal acoustic meatus

Mastoid processMastoid notch

Condylar canalTemporal bone



Occipital bone

Parietal bone

Occipital condyle

Vomer


8-20

Location of Maxillary Sinus

• maxillary sinus fills maxillae bone• larger in volume than frontal, sphenoid

and ethmoid sinuses

Figure 8.8


Sphenoidsinus

Frontalsinus

Ethmoidsinus

Maxillarysinus

Figure 8.8

Palatine Bones• form the posterior portion

of the hard palate

Supraorbital foramen

Orbital plate of ethmoid bone

Lacrimal bone

Optic foramen

Orbital plate of frontal bone

Lesser wing of sphenoid bone

Frontal process of maxillaSuperior orbital fissure

Roof oforbit

Orbital process ofpalatine bone

Orbital surface ofmaxilla

Floor oforbit

Medialwall

Zygomatic processof frontal bone

Greater wing ofsphenoid bone

Orbital surface ofzygomatic bone

Inferior orbitalfissure

Lateral wallof orbit

Infraorbitalforamen


Figure 8.148-21

Frontal sinus

Inferior

Anterior nasal spine

Maxilla

Incisive foramen

Lacrimal bone

Nasal bone

Nasal cartilages

Superior

Middle

Sphenoid sinus

Palatine bone

Sphenoid bone

Crista galli

Sella turcica

Cribriform plate

Cribriform foramina

Occipital bone

Lip

Frontal bone

Incisor

Nasal conchae:


Figure 8.13

8-22

Zygomatic Bones

• forms angles of the cheekbones and part of lateral orbital wall

• zygomatic arch is formed from temporal process of zygomatic bone and zygomatic process of temporal bone

Figure 8.4a


Parietal bone

Frontal bone

Lambdoid suture

Sphenoid bone

Temporal bone

Zygomatic process


Mandible

Temporal lines

Coronal suture

Ethmoid bone

Lacrimal bone

Nasal bone


Zygomatic bone

Temporal process


Maxilla

Mental foramen

Occipital bone

Squamous suture

Mandibular condyle

Styloid process

Mastoid process


8-23

Lacrimal Bones

• form part of medial wall of each orbit

• smallest bone of skull

• lacrimal fossa houses lacrimal sac in life– tears collect in lacrimal sac

and drain into nasal cavity


Parietal bone

Frontal bone

Lambdoid suture

Sphenoid bone

Temporal bone

Zygomatic process


Mandible

Temporal lines

Coronal suture

Ethmoid bone

Lacrimal bone

Nasal bone


Zygomatic bone

Temporal process


Maxilla

Mental foramen

Occipital bone

Squamous suture

Mandibular condyle

Styloid process

Mastoid process


Figure 8.4a

8-24

Nasal Bones

• forms bridge of nose

• supports cartilages that shape lower portion of the nose

Figure 8.3


Frontal bone

Coronal suture

Lacrimal bone

Squamous suture


Vomer

Mandible

Sphenoid bone

Ethmoid bone

Nasal bone

Zygomatic bone

Maxilla

Mental foramen

Temporal bone

Glabella

Mental protuberance

Parietal bone

Middle nasalconcha


Supraorbitalmargin

Supraorbitalforamen

8-25

Vomer

• 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


Coronal suture

Frontal bone

Sphenoid sinus

Frontal sinus

Crista galli

Parietal bone

Temporal bone


Jugular foramen

Hypoglossal canal

Mandibular foramen

Styloid process

Squamous suture


Occipital bone

Vomer

Palatine bone

Maxilla

Mandible

Mental spines

Nasal bone

(b) Median section




Figure 8.4b

8-26

• strongest bone of the skull• only bone of skull that moves noticeably• supports lower teeth

• provides attachments for muscles of facial expression and mastication

MandibleCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Zygomatic bone

Lambdoid suture

Foramen magnum

Mastoid foramen

Jugular foramen


Carotid canal


Palatine bone




Foramen ovale

Foramen spinosum

Foramen lacerum

Incisive foramen

Sphenoid bone

Zygomatic arch

Mandibular fossa

Styloid process


Mastoid process

Mastoid notch

Condylar canal

Temporal bone



Occipital bone

(a) Inferior view

Parietal bone

Occipital condyle

Vomer





Mandibular condylesCondylar process

Mandibular notch

Coronoid process

Mandibular foramen

Body

Angle

Ramus

Mental protuberance

Mental foramen

Alveolar process

Figure 8.5a

Figure 8.15


Ramus, Angle and Body of Mandible

• 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

8-27

Figure 8.15

Mandibular condylesCondylar process

Mandibular notch

Coronoid process

Mandibular foramen

Body

Angle

Ramus

Mental protuberance

Mental foramen

Alveolar process


8-28

• auditory ossicles

• 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

Bones Associated With Skull

Figure 8.16


Hyoid

Larynx

Styloid process

Stylohyoid muscle

Greater horn

Lesser horn

Body

8-29

Skull in Infancy and Childhood• fontanels - spaces between

unfused bones– filled with fibrous membrane

– allow shifting of bones during birth and growth of brain

• two frontal bones fuse by age 6

• skull reaches adult size by 8 or 9 years of age

Figure 8.17


Parietal bone

Occipital boneMaxilla

Frontal bone

Anterior fontanel

Sagittal suture

Posterior fontanel

Mandible

(b) Superior view

(a) Lateral view

Lambdoidsuture

Squamoussuture

Mastoidfontanel

Temporal bone

Parietalbone

Sphenoidbone

Coronalsuture

Frontalbone

Sphenoidfontanel

Nasalbone

Zygomaticbone

8-30

The Vertebral Column (Spine)• 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

• 33 vertebrae with intervertebral discs of fibrocartilage between most of them

Figure 8.18


Cervical vertebrae

Thoracic vertebrae

Atlas (C1)

Axis (C2)

C7

Lumbar vertebrae

Sacrum

Coccyx Coccyx

Anterior view Posterior view

T1

T12

L1

L5

S1

S5

8-31

The Vertebral Column (Spine)• 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

Figure 8.18


Cervical vertebrae

Thoracic vertebrae

Atlas (C1)

Axis (C2)

C7

Lumbar vertebrae

Sacrum

Coccyx Coccyx

Anterior view Posterior view

T1

T12

L1

L5

S1

S5

8-32

General Structure of Vertebra• body (centrum)

– 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– projection extending from the apex of arch– extends posteriorly and downward

• transverse process– extends laterally

• 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

Figure 8.22


Spinous process

Lamina

Pedicle

Body

(a) 2nd lumbar vertebra (L2)

Anterior

Posterior

Superior articularfacet

Transverseprocess

Vertebral foramen

Vertebralarch

Nucleus pulposus

Anulus fibrosus

(b) Intervertebral disc

8-33

Intervertebral Foramen and Discs• intervertebral foramen

– passageway for spinal nerves

• intervertebral discs (23)– first one between C2 and C3– last one between L5 and sacrum– 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

Figure 8.23b


L1

L2

L3

Intervertebral disc

Spinous process

(b) Left lateral view

Superior articularprocess of L1

Inferior vertebralnotch of L1

Superior vertebralnotch of L2

Inferior articularprocess of L3

Intervertebralforamen

8-34

Cervical Vertebra C1 + C2

atlas (C1) articulates with occipital condyles allows nodding motion of skull gesturing ‘yes’

axis (C2) allows rotation of the head gesturing ‘no’

8-35

Cervical Vertebra C2 - Axis

• axis (C2)– allows rotation of the head gesturing ‘no’

8-36

Atlas and Axis Articulation

Figure 8.24c


Dens

Axis of rotation

Atlas

Axis

Transverseligament

(c) Atlantoaxial joint

8-37

Sacrum and Coccyxsacrum – bony plate that forms the posterior wall of the pelvic cavityin children, five separate sacral vertebrae

coccyx – usually consists of four sometimes five, fuse into a single, triangular bone by age 20 – 30


Transverse lines

Coccyx

Ala S1

S2

S3

S4

S5

Co1Co2Co3Co4

(a) Anterior view

Superior articularprocess

Sacralpromontory

Anterior sacralforamina

Figure 8.26a

8-38

Thoracic Cage

• consists of thoracic vertebrae, sternum and ribs

• provides attachment for pectoral girdle and upper limbs

Figure 8.27


Sternoclavicular joint

Acromioclavicular joint

ClavicleScapula

Suprasternal notch

Clavicular notch

Manubrium

Angle

Body

Xiphoid process

Costal cartilages

Costal margin

True ribs (1–7)

1

2

3

4

5

6

7

8

9

10

11

12 T12

T1

L1

False ribs (8–12)

Sternum:

Pectoral girdle:

Floating ribs(11–12)

8-39

Sternum• sternum (breastbone) – bony plate anterior to the heart• divided into three regions:

– Manubrium

– body

– xiphoid

8-40

Articulation of Rib 6 with Vertebrae T5 and T6

Figure 8.29 Head

Neck

Tubercle

Rib 6

T6

(b) Superior view

Rib 6

Inferior costalfacet of T5

Superior articularfacet of rib 6

Inferior articularfacet of rib 6

Superior costalfacet of T6

(a) Anterior view

Vertebralbody T5

Vertebralbody T6

Transversecostal facetfor rib 6

Superiorarticularfacet

Superiorcostalfacetfor rib 6


8-41

True and False Ribs• true ribs (ribs 1 to 7)

– each has its own costal cartilage connecting it to the sternum

• false ribs (ribs 8-12)– lack independent

cartilaginous connection to the sternum

– floating ribs (ribs 11 – 12)

Figure 8.27


Sternoclavicular joint

Acromioclavicular joint

ClavicleScapula

Suprasternal notch

Clavicular notch

Manubrium

Angle

Body

Xiphoid process

Costal cartilages

Costal margin

True ribs (1–7)

1

2

3

4

5

6

7

8

9

10

11

12 T12

T1

L1

False ribs (8–12)

Sternum:

Pectoral girdle:

Floating ribs(11–12)

8-42

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

• scapula articulates with the humerus– glenohumeral joint - shoulder joint

8-43

Clavicle

• clavicle - S-shaped, somewhat flattened bone• inferior – grooves and ridges for muscle attachment• sternal end - rounded head• acromial end – flattened

• braces the shoulder keeping upper limb away from the midline of the body

Figure 8.30


Conoid tubercle

Conoid tubercle

(a) Superior view

(b) Inferior view

Sternalend

Acromialend

Acromialend

Sternalend

8-44

Scapula• scapula

• lateral angle of scapula has three main features:– acromion

• forms apex of the shoulder• articulates with the clavicle

– coracoid process• 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

8-45

Scapula

Figure 8.31


Superior angle

Acromion

Spine

Acromion

Inferior angle

(a) Anterior view (b) Posterior view

Suprascapularnotch

Coracoidprocess

Glenoidcavity

Subscapularfossa

Lateralborder

Medialborder

Superiorborder

Supraspinousfossa

Lateralangle

Infraspinousfossa

8-46

Upper Limb• Humerus

• Radius and ulna

• Carpal bones (wrist)

• 5 metacarpals in palm

• 14 phalanges in fingers

8-47

Humerus • proximal end– hemispherical head that

articulates with the glenoid cavity of scapula

– greater and lesser tubercles and deltoid tuberosity

– intertubercular sulcus holds biceps tendon

• distal end– rounded capitulum

articulates with head of radius– trochlea articulates with ulna – lateral and medial

epicondyles– olecranon fossa holds

olecranon process of ulna

Capitulum

Head

Trochlea(a) Anterior view (b) Posterior view

Greatertubercle

Lessertubercle

Intertubercularsulcus

Deltoidtuberosity

Coronoidfossa

Radialfossa

Lateralepicondyle

Surgicalneck

Greatertubercle

Anatomicalneck

Nutrientforamen

Deltoidtuberosity

Medialsupracondylar

ridge

Medialepicondyle

Lateralsupracondylarridge

Lateralepicondyle

Olecranonfossa


Figure 8.32

8-48

Radius

• radius– head – disc-shape, 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

– radial tuberosity for biceps muscle

– styloid process can be palpated near thumb

– ulnar notch

Figure 8.33

Olecranon Olecranon


Articular facets

Ulna

Radius

Ulnar tuberosity

Coronoid process

Trochlear notch

Radial notchof ulna

Head ofradiusNeck ofradius

Radialtuberosity

Styloidprocess

Interosseousborders

Interosseousmembrane

Ulnar notchof radius

Head of ulna

Styloid processStyloidprocess


Head ofradius

Neck ofradius

8-49

Ulna and Interosseous Membrane

• ulna– 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– ligament attaches radius to

ulna along interosseous margin of each bone

– enables the two elbow joints to share the load

Figure 8.33

Olecranon Olecranon


Articular facets

Ulna

Radius

Ulnar tuberosity

Coronoid process

Trochlear notch

Radial notchof ulna

Head ofradiusNeck ofradius

Radialtuberosity

Styloidprocess

Interosseousborders


Ulnar notchof radius

Head of ulna

Styloid processStyloidprocess

Head ofradius

Neck ofradius


8-50

Carpal Bones

Figure 8.34a

I

IIIIIIV

V

Distal phalanx II

Middle phalanx II

Proximal phalanx II

Head

Body

Base

Hamulus of hamateHamatePisiformTriquetrumLunate

CapitateTrapeziumTrapezoid

Body

Head

Scaphoid

Base

Phalanges

Key to carpal bones

Distal row

Proximal row

Distalphalanx I

Proximalphalanx I

Firstmetacarpal

Carpalbones

Metacarpalbones

Carpalbones


(a) Anterior view

8-51

Metacarpals and Phalanges

Figure 8.34a

I

IIIIIIV

V

Distal phalanx II

Middle phalanx II

Proximal phalanx II

Head

Body

Base

Hamulus of hamateHamatePisiformTriquetrumLunate

CapitateTrapeziumTrapezoid

Body

Head

Scaphoid

Base

Phalanges

Key to carpal bones

Distal row

Proximal row

Distalphalanx I

Proximalphalanx I

Firstmetacarpal

Carpalbones

Metacarpalbones

Carpalbones


(a) Anterior view

8-52

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 that is also part of the vertebral column

• 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 limbsand protects viscera, lower colon, urinary bladder, and internal reproductive organs

• sacroiliac joint - joins hipbone tothe vertebral column

– auricular surface of ileum to auricular surface of sacrum

• anteriorly, interpubic disc – pad of fibrocartilage joins pubic bones

• pubic symphysis – the interpubic disc and adjacent regions of the pubic bone on each side

Figure 8.35a

Ilium

Ischium

Coccyx

Body

Ramus

Pubis

(a) Anterosuperior view

Pubic symphysis

Acetabulum

Spine

Pelvic inlet

Sacroiliac joint

Body

Superior ramus

Inferior ramus

Iliaccrest

Iliacfossa

Anteriorsuperioriliac spine

Anterior inferioriliac spine

Base ofsacrum

Pelvic surfaceof sacrum

Interpubicdisc

Obturatorforamen


8-53

Pelvic Inlet and Outlet

• 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

Figure 8.35bFigure 8.35a

Ilium

Ischium

Coccyx

Body

Ramus

Pubis

(a) Anterosuperior view

Pubic symphysis

Acetabulum

Spine

Pelvic inlet

Sacroiliac joint

Body

Superior ramus

Inferior ramus

Iliaccrest

Iliacfossa

Anteriorsuperioriliac spine


Base ofsacrum

Pelvic surfaceof sacrum

Interpubicdisc

Obturatorforamen


(b) Median section

Pelvic inlet

Pelvic brim

Greater pelvis

Pelvic outlet


Lesserpelvis

8-54

Hip Bone• three distinct features of hip bone

– iliac crest – superior crest of hip– acetabulum – the hip socket– obturator foramen – large hole

below acetabulum

• each adult hip bone is formed by the fusion of three childhood bones– ileum

– ischium

– pubis (pubic bone)

Figure 8.36a


Ilium Ischium Pubis

Posterior superiorIliac spine

Anterior superioriliac spine

Greater sciatic notch

Inferior glutealline

Anterior glutealline

Ischial spine

Acetabulum

Ischial tuberosity

(a) Lateral view

Body of ischium

Lesser sciatic notch

Iliac crest


r

Body of ilium

Body of pubis

Inferior ramusof pubis

Obturator foramen

Ramus of ischium

Superior ramusof pubis

Posterior glutealline

Posterior inferiorIliac spine

8-55

Comparison of Male and Female

• 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


Male Female

90 120Pubic arch

Obturator foramen

Pelvic inlet

Pelvic brim

Figure 8.37

8-56

Lower Limb• Femur (upper leg)• Patella (knee cap)• medial tibia and lateral fibula (lower leg)• 7 tarsal bones, 5 metatarsals, and 14 phalanges in the toes (foot)

8-57

Femur • head that articulates with the acetabulum of the pelvis

– forms ball-and-socket joint

• greater and lesser trochanters for muscle attachment

• medial and lateral condyles and epicondyles found distally

Figure 8.38


Greater trochanter

Intertrochanteric line

Lateral epicondyle

Patellar surface

(b) Posterior view

Lateral epicondyle

Medial supracondylar line

Lateral condyle

Linea aspera

Intertrochanteric crest

Gluteal tuberosity

Greater trochanterHead

Fovea capitis

Neck

Lesser trochanter

Spiral line

Shaft

Medial epicondyle

Popliteal surface

Medial condyle Intercondylar fossa

Base of patellaArticular facets

Apex of patella

Lateral supracondylarline

(a) Anterior view

8-58

Tibia• tibia - thick, medial, weight-

bearing bone– medial and lateral condyles

• fairly flat articular surfaces• articulate with condyle of

femur

– tibial tuberosity – attachment of quadricep muscles

– medial malleolus – bony knob on inside of ankle

Lateral condyle

Apex

Head of fibula

Intercondylar eminence

Lateral surface

Distal tibiofibular joint

Lateral malleolus

Fibula

Anterior crest

Lateral malleolus

(b) Posterior view

Proximal tibiofibularjoint

Tibia

Medial malleolus

Medialcondyle

Tibialtuberosity


(a) Anterior view


Figure 8.39

8-59

Fibula• fibula – slender, lateral

strut that helps stabilizes ankle

• does not bear any body weight

• lateral malleolus - distal expansion, bony knob on lateral side of ankle

• joined to tibia by interosseous membrane

Lateral condyle

Apex

Head of fibula

Intercondylar eminence

Lateral surface

Distal tibiofibular joint

Lateral malleolus

Fibula

Anterior crest

Lateral malleolus

(b) Posterior view

Proximal tibiofibularjoint

Tibia

Medial malleolus

Medialcondyle

Tibialtuberosity


(a) Anterior view


Figure 8.39

8-60

The Ankle and Foot• tarsal bones – arranged in

proximal and distal groups

• calcaneus – largest tarsal bone– forms heel– distal portion is point of attachment

for calcaneal (Achilles) tendon• talus is most superior tarsal bone

– forms ankle joint with tibia and fibula

– sits upon calcaneus and articulates with navicular

Key to tarsal bones

Distal group

Proximal group

Distal phalanx I

Proximal phalanx I

Metatarsal

Medial cuneiform

Intermediate cuneiform

Lateral cuneiform

Navicular

Talus

(a) Superior (dorsal) view

Calcaneus

Cuboid

V

IVIIIIII

Trochlear surfaceof talus

Tuberosity of calcaneus

Proximalphalanx V

Middlephalanx V

Distalphalanx V


Figure 8.40a

8-61

The Foot• remaining bones of foot are

similar in name and arrangement to the hand

• metatarsals

• phalanges

Key to tarsal bones

Distal group

Proximal group

Distal phalanx I

Proximal phalanx I

Metatarsal

Medial cuneiform

Intermediate cuneiform

Lateral cuneiform

Navicular

Talus

(a) Superior (dorsal) view

Calcaneus

Cuboid

V

IVIIIIII

Trochlear surfaceof talus

Tuberosity of calcaneus

Proximalphalanx V

Middlephalanx V

Distalphalanx V


Figure 8.40a

The Skeletal System - Dr. Michael...

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