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SKELETAL SYSTEM. SKELETAL SYSTEM. Form strong & flexible body framework Bone 206 bones in human skeleton Cartilage All three types Ligaments. SKELETAL CARTILAGE. Cartilage tissue High water content Confers resilience Avascular, no nerves

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skeletal system2
SKELETAL SYSTEM
  • Form strong & flexible body framework
  • Bone
    • 206 bones in human skeleton
  • Cartilage
    • All three types
  • Ligaments
skeletal cartilage
SKELETAL CARTILAGE
  • Cartilage tissue
  • High water content
    • Confers resilience
  • Avascular, no nerves
  • Surrounded by dense irregular connective tissue
    • “Perichondrium”
    • Vascular, supplies nutrients
    • Prevents outward expansion of cartilage during compression
  • All three types of cartilage represented
    • Hyaline cartilage
    • Elastic cartilage
    • Fibrocartilage
skeletal cartilage4
SKELETAL CARTILAGE

Hyaline cartilage

  • Most abundant skeletal cartilage
  • Chondrocytes, fine collagen fibers
  • Subtypes
    • Articular cartilages
      • Cover ends of most bones at movable joints
    • Costal cartilages
      • Connect ribs to sternum
    • Respiratory cartilages
      • Form skeleton of larynx
      • Reinforce other respiratory organs
    • Nasal cartilages
      • Support the external nose
skeletal cartilage5
SKELETAL CARTILAGE

Elastic cartilage

  • Similar to hyaline cartilage
  • Contain more stretchy elastic fibers
  • Withstand repeated bending
  • Locations
    • External ear
    • Epiglottis
skeletal cartilage6
SKELETAL CARTILAGE

Fibrocartilage

  • Highly compressible
  • Great tensile strength
  • Intermediate between hyaline and elastic cartilages
  • Parallel rows of chondrocytes alternating with thick collagen fibers
  • Occur in areas subjected to heavy pressure and stretch
    • e.g., knee, between vertebrae
cartilage growth
CARTILAGE GROWTH
  • Appositional growth
    • Cartilage-forming cells in perichondrium secrete new matrix against external face of existing cartilage tissue
    • “Growth from the outside”
  • Interstitial growth
    • Lacunae-bound chondrocytes divide and secrete new matrix
    • “Growth from the inside”
  • Cartilage growth typically ends during adolescence
bones
BONES
  • 206 named bones of human skeleton
  • Divided into two groups
  • Axial skeleton
    • Forms long axis of body
    • Includes bones of skull, vertebral column, and rib cage
  • Appendicular skeleton
    • Consists of bones of limbs and girdles attaching these bones to the axial skeleton
      • Arms, legs, hip bones, shoulder bones
bone shapes
Long bones

Short bones

Flat bones

Irregular bones

BONE SHAPES
bone shapes10
BONE SHAPES

Long bones

  • e.g., femur, humerus, tibia, fibula, radius, ulna
  • Longer than wide
  • Rigid levers + muscle  movement

Short bones

  • e.g., carpals, tarsals
  • Similar in length and width
  • Glide across each other
bone shapes11
BONE SHAPES

Flat bones

  • e.g., scapula, ribs, sternum, os coxae, most cranial bones
  • Enclose and protect soft organs
  • Provide broad surfaces for muscle attachment

Irregular bones

  • e.g., vertebrae, some skull bones (sphenoid, ethmoid)
  • Elaborate shapes
bone functions
BONE FUNCTIONS
  • Support
  • Protection
    • e.g., ribs, skull
  • Movement
    • Muscles use bones as levers to move
  • Mineral storage
    • Most importantly Ca & P
  • Hematopoiesis
    • Formation of most of the circulating blood cells
bone structure
BONE STRUCTURE
  • Bones are organs containing various types of tissue
  • Osseous tissue dominates bones
  • Bones also contain
    • Nervous tissue in nerves
    • Cartilage tissue in articular cartilages
    • Fibrous connective tissue lining cavities
    • Muscle and epithelial tissue in blood vessels
bone structure14
BONE STRUCTURE

Gross Anatomy: Bone Markings

  • Bone surfaces display various features
    • “Bone markings”
    • Depressions, projections, & openings
      • Sites of muscle, ligament, and tendon attachment
      • Joint surfaces
      • Conduits for muscles or nerves
bone structure15
BONE STRUCTURE

Gross Anatomy: Bone Textures

  • Dense outer layer
    • “Compact bone”
    • Appears smooth to naked eye
  • Honeycomb-like inner layer
    • “Spongy bone”
    • Small needle-like or flat pieces (“trabeculae”)
    • Spaces between trabeculae filled with bone marrow
      • Red or yellow bone marrow
bone structure16
BONE STRUCTURE

Gross Anatomy: Long Bone Structure

  • Diaphysis
    • Shaft forming long axis of bone
    • Relatively thick collar of compact bone
    • Central medullary cavity
      • “Marrow cavity”
      • Yellow bone marrow cavity
      • Contains fat in adults
bone structure17
BONE STRUCTURE

Gross Anatomy: Long Bone Structure

  • Epiphyses
    • Bone ends
    • Generally more expanded than diaphysis
    • Compact bone forms exterior
    • Spongy bone forms interior
    • Joint surface covered with thin layer of articular (hyaline) cartilage
      • Absorbs stress, cushions during movement
bone structure18
BONE STRUCTURE

Gross Anatomy: Long Bone Structure

  • Epiphyseal line
    • a.k.a., “metaphysis”
    • Found between diaphysis and each epiphysis of adult long bone
    • Remnant of epiphyseal plate
      • Hyaline cartilage disk that grows during childhood to lengthen bone
bone structure19
BONE STRUCTURE

Gross Anatomy: Long Bone Structure

  • Membranes
    • Most of external surface of entire bone is covered by a double-layered membrane
      • “Periosteum”
      • Absent on joint surfaces
bone structure20
BONE STRUCTURE

Gross Anatomy: Long Bone Structure

  • Membranes: Periosteum
    • Outer fibrous layer is dense irregular connective tissue
    • Inner osteogenic layer consists mainly of osteoblasts and osteoclasts
      • Osteoblasts are bone-forming cells
      • Osteoclasts are bone-destroying cells
bone structure21
BONE STRUCTURE

Gross Anatomy: Long Bone Structure

  • Membranes: Periosteum
    • Numerous nerve fibers, lymphatic vessels, & blood vessels
      • Enter diaphysis via a nutrient foramen
    • Secured to underlying bone by perforating fibers
      • a.k.a., “Sharpey’s fibers”
      • Tufts of collagen fibers
bone structure22
BONE STRUCTURE

Gross Anatomy: Long Bone Structure

  • Membranes: Endosteum
    • Internal bone surfaces covered with delicate membrane
      • “Endosteum”
      • Contains both osteoblasts and osteoclasts
bone structure23
BONE STRUCTURE

Gross Anatomy: Structure of Short, Irregular, & Flat Bones

  • Outside: thin plates of periosteum-covered compact bone
  • Inside: endosteum-covered spongy bone
  • Not cylindrical
    • No diaphysis, epiphyses
  • Contain marrow between trabeculae
    • No marrow cavity
bone structure24
BONE STRUCTURE

Gross Anatomy: Location of Hematopoietic Tissue in Bones

  • “Red marrow” typically found within trabecular cavities of spongy bone within long bones
    • Medullary cavity of diaphysis also filled with red marrow in newborn
    • Medullary cavity contains fat in adult long bones
      • Fat extends into epiphyses
      • Only head of femur and humerus possess red marrow
      • Most blood cell production occurs elsewhere
        • Flat bones (e.g., sternum) & irregular bones (e.g., hip bone)
      • Yellow marrow in medullary cavity can revert to red marrow in the severely anemic
bone structure25
BONE STRUCTURE

Microscopic Anatomy: Compact Bone

  • Compact bone appears dense and solid
  • Actually contains numerous passageways
    • Conduits for nerves, blood & lymphatic vessels
bone structure26
BONE STRUCTURE

Microscopic Anatomy: Compact Bone

  • Structural unit of compact bone is the osteon
    • a.k.a., Haversian system
    • Elongated cylinder parallel to long axis of bone
      • Tiny, weight-bearing pillars
bone structure27
BONE STRUCTURE

Microscopic Anatomy: Compact Bone

  • Osteon
    • Group of concentric hollow tubes
      • “Lamellae”
      • (Compact bone is sometimes called “lamellar bone)
bone structure28
BONE STRUCTURE

Microscopic Anatomy: Compact Bone

  • Not all lamellae are part of an osteon
    • Interstitial lamellae are incomplete lamellae between osteons
    • Circumferential lamellae extend around circumference of diaphysis
      • Just deep to the periosteum and just superficial to the endosteum
bone structure29
BONE STRUCTURE

Microscopic Anatomy: Compact Bone

  • Osteon
    • Collagen fibers
      • Parallel within each lamella
      • Perpendicular in adjacent lamella
      • Arrangement withstands twisting force ( torsion)
    • Crystals of bone salts align with collagen fibers
bone structure30
BONE STRUCTURE

Microscopic Anatomy: Compact Bone

  • Osteon
    • Central canal runs through osteon core
      • a.k.a., Haversian canal
      • Lined with endosteum
      • Contains nerve fibers and small blood vessels
bone structure31
BONE STRUCTURE

Microscopic Anatomy: Compact Bone

  • Osteon
    • Perforating canals lie at right angles to long axis of bone
      • a.k.a., Volkman’s canals
      • Lined with endosteum
      • Connect to blood and nerve supply of periosteum
      • (Also connects to that of medullary cavity)
bone structure32
BONE STRUCTURE

Microscopic Anatomy: Compact Bone

  • Osteon
    • Osteocytes occupy lacunae between lamellae
      • Mature bone cells
    • Lacunae connected by canaliculi
      • Hair-like canals
      • Also connect to central canal
bone structure33
BONE STRUCTURE

Microscopic Anatomy: Compact Bone Formation

  • Osteoblasts surround blood vessels
    • Maintain contact through gap junctions
  • Osteoblasts secrete bone matrix
    • Mature cells become trapped as matrix hardens
    • Canaliculi form around processes
    • Osteocytes are all connected through these canaliculi
      • Nutrients shared, wastes jointly removed
bone structure34
BONE STRUCTURE

Microscopic Anatomy: Spongy Bone

  • Appears poorly organized
    • Trabeculae contain irregularly arranged lamellae and osteocytes
      • No osteons
  • Trabeculae align along lines of stress
    • Help bone resist stress
    • (similar to flying buttresses of a Gothic cathedral)
  • Nutrients: capillaries of endosteum  canaliculi  osteocytes
bone composition
BONE COMPOSITION

Organic Components

  • Cells
    • Osteoblasts, -clasts, & -cytes
  • Osteoid
    • Organic ~1/3 portion of matrix
      • Ground substance
        • Proteoglycans & glycoproteins
      • Collagen fibers
    • Contribute to structure, flexibility, and tensile strength
bone composition36
BONE COMPOSITION

Inorganic Components

  • ~65% of bone mass
  • Hydroxyapatites
    • a.k.a., Mineral salts
    • Mainly calcium phosphate
  • Form tiny, tightly-packed crystals surrounding collagen fibers
  • Impart hardness
    • Ability to resist compression
bone development
BONE DEVELOPMENT

Ossification / osteogenesis

  • Process of bone formation
    • Formation of the bony skeleton in the embryo
    • Bone growth until early adulthood
    • Bone remodeling throughout life
skeleton formation
SKELETON FORMATION
  • Prior to week 8
    • Embryonic skeleton is comprised of hyaline cartilage and fibrous membranes
  • Week 8 and beyond
    • Bone tissue begins to develop
    • Majority of fibrous or cartilaginous structures eventually replaced with bone
    • Fibrous membrane  (membrane) bone
      • Intramembranous ossification
    • Hyaline cartilage  (cartilage) bone
      • Endochondral ossification
ossification
OSSIFICATION

Intramembranous Ossification

  • Formation of clavicles and cranial bones
ossification40
OSSIFICATION

Endochondral Ossification

  • Formation of almost all bones
postnatal growth
POSTNATAL GROWTH
  • Long bones lengthen by interstitial growth of epiphyseal plates
    • “Growth from the inside”
  • All bones grow in thickness by appositional growth
    • “Growth from the outside”
  • Most bones stop growing during adolescence
    • Some bones continue very slow growth
      • e.g. some bones of nose and lower jaw
long bone growth
LONG BONE GROWTH
  • Cartilage of epiphyseal plate
    • Inactive on side facing epiphysis
    • Active on side facing diaphysis
      • Rapid mitosis forms tall columns of chondrocytes
      • Cells at “top” push epiphysis away from diaphysis
      • Long bone lengthens
  • Then…
    • “Bottom” chondrocytes hypertrophy
    • Lacunae erode & enlarge
    • Surrounding cartilage matrix calcifies
    • Chondrocytes die and deteriorate
long bone growth43
LONG BONE GROWTH
  • Long spicules of calcified cartilage
    • (This is different than bone)
    • Invaded by marrow elements from medullary cavity
    • Spicules partially eroded by osteoclasts
    • Spicules covered with bone matrix
    • Spongy bone formed
    • Spicule tips ultimately digested by osteoclasts
    • Medullary cavity grows longer
long bone growth44
LONG BONE GROWTH
  • Epiphyseal plate maintains a constant thickness
    • Rate of cartilage growth = rate of replacement
  • Longitudinal growth is accompanied by remodeling of epiphyseal ends
    • Involves new bone formation
    • Involves bone reabsorption
    • (More on this later)
  • End of adolescence
    • Epiphyseal plate chondrocytes divide less often
    • Plates become thinner
    • Entire replacement  epiphyseal line
      • “Epiphyseal plate closure” at ~18 (♀) – 21 (♂)
long bone growth45
LONG BONE GROWTH

Growth in Width

  • Growing bones widen as they lengthen
    • Appositional growth
      • “Growth from the outside”
  • Two processes
    • Osteoblasts beneath periosteum secrete bone matrix onto external bone surface
    • Osteoclasts on endosteal surface remove bone
bone growth
BONE GROWTH

Hormonal Regulation

  • Growth of epiphyseal plate stimulated by growth hormone
    • Released by pituitary
    • Activity modulated by thyroid hormone
  • Regulated by testosterone and estrogens
    • Growth spurt in adolescence
    • Masculinization / feminization of skeleton
    • Later induce epiphyseal plate closure
bone remodeling
BONE REMODELING
  • Bone tissue is active and dynamic
    • ~5-7% of bone mass recycled weekly
    • Spongy bone replacement every ~3-4 years
    • Compact bone replacement every ~10 years
  • Bone deposition and absorption
    • Occur at surfaces
      • Periosteum and endosteum
    • Coordinated by packets of cells
      • Osteoblasts and osteoclasts
bone deposition
BONE DEPOSITION
  • Occurs when bone is injured
  • Occurs when added bone strength is required
bone resorption
BONE RESORPTION
  • Accomplished by osteoclasts
    • Giant multinucleate cells
      • Arise from hematopoietic stem cells
        • Same cells give rise to macrophages
    • Dig grooves into bone surface
      • “Resorption bays”
    • Release of HCl and lysosomal enzymes
      • Solubilizes calcium salts
    • Phagocytosis of demineralized matrix
remodeling control
REMODELING CONTROL

Hormonal negative feedback mechanism

  • Maintains blood Ca2+ homeostasis
    • Calcium is important in many processes
      • Nerve impulses
      • Muscle contraction
      • Blood coagulation
      • Secretion
      • Cell division
      • Etc.
remodeling control51
REMODELING CONTROL

Hormonal negative feedback mechanism

  • Regulated by two hormones
    • Parathyroid hormone (PTH)
      • Produced in parathyroid
      • Low [Ca2+]  release
      • Osteoclasts stimulated
    • Calcitonin
      • Produced in thyroid
      • High [Ca2+]  release
      • Inhibits resorption
      • Stimulated salt deposition
remodeling control52
REMODELING CONTROL

Response to mechanical & gravitational forces

  • Bone is remodeled in response to demands placed upon it
    • Hormonal mechanisms act to regulate blood Ca2+ levels
  • Bone deposition occurs where stress occurs
    • Hormonal regulation determines if bone remodeling will occur, mechanical stress determines where it will occur
    • e.g., Stronger compact bone on outside
    • e.g., Bony projections at sites of muscle attachment
bone repair
BONE REPAIR
  • Bones are susceptible to fractures
  • Fractures classified by
    • Position of bone ends after fracture
      • Displaced vs. nondisplaced (alignment altered)
    • Completeness of break
      • Complete vs. incomplete
    • Orientation of break relative to long axis of bone
      • Linear (parallel) vs. transverse (perpendicular)
    • Whether bone ends penetrate skin
      • Open (ends penetrate skin) vs. closed
bone repair54
BONE REPAIR
  • Treated by reduction
    • Realignment of bone ends
    • Closed reduction
      • Coaxed into place by hand
    • Open reduction
      • Bone ends surgically secured together
  • Immobilization follows reduction
    • Facilitates healing
bone repair55
BONE REPAIR
  • Bone repair involves multiple steps
    • Hematoma formation
    • Fibrocartilaginous callus formation
    • Bony callus formation
    • Bone remodeling
bone repair56
BONE REPAIR

Hematoma formation

  • Blood vessels are torn and hemorrhage
    • Bone, periosteum, surrounding tissue
  • Hematoma formed at fracture site
    • Mass of clotted blood
  • Some cell death, swelling, pain, inflammation
bone repair57
BONE REPAIR

Fibrocartilaginous callus formation

  • Formation of soft granulation tissue (“soft callus”)
    • Capillaries grow into hematoma
    • Phagocytic cells enter
      • Clean up debris
    • Fibroblasts, osteoblasts enter
      • Produce collagen fibers
        • Span break, connect broken bone ends
      • Some differentiate into chondroblasts
        • Secrete cartilage matrix
    • Osteoblasts enter
      • Form spongy bone
bone repair58
BONE REPAIR

Bony callus formation

  • New bone trabeculae appear in fibrocartilaginous callus within ~ 1 week
    • Gradual conversion to bony (hard) callus
      • Spongy bone
bone repair59
BONE REPAIR

Bone remodeling

  • Bony callus is remodeled
    • Begins during bony callus formation
    • Continues for several months
    • Excess material removed
    • Compact bone laid down
bone imbalances
Osteoporosis

Bone resorption outpaces bone deposition

Bones become fragile

Spine, neck of femur especially susceptible

Occurs most often in aged

Especially postmenopausal women

Estrogen and testosterone reduce osteoclast activity

Treatment

Calcium, vitamin D supplements

Hormone (estrogen) replacement therapy

Slows loss, does not reverse loss

BONE IMBALANCES
what are joints
WHAT ARE JOINTS?
  • a.k.a., “Articulations”
  • Sites where two or more bones meet
  • Functions
    • Hold skeleton together
    • Confer mobility
joint classification
Functional classification

Synarthroses

Immovable joints

Amphiarthroses

Slightly movable joints

Diarthroses

Freely movable joints

Structural classification

Fibrous joints

Generally immovable

Cartilaginous joints

Some immovable

Some slightly movable

Synovial joints

Generally freely movable

JOINT CLASSIFICATION
fibrous joints
FIBROUS JOINTS
  • Bones joined by fibrous tissue
  • No joint cavity present
  • Most immovable, some slightly movable
    • Amount of movement dependent on length of connective tissue fibers connecting bones
  • Three types
    • Sutures
    • Syndesmoses
    • Gomphoses
fibrous joints65
FIBROUS JOINTS

Sutures

  • Occur only between bones of the skull
    • Wavy articulating bone edges interlock
    • Junction filled with very short connective tissue fibers
      • Continuous with periosteum
  • Functions
    • Hold bones tightly together
    • Allow bone growth during youth
      • Ossified later in life
        • “Synostoses”
fibrous joints66
FIBROUS JOINTS

Syndesmoses

  • Bones connected by a ligament
    • Cord or band of fibrous tissue
      • Variable length, but longer than fibers in sutures
      • Amount of movement depends on length of fibers
      • e.g., short tibia-to-fibula ligament  slight movement
      • e.g., longer radius-to-ulna connection  allows rotation
fibrous joints67
FIBROUS JOINTS

Gomphoses

  • Peg-in-socket fibrous joint
  • Articulation of tooth into alveolar socket
  • Fibrous connection is short peridontal ligament
cartilaginous joints
CARTILAGINOUS JOINTS
  • Articulating bones joined by cartilage
  • Lack a joint cavity
  • Two types
    • Synchondroses
    • Symphyses
cartilaginous joints69
CARTILAGINOUS JOINTS

Synchondroses

  • Bar or plate of hyaline cartilage unites bones
    • Generally immovable joints
    • e.g., Epiphyseal plate joining diaphysis to epiphysis (a temporary joint)
    • e.g., Joint between sternum and ribs
cartilaginous joints70
CARTILAGINOUS JOINTS

Symphyses

  • Amphiarthrotic joints
    • Limited movement
  • Articular surfaces of bones covered with articular (hyaline) cartilage
    • Cartilage fused to shock-absorbing pad of fibrocartilage
  • e.g., Intervertebral joints, pubic symphysis
synovial joints
SYNOVIAL JOINTS
  • Articulating bones separated by a fluid-filled joint cavity
    • Permits freedom of movement
  • Features
    • Articular cartilage
    • Joint cavity (synovial cavity)
    • Articular capsule
    • Synovial fluid
    • Reinforcing ligaments
synovial joints72
SYNOVIAL JOINTS

Articular Cartilage

  • Hyaline cartilage covers opposing bone surfaces
    • Thin (1 mm thick or less)
    • Spongy, cushioning

Joint Cavity (Synovial Cavity)

  • Potential space containing small amount of fluid
synovial joints73
SYNOVIAL JOINTS

Articular Capsule

  • Two-layered capsule enclosing joint cavity
  • External layer is fibrous capsule
    • Dense irregular connective tissue
    • Continuous with periostea
    • Strengthens joint
  • Inner layer is a synovial membrane
    • Loose connective tissue
    • Covers all internal joint surfaces not hyaline cartilage
synovial joints74
SYNOVIAL JOINTS

Synovial Fluid

  • Occupies all free space within capsule
    • Also present within cartilages
  • Viscous fluid
    • Large amount of hyaluronic acid
    • Reduces friction between cartilages

Reinforcing Ligaments

  • Numerous band-like ligaments
    • Mainly thickened parts of fibrous capsule
    • Reinforce and strengthen joint
synovial joints75
SYNOVIAL JOINTS
  • Some synovial joints have additional features
  • Fatty pads between fibrous capsule and synovial membrane or bone
    • Provide cushioning
    • e.g., hip and knee joints
  • Fibrocartilage disks separating articular surfaces
    • “Articular disks” / “menisci”
    • Improve fit between articulating bone ends
      • Stabilize joint
      • Reduce wear and tear
    • e.g., knee, jaw
synovial joints76
SYNOVIAL JOINTS

Bursae and Tendon Sheaths

  • Closely associated with synovial joints
  • Bags of lubricant
    • Reduce friction
  • Bursae
    • Flattened fibrous sacs
    • Lined with synovial membrane
    • Filled with synovial fluid
  • Tendon sheath
    • Elongated bursa wrapping around a tendon
synovial joints77
SYNOVIAL JOINTS

Factors Influencing Stability

  • Shapes of articular surfaces
    • Determine possible movements
    • Generally minor role in joint stability
      • Ball and deep socket of hip does provide stability
  • Number and positioning of ligaments
    • More ligaments = stronger joint
    • Insufficient alone
  • Muscle tone
    • Muscle tendons crossing joint usually most important stabilizing factor
    • Muscle tone keeps tendons taut
    • Especially important in shoulder, knee, arch of feet
synovial joints78
SYNOVIAL JOINTS

Movements Allowed by Synovial Joints

  • Skeletal muscles attached to bone or other features at two or more points
    • Muscle’s origin attached to less movable bone
    • Muscle’s insertion attached to movable bone
  • Movement occurs when muscles contract across joints
    • Insertion moves toward origin
    • Different joints allow different types of movement
synovial joints79
SYNOVIAL JOINTS

Gliding Movements

  • One flat or nearly flat bone surface glides or slips over another without appreciable angulation or rotation
synovial joints80
SYNOVIAL JOINTS

Angular Movements

  • Increase or decrease angle between two bones
  • May occur in any body plane
  • Include
    • Flexion
    • Extension
    • Hyperextension
    • Abduction
    • Adduction
    • Circumduction
synovial joints81
SYNOVIAL JOINTS

Angular Movements: Flexion

  • Bending movement decreasing angle of joint
    • Brings articulating bones closer together
    • Bending usually along sagittal plane
synovial joints82
SYNOVIAL JOINTS

Angular Movements: Extension & Hyperextension

  • Reverse of flexion occurring at same joints
    • Bending movement increasing angle of joint
    • Brings articulating bones further apart
synovial joints83
SYNOVIAL JOINTS

Angular Movements: Dorsiflexion & Plantar Flexion

  • Up-and-down movements of the foot at the ankle joint
synovial joints84
SYNOVIAL JOINTS

Angular Movements: Abduction

  • Movement of a limb along frontal plane & away from midline or median plane of body
synovial joints85
SYNOVIAL JOINTS

Angular Movements: Adduction

  • Opposite of abduction
  • Movement of a limb along frontal plane & toward midline or median plane of body
synovial joints86
SYNOVIAL JOINTS

Angular Movements: Circumduction

  • Moving a limb to describe a cone in space
  • Flexion, abduction, extension, & adduction performed in succession
  • Quickest way to exercise the many muscles moving hip and shoulder ball-in-socket joints
synovial joints87
SYNOVIAL JOINTS

Rotation

  • The turning of a bone around its long axis
    • Only movement allowed between first two cervical vertebrae
    • Common at the hip
synovial joints88
SYNOVIAL JOINTS

Special Movements: Supination & Pronation

  • Movement of radius around ulna
    • Supination = “turning backward”
    • Pronation = “turning forward”
synovial joints89
SYNOVIAL JOINTS

Special Movements: Inversion & Eversion

  • Special movement of the feet
    • Inversion: sole turns medially
    • Eversion: sole turns laterally
synovial joints90
SYNOVIAL JOINTS

Special Movements: Protraction & Retraction

  • Nonangular movement in a transverse plane
    • Protraction: anterior movement
    • Retraction: posterior movement
synovial joints91
SYNOVIAL JOINTS

Special Movements: Elevation & Depression

  • Elevation: lifting a body part superiorly
  • Depression: moving a body part inferiorly
synovial joints92
SYNOVIAL JOINTS

Special Movements: Opposition

  • Movement allowed by the saddle joint between the thumb’s metacarpal and the carpals
    • Opposable thumbs are nice things to have
synovial joints93
SYNOVIAL JOINTS
  • Types of synovial joints
    • Plane joints
    • Hinge joints
    • Pivot joints
    • Condyloid joints
    • Saddle joints
    • Ball-and-socket joints
joint injuries
JOINT INJURIES

Sprains

  • Ligaments reinforcing a joint stretched or torn
    • esp., ankle, knee, lumbar region of spine
  • Partially torn ligaments will repair themselves
    • Slow to heal sue to poor vascularization
  • Completely torn ligaments require surgery
    • Surgical repair difficult
    • Replacement with grafts or substitutes common
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JOINT INJURIES

Cartilage Injuries

  • Typical injuries
    • Tearing of knee menisci
    • Overuse damage to articular cartilages
  • Cartilage is avascular
    • Insufficient nutrients for repair
    • Generally remains torn
    • Arthroscopic removal of damaged cartilage
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JOINT INJURIES

Dislocations

  • Bones are forced out of alignment
    • Generally accompanied by sprains, inflammation, and joint immobilization
    • Commonly result from falls or sports injuries
      • esp., shoulders, fingers, thumb
  • Dislocation must be reduced
    • Manipulation by hand restores proper alignment
joint conditions
JOINT CONDITIONS

Bursitis

  • Inflammation of the bursa
    • Usually caused by a blow or friction
    • Can be caused by repeated prolonged joint stress
    • Rest, ice, anti-inflammatory drug treatment

Tendonitis

  • Inflammation of tendon sheaths
    • Typically caused by overuse
    • Similar symptoms and treatment to bursitis
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JOINT CONDITIONS

Arthritis

  • Over 100 different types of inflammatory and degenerative diseases that damage joints
    • Pain, stiffness, swelling of the joint
  • Most widespread crippling disease in the U.S.
    • 1/7 of population suffers
  • Acute
    • Generally result from bacterial infection
  • Chronic
    • Osteoarthritis, rheumatoid arthritis, gouty arthritis
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JOINT CONDITIONS

Osteoarthritis

  • Most common chronic arthritis
    • “Wear-and-tear arthritis”
    • 85% of all Americans develop
      • Most prevalent in aged
      • More women than men
  • Cartilage destroyed  bone exposed  exposed bone tissue thickens  joint movement restricted
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JOINT CONDITIONS

Rheumatoid Arthritis

  • Autoimmune disease
    • Body’s immune system attacks body’s own tissues
  • Usually arises between 40 and 50
    • Affects >1% of American population
    • Affects more women than men (3:1)
  • Inflammation in synovial membranes
    • Excessive inflammatory response causes tissue damage
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JOINT CONDITIONS

Gouty Arthritis (“Gout”)

  • Uric acid produced as waste product of nucleic acid metabolism
    • Uric acid level in blood can rise
    • Deposition as needle-like crystals in soft tissue of joints
    • Inflammatory response  pain, joint damage
  • Who gets it?
    • More common in males than females
      • Naturally higher levels of uric acid
    • Genetic factors contribute
  • Treatment
    • Colchicine, anti-inflammatory drugs, etc.