SKELETAL SYSTEM

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SKELETAL SYSTEM
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SKELETAL SYSTEM

• Form strong flexible body framework
• Bone
• 206 bones in human skeleton
• Cartilage
• All three types
• Ligaments

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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

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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

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SKELETAL CARTILAGE

• Elastic cartilage
• Similar to hyaline cartilage
• Contain more stretchy elastic fibers
• Withstand repeated bending
• Locations
• External ear
• Epiglottis

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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

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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

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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

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BONE SHAPES

• Long bones
• Short bones

• Flat bones
• Irregular bones

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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., Sharpeys fibers
• Tufts of collagen fibers

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BONE STRUCTURE

• Gross Anatomy Long Bone Structure
• Membranes Endosteum
• Internal bone surfaces covered with delicate
  membrane
• Endosteum
• Contains both osteoblasts and osteoclasts

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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

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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

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BONE STRUCTURE

• Microscopic Anatomy Compact Bone
• Compact bone appears dense and solid
• Actually contains numerous passageways
• Conduits for nerves, blood lymphatic vessels

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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

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BONE STRUCTURE

• Microscopic Anatomy Compact Bone
• Osteon
• Group of concentric hollow tubes
• Lamellae
• (Compact bone is sometimes called lamellar bone)

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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

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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

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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

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BONE STRUCTURE

• Microscopic Anatomy Compact Bone
• Osteon
• Perforating canals lie at right angles to long
  axis of bone
• a.k.a., Volkmans canals
• Lined with endosteum
• Connect to blood and nerve supply of periosteum
• (Also connects to that of medullary cavity)

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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

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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

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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

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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

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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

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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

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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

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OSSIFICATION

• Intramembranous Ossification
• Formation of clavicles and cranial bones

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OSSIFICATION

• Endochondral Ossification
• Formation of almost all bones

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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

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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

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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

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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 (?)

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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

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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

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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

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BONE DEPOSITION

• Occurs when bone is injured
• Occurs when added bone strength is required

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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

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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.

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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

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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

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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

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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

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BONE REPAIR

• Bone repair involves multiple steps
• Hematoma formation
• Fibrocartilaginous callus formation
• Bony callus formation
• Bone remodeling

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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

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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

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BONE REPAIR

• Bony callus formation
• New bone trabeculae appear in fibrocartilaginous
  callus within 1 week
• Gradual conversion to bony (hard) callus
• Spongy bone

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BONE REPAIR

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

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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

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JOINTS
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WHAT ARE JOINTS?

• a.k.a., Articulations
• Sites where two or more bones meet
• Functions
• Hold skeleton together
• Confer mobility

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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

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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

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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

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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

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FIBROUS JOINTS

• Gomphoses
• Peg-in-socket fibrous joint
• Articulation of tooth into alveolar socket
• Fibrous connection is short peridontal ligament

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CARTILAGINOUS JOINTS

• Articulating bones joined by cartilage
• Lack a joint cavity
• Two types
• Synchondroses
• Symphyses

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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

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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

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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

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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

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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

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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

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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

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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

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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

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SYNOVIAL JOINTS

• Movements Allowed by Synovial Joints
• Skeletal muscles attached to bone or other
  features at two or more points
• Muscles origin attached to less movable bone
• Muscles insertion attached to movable bone
• Movement occurs when muscles contract across
  joints
• Insertion moves toward origin
• Different joints allow different types of movement

79
SYNOVIAL JOINTS

• Gliding Movements
• One flat or nearly flat bone surface glides or
  slips over another without appreciable angulation
  or rotation

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SYNOVIAL JOINTS

• Angular Movements
• Increase or decrease angle between two bones
• May occur in any body plane
• Include
• Flexion
• Extension
• Hyperextension
• Abduction
• Adduction
• Circumduction

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SYNOVIAL JOINTS

• Angular Movements Flexion
• Bending movement decreasing angle of joint
• Brings articulating bones closer together
• Bending usually along sagittal plane

82
SYNOVIAL JOINTS

• Angular Movements Extension Hyperextension
• Reverse of flexion occurring at same joints
• Bending movement increasing angle of joint
• Brings articulating bones further apart

83
SYNOVIAL JOINTS

• Angular Movements Dorsiflexion Plantar Flexion
• Up-and-down movements of the foot at the ankle
  joint

84
SYNOVIAL JOINTS

• Angular Movements Abduction
• Movement of a limb along frontal plane away
  from midline or median plane of body

85
SYNOVIAL JOINTS

• Angular Movements Adduction
• Opposite of abduction
• Movement of a limb along frontal plane toward
  midline or median plane of body

86
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

87
SYNOVIAL JOINTS

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

88
SYNOVIAL JOINTS

• Special Movements Supination Pronation
• Movement of radius around ulna
• Supination turning backward
• Pronation turning forward

89
SYNOVIAL JOINTS

• Special Movements Inversion Eversion
• Special movement of the feet
• Inversion sole turns medially
• Eversion sole turns laterally

90
SYNOVIAL JOINTS

• Special Movements Protraction Retraction
• Nonangular movement in a transverse plane
• Protraction anterior movement
• Retraction posterior movement

91
SYNOVIAL JOINTS

• Special Movements Elevation Depression
• Elevation lifting a body part superiorly
• Depression moving a body part inferiorly

92
SYNOVIAL JOINTS

• Special Movements Opposition
• Movement allowed by the saddle joint between the
  thumbs metacarpal and the carpals
• Opposable thumbs are nice things to have

93
SYNOVIAL JOINTS

• Types of synovial joints
• Plane joints
• Hinge joints
• Pivot joints
• Condyloid joints
• Saddle joints
• Ball-and-socket joints

94
SYNOVIAL JOINTS
95
SYNOVIAL JOINTS
96
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

97
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

98
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

99
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

100
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

101
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

102
JOINT CONDITIONS

• Rheumatoid Arthritis
• Autoimmune disease
• Bodys immune system attacks bodys own tissues
• Usually arises between 40 and 50
• Affects gt1 of American population
• Affects more women than men (31)
• Inflammation in synovial membranes
• Excessive inflammatory response causes tissue
  damage

103
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.