1. Arthrology Function of joint Def: Science deals with joints
Joint = union between 2 or more bones or cartilages by uniting medium
Function of joint
directed movement
stability between bones
bone growth
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2. Classification of joints
According to types of uniting medium
Fibrous joints
Uniting medium is fibrous tissue
No joint cavity
are temporary (ossify with age)
No movement
Cartilagenous joints
Uniting medium is cartilage
are temporary
No or very limited movement
synovial joints
uniting medium is joint capsule
Joint cavity present
Movable
Dr: Ahmed Saber Vet. Anat

3. I- Fibrous joints (Synarthrosis)
Types of fibrous joints
Large metacrpal
small metacrpal
syndesmosis
1-Syndesmosis
The uniting medium is fibrous connective tissue (interosseous ligament)
ex. Union of metacarpal bones, radius and ulna and tibia and fibula
Dr: Ahmed Saber Vet. Anat

4. Dr: Ahmed Saber Vet. Anat. 1. 2008
2-Gomphosis
Implantation of teeth into the alveoli by periodontal ligament
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3-Sutures
fibrous tissues bond the bones of skull.
Based on the edges of the articulating bones, it may be
sutures
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A- Serrated sutures:
the interlocking borders are saw like as interfrontal suture
B- Squamous sutures:
borders are flat and overlapped as temporal and parietal suture
C- Plane suture:
the interlocking borders are smooth as nasal suture
D- Foliate suture:
the edge of one bone fits into a fissure in the adjacent bone as zygomatico-maxillary suture. A B C D
Dr: Ahmed Saber Vet. Anat

7. II- Cartilaginous joints (amphiarthrosis)
Types of cartilaginous joints
1. Synchondrosis (hyaline cartilage joint):
the uniting medium is hyaline cartilage. EX. Costochondoral junction and epiphyseal and metaphyseal junction
Ribs
Costochondral junction
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2. Symphesis (fibrocartilage joint):
the uniting medium is fibro cartilage as the pelvic symphysis and joint between vertebral bodies
Fibrocartilaginous disc
Vertebrae
Dr: Ahmed Saber Vet. Anat

9. III. Diarthroidal joint (Synovial, movable or true joint)
Structures of synovial joints
A-constant structures
Articular surface
Articular cartilage
Articular capsule
Joint cavity
B- inconstant (additional features)
Ligaments
Articular disc &menisci
Marginal cartilage
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11. A-constant structures ( essential)
Structures of synovial joints (cont.)
A-constant structures ( essential)
I - Articular surfaces
It is formed of compact bone
It is smooth but sometime interrupted by synovial fossa
Covered by articular cartilage except synovial fossa
Dr: Ahmed Saber Vet. Anat

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II - Articular cartilages
It is smooth hyaline cartilage
Cover the articular surfaces except at the synovial fossa
Almost one convex and the other is concave
The concave one is thickest at the periphery and thin at the center and vise versa
Its function :
increase the curvature of bones
facilitate movements and reduce frictions
Dr: Ahmed Saber Vet. Anat

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III-Joint capsule
It is fibroserous tube
Originated from the periosteum of bones
attached around the articular margins and surrounds the joint cavity, it is consisted of:
􀁦 Outer fibrous layer (external layer)
it may contain ligaments
􀁦 Inner synovial layer (internal layer)
it is a thin single layer of epithelium
line the joint cavity except the articular cartilage
it secrete and/or absorb synovia.
Dr: Ahmed Saber Vet. Anat

14. Structures of synovial joints (cont.)
B- Additional features: present in some joint
1- ligaments:
Strong white fibrous band unite 2 or more bones
A- internal (Intraarticular) lig.:
placed within the fibrous layer
covered with the synovial membrane
Ex. Cruciate ligament
B- Extrnal (periarticular) lig.:
situated outside the joint capsule
Ex. Collateral ligaments
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2- Articular disc &menisci:
fibrocartilage plate present between the articular cartilages
divide the joint cavity partially (disc) completely (menisci) into 2 parts
Ex. Disc of tempro-mandibular joint, menisci of stifle joint
function:
correct the incongruent surfaces
anti concussion & allow greater movement
Dr: Ahmed Saber Vet. Anat

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3- Marginal cartilage:
ring of fibrocartilage encircle the rim of articular cartilage
Ex. acetabulum of hip joint
function:
enlarge the joint cavity
protect the rim from fractures
Dr: Ahmed Saber Vet. Anat

17. Synovia (synovial fluid)
Secreted and absorbed by synovial membrane
It present within synovial joint, around some tendons and within bursae
chemical composition: (mucin, salts, albumin, fat droplets, and cellular debris)
Function
1. Lubricate the articular surfaces and tendons
2. Nutrition of cartilage
3. Remove waste metabolites
4. Enable wandering leukocyte to circulate in the joint cavity
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18. Blood and nerve supply of synovial joint
Synovial joint receives vessels from surrounding muscles
Sensory nerves terminates in the joint capsule and ligaments
Autonomic innervations terminate in the arteries
Dr: Ahmed Saber Vet. Anat

19. Anatomical types of synovial joints
I- According to the number of articulating bones
Simple joint : between two bones
Compound joint: between more than two bones
II- according to fitting of articular surfaces
Congruent joint: adapted to each other
In congruent joint: are not adapted, ex stifle joint
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III-according to the shape of articular surfaces
Types
Shape
Example
1- Ball and socket
Spheroidal
Enartherosis
Ball and other is
a cavity
Ball is the largest
The socket is the largest
Shoulder
hip
2-Hinge (ginglymis)
Like door hinge, one concave and other is convex
elbow 1 2 1
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21. Dr: Ahmed Saber Vet. Anat. 1. 2008
Types
Shape
Example
3- Ellipsoid
The convex and
concave are
ellipsoidal oval
Atlantooccipital
radiocarpal
4- gliding (plane)
Flat surfaces
joint
Intercarpal
skull
Atlas 3 4
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Types
Shape
Example
5- pivot
One ring moved
around axis of other
atlanoaxial
6-saddle
Concavoconvex as horse saddle
Caffin and pastern 5
Pastern joint
Coffin joint 6
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23. Lateral condyle of femur Lateral condyle of tibia
Types
Shape
Example
7- cochlear
Cochlea (cavity) receives ridge of other bone
Tibio-tarsal
8-Bi-condylar
Both are convex
condyles
femorotibial
Tibia
Talus
Tarsal bones 7
Tibia
Femur 8
Lateral condyle of femur
Lateral condyle of tibia
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24. Physiological types of synovial joints
I-According to the axis of movement:
uniaxial: around one axis
Transverse axis as hing joints (elbow joint)
Vertical axis as pivot joints (atlantoaxial)
biaxial : arround two axis
Biocodylar joints
Ellipsoid joints
Saddle joints
multiaxial : more than two
ball and socket

25. Movements of synovial joints
A- According to causes
Active movements: due to muscle contraction
Passive movements: due to gravity or the movement of other joints
B- According to the shape of articular surface
1-Gliding : one surface glides over another
Ex. Intercarpal, femoropatellar and the joints between the articular process of cervical vertebrae
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2- angular movements
A- flexion: (decrease the joint angle)
B- extension: (increase the joint angle)
C- adduction: (towards the median plane)
D-abduction: (away from the median plane)
E- circumduction: (combination of A,B,C and D)
3- rotatory movement
Rotation of one segment around the longitudinal axis of other segments atlantoaxial joint
Dr: Ahmed Saber Vet. Anat

27. Factor affecting joint stability
Shape and size of articulating bone
Arrangements of articulating bone
Tone of surrounding muscles
Strength of the ligaments
To be continued in applied anatomy
Dr: Ahmed Saber Vet. Anat