Human AnatomyBio 22

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Human Anatomy-Bio 22 Lecture 9 Joints 9-29-05 Pre
sented By Tealia Davis, MSc
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Joints (Articulations)
Weakest parts of the skeleton site where two
or more bones meet Functions of joints Give
the skeleton mobility Hold the skeleton together
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Classification of Joints Structural
Structural classification focuses on the material
binding bones together and whether or not a joint
cavity is present The three structural
classifications are 1. 2. 3.
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Classification of Joints Functional
Functional classification is based on the amount
of movement allowed by the joint The three
functional classes of joints are immovable
slightly movable freely movable
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Fibrous Structural Joints

• The bones are joined by fibrous tissues
• There is no joint cavity
• Most are immovable
• There are three types , , and

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Fibrous Structural Joints Sutures

• Occur between the
• Comprised of interlocking junctions completely
  filled with connective tissue fibers
• Bind bones tightly together, but allow for growth
  during youth
• In middle age, skull bones fuse and are called
  synostoses

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Fibrous Structural Joints Syndesmoses
Bones are connected by a fibrous tissue
ligament Movement varies from immovable to
slightly variable Examples include the
connection between the tibia and fibula, and the
radius and ulna
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Fibrous Structural Joints Gomphoses
The peg-in-socket fibrous joint between a tooth
and its alveolar socket The fibrous connection
is the periodontal ligament
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Cartilaginous Joints
Articulating bones are united by cartilage Lack
a joint cavity Two types and
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Cartilaginous JointsSynchrondroses
A bar or plate of hyaline cartilage unites the
bones All synchondroses are synarthrotic Example
s include Epiphyseal plates of children Joint
between the costal cartilage of the first rib and
the sternum
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Cartilaginous Joints Symphyses
Hyaline cartilage covers the of the bone and
is fused to an intervening pad of joints
designed for strength and flexibility Examples
include intervertebral joints and the pubic
symphysis of the pelvis
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Synovial Joints
Those joints in which the articulating bones are
separated by a fluid-containing joint cavity All
are freely movable Examples all limb joints,
and most joints of the body
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Synovial Joints General Structure
Synovial joints all have the following 1. 2.
3. 4. 5.
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Synovial Joints Friction-Reducing Sutures
flattened, fibrous sacs lined with synovial
membranes and containing synovial fluid Common
where ligaments, muscles, skin, tendons, or bones
rub together elongated bursa that wraps
completely around a tendon
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Synovial Joints Stability
Stability is determined by Articular surfaces
shape determines what movements are
possible Ligaments unite bones and prevent
excessive or undesirable motion Muscle tone is
accomplished by Muscle tendons across joints
acting as stabilizing factors Tendons that are
kept tight at all times by muscle tone
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Synovial Joints Movement
The two muscle attachments across a joint
are attachment to the immovable bone
attachment to the movable bone Described as
movement along transverse, frontal, or sagittal
planes
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Types of Synovial Joints
Plane joints Articular surfaces are essentially
flat Allow only slipping or gliding
movements Only examples of nonaxial joints
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Types of Synovial Joints
Hinge joints Cylindrical projections of one bone
fits into a trough-shaped surface on
another Motion is along a single plane Uniaxial
joints permit flexion and extension
only Examples elbow and interphalangeal joints
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Types of Synovial Joints
Pivot Joints Rounded end of one bone protrudes
into a sleeve, or ring, composed of bone (and
possibly ligaments) of another Only uniaxial
movement allowed Examples joint between the
axis and the dens, and the proximal radioulnar
joint
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Types of Synovial Joints

• Condyloid or Ellipsoidal JointsOval articular
  surface of one bone fits into a complementary
  depression in another
• Both articular surfaces are oval
• Biaxial joints permit all angular motions
• Examples radiocarpal (wrist) joints, and
  metacarpophalangeal (knuckle) joints

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Types of Synovial Joints

• Saddle Joints
• Similar to condyloid joints but allow greater
  movement
• Each articular surface has both a concave and a
  convex surface
• Example carpometacarpal joint of the thumb

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Types of Synovial Joints

• Ball and Socket Joints
• A spherical or hemispherical head of one bone
  articulates with a cuplike socket of another
• Multiaxial joints permit the most freely moving
  synovial joints
• Examples shoulder and hip joints

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Synovial Joint Knee

• Largest and most complex joint of the body
• Allows flexion, extension, and some rotation
• Three joints in one surrounded by a single joint
  cavity
• Femoropatellar
• Lateral and medial tibiofemoral joints

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Synovial Joint Knee-Ligaments and
Tendons Anterior View
Tendon of the quadriceps femoris muscle Lateral
and medial patellar retinacula Fibular and
tibial collateral ligaments Patellar ligament
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Synovial Joint Knee-Other Supporting Structures

• Anterior cruciate ligament
• Posterior cruciate ligament
• Medial meniscus (semilunar cartilage)
• Lateral meniscus

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Synovial Joint Shoulder Stability
Weak stability is maintained by Thin, loose
joint capsule Four ligaments coracohumeral,
and three glenohumeral Tendon of the long head of
biceps, which travels through the intertubercular
groove and secures the humerus to the glenoid
cavity Rotator cuff (four tendons) that
encircles the shoulder joint and blends with the
articular capsule
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Synovial Joint Shoulder Stability
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Synovial Joint Shoulder Stability
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Synovial Joint Hip Stability

• Acetabular labrum
• Iliofemoral ligament
• Pubofemoral ligament
• Ischiofemoral ligament
• Ligamentum teres

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Synovial Joint Elbow Stability

• Annular ligament
• Ulnar collateral ligament
• Radial collateral ligament

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Joint Disorders or Injuries
Sprains Cartilage Injuries Dislocations Inflamm
atory and Degenerative Diseases Arthritis Osteoar
thritis Rheumatoid Arthritis Gouty Arthritis
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Gliding Movements
One flat bone surface glides or slips over
another similar surface Examples intercarpal
and intertarsal joints, and between the flat
articular processes of the vertebrae
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Angular Movements
Flexion bending movement that decreases the
angle of the joint Extension reverse of
flexion joint angle is increased Dorsiflexion
and plantar flexion up and down movement of the
foot Abduction movement away from the
midline Adduction movement toward the
midline Circumduction movement describes a
cone in space