Date post: | 17-Aug-2015 |
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Health & Medicine |
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Dr. R. S. Daisy
Joint
Articulation or junction
between two bones
or
Articulation or junction
between more than two
bones
orArticulation or junction
between parts of a bone of
Skeleton
Movement :
• A joint may not move or
• A joint may move in a limited amount
or
• wide range of movement may occur in a joint
Joint : Features:
BONE+ MATERIALS CONNECTED BONE
+BONE
=JOINT
JOINT
Joints are 3 types: According to type of material by which bones are articulate/connected
Classification of joint
1.FIBROUS JOINTS
2.CARTILAGINOUS JOINT
3.SYNOVIAL JOINT
FIBROUS JOINT=BONE+FIBROUS TISSUE+BONE
Two important features of it :
1. Bones are separated only by connective tissue
2. No movement / negligible.
Fibrous joints:
1. Suture : this joint unite the bones of the vault of the skull. ex: sagital suture, coronal suture etc.
2. Gomphosis : dentoalveolar joint
3. Syndesmosis: radio-ulnar joint
Classification of fibrous joint
Suture Sagital SutureCoronal suture
Inter-osseous membrane
( a connective tissue membrane) articulates two bones. Exa:
• Middle radio ulnar joint
• Middle and inferior tibio fibular joint
Syndesmosis
Middle radio ulnar joint
Radius
Inter osseous membrane
Ulna
• Tooth • Fibrous tissue • Socket ( present in
alveolar process of maxilla & mandible)
Gomphosis
Bone
Bone
Cartilaginous joint =
Bone +cartilage+bone
2. Secondary cartilaginous joint= Bone+ hyaline cartilage+fibrocartilage +hyaline
cartilage+bone
Classification of cartilaginous jointare two types:
1. Primary cartilaginous joint=Bone+ hyaline cartilage+bone
Primary cartilaginous jointfeatures:
• All primary cartilaginous joint are strong and immobile
• These are temporary joint (in adult,
it is replace by bone)
Primary cartilaginous jointExamples:
• all epiphyses are primary cartilaginous joint
• head of humerus + hyaline cartilage + shaft of humerus
= Primary cartilaginous joint
Primary cartilaginous joint
Black line is cartilage
Primary cartilaginous joint is temporaryThe cartilage is replace by bone
Black line is cartilageThe primary cartilaginous joint
No black line in between head & shaft of humerusNo Primary cartilaginous joint
Adult Children
Secondary Cartilaginous joints
Articular surface of bone is covered by thin plate of hyaline cartilage
Fibrocartilage
Bone Bone
Secondary cartilaginous joint
• It is a union between bones whose articular surfaces are covered with a thin lamina of hyaline cartilage.
• The hyaline laminae are united by fibrocartilage,
but it is never lined with synovial membrane and it contains only tissue fluid
• A limited amount of movement is possible in this joint
• Usually situated in the midline of body
• Examples : pubic symphysis inter-vertebral
joint
2nd cartilaginous joint
Hyaline cartilage
Fibro cartilage cartilage
Synovial joint
Two bones are separated by a joint cavity
Red colour : articular surface of bones
Blue colour: articular surfaces of bones are covered by articular cartilage(hyaline cartilage)
Articular capsule has two layer outer fibrous layer(brown colour)
Articular capsule has two layer outer fibrous layer (brown colour) & inner synovial membrane (green colour)
Joint cavity the most unique feature of synovial joint is filled by synovial fluid (the secretion of
synovial membrane)
Synovial joint freely move due to presence of joint cavity
Plane x-ray of synovial joint
Articular capsule
Menisci
Articular cartilage
Typical synovial joint :Features:
1. Contains a joint cavity which is filled with synovial fluid
2. The articular surfaces of bones are covered by articular cartilages
3. The joint cavity is enveloped by a complete articular capsule, which consists of
outer fibrous capsule and inner synovial membrane • The articulating bones are connected by a
number of ligaments • Sometimes, the joint cavity is divided
completely or incompletely by articular disc or meniscus, which is composed of fibro-cartilage.
Classification of synovial jointit can be classify according to different logic
1. According to the number of articulating bones
2. According to the shape of articular surfaces of bones
3. According to axis of movement
Simple joint :Two bones separated by single joint cavity
Compound jointMore than two bones are separated by single
joint cavity
Complex joint :Articular disc( fibrocartilage) divide the
joint cavity into two compartment
Articular disc
According to the axis of movements
• Uni-axial• Bi-axial• Multi-axial
Uni-axial joint
Bi-axial joint
Multi axial joint
According to the axis of movements
• Uni-axial: pivot plane hinge • Bi-axial: saddle condyloid ellipsoid • Multi-axial: ball and socket
According to the shape of articular surfaces
1. pivot 2. plane 3. hinge4. saddle 5. condyloid 6. ellipsoid 7. ball and socket
Pivot
• A round process of bone that fits into a bony ligamentous socket
• Movement is rotation around one axis
• Rotation of radius during pronation and supination
Pivot joint
• Distal radio ulnar joint
Pivot joint
Articular discLooks black in xray
Hinge• Convex cylinder applied to a concave
bone • Movement in one plane, it permit flexion
and extension only
Plane
• Two flat surfaces approximately equal in size
• Movement gliding or slightly twisting
Saddle• Two concavo-convex surfaces are
applied to each other • Permit movement in two different
plane
Condyloid(bi-condylar joint) • It has two convex
condyles which articulate with concave or flat surfaces
• It is biaxial but movement is greater in one plane than in the other
Ellipsoid
• It consists of oval convex surfaces apposed to an elliptical concavity
• They are bi-axial joint • Movement flexion
extension abduction adduction and circumduction
Ball and socket• Round head fitting into a round
depression • Wide range of movement
Articular discLooks black in xray
• Articular disc:
is a thin, oval plate of
fibrocartilage present in
several joints which
separates synovial
cavities. This separation
of the cavity space
allows for separate
movements to occur in
each space.
Bursa • A bursa (plural bursae or bursas)
is a small fluid-filled sac lined by synovial membrane.
• It provides a cushion between bones and tendons and/or muscles around a joint.
• This helps to reduce friction between the bones and allows free movement.
• Bursae are filled with synovial fluid and are found around most major joints of the body.
Homework
1.Identify the joint.
ABCD
A
BC
D
2. Questions
• What do you mean by very similar terms:
1. Articular surface
2. Articular cartilage
3. Articular capsule
4. Articular disc
3. Questions
1. Which type of joint is most common in our body?
2. Which type of joint is temporary?
3. Which type of joint can’t move?
4. Which type of joint is situated in the midline?
5. Which type of joint has great range of movement?