Download 7-2

Chapter 7
The Skeletal System:The Axial Skeleton
• Axial Skeleton
– 80 bones
– lie along longitudinal axis
– skull, hyoid, vertebrae,
ribs, sternum, ear ossicles
• Appendicular Skeleton
– 126 bones
– upper & lower limbs and
pelvic & pectoral girdles
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The Skeletal System-Function
1. Support
2. Protection
3. Movement
4. Mineral storage
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Types of Bones
•
5 basic types of bones:
1. long = compact
2. short = spongy except
surface
3. flat = plates of compact
enclosing spongy
4. irregular = variable
5. sesamoid = develop in
tendons or ligaments
(patella)
•
Sutural bones = in joint
between skull bones
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Anatomy of a Long Bone
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•
•
Diaphysis = shaft
Epiphysis = one end of a long bone
Metaphysis = growth plate region
Articular cartilage over joint surfaces
acts as friction & shock absorber
• Medullary cavity = marrow cavity
• Endosteum = lining of marrow cavity
• Periosteum = tough membrane
covering bone but not the cartilage
– fibrous layer = dense irregular CT
– osteogenic layer = bone cells & blood
vessels that nourish or help with repairs
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Compact or Dense Bone
• Looks like solid hard
layer of bone
• Makes up the shaft of
long bones and the
external layer of all
bones
• Resists stresses
produced by weight
and movement
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The Trabeculae of Spongy Bone
• Latticework of thin plates of bone called
trabeculae oriented along lines of stress
• Spaces in between these struts are filled with red
marrow where blood cells develop
• Found in ends of long bones and inside flat bones
such as the hipbones, sternum, sides of skull, and
ribs.
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Bone Growth and Repair
7-7
The Skull
• 8 Cranial bones
– protect brain & house ear ossicles
– muscle attachment for jaw, neck & facial muscles
• 14 Facial bones
– protect delicate sense organs -- smell, taste, vision
– support entrances to digestive and respiratory systems
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The 8 Cranial Bones
Frontal
Parietal (2)
Temporal (2)
Occipital
Sphenoid
Ethmoid
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14 Facial Bones
Nasal (2)
Mandible (1)
Inferior nasal conchae (2)
Maxillae (2)
Lacrimal (2)
Zygomatic (2)
Palatine (2)
Vomer (1)7-10
Le Fort Fractures
7-11
Sutures
• Lambdoid suture unites parietal and occipital
• Sagittal suture unites 2 parietal bones
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Sutures
• Coronal suture unites frontal and both parietal bones
• Squamous suture unites parietal and temporal bones
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Paranasal Sinuses
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Paired cavities in ethmoid, sphenoid, frontal and maxillary
Lined with mucous membranes and open into nasal cavity
Resonating chambers for voice, lighten the skull
Sinusitis is inflammation of the membrane (allergy)
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Fontanels of the Skull at Birth.
• Dense connective tissue membrane-filled
spaces
(soft spots)
• Unossified at birth but close early in a child's
life.
• Fetal skull passes
through the birth
canal.
• Rapid growth of the
brain during infancy
7-15
Vertebral Column
• Backbone or spine built of
26 vertebrae
• Five vertebral regions
– cervical vertebrae (7) in
the neck
– thoracic vertebrae ( 12 ) in
the thorax
– lumbar vertebrae ( 5 ) in the
low back region
– sacrum (5, fused)
– coccyx (4, fused)
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Normal Curves of the Vertebral Column
• Primary curves
– thoracic and sacral are formed during fetal development
• Secondary curves
– cervical if formed when infant raises head at 4 months
– lumbar forms when infant sits up & begins to walk at 1 year
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Typical Vertebrae
• Body
– weight bearing
• Vertebral arch
– pedicles
– laminae
• Vertebral foramen
• Seven processes
– 2 transverse
– 1 spinous
– 4 articular
• Vertebral notches
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Typical Cervical Vertebrae (C3-C7)
• Smaller bodies
• Larger spinal canal
• Transverse processes
– shorter
– transverse foramen
for vertebral artery
• Spinous processes of
C2 to C6 often bifid
• 1st and 2nd cervical
vertebrae are unique
– atlas & axis
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Atlas & Axis (C1-C2)
• Atlas -- ring of bone, superior facets for occipital condyles
– nodding movement at atlanto-occipital joint signifies “yes”
• Axis -- dens or odontoid process is body of atlas
– pivotal movement at atlanto-axial joint signifies “no”
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Thoracic Vertebrae
(T1-T12)
• Larger and stronger bodies
• Longer transverse &
spinous processes
• Facets or demifacets on
body for head of rib
• Facets on transverse
processes (T1-T10) for
tubercle of rib
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Lumbar Vertebrae
• Strongest & largest
• Short thick spinous &
transverse processes
– back musculature
7-22
Sacrum and Coccyx
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Union of 5 vertebrae (S1 - S5) by age 30
Sacral canal ends at sacral hiatus
Auricular surface & sacral tuberosity of SI joint
Coccyx- Union of 4 vertebrae (Co1 - Co4) by age 30
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Thorax
– Bony cage flattened
from front to back
– Sternum (breastbone)
– Ribs
• 1-7 are true ribs
• 8-12 are false ribs
• 11-12 are floating
– Costal cartilages
– Bodies of the
thoracic vertebrae.
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Sternum
• Manubrium
– 1st & 2nd ribs
– clavicular notch
• Body
– costal cartilages
of 2-10 ribs
• Xiphoid
– ossifies by 40
– CPR position
– abdominal mm.
• Sternal puncture
– biopsy
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Ribs
Fracture at site of
greatest curvature.
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Increase in length from ribs 1-7, thereafter decreasing
Head and tubercle articulate with facets
Body with costal groove containing nerve & blood vessels
Intercostal spaces contain intercostal muscles
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Rib Articulation
• Tubercle articulates with transverse process
• Head articulates with vertebral bodies
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Chapter 8
Skeletal System: Appendicular Skeleton
• Pectoral girdle
• Pelvic girdle
• Upper limbs
• Lower limbs
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Pectoral (Shoulder) Girdle
• Consists of scapula and clavicle
• Clavicle articulates with sternum
(sternoclavicular joint)
• Clavicle articulates with scapula
(acromioclavicular joint)
• Scapula held in place by muscle only
• Upper limb attached to pectoral girdle at
shoulder (glenohumeral joint)
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Upper Extremity
• Each upper limb = 30
bones
– humerus within the arm
– ulna & radius within the
forearm
– carpal bones within the
wrist
– metacarpal bones within the
palm
– phalanges in the fingers
• Joints
– shoulder (glenohumeral),
elbow, wrist,
metacarpophalangeal,
interphalangeal
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Pelvic Girdle and Hip Bones
• Pelvic girdle = two hipbones united at pubic symphysis
– articulate posteriorly with sacrum at sacroiliac joints
• Each hip bone = ilium, pubis, and ischium
– fuse after birth at acetabulum
• Bony pelvis = 2 hip bones, sacrum and coccyx
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Lower Extremity
• Each lower limb = 30 bones
– femur and patella within the
thigh
– tibia & fibula within the leg
– tarsal bones in the foot
– metatarsals within the forefoot
– phalanges in the toes
• Joints
– hip, knee, ankle
– proximal & distal tibiofibular
– metatarsophalangeal
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Chapter 9: Classification of Joints
• Structural classification based upon:
– presence of space between bones-Synovial
space
– type of connective tissue holding bones
together
• collagen fibers
• cartilage
• joint capsule & accessory ligaments
• Fibous Joints, Cartilageous and synovial
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Fibrous Joints
• Lack a synovial cavity
• Bones held closely together by fibrous
connective tissue
• Little or no movement
• 3 structural types
– Sutures - skull
– Syndesmoses- growth plate
– Gomphosese.eg. teeth
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Sutures
• Thin layer of dense
fibrous connective
tissue unites bones of
the skull
• Immovable
• If fuse completely in
adults
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Cartilaginous Joints
• Lacks a synovial cavity
• Allows little or no movement
• Bones tightly connected by fibrocartilage or
hyaline cartilage
• 2 types
– Synchondroses=growth plate
– symphyses
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Synchondrosis-Growth Plates
-Epiphyseal Plate-
• Connecting material is hyaline cartilage
• Immovable
• =Epiphyseal plate or joints between ribs and
sternum
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Symphysis
• Fibrocartilage is
connecting material
• Slightly movable
• E.g. Intervertebral
discs and pubic
symphysis
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Synovial Joints
• Synovial cavity separates
articulating bones
• Freely moveable
• cartilage
– reduces friction
– absorbs shock
• capsule
– surrounds joint
– thickenings in fibrous
capsule called ligaments
• Synovial membrane
– inner lining of capsule
– secretes synovial fluid containing
hyaluronic acid slippery)
– brings nutrients to cartilage
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Other Special Features
• Accessory ligaments
• Articular discs or menisci
– attached around edges to capsule
– allow 2 bones of different shape to fit
tightly
– increase stability of knee - torn
cartilage
• Bursae = saclike structures
between structures -bursitis
– skin/bone or tendon/bone or
ligament/bone
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Planar Joint (Plane)-Gliding
• Bone surfaces are flat or
slightly curved
• Side to side movement only
• Rotation prevented by
ligaments
• Examples
– intercarpal or intertarsal
joints
– sternoclavicular joint
– vertebrocostal joints
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Hinge Joint
• Convex surface of one
bones fits into concave
surface of 2nd bone
• Uniaxial like a door hinge
• Examples
– Knee, elbow, ankle,
interphalangeal joints
• Movements produced
– flexion = decreasing the joint
angle
– extension = increasing the
angle
– hyperextension = opening the
joint beyond the anatomical
position
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Flexion, Extension & Hyperextension
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Pivot Joint
• Rounded surface of bone
articulates with ring formed
by 2nd bone & ligament
• Monoaxial since it allows
only rotation around
longitudinal axis
• Examples
– Proximal radioulnar joint
• supination
• pronation
– Atlanto-axial joint
• turning head side to side “no”
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Abduction and Adduction
Condyloid joints
Ball and Socket joints
7-45
Ball and Socket Joint
• Ball fitting into a
cuplike depression
• Multiaxial
– flexion/extension
– abduction/adduction
– rotation
• Examples
– shoulder joint
– hip joint
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Circumduction
• Movement of a distal end of a body part in a circle
• Combination of flexion, extension, adduction and
abduction
• Occurs at ball and socket, saddle and condyloid
joints
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Rotation
• Bone revolves around its own
longitudinal axis
– medial rotation is turning of
anterior surface in towards the
midline
– lateral rotation is turning of
anterior surface away from the
midline
• At ball & socket and pivot type
joints
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Special Movements of Mandible
• Elevation = upward
• Depression =
downward
• Protraction = forward
• Retraction =
backward
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Special Hand & Foot Movements
Inversion
Eversion
Dorsiflexion
Plantarflexion
Pronation
Supination
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Homework
• See sheet
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