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Joints &
Articulation
T U R N ER COL L EG E & CA R E E R HI G H S CHOOL  2 0 1 5
Types of Joints
Classification of Joints
Classification By Function (degree of movement
possible):
1. Synarthroses (Syn=connected, immovable)
◦ Joints with little or no movement
◦ Skull sutures, cranium (minus the mandible)
2. Amphiarthroses (Amphi = on both sides, between)
◦ Slightly moveable joints
◦ Intervertebral discs, costosternal joints, cartilaginous
joints(vertebrate between spine)
3. Diarthroses (Diar=passing through, free moving)
◦ Freely moveable joints
◦ Shoulder, knee, hip, elbow, interphalangeal, tarsal, and carpal
joints
Joint Classification
Classification by
structure:
1. Synovial joints:
◦ 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:
◦ 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:
◦ 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 on
the skull:
◦ What function do you
suppose sutures are
designed for?
Types of Joints in the
Human Body
Immovable: fixed joint such as the cranium
Ball-and-socket joints: such as the shoulder and hip joints, allow
backward, forward, sideways, and rotating movements.
Hinge joints: such as in the fingers, knees, elbows, and toes, allow only
bending and straightening movements.
Pivot joints: such as the neck joints, allow limited rotating movements.
Sliding joint: found in the vertebral column and allows small sliding
movements. The vertebrae have pads of cartilage between them, and the
bones slide over these pads. This is what makes the backbone so flexible.
Ellipsoidal joint: similar to a ball and socket joint. They allow the same
type of movement to a lesser magnitude such as the wrist
Structure and Function
Now let’s talk about synovial joints.
◦ 5 main structural characteristics:
1. Articular cartilage
◦ What kind of cartilage is it?
◦ Where do we find it?
◦ What does it do?
Structure and Function
2. Articular capsule
◦ 2 layered. Surrounds both
articular cartilages and the
space between 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.
◦ It covers all internal joint
surfaces except for those areas
covered by the articular
cartilage.
Structure and Function
3. Joint (Synovial) Cavity
◦ The potential space within the
joint capsule and articular
cartilage
4. Synovial Fluid
◦ A small amount of slippery fluid
occupying all free space in 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
◦ What kind of tissue are they?
◦ What do you suppose their
function is?
◦ Double-jointed-ness results from
extra-stretchy 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 between
bone ends, thus stabilizing the
joint.
◦ Found in the knee, jaw, and
sternoclavicular joint.
Bursae are basically bags of
lubricant - fibrous membrane bags
filled with synovial fluid. Often
found where bones, muscles,
tendons, or ligaments rub together.
Types of Synovial Joints
1. Plane joints
◦ Articular surfaces are flat and
allow short slipping or gliding
movements.
◦ Intercarpal and intertarsal joints
2. Hinge joints
◦ A cylindrical projection of one
bone fits into a trough-shaped
surface on another (like a hotdog
in a bun)
◦ Movement resembles a door
hinge.
◦ Elbow joint – ulna and humerus;
Interphalangeal joints
Types of Synovial Joints
3. Pivot joints
◦ 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
4. Condyloid joints
◦ Oval articular surface of one bone
fits into a complementary
depression on another.
◦ Radiocarpal joints
◦ Metacarpophalangeal joints
Types of Synovial Joints
5. Saddle joints
◦ Each articular surface has
convex and concave areas. Each
articular surface is saddleshaped.
◦ Carpometacarpal joints of the
thumbs.
6. Ball-and-Socket joints
◦ 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 Knee
The lateral and medial condyles
of the femur articulate with the
lateral and medial condyles of
the tibia.
◦ Between 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.
ACL Injuries
http://video.about.com/sportsmedicine/Anterior-Cruciate-Ligament.htm
http://video.about.com/sportsmedicine/Medial-Meniscus-Injury.htm
Articulations (Movements)
Flexion & Extension of
the Vertebral Column
Flexion & Extension of
the Head
Articulation & other
Movements
Additional Movements
at Biaxial Joints
Rotation of the Radius
Movements of the Foot