Joints

Joint
 
Classification of Joint
 
A/c to Degree of Mobility (Functional Classification)
1. Synathroses
• Solid joints without any cavity
• Example
- Fibrous joints
- Cartilaginous joints
2. Diarthroses
• Form synovial joints, which possess a joint cavity filled with synovial fluid and permit free movement
• Example
- Synovial joints
 
 
Structural / Morphological Classification
1. Fibrous Joint
In these joints, bone are united by fibrous tissue.
Subdivided into
- Suture Joint
- Syndesmosis Joint
- Gomphosis Joint

2. Cartilaginous Joint
• Binding media is cartilage
• Little movement possible
Subdivided into
- Primary Cartilaginous (Synchondrosis)
- Secondary Cartilaginous (Symphysis)
 
3. Synovial Joint
Cavity containing joint containing synovial fluid in it.
Subdivided into
• Ball & Socket type of synovial joint
• Saddle type of synovial joint
• Condylar type of synovial joint
• Ellipsoid type of synovial joint
• Hinge type of synovial joint
• Pivot type of synovial joint
• Plane type of synovial joint
 
 
Fibrous Joint Types
A). Suture
• All joints present in the skull is of Suture type of fibrous joint except
- AtlantoOccipital Joint
- Temperomandibular joint
- Joint between Socket present in mandible & maxilla with teeth
• Uniting media is dense fibrous tissue
• The uniting fibrous tissue may be replaced by bones tissue in later life
 
Types of suture
1. Serrate suture:
• Saw tooth-like appearance
• Example
Sagittal suture of the
skull
2. Denticular suture:
• Teeth like margin
• Eg.Lamboid suture
3. Squamous suture:
• Edges are united by overlapping
• Eg. Between parietal & squamous part of the temporal bone of the skull
4. Limbous suture:
• Eg. Mastoid process of temporal bone
5. Wedge & Groove suture:
• Eg.Between the rostrum of sphenoid and Vomer
6. Plane suture:
• Border are plane
• Eg.Between palatine processes of maxilla
 
B). Syndesmosis
• Fibrous joint where the surfaces bones are united by interosseous ligaments
• Example:
- Inferior Tibiofibular joint,
- Middle radio-ulnar joint
 
C). Gomphosis
• Roots of teeth fit in the socket of the jaw and are united by fibrous tissue
• Example:
- Between root of teeth and
alveoli of the maxilla and mandible
 
 
Types of cartilaginous Joints
• Binding media is Cartilage
• No joint cavity 
 
A) Primary Cartilaginous Joint (Synchondrosis)
Binding media is Hyaline cartilage in nature
No movement
Temporary and the cartilages become ossified replaced by bone (called as synostosis)
Example:
• Junction between epiphysis and diaphysis of growing long bone
• 1st chondrosternal joint
• Xiphisternal joint
• Articulation between basi-occipital and basi-sphenoid (between basilar part of occipital bone & Body of Sphenoid bone)

Synostosis Means bone to bone joint by bonny tissues
Fate of Primary Cartilaginous Joint
With the age, the Cartilage is wholly replaced by complete bony Union i.e has formed synostosis
 
B) Secondary Cartilaginous Joint (Symphysis)
Articular surfaces of bones are covered with hyaline cartilage and are united by a plate of fibrocartilagenous structure (which is present between the middle of joint)
Permanent - persist throughout the life
Example:
• All joint lying in the midline of body except xiphisternal joint
• Intervertebral joint between bodies of vertebrae
• Symphysis menti
• Pubic Symphysis
• Sterno-manubrial joint
• Lumbosacral joint
• Sacrococcygeal joint
 
 
Synovial Joint (Cavity containing joint)
 
Characteristics of Synovial Joint
1. Articular surface of bones are covered by hyaline cartilage
2. Joint present a cavity which is filled with colorless synovial fluid
3. Joint cavity is enveloped by an articular capsule, which consists of an outer fibrous capsule and inner synovial membrane
4. The synovial membrane lines the whole of the interior of the joint cavity except the articular surface which is lined by hyaline cartilage.
5. Sometimes, the joint cavity is divided into two compartments by fibrocartilagenous structures like articular disc, meniscus.
Like in temporomandibular joint cavity has two compartments divided by articular disc.
6. Movement is permitted from limited to a wide range
7. Articulating bones are connected by a no.of accessory ligament
 
 
Four distinguishing features of synovial joint are:
• Joint cavity
• An articular cartilage (Articular surface lined by hyaline cartilage)
• A synovial membrane (which produce synovial fluid)
• An articular capsule
 
 
 
Classification of synovial joint
A) A/c to the shape of articular surfaces
(Morphological Classification)
 
1. Hinge Joint of synovial joint
Movement over one axis only
Uniaxial movement i.e

- Flexion & Extension
Example
• Elbow joint (Humeroulnar-Humeroradial joint)
• Ankle Joint
• Interphalangeal joints of finger & toes


2. Pivot Joint of synovial joint
 Uniaxial movement i.e
- Flexion & extension
Example
• Proximal radioulnar joint
• Distal Radioulnar joint
• Median atlanto_axial joint


3. Condylar type of synovial joint
Movement:
Flexion & Extension
Example
• Temperomandibular joint
• Knee joint


4. Ellipsoid type of synovial joint
Movement over two axis
Biaxial movement:
- Flexion, extension,
- Abduction, abduction,
- and Circumduction
Example
• Metatarsal-phalangeal joint
• Metacarpal-phalangeal joint
• Wrist joint (RadioCarpal joint)
• AtlantoOccipital joint
 
5. Saddle type of synovial joint
Example
• Sternoclavicular joint
• 1st carpometacarpal
• Between patella & femur
 
6. Ball & Socket type of synovial joint
Multiaxial movement:
- Flexion, extension,
- Abduction, abduction,
- Medial & lateral rotation,
- and circumduction
Example
• Hip joint
• Shoulder joint
• Between incus & stapes
 
7. Plane type of synovial joint
Only gliding movement
Example
• Sacroiliac joint
• Costovertebral joint
• Costotransverse joint
• Between articular processes of vertebrae (facet joint)
• Except 1st chondrosternal joint
• Interchondral joint (5-9th)
• Intertarsal joint
• Intercarpal joint
• All Carpometacarpal (except 1st)
• Tarsometatarsal joint
• Superior tibiofibular joint



B) A/c to the number of articular surfaces
 
1. Simple synovial joint
- Possesses two articular surfaces
- And only one joint cavity
Example
• Hip joint
• Interphalangeal joint of finger & toe
 
2. Compound synovial joint
- Possesses more than two articular surfaces
- But only one joint cavity
Example
• Wrist joint(radio-carpal joint)
• Ankle joint


3. Complex synovial joint
Possesses more than two articular surfaces
and two joint cavity, formed by the presence of articular disc or meniscus
Example
• Knee joint
• Sternoclavicular joint
• Temperomandibular joint


C) A/c to the axis of movement
1. Uniaxial joint
When joint move around one axis only 
Example
• Joints of Hinge type (elbow joint) Flexion & extension
• Joints of Pivot type (Proximal radioulnar joint) Rotation only


2. Biaxial joints
When joints moves around two axis
Example
• Joints of condylar type (knee joint) Flexion, extension & limited rotation
• Joints of ellipsoid type (wrist joint) Flexion, extension
Abduction, adduction, circumduction
 
3. Multiaxial joints
When joints move around more than two axis
Example
• Joints of saddle type(1st carpometacarpal joint) Flexion, extension, Abduction, adduction & 
- In thumb
Additional Opposition movement
• Joints of ball & socket type(hip joint)  

Joint is the meeting point between two or more bones