There are 360 joints in the human body. There are 86 skull joints, six throat joints, 66 thorax joints and 76 in your spine and pelvis. Also there are 32 in each upper limb and 31 in each lower limb. Two bones in our body meet to form a joint. Joints make our body flexible and to make movements. There are many different kinds of joints located in different parts of the body and responsible for different actions. These joints are Saddle joint, Pivot joint, Hinge joint, Fixed joint, Ellipsoidal joint, Ball and socket joint, Gliding joint, slightly movable joint and Spine joints.
Types of Joint
A joint is the point where two or more bones meet. There are three main types of joints; Fibrous (immoveable), Cartilagenous (partially moveable) and the Synovial (freely moveable) joint.
Fibrous (synarthrodial): This type of joint is held together by only a ligament. Examples are where the teeth are held to their bony sockets and at both the radioulnar and tibiofibular joints. Fibrous joints connect bones without allowing any movement. The bones of your skull and pelvis are held together by fibrous joints.The union of the spinous processes and vertebrae are fibrous joints.
Cartilagenous (synchondroses and sympheses): These joints occur where the connection between the articulating bones is made up of cartilage for example between vertebrae in the spine. Synchondroses are temporary joints which are only present in children, up until the end of puberty. For example the epiphyseal plates in long bones. Symphesis joints are permanant cartilagenous joints, for example the pubic symphesis. Cartilaginous joints are joints in which the bones are attached bycartilage. These joints allow for only a little movement, such as inthe spine or ribs.
Synovial (diarthrosis): Synovial joints are by far the most common classification of joint within the human body. They are highly moveable and all have a synovial capsule (collagenous structure) surrounding the entire joint, a synovial membrane (the inner layer of the capsule) which secretes synovial fluid (a lubricating liquid) and cartilage known as hyaline cartilage which pads the ends of the articulating bones. There are 6 types of synovial joints which are classified by the shape of the joint and the movement available. Synovial joints allow for much more movement than cartilaginous joints. Cavaties between bones in synovial joints are filled withsynovial fluid. This fluid helps lubricate and protect the bones.Bursa sacks contain* the synovial fluid.HingeA hinge joint allows extension and retraction of an apendage.
Types of Synovial Joint
- Hinge (Flexion/Extension) – A hinge joint allows extension and retraction of an apendage.
- Pivot (Rotation of one bone around another) – Pivot joints allow rotation arround an axis. The neck and forearmshave pivot joints. In the neck the occipital bone spins over the topof the axis. In theforearmsthe radius and ulna twist arround eachother.
- Ball and Socket (Flexion/Extension/Adduction/Abduction/Internal & External Rotation) – A ball and socket joint allows for radial movement in almost anydirection. They are found in the hips and shoulders.
- Saddle (Flexion/Extension/Adduction/Abduction/Circumduction) – A saddle joint allows movement back and forth and up and down, bot does not allow for rotation like a ball and socket joint.
- Condyloid (Flexion/Extension/Adduction/Abduction/Circumduction)
- Gliding (Gliding movements) – In a gliding or plane joint bones slide past each other. Midcarpaland midtarsal joints are gliding joints.
- Ellipsoid – Ellipsoid joints are similar to a ball and socket joint. They allowthe same type of movment to a lesser magnitude. The wrist is anellipsoid joint.