Joint Articulations
Synarthrosis
• Synarthroses
• A junction between bones that is held
together by dense irregular connective tissue
• Function is to bind bones together and to
transmit force from one bone to the next with
minimal joint motion
• Movement?:
• E.g.,
____________
ƒ
____________
ƒ
ƒ
A junction between
bones that is formed
primarily by
fibrocartilage and/or
hyaline cartilage. Can
have disks or pads
between two
articulating surfaces
Examples:
Intervertebral joints
(disk), pubic
symphysis (disk); First
rib & sternum (hyaline
cartilage)
1
Diarthroses Joints
• Diarthroses = __________
• All ___________ have the following
features:
1. Synovial fluid
• Provides nutrition and lubrication inside the joint
cavity for the…
2. _________________
• Covers the ends of the bones
3. Articular capsule
• Connective tissue that encloses the joint
• Is composed of 2 distinct layers, internal layer is
called…
Diarthroses (cont.)
4. _____________
•
•
Average 3-10 cell layers thick
Cells of synovial membrane also manufacture and add
hyaluronate and lubricating glycoproteins (i.e., lubricin)
to the joint fluid
5. Capsular ligaments
•
Are a part of the external, or fibrous, layer of the
capsule. Thickened regions of the fibrous capsule are
these ligaments
6. Blood vessels
•
Have capillary beds that penetrate as far as the
junction of the fibrous capsule and synovial membrane
7. Sensory Nerves
•
Also supply the fibrous capsule
Other parts of synovial joint
• __________
• Pads of fibrocartilage which increase congruency and
improve force dispersion
• Peripheral labrum of fibrocartilage
• Deepen the concave member of these joint and support
and thicken the attachment of the joint capsule
• E.g., :
• Fat Pads
• Lie between fibrous capsule and the synovial membrane
• Synovial plicae
• Overlapped pleats of synovial tissue
• Increase synovial surface area and allow joint motion
without undue tension on the synovial lining
2
Quick Review
• 3 Types of Joints:
• 2 parts of the articular
capsule?
Categories of Synovial Joints
Gliding Joint (_____)
1)
•
•
Two flat bony surfaces
that allow limited
gliding motion
E.g.,
_____ joint
2)
•
•
Allows rotational
movement around a
long axis
E.g., rotation of radius
and radio-ulnar joint
Categories of Synovial Joints
3. Biaxial Ball & Socket
joint (__________)
•
•
Joint in where
movement occurs in
two planes
E.g., knee joint
4. Multiaxial Ball &
Socket joint (Ball &
Socket)
•
•
Permits movement in
______ planes
E.g., shoulder and hip
joints
3
Categories of Synovial Joints
_______ Joints
5)
•
Permits wide range
of movement in only
one plane
E.g., humeroradial
joint &
interphalangeal joints
•
Saddle joint
6)
•
•
Each partner of joint
has one surface is
concave , the other
convex
Best example at
carpometacarpal joint
Stability of Synovial Joints
• Stability is defined as resistance to
displacement
• Structure of joints is related to their
function
• Highly moveable joints lack stability, i.e, there
is an inverse relationship between mobility
and stability
Factors that affect joint stability
1. _____ of bony structure
•
Shoulder vs. hip
2. ______________ arrangement
•
Ligaments are stress resistant tissue that connects
bone to bone
3. ___________ arrangement
•
Increased mobility requires increased contribution
by the musculature that crosses the joint
4. Fascia
•
IT band in knee provides additional support
5. Atmospheric Pressure
•
Joints act as a vacuum to approximate joint
surfaces
4
Joint Motion
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Osteokinematic Motion
•
•
•
•
Examples are flexion, extension, abduction,
etc.
___________ = ROM exceeds normal
anatomic limits
___________ = ROM is less than would be
normally permitted by joint
Causes of hypomobility include:
•
•
Bony or cartilaginous block
Ligament, capsule, or muscle contracture
Joint Motion
ƒ
Arthrokinematics
•
•
•
Refer to the movement of the joint surfaces
____________________________ are
examples of arthrokinematic motion
Concave-Convex Rule:
•
•
When a concave surface moves on a stable
convex surface, sliding occurs in the same
direction as motion of the bony lever
When a convex surface moves on a stable
concave surface, sliding occurs in the opposite
direction as motion of the bony lever
5
Tissues That Form Joints
• 4 Primary types of connective tissues:
•
•
•
•
Dense Irregular Connective Tissue
Articular Cartilage
Fibrocartilage
Bone
6
Dense Irregular Connective Tissue
• Anatomic Location:
• External fibrous layer of joint capsule
• Forms ___________
• Fibers:
• High ________ collagen fiber content
• Low _______ fiber content
• Ground Substance:
• Low amount
• Purpose:
• Restrains unwanted movement between bones
• Read last paragraph of section on page _____
Articular Cartilage
• Specialized type of hyaline cartilage
• No ___________ – a layer of connective tissue that
covers most cartilage
• ___________ contains _______ and able to repair itself
• It is Avascular & ___________
• Very low coefficient of friction
• Anatomic Location:
• Ends of articulating bones in synovial joints
• Fibers:
• High __________ collagen fiber
• Ground Substance:
• High amount
• Purpose:
• Resists and distributes compressive forces and shear
forces
Fibrocartilage
• Perichondrium is poorly organized and contains
small blood vessels located only near the
____________ of the tissue
• Nutrition of fibrocartilage in synovial joints is
dependent on the synovial fluid
• Nutrition of fibrocartilage in amphiarthroses is
assisted by the “milking” action of intermittent weight
bearing
• E.g., Intervertebral disks are insufficiently nourished
when the spine is held in fixed postures for extended
periods
• Anatomic location:
• Intervertebral disks; disks within pubic symphasis;
Menisci; labrum
7
Fibrocartilage (cont.)
• Fibers:
• Multidirectional ______ collagen
• Ground Substance:
• Moderate amount
• Function:
• Can provide some joint stabilization
• Primary function is to provide __________
Closure
• What type of joint is
between your tooth
and mandible?
• Which direction do
you need mobilize the
tibia to increase knee
extension?
Closure
• All synovial joints
have these 7 things in
common:
• What factors affect
joint stability?
8
Closure
• What is the difference between
osteokinematic and arthrokinematic
motion?
• What are the main differences between
dense irregular connective tissue, articular
cartilage, and fibrocartilage?
9