Anatomy and Physiology of the Skeletal System

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Anatomy and Physiology of the Skeletal System
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Introduction

• The skeletal system provides a rigid framework to
  support and protect the body. Bones function
  closely with the muscular system to permit
  movement.
• In this lecture, we will discuss the functions
  and structure of bones and how they are formed.
• We will also learn the names of the major bones
  and where they are located.
• In order to be effective in working with
  orthopedic patients, the medical assistant must
  have an understanding of the diseases and
  conditions that affect the skeletal system.
• Since bones play a major role in body movement
  and support, injuries may seriously alter the
  activities of daily living.
• Therefore, we will discuss diseases and injuries
  of the bones and joints along with procedures
  used in diagnosis and treatment.

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Skeletal System

• Function
• Support
• Provides the framework to support the bodys fat,
  muscle, and skin.
• Protection
• Protects the bodys vital organs.
• Leverage
• Serves as a point of attachment for skeletal
  muscles responsible for movement.
• Storage
• Stores most of the bodys calcium supply.
• Blood cell production
• Forms red and white blood cell and platelets.
• Form
• Gives shape to the body.

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Skeletal System (cont'd)

• Bone Structure
• Composition
• 20 water
• 2/3 inorganic materials
• 1/3 organic materials

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Skeletal System (cont'd)

• Types of Bone Tissue
• Compacthard dense found near the surface where
  strength is required.
• Spongy (cancellous)mesh-like found in ends of
  long bones and center of flat bones.
• Marrowloose connective tissue that fills
  cavities of bone.
• Redproduces formed elements of blood.
• Yellowmade up of fatty tissuehas no blood
  production function.
• Periosteumconnective tissue around a bone.
• Endosteuminner lining of bones.
• Haversian canalduct in bone that contains blood
  vessels.
• Osteocytesbone cells.

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Long Bone Features
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Skeletal System (cont'd)

• Four General Shapes
• Long
• Short
• Flat
• Irregular

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Skeletal System (cont'd)

• Growth and Development
• Bone formation (ossification) begins six weeks
  after fertilization.
• Continues through adolescence (some parts do not
  stop growing until ages 18 to 25).
• Bone growth increases at puberty with the
  increase of the sex hormone.
• While the bone lengthens, it also grows in
  diameter due to the formation of cell layers on
  the outer surface of bone, and the erosion of the
  cell layers beneath.
• Bones become thinner and weaker as a normal
  process of aging.
• Reduction in bone mass begins to occur between
  ages 30 and 40.
• Once bone mass reduction begins
• Females lose approximately 8 of bone mass every
  decade.
• Males lose approximately 3 of bone mass every
  decade.
• Osteoporosis results from bones becoming so thin
  they can no longer withstand normal stress.

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Skeletal System (cont'd)

• Number of Bones
• 270 at birth
• 206 at adulthood
• Difference between number at birth and adulthood
  due to fusion of bones

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Skeletal System (cont'd)

• Divisions of the Skeletal System
• Axial skeleton
• Spinal column
• Skull
• Rib cage
• Appendicular
• Arms
• Hands
• Legs
• Feet
• Shoulders
• Pelvis

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Cranial and Facial Bones
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Identification of Bones

• Spinal Column
• Supports the head, keeps trunk erect, protects
  spinal cord.
• Sections
• Cervicalfirst 7 neck vertebrae (C1C7)
• Thoracic12 chest vertebrae (T1T12)
• Lumbar5 back vertebrae (L1L5)
• Sacral1 large vertebra fused from five original
  bones
• Coccyx (tailbone)1 vertebra fused from four
  original bones
• Cartilage disks separate the vertebrae to absorb
  shock and allow flexibility.

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Identification of Bones (cont'd)

• Skull
• Cranium
• Protects the brain from injury.
• Fontanels
• Unossified space or soft spot located between
  cranial bones.
• Allows for molding of skull during childbirth and
  for enlargement of skull as growth occurs.
• Found in newborn and infancy closed by age two.
• Composed of the fusion of eight cranial bones
• Frontal1
• Parietal2
• Temporal2
• Occipital1
• Sphenoid1
• Ethmoid1

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Identification of Bones (cont'd)

• Skull (cont)
• Facial
• Nasal2
• Zygoma2
• Maxilla
• Mandible
• Palate2
• Concha2
• Vomer1
• Hyoid1

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Identification of Bones (cont'd)

• Skull (cont)
• Ear bones (ossicles) smallest bones in the body
• Malleus (hammer)2
• Incus (anvil)2
• Stapes (stirrup)2

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Identification of Bones (cont'd)

• Rib Cage
• Twelve pairs of long slender bones attached to
  vertebrae.
• True ribsfirst seven pairsattached directly to
  sternum and spine.
• False ribslast 5 pairsattached to cartilage of
  rib above or have only anterior attachment.
• Last 2 pairs of false ribs referred to as
  floating ribs only attach to vertebrae.
• Sternum (breast bone)1

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Bones of the Rib Cage
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Identification of Bones (cont'd)

• Upper Extremities
• Clavicle (collar bone)1
• Scapula (shoulder blade)2
• Humerus (arm) 2
• Ulna2
• Radius2
• Carpals (wrist) eight in each wrist
• Metacarpals (palm) 5 in each palm
• Phalanges (fingers) each finger has 3 bones, each
  thumb has 2, 14 in each hand

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Identification of Bones (cont'd)

• Pelvic Girdle
• Differences between male and female female must
  accommodate pregnancy and childbirth
• Iliumupper wedge called iliac crest wider in
  females2
• Ischium2
• Pubis2

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The Male Pelvis
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The Female Pelvis
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Identification of Bones (cont'd)

• Lower Extremities
• Femur (thigh) strongest bone in body2
• Patella (kneecap)2
• Tibia (shinbone)2
• Fibula2
• Tarsal (ankle) 7 in each ankle
• Metatarsals (instep) 5 in each instep
• Phalanges (toes) 14 in each foot

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Joints

• A place where any two or more bony parts join
  together also called an articulation.
• Held together by bands of connective tissue
  called ligaments.

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Joints
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Joints (cont'd)

• Joint Classifications
• Diarthrosis
• Moveable
• Knee, elbow, which has action of a hinge
• Shoulder or hip, which has action like that of
  ball and socket
• Most joints are diarthrotic and contain
• Articular cartilage
• Bursa, sack-like capsules for cushioning
• Synovial cavity, filled with synovial fluid for
  lubrication
• Synovial membrane around and between tendons to
  lubricate and reduce friction

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Joints (cont'd)

• Joint Classifications (cont'd)
• Amphiarthrosis/cartilaginous
• Partly moveable
• Vertebrae
• Synarthrosis/fibrous
• Immovable
• Cranial sutures

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Joints (cont'd)

• Types of Joints
• Gliding joints
• Found at the end of clavicles, between carpals
  and tarsalsslight movement.
• Hinge joint
• Angular movement in a single planeknee, elbow.
• Pivot joint
• Permit rotation onlyjoint between C1 and C2
  allows the head to rotate to either side.
• Ball and socket
• Round head of one bone rests within the cup-like
  depression in anothershoulder, hip.

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Joints (cont'd)

• Types of Movement
• Flexion
• Movement that reduces the angle between
  articulating joints.
• Extension
• Movement that increases the angle between
  articulating joints.
• Abduction
• Movement away from the longitudinal axis of the
  body.
• Adduction
• Movement towards the longitudinal axis of the
  body.
• Rotation
• Turning around the longitudinal axis of the body
  or limb.

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Diagnostic Examinations

• Athroscopy
• Visual inspection of a joint with an endoscope.
• Computer Tomography (CT scan)
• An x-ray which allows three dimensional views.
• Magnetic Resonance Imaging (MRI)
• Process uses strong magnets and radio waves to
  construct a three dimensional image.
• Advantages over CT scan
• No radiation used.
• Soft tissues seen in more detail.
• Disadvantages
• More expensive.
• Patients put in tube obesity or claustrophobia
  could be a problem for some patients.
• X-ray
• Image produced by ionizing radiation.

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Fractures

• Types of Fractures
• Greenstickbone cracks but does not break, common
  in children.
• Simple or closedcomplete break, does not break
  skin.
• Compound or opencomplete break, bone protrudes
  through skin.
• Impactedbroken ends are jammed into each other.
• Comminutedmore than one fracture, bone
  fragments.
• Depressedbroken pieces of skull driven inward.
• Spiralbreak winds around bone, common in sports
  accidents.
• Collesfracture of distal end of radius and/or
  ulna.

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Examples of Fracture Types
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Fractures (cont'd)

• Treatment
• Immobilization of the affected part.
• Prevention of shock.
• Elevate.
• Cold pack or ice.
• Reducing the fracture
• Alignment of the bones.
• Splint or cast keeps bone immobilized.
• Open reduction is a surgical procedure to achieve
  alignment of the bone and repair tissues and skin.

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Fractures (cont'd)

• Healing Process
• When a fracture occurs, a collection of blood
  forms at site.
• This begins the inflammatory reaction which
  begins the healing
• process.
• A fibrous bridge formed between the fracture
  fragments is called a callus.
• As time passes this callus turns first to
  cartilage and then to bone.
• Amputation
• Loss of an extremity due to injury or disease.
• Phantom limb is the sensation that the missing
  limb is present.
• Prosthesis is an artificial limb.

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Common Diseases and Disorders

• Arthritis
• Description joint inflammation.
• More than 100 different types.
• Currently affects 40 million Americans, mostly
  women.
• Most common forms
• Osteoarthritis
• Rheumatoid arthritis
• Gout
• Fibromyalgia
• Lupus

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Arthritis
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Common Diseases and Disorders (cont'd)

• Bursitis
• Description inflammation of sac located around a
  joint most often occurs at hip, shoulder, or
  knee.
• SX pain upon movement, limited motion of joint.
• Causes usually occurs in middle age and is
  result of recurring trauma or inflammatory joint
  disease.
• TX joint rest, pain medication, steroid
  injection combined with anesthetic, removal of
  fluid by aspiration, physical therapy.

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Common Diseases and Disorders (cont'd)

• Dislocation
• Description displacement of the bones of a
  joint.
• SX pain.
• Causes congenital, trauma, disease of
  surrounding joint.
• TX reduction, splint, cast, traction.

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Common Diseases and Disorders (cont'd)

• Herniated Disk (ruptured disk)
• Description the soft gel-like material within an
  intervertebral disk has been forced through its
  outer surface causing pressure on a spinal nerve.
• SX severe lower back pain, frequently radiating
  deep into the buttocks and down the back of the
  leg sensory loss from compression of nerve
  motor difficulties.
• Causes severe trauma or strain, degeneration of
  the intervertebral joints occurs in adults,
  mainly men under 45 often occurs from trauma in
  elderly.

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Common Diseases and Disorders (cont'd)

• Lumbar Myositis
• Description inflammation of the lumbar region
  muscles of the back.
• SX low back pain.
• Causes straining of back muscles.
• TX rest, mild analgesics, and muscle relaxers.
• Osteoporosis
• Description metabolic bone disorder where the
  bone becomes porous, brittle and prone to
  fracture.
• Two types Primary, which is postmenopausal and
  Secondary, following various abuses to the body
  such as steroid therapy.
• SX snapping sound followed by instant pain,
  spinal curvatures, fractures, loss of height.
• Causes aging, inadequate calcium, faulty
  metabolism, tobacco, family history.
• TX increasing exercise, estrogen supplement,
  calcium, vitamin D.

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Common Diseases and Disorders (cont'd)

• Spinal Curvatures
• Kyphosis
• Description bowing of the back, usually at the
  thoracic level.
• SX visible curving, pain, stiffness, tightening
  of hamstring muscles.
• Causes growth retardation, degeneration of
  intervertebral disks, osteoporosis.
• TX exercise, firm mattress, surgery.

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Common Diseases and Disorders (cont'd)

• Spinal Curvatures (cont'd)
• Lordosis
• Description anterior convex curvature of the
  lumbar spine.
• SX visual curvature.
• Causes poor posture, wearing high heels.
• TX exercise, improving posture, proper footwear.
• Scoliosis
• Description lateral curvature of the spine
  usually in the thoracic region.
• SX uneven hemlines or unequal pants legs, one
  hip appearing higher than the other, one shoulder
  appearing higher.
• Causes congenital defects, muscular dystrophy,
  paralysis, transmitted trait that develops during
  the growing process, poor posture, uneven leg
  lengths.
• TX exercise, brace, surgery.

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SPINAL CURVATURES
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Common Diseases and Disorders (cont'd)

• Sprain
• Description complete or incomplete tear in the
  supporting ligament of a joint.
• SX pain, swelling, black and blue discoloration
  ankle most common site.
• Causes twisting action.
• TX follow R.I.C.E.Rest, Ice, Compression, and
  Elevation may require surgery.
• Carpal Tunnel Syndrome
• Cause compression of median nerve at the wrist.
• SX numbness, pain in hand.
• TX surgery to relieve pressure.

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Questions

• Name the bones and locate them on a skeleton.
• What is the difference between compact and spongy
  bone?
• How many phalanges are there?
• What is the difference between true and false
  ribs?
• Name three types of spinal curvatures and
  describe their physical characteristics.
• What is a greenstick fracture?
• What does the abbreviation R.I.C.E. stand for?
• What does open reduction mean?
• What is the cause of lumbar myositis?
• How many bones are in the human body?
• How many bones are there in the human body at
  birth?