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The Skeletal System

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Describe the functions of articular cartilage. Describe the functions of synovial fluid ... articular cartilage: a protective layer of dense white connective tissue ... – PowerPoint PPT presentation

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Title: The Skeletal System


1
The Skeletal System
  • Dr. Rodney Kennedy

2
Objectives
  • Identify the partitions of the skeletal system
  • Describe the functions of the skeletal system
  • Describe the anatomical features of bones
  • Classify bones based on their structure and
    function
  • Describe the growth process of long bones
  • Classify joints based on their structure and
    function
  • (continued)

3
Objectives
  • Sub-classify synovial joints according to their
    structure and function
  • Describe the anatomical features of synovial
    joints
  • Describe the functions of articular cartilage
  • Describe the functions of synovial fluid
  • Identify the factors that contribute to the
    stability of synovial joints
  • Identify the factors that contribute to the
    flexibility of synovial joints

4
The human skeleton
  • Two partitions
  • axial skeleton
  • appendicular skeleton

5
The human skeleton
6
The human skeleton
  • axial skeleton
  • skull
  • vertebrae
  • sternum
  • ribs
  • appendicular skeleton
  • bones composing the body appendages

7
The vertebral column
  • Divided into 4 main regions
  • Cervical (7)
  • Thoracic (12)
  • Lumbar (5)
  • Sacral
  • the 5 sacrum vertebrae and 4
  • coccygeal vertebrae are fused to
  • form one solid bone.

8
The human skeleton functions
  • Mechanical functions
  • support
  • protection
  • movement
  • Physiological functions
  • haemopoiesis (blood cell production)
  • mineral storage calcium phosphorous

9
Categories of bone
  • Compact cortical compact mineralized bone with
    low porosity found in the shafts of long bones
  • Cancellous trabecular less compact bone with
    high porosity found in the ends of long bones
    and the vertebrae

10
Categories of bone
11
Types of bones
  • short approximately cubical
  • flat protect organs provide surfaces for
    muscle attachments
  • irregular have different shapes to serve
    different functions
  • long form the framework of the appendicular
    skeleton
  • sesamoid develop within tendons

12
Short bones
13
Types of bones
  • short approximately cubical
  • flat protect organs provide surfaces for
    muscle attachments
  • irregular have different shapes to serve
    different functions
  • long form the framework of the appendicular
    skeleton
  • sesamoid develop within tendons

14
Flat bones
15
Types of bones
  • short approximately cubical
  • flat protect organs provide surfaces for
    muscle attachments
  • irregular have different shapes to serve
    different functions
  • long form the framework of the appendicular
    skeleton
  • sesamoid develop within tendons

16
Irregular bones
17
Types of bones
  • short approximately cubical
  • flat protect organs provide surfaces for
    muscle attachments
  • irregular have different shapes to serve
    different functions
  • long form the framework of the appendicular
    skeleton
  • sesamoid develop within tendons

18
Long bones
19
Types of bones
  • short approximately cubical
  • flat protect organs provide surfaces for
    muscle attachments
  • irregular have different shapes to serve
    different functions
  • long form the framework of the appendicular
    skeleton
  • sesamoid develop within tendons

20
Sesamoid bones
21
Structure of long bone
  • Diaphysis is the long, hollow
  • cylinder of hard, compact bone
  • At the end of the diaphysis is an
  • epiphysis
  • The medullary marrow cavity
  • in the center, is filled with marrow,
  • and is surrounded by compact
  • bone.

22
Structure of long bone
  • Epiphyseal plate or growth plate
  • is the cartilage plate in the long
  • bones of children and adolescents.
  • Periosteum a tough, fibrous
  • tissue that covers the external
  • surface of bone
  • Endosteum a tough, fibrous
  • tissue that covers the internal
  • surface of bone

23
Bone growth and development
  • How do bones grow in length?
  • the epiphyses, or epiphyseal plates, are growth
    centers where mineral matter (calcium,
    phosphorous, magnesium) starts to replace
    cartilage, creating new bone
  • the process is called ossification
  • continues until the epiphysis closes during late
    adolescence or early adulthood early 20s

24
Bone growth and development
  • How do bones grow in circumference?
  • the inner layer of the periosteum, builds
    concentric layers of new bone on top of existing
    ones
  • The changes in bone size and shape are the work
    of specialized cells called osteoblasts and
    osteoclasts

25
Joint classifications
  • Fibrous or synarthrodial (immovable)

26
Joint classifications
  • Cartilaginous or amphiarthrodial (slightly
    moveable)

27
Joint classifications
  • Synovial or diarthrodial (freely moveable)

28
Types of synovial joints
  • Ball Socket
  • spherical head round socket
  • multiaxial movement
  • Condyloid
  • egg-shape articular surface oval concavity
  • side-to-side, backforth movement
  • Gliding
  • articular surface in flat plane
  • Short gliding movement

29
Types of synovial joints
30
Types of synovial joints
  • Ball Socket
  • spherical head round socket
  • multiaxial movement
  • Condyloid
  • egg-shape articular surface oval concavity
  • side-to-side, backforth movement
  • Gliding
  • articular surface in flat plane
  • Short gliding movement

31
Types of synovial joints
32
Types of synovial joints
  • Ball Socket
  • spherical head round socket
  • multiaxial movement
  • Condyloid
  • egg-shape articular surface oval concavity
  • side-to-side, backforth movement
  • Gliding
  • articular surface in flat plane
  • Short gliding movement

33
Types of synovial joints
34
Types of synovial joints
  • Hinge
  • cylindrical end of 1 bone fits into trough shape
    of other
  • angular movement-1 plane
  • Pivot
  • round end fits into ring of bone ligament
  • rotation on long axis
  • Saddle
  • articular surface both concave convex
  • side-to-side, back-forth movement

35
Types of synovial joints
36
Types of synovial joints
  • Hinge
  • cylindrical end of 1 bone fits into trough shape
    of other
  • angular movement-1 plane
  • Pivot
  • round end fits into ring of bone ligament
  • rotation on long axis
  • Saddle
  • articular surface both concave convex
  • side-to-side, back-forth movement

37
Types of synovial joints
C1 C2
38
Types of synovial joints
  • Hinge
  • cylindrical end of 1 bone fits into trough shape
    of other
  • angular movement-1 plane
  • Pivot
  • round end fits into ring of bone ligament
  • rotation on long axis
  • Saddle
  • articular surface both concave convex
  • side-to-side, back-forth movement

39
Types of synovial joints
40
Structure of synovial joints
  • They are characterized by
  • articular cartilage a protective layer of dense
    white connective tissue covering the articulating
    bone surfaces
  • articular capsule a double-layered membrane that
    surrounds the joint
  • (continued)

41
Structure of synovial joints
  • They are characterized by
  • synovial fluid a clear, slightly yellow liquid
    that provides lubrication inside the articular
    capsule
  • associated bursae small capsules filled with
    synovial fluid that cushion the structures they
    separate

42
Functions of articular cartilage
  • it spreads loads over a wide area, thereby
    reducing contact stress
  • it provides a protective lubrication that
    minimizes friction and mechanical wear at the
    joint

43
Fibrocartilage
  • Soft-tissue discs or menisci that intervene
  • between articulating bones, as exemplified by
  • the menisci of the knee above

44
Functions of fibrocartilage
  • distributing loads over joint surfaces
  • improving the fit of articulations
  • limiting slip between articulating bones
  • protecting the joint periphery
  • lubricating the joint
  • absorbing shock at the joint

45
Articular connective tissue
  • tendons connect muscles to bones
  • ligaments connect bones to other bones

46
Joint stability
  • Refers to the ability of a joint to resist
    abnormal
  • displacement of the articulating bones.
  • Factors that increase joint stability
  • a closely reciprocating match of the articulating
    bone surfaces (stability is maximal when joints
    are in the close-packed position)
  • a strong array of ligaments and muscle tendons
    crossing the joint
  • absence of muscle fatigue

47
The Knee Joint
48
Joint flexibility
  • Refers to the relative ranges of motion allowed
  • at a joint in different directions. Limited by
  • Ligaments
  • Muscles
  • Bones
  • Joint damage

49
Joint flexibility
Muscles that cross more than one joint e.g
hamstrings on hip flexion
50
Further Reading
  • Chapter 10 from
  • McGinnis, P. M. (2005) Biomechanics of sport and
    exercise. 2nd ed.
  • ChampaignHuman Kinetics.
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