- JOINTS
- Joint is a point of contact between bones and cartilage or between bone and teeth.
- the site where more than two bones made to carry out the movement is known as joint or articulation.
- More than hundred type of joint are present in the human body.
- Some joint have no movement ( fibrous) , some have only slight movement (cartilaginous) , and some are freely moveable (synovial)
Asthrology :-
is the science considered concerned with the study of anatomy, function, dysfunction and treatment of joint and articulation.
Classification of joints :-
Joints are classified on the basis of structure and function:-
1- Structural classification of joints
Structural classification is based on the material that hold the join together and whether or not a cavity is present in the joint.
- structurally joints are of three types :-
- Fibrous joint - there is no saddle joint and the bones are held together by fibrous joint.
- Cartilage joint - there is no synovial joint cavity and bones are held together by cartilage.
- Synovial joint - there is no synovial cavity and bones are held together by dense irregular connective tissue of an articular capsule and accessory ligament.
Based on structural function joints are following types :-
a). Fibrous joint and fixed joint
The characteristics feature of fibrous joints are-
• The joint which joint bones fibrous connective tissue are called fibrous joint.
• Joint cavities absent in the fibrous joint.
•fibrous joints are divided into three types :-
1. Sutures :- the layer of connective tissue is called sutural ligament connects the articulating surfaces.
- It present only in skull and show no movement i.e they are immovable.
- It is divided into subtypes are plane suture, limb suture etc.
2. syndesmoses :- in syndesmoses a greater distance is present between the articulating surfaces.
It contained denser irregular connective tissue than a suture.
Example of sutures include
Inferior tibiofibular joint, tympano stapedisl joint joint.
3. Gomphoses( peg and socket joint) :-
• these are special type of fibrous joint which are involved in fixing of teeth (peg) in the alveolar socket of of maxilla and mandible.
• the periodontal ligament help in the attachment of the root of tooth to the socket within the alveolus.
b) Cartilage joint :-
cartilaginous joint the bone are attached to each other by hyaline cartilage or fibrocartilage.
• These joints are devoid of joint cavity.
The two type of of cartilaginous joints are :-
i) Synchondroses :- it is a primary carton a joint.
• Bones are joint by a hyaline cartilage.
• Immovable joint
• Most temporary in nature.
ii) dymphyses :- it is a secondary cartilaginous joint.
• bones are joined by the plates of hyaline cartilage.
• all symphyses occurs in the midline of the body.
c) Synovial joint :-(diarthrodial joint)
• deserve freely movable joint
• these are highly involved in nature
• these types of joint have a cavity and closed in fibrous capsule.
• aarthi plate of hyaline cartilage covers the articular surfaces.
Types of synovial joint :-
There are six types of synovial joints
1. Ball and socket joint - it is a ball shaped head of one bone fit in a socket line concavity or another.
• it is present in hip joint shoulder joint etc.
2. Condyloid joint - it have two convex surfaces that articulate two concave surfaces.
• it is present in temporomandibular, metacerpophalongeal.
3. Plane or glinding joint - in plain joint the opposite articular surface are flat or almost flat.
• intercorpal, intertarsal
4.Hinge joint :- hinge joint assemble a hinge on a door so that flexion and extension are possible.
• elbow, knee , ankle etc.
5. Pivot joint :- Central bony pivot surrounded by bony ligamentous ring and rotation is the only movement possible.
• superior radio ulnar.
6. Saddle joint :- the articular surface are reciprocally concave or convex and assemble a saddle on a horse back.
• first carpometacarpel, sternoclavicolar, calcaneo cuboid.
Types of joint movement :-
1. Glinding movement- movement of relatively flat bone surface back and forth and side to side over and one another.
• little changes in the angle between bones.
2. Angular - increase or decrease in the angle between bones.
• flexion - decrease the angle between articulating bones, usually in the sagittal plane
example band trunk or knee.
• extension - increasing in the the angle between articulating bones usually in sagittal plane.
• abduction - movement of a bone away from the midline usually in the frontal plane.
• adduction - movement of a bone towards the midline usually in the frontal plane.
3. Rotation -
Movement of a bone around its longitudinal access in the limbs it may be medial or lateral.
4.Circumduction -
Circumduction is a movement of limb and ise in a circular direction i.e 360°
Joint Articulation -
joint or articulation present in different parts of the body summarised as:-
• axial skeleton articulation.
• appendicular skeleton articulation.
i) Axial skeleton - include like skull hyoid bone, vertebral column (vertebrae and invertebral disks) and thorax ( ripsand sternum).
ii) The appendicular skeleton - comprises of pectoral girdle (scapulae and clavicles), upperlimbs (humerus, radius, ulna, carpals, metacarpal andphalanges), pelvic girdle (coxal bone articulating with the sacrum) and lower limbs ( femur, tibia, patalla,etc.)
Comments
Post a Comment