Download Joints!

Joints!
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3 types of joints classified by function
1. Diarthroses
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Freely moveable joints
Shoulder, knee, hip, elbow, interphalangeal, tarsal,
and carpal joints
2. Amphiarthroses
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Slightly moveable joints
Intervertebral discs, costosternal joints, pubic
symphysis
3. Synarthroses
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Joints with little or no movement
Skull sutures, mental symphysis, teeth in sockets,
1st costosternal joint.
Joint Classification
Classification by
structure:
1. Synovial joints:
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Bones separated by a
joint cavity; lubricated
by synovial fluid;
enclosed in a fibrous
joint capsule.
Shoulder, hip, elbow,
knee, carpal,
interphalangeal
How would we classify these
joints functionally?
Joint Classification
2. Fibrous joints:
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Bones held together by collagenous fibers
extending from the matrix of one bone into the
matrix of the next.
No joint cavity
Skull sutures, teeth in joints, distal radioulnar
joints & tibiofibular joints
Joint Classifications
3. Cartilaginous joints:
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Bones held together by cartilage; no joint cavity
Epiphyseal plates of long bones, costosternal joints,
pubic symphysis, intervertebral discs
Structure and Function
 Joints are designed
for their function.
 Let’s look at sutures
as our 1st example:
 Name 4 sutures!
 What function do you
suppose sutures are
designed for?
Structure and Function
 Let’s look at some symphyses.
 What kind of joint is a symphysis? What kind of
movement is possible?
 Name a symphysis! (an obvious one is in the picture)
 What connects the bones in these joints?
Structure and Function
Now let’s talk about
synovial joints.
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How do they differ from
the previous 2?
5 main structural
characteristics:
1. Articular cartilage
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What kind of cartilage is
it? (H _ _ _ _ _ _ )
Where do we find it?
What does it do?
Structure and Function
2. Articular capsule
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2 layered. Surrounds both articular cartilages and the
space btwn them.
External layer is made of dense irregular CT & is
continuous w/ the perisoteum.
Inner layer is a synovial membrane made of loose
connective tissue.
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It covers all internal joint surfaces except for those areas covered
by the articular cartilage.
Structure and Function
3.
Joint (Synovial) Cavity
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4.
The potential space within
the joint capsule and
articular cartilage
Synovial Fluid
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A small amount of slippery
fluid occupying all free
space w/i the joint capsule
Formed by filtration of
blood flowing thru
capillaries in the synovial
membrane
Synovial fluid becomes
less viscous as joint
activity increases.
Structure and Function
5.
Reinforcing Ligaments
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What kind of tissue are
they?
What do you suppose
their function is?
Double-jointed-ness
results from extrastretchy ligaments and
joint capsules. Is this
necessarily a good
thing?
Other Synovial Structures
 The knee and hip joints
have cushioning fatty
pads btwn the fibrous
capsule and the synovial
membrane or bone.
 Discs of fibrocartilage
(i.e., menisci) which
improve the fit btwn bone
ends, thus stabilizing the
joint.
 Found in the knee, jaw, and
sternoclavicular joint.
 Bursae are basically bags
of lubricant - fibrous
membrane bags filled w/
synovial fluid. Often
found where bones,
muscles, tendons, or
ligaments rub together.
Types of
Synovial Joints
1.
Plane joints
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2.
Articular surfaces are flat and
allow short slipping or gliding
movements.
Intercarpal and intertarsal
joints
Hinge joints
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A cylindrical projection of one
bone fits into a troughshaped surface on another
(like a hotdog in a bun)
Movement resembles a door
hinge.
Elbow joint – ulna and
humerus; Interphalangeal
joints
Type of
Synovial Joints
3.
Pivot joints
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4.
Rounded end of one bone
protrudes into a ring formed by
another bone or by ligaments of
that bone.
Proximal radioulnar joint
Atlas-axial joint
Condyloid joints
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Oval articular surface of one
bone fits into a complementary
depression on another.
Radiocarpal joints
Metacarpophalangeal joints
Types of
Synovial Joints
5. Saddle joints
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Each articular surface has convex
and concave areas. Each
articular surface is saddleshaped.
Carpometacarpal joints of the
thumbs.
6. Ball-and-Socket joints
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Spherical or semi-spherical head
of one bone articulates with the
cuplike socket of another.
Allow for much freedom of
motion.
Shoulder and hip joints.
The Knee
 Largest and most complex
diarthrosis in the body.
 Primarily a hinge joint, but
when the knee is flexed, it is
also capable of slight rotation
and lateral gliding.
 Actually consists of 3 joints:
 Patellofemoral joint
 Medial and lateral tibiofemoral
joints
 The joint cavity is only partially
enclosed by a capsule – on
the medial, lateral, and
posterior sides.
 The lateral and medial
condyles of the femur
articulate with the
lateral and medial
condyles of the tibia.
 Btwn these structures,
we have the lateral and
medial menisci.
 Anteriorly, the patellar
ligament binds the
tibia (where?) to the
inferior portion of the
patella. The superior
portion of the patella
is then connected to
the quadriceps
femoris muscle
The Knee
 At least a dozen
bursae are associated
with the knee.
 Multiple ligaments are
present.
 The fibular collateral
ligament extends from
the lateral epicondyle
of the femur to the
head of the fibula.
 The tibial collateral
ligament connects
medial epicondyle of
the femur to the medial
condyle of the tibial
shaft and is also fused
to the medial
meniscus.
 Both of these ligaments
prevent excessive
rotation
The Knee
 The anterior and posterior
cruciate ligaments are
also very important.
 ACL connects the anterior
intercondylar area of the
tibia to the medial side of the
lateral femoral condyle.
 Prevents forward sliding of
the tibia and hyperextension
of the knee.
 PCL connects the posterior
intercondylar area of the
tibia to the lateral side of the
medial femoral condyle.
 Prevents backward
displacement of the tibia or
forward sliding of the femur.
The Knee
Clinical
Conditions
 Arthritis describes about
100 different types of
inflammatory or
degenerative joint
diseases.
 Osteoarthritis
 Most common arthritis.
 Normal joint use prompts
the release of cartilagedamaging enzymes. If
cartilage destruction
exceeds cartilage
replacement, we’re left with
roughened, cracked,
eroded cartilages.
 Eventually bone tissue
thickens and forms spurs that
can restrict movement.
 Most common in C and L
spine, fingers, knuckles,
knees, and hips.
 Rheumatoid arthritis
 Chronic inflammatory
disorder
 Marked by flare-ups
 Autoimmune disease.
 Body creates antibodies
which attack the joint
surfaces
 The synovial membrane
can inflame and eventually
thicken into a pannus – an
abnormal tissue that clings
to the articular cartilage.
 The pannus erodes the
cartilage and eventually
scar tissue forms and
connects the 2 bone ends.
This scar tissue can later
ossify, fusing the bones
together. This is known as
ankylosis.
Clinical
Conditions
Clinical
Conditions
 Gouty arthritis
 When nucleic acids (such as ????) are
metabolized uric acid is produced.
Normally uric acid is excreted in the urine.
 If blood [uric acid] rises due to decreased
excretion or increased production, it may
begin to form needle-shaped crystals in
the soft tissues of joints.
 Inflammation ensues causing painful
arthritis.