2. Joints
A union or junction between two or
more bones.
Articulation
3. Joint Classification
Joints can be classified by several
criteria-
Simple or Compound- by the number
of bones articulating with each other.
Simple- articulations united by two bones.
Compound- articulations united by more
than two bones.
4. Joint Classification
Structural Classification- classified by
their uniting medium.
Fibrous- an articulation united by fibrous
tissue allowing little or no movement.
Cartilagenous- an articulation united by
fibrocartilage, hyline cartilage, or both as
in a symphysis.
Synovial- an articulation united by a
synovial joint capsule, these joints are
freely movable.
5. Joint Classification
Functional Classification- indicates the
degree of motion possible.
Synarthrosis- the tight, fixed union allowing
little or no movement and having great strength.
Ex. Skull bones
Amphiarthrosis- connected by CT or
fibrocartilage allowing slight motion. Ex.
Vertebrae
Diarthrosis- united by a joint capsule and are
freely moveable- synovial joints.
Gomphosis- the name for fibrous implantation of
teeth into the jaw.
6. Synovial Joints
Characterized by their
mobility, joint cavity,
articular cartilage,
synovial membrane,
and fibrous capsule.
This is the most
common type of joint.
Functionally, it is
freely moveable.
7. Synovial Joints
Joint capsule- the 2 layered structure
surrounding the joint.
Fibrous layer- the white & yellow elastic
fibrous part of the joint capsule.
It attaches to the periosteum on or near the
margin of the articular cartilage.
Synovial membrane- the inner lining of the
fibrous layer.
It is highly vascular, nerve rich, and produces
synovial fluid.
8. Synovial Joints
Synovial fluid- the viscous liquid that
lubricates the joint and supplies nutrients.
Articular cartilage- the translucent cartilage
covering the ends of bones.
It reduces the effects of friction.
Ligaments- strong bands of white fibrous CT
uniting bones.
They function to keep joint surfaces in apposition
and still allow movement.
9. Synovial Joints
Meniscus or Disc- a plate of
fibrocartilage partially or completely
dividing a joint cavity.
It functions to allow a greater variety of
motion and alleviate friction.
Bursa- a sac-like structure between
different tissue that reduces friction
between these tissues.
10. Classification of Synovial Joints
By movement- the contraction of
muscles crossing a joint and the shape
of a joint produce its characteristic
movements.
Plane- arthroidal joint having flat
articular surfaces allowing a gliding or
sliding motion.
Ball & Socket- a spheroidal joint
consisting of a spheroidal head fitting into
a pit or socket.
11. Classification of Synovial Joints
By movement…
Hinge- a joint allowing movement at right
angles.
Pivot- allows rotation around a
longitudinal axis of a bone.
Condylar- formed by 2 condyles of one
bone fitting into the cavities of another
bone.
12. Movement of Synovial Joints
Flexion- decreasing the angle between 2 bones.
Extension- increasing the angle between 2 bones.
Abduction- moving a part away from the medial
plane.
Adduction- moving a part toward the medial plane.
Circumdunction- movement circumscribing a cone
shape accomplished by combining flexion,
abduction, extension, & adduction.
Rotation- movement around the long axis of a part.
Universal- all of the above movements.
15. Humeroradioulnar
Head of the radius-
articulates with the hureral
condyle & the ulna.
Trochlear notch of the Ulna-
articulates with the trochlea
of the humeral condyle.
Anconeal process of the
Ulna- fits into the olecranon
fossa of the humerus.
17. Carpal Joints
A hinge joint allowing flexion and
extension with some lateral
movement.
It consists of 3 main joints:
antebrachiocarpal, middle carpal, &
carpometacarpal.
21. Intercarpal Joints
Plane joints between the individual carpal
bones.
Articulations between the proximal ends
of the metacarpal bones.
22. Metacarpaophalangeal Joints
The articulation
between the
metacarpals & the
proximal phalanges
including the palmar
sesamoid bones.
A modified hinge joint
allowing flexion &
extension.
23. Phalangeal Joints
Proximal
Interphalangeal
joints- synovial
joints between the
proximal and middle
phalanges.
Distal
Interphalangeal
Joints- between the
middle and distal
phalanges.
24. Pelvic Joints
relatively
immovable
articulation
between the wings
of the sacrum & the
ilium.
This is a combined
cartilagenous and
synovial joint.
25. Pelvic Joints
Pelvic Symphysis- a
slightly moveable
joint between the 2
hip bones.
Coxofemoral- the
ball & socket type
synovial joint
between the head
of the femur and
the acetabulum of
the pelvis.
26. Stifle
A condylar joint
which acts like a
hinge joint with a
little rotation.
27. Stifle
**Patellar Ligament-
the part of the tendon
insertion of the
quadriceps muscle
between the patella
and tibial tuberosity.
28. Stifle
Medial & Lateral
Menisci- the crescent,
fibrocartilagenous discs
between the tibial &
femoral articulating
condyles.
29. Stifle
Cranial & Caudal
Cruciate Ligaments-
intra-articular
ligaments named for
their tibial
attachments.
**Cranial CL- inserts
cranially on the tibia.
**Caudal CL- inserts
caudally on the tibia.
32. Skull Joints
Mandibular Symphysis-
cartilagenous joint
joining the left & right
mandibular bodies.
33. Vertebral Column
Intervertebral articulations consist of
2 types of joints:
Cartilagenous- are formed by
interveterbral disks joining adjacent
vertebral bodies.
Synovial- are formed by caudal and
cranial articular processes of adjacent
vertebrae.
34. Vertebral Column
Costovertebral Joints- the 2 distinct
articulations between most ribs and
the vertebral column.
The head of each rib forms a ball & socket
joint with the vertebrae.
The tubercle of each rib forms a joint with
the transverse process of the vertebrae.
Each has a joint capsule.
35. Vertebral Column
Atlanto-occipital Joint- the “yes”
joint.
Atlanto-axial Joint- the “no” joint.
A pivot joint between the axis & atlas.
Intervertebral Disks-
The layers of fibrocartilage between
bodies of adjacent vertebrae each
consisting of an outer fibrous ring and an
inner pulpy nucleus.
38. Osteochondrosis Dessicans
A failure of
cartilage
maturation.
Pressure on such
defective cartilage
may cause a piece
(joint mouse) to be
separated and float
free in the synovial
space.
39. Pathology…
Arthritis-
Inflammation of a joint
Bursa-
Small, fluid-filled sac in places where
friction might occur
Bursitis-
Inflammation of the bursa
40. Pathology…
False Joints- a joint formed in an
unreduced (unhealed) fracture, having
all the structures of a synovial joint.
Luxation or Dislocation- an articular
separation usually due to injury or
degenerative changes.
41. Hip Dysplasia
A malformed hip
joint resulting in a
progressive
degenerative
disease having a
high incidence in
some breeds.
43. Cranial Cruciate Ligament Rupture
and Repair
When the cruciate ligament is
torn or stretched, instead of
moving like a hinge, the knee
joint will actually make a
sliding motion.
This abnormal motion and
instability creates trauma
within the joint that leads to
wearing of cartilage, increased
synovial fluid production and
inflammation.
44. CCLR
A torn cruciate ligament can occur in any
dog if just the right (or wrong!) forces
impact the knee joint.
Most commonly seen in larger breeds of dogs
and in dogs that are overweight
The ACL surgical procedure does not actually
repair the torn ligament but rather replaces
the ligament with artificial material that
takes over the function of the Cruciate
Ligament.
46. Patellar Luxation
Patellar luxation is usually a congenital condition in
which the kneecap, or patella, dislocates outside of
its normal trochlear groove.
Dislocation, clinically referred to as luxation, can
occur on either the medial, or inside surface, or the
lateral, or outside surface, of the knee.
There are varying degrees of patellar luxation that
are graded depending on whether the patella is
intermittently or constantly luxated.
This abnormal displacement of the kneecap results
in pain, cartilage damage, and arthritis.
There are varying degrees of severity of this
disease, and surgery may be needed.
48. Indications
Helps determine the cause of pain or
swelling in a joint
Synovial fluid is collected for
cytological, bacterial or biochemical
analysis
49. Normal synovial fluid has a low cellularity,
with virtually no red blood cells & only small
numbers of leukocytes.
The main functions of synovial fluid are
nutritive support, lubrication, and
“cushioning” of the articular cartilage.
50. In addition to cytologic evaluation, the
fluid should be assessed for:
Volume obtained
Turbidity
Mucin quality/concentration
Protein concentration
Color
Viscosity
51. Sample Handling & Test Priorities
Normal synovial fluid does not clot.
However, with hemorrhage or blood
contamination, samples may clot unless
processed immediately or placed in an
anticoagulant tube.
EDTA is preferred for cytologic
examination, while heparin is
recommended for the mucin clot test.
52. Color & Turbidity
Normal synovial fluid is clear to straw
yellow and non-turbid.
Turbidity, when present, is caused by
cells, protein (or fibrin), or cartilage.
