Joint Joint

ByDr. Ajay Kumar

ProfessorSchool of Physical Education

DAVV Indore

IntroductionIntroduction

We have already learnt that the human skeleton We have already learnt that the human skeleton consists of more than 200 bones. The individual consists of more than 200 bones. The individual bones are attached in such a way that a large variety bones are attached in such a way that a large variety of co-ordinated movements are made possible in of co-ordinated movements are made possible in different parts of the body. These movements are different parts of the body. These movements are made possible by made possible by skeletal musclesskeletal muscles, the fact that the , the fact that the bones act as bones act as leverslevers, , cartilagecartilage which reduces fricton which reduces fricton and and ligaments ligaments which prevent dislocation and the which prevent dislocation and the presence of presence of movable jointsmovable joints. The site or place where 2 . The site or place where 2 or more bones of the skeleton are attached to each or more bones of the skeleton are attached to each other is called a joint or place of articulation. other is called a joint or place of articulation.

Joint DefinitionJoint Definition

A joint can be defined as follows: A joint can be defined as follows: A joint or place of articulation is formed A joint or place of articulation is formed

where 2 or more bones come inclose contact where 2 or more bones come inclose contact in the body and are attached to each other in the body and are attached to each other by ligaments or cartilage.by ligaments or cartilage.

Types of JointsTypes of Joints

Joints can be classified according to the degree Joints can be classified according to the degree and type of movement they allow. The and type of movement they allow. The following types of joints can be recognized: following types of joints can be recognized:

Fibrous (or Immovable) Joints.Fibrous (or Immovable) Joints.

These joints are firmly These joints are firmly held together by a held together by a thin thin layer of strong layer of strong connectice tissueconnectice tissue. . There is There is no movementno movement between the bones such between the bones such as the as the sutures of the sutures of the skullskull and the and the teeth in teeth in their socketstheir sockets. .

Cartilagenous JointsCartilagenous Joints

Cartilagenous joints are joints where the articular Cartilagenous joints are joints where the articular surfaces of the bones forming the joints are attached surfaces of the bones forming the joints are attached to each other by means of to each other by means of white fibrocartilaginous white fibrocartilaginous discsdiscs and and ligamentsligaments which allow only a which allow only a limited limited degree of movementdegree of movement. Examples are the . Examples are the cartilaginous between the vertebraecartilaginous between the vertebrae, the , the cartilage cartilage in the symphysisin the symphysis which binds the pubic bones which binds the pubic bones together at the front of the pelvic girdle and the together at the front of the pelvic girdle and the cartilage in the joint between the sacrum and the cartilage in the joint between the sacrum and the hip bone.hip bone.

Cartilagenous JointsCartilagenous Joints

Synovial JointsSynovial Joints These are These are freely movable jointsfreely movable joints. Most of the joints in . Most of the joints in

the body are of the synovial type. The following are the body are of the synovial type. The following are the the main characteristicsmain characteristics of a synovial joint: of a synovial joint:

The ends of the bones are covered with a lThe ends of the bones are covered with a layer of ayer of smooth hyaline cartilage, called articular cartilagesmooth hyaline cartilage, called articular cartilage in the joint regions. This rin the joint regions. This reduces frictoneduces fricton at the point. at the point.

The joint is completely enclosed by a The joint is completely enclosed by a bag-like bag-like capsular ligamentcapsular ligament which which holds the joint togetherholds the joint together and helps to contain the and helps to contain the synovial fluidsynovial fluid. .

Synovial Joints (cont)Synovial Joints (cont)

The The capsular ligamentcapsular ligament is lined with a is lined with a synovial synovial membranemembrane. This membrane . This membrane secretes synovial fluidsecretes synovial fluid into the into the synovial cavitysynovial cavity and acts as a and acts as a seal, seal, waterproofing the jointwaterproofing the joint. The synovial fluid . The synovial fluid lubricateslubricates the joint. the joint.

In addition to the capsule, the bones are also attached In addition to the capsule, the bones are also attached and held together by strong, tough and held together by strong, tough ligamentsligaments made of made of dense connective tissuedense connective tissue. These ligaments . These ligaments prevent prevent dislocation dislocation during normal movement. during normal movement.

The articulating surfaces of adjacent bones are The articulating surfaces of adjacent bones are reciprocally shaped.reciprocally shaped.

Synovial JointsSynovial Joints

Ball-and-socket jointBall-and-socket joint

Consists of a bone with a globular or slightly Consists of a bone with a globular or slightly egg-shaped head that articulates with the cup-egg-shaped head that articulates with the cup-shaped cavity of another bone. Such a joint shaped cavity of another bone. Such a joint allows a wider range of motion than does any allows a wider range of motion than does any other kind, permitting movements in all other kind, permitting movements in all planes, as well as rotational movement around planes, as well as rotational movement around a central axis. The hip and shoulder contain a central axis. The hip and shoulder contain joints of this type.joints of this type.

Ball-and-socket jointBall-and-socket joint

Condyloid jointCondyloid joint

The ovoid condyle of one bone fits into the The ovoid condyle of one bone fits into the elliptical cavity of another bone, as in the elliptical cavity of another bone, as in the joints between the metacarpals (bones of the joints between the metacarpals (bones of the palm) and phalanges (bones of the fingers and palm) and phalanges (bones of the fingers and toes). This type of joint permits a variety of toes). This type of joint permits a variety of movements in different planes; rotational movements in different planes; rotational movement, however, is not possible.movement, however, is not possible.

Gliding jointsGliding joints

The articulating surfaces are nearly flat or The articulating surfaces are nearly flat or slightly curved. These joints allow sliding or slightly curved. These joints allow sliding or back-and-forth motion and twisting back-and-forth motion and twisting movements. Most of the joints within the wrist movements. Most of the joints within the wrist and ankle, as well as those between the and ankle, as well as those between the articular processes of adjacent vertebrae, articular processes of adjacent vertebrae, belong to this group. The sacroiliac joints and belong to this group. The sacroiliac joints and the joints formed by ribs 2 though 7 the joints formed by ribs 2 though 7 connecting with the sternum are also gliding connecting with the sternum are also gliding joints.joints.

Gliding jointsGliding joints

Hinge jointHinge joint

The convex surface of one bone fits into the The convex surface of one bone fits into the concave surface of another, as in the elbow concave surface of another, as in the elbow and the joints of the phalanges. Such a joint and the joints of the phalanges. Such a joint resembles the hinge of a door in that it permits resembles the hinge of a door in that it permits movement in one plane only.movement in one plane only.

Hinge jointHinge joint

Pivot JointPivot Joint The cylindrical surface of one bone rotates within a The cylindrical surface of one bone rotates within a

ring formed of bone and fibrous tissue of a ligament. ring formed of bone and fibrous tissue of a ligament. Movement at such a joint is limited to rotation around Movement at such a joint is limited to rotation around a central axis. The joint between the proximal ends of a central axis. The joint between the proximal ends of the radius and the ulna, where the head of the radius the radius and the ulna, where the head of the radius rotates in a ring formed by the radial notch of the ulna rotates in a ring formed by the radial notch of the ulna and a ligament (annular ligament), is of this type. and a ligament (annular ligament), is of this type. Similarly, a pivot joint functions in the neck as the Similarly, a pivot joint functions in the neck as the heard turns from side to side. In this case, the ring heard turns from side to side. In this case, the ring formed by a ligament (transverse ligament) and the formed by a ligament (transverse ligament) and the anterior arch of the atlas rotates around the dens of anterior arch of the atlas rotates around the dens of the axis.the axis.

Pivot JointPivot Joint

Saddle jointSaddle joint

Forms between bones whose articulating Forms between bones whose articulating surfaces have both concave and convex surfaces have both concave and convex regions. The surface of one bone fits the regions. The surface of one bone fits the complementary surface of the other. This complementary surface of the other. This physical relationship permits a variety of physical relationship permits a variety of movements, mainly in two planes, as in the movements, mainly in two planes, as in the case of the joint between the carpal case of the joint between the carpal (trapezium) and the metacarpal of the thumb.(trapezium) and the metacarpal of the thumb.

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