Joints of the human body Joints of the

Joints of the human body

Joints of the human body �Joints are the point of contact (articulations) between two connecting bones. �The stability and the integrity of joints are maintained by strands of connective tissue called ligaments, which hold bones together.

Classification of Joints �Structural classification of joints recognize three types of joints. Fibrous Joints Cartilaginous Joints Synovial Joints

Classification of Joints (Structure) Joint types Fibrous Joints Cartilaginous Joints: Synovial Joints: Description Examples Bound tightly together by connective tissue and allow no movement. The sutures between the bones of the skull (vault) The body of one bone connects with the body of another by means of cartilage. These joints can absorb shock, and allow slight movement. The intervertebral disks of the vertebral column & Symphysis pubis Joints that allow the greatest range of motion. Bony surfaces are separated by a lubricating fluid and by cartilage. They are also joined by ligaments that enclose the end of articulating bones and form the capsule containing the synovial membrane Knee joint Shoulder joint Hip joint Etc.

Characteristics of a Synovial Joint 1. Articulating cartilage: �The hyaline cartilage located at the ends of the bones allow for smooth contact surfaces for bones to move. �They also act as shock absorbers

Characteristics of a Synovial Joint 2. Joint capsule: � Consists of a synovial membrane and a fibrous capsule. Synovial membrane: � Allows certain nutrients to pass through Fibrous capsule: � Keeps synovial fluid is

Characteristics of a Synovial Joint 3. Joint Cavity � Located between to bony surfaces, this cavity is filled with synovial fluid which lubricates the joint. � This lubricant reduces friction between the bones, and also provides nutrients for the articulating cartilage

Characteristics of a Synovial Joint 4. Bursae �These small fluid-filled sacs are found at friction points between ligaments, tendons, and bones. �They provide cusion, reduce friction and allow free movement in the joint.

Characteristics of a Synovial Joint 5. Intrinsic Ligaments 6. Extrinsic Ligaments � Thick bands of connective tissue that reinforce the joint capsule � Seperate from the joint capsule, they help reinforce the joint by attaching the bones together

Types of Synovial Joints �Synovial joints are often distinguished by the kind of movement the joint permits. �There are 6 types of synovial joints: �Hinge Joints �Pivot Joints �Ellipsoid (Condyloid) Joints �Saddle Joints �Ball and socket Joints �Plane (Glidding) Joints

Hinge Joints �Unilateral Joint �One articulating surface is convex and the other is concave Examples: �Humero-ulnar joint �Interphalangeal joints (fingers)

Pivot Joints �Unilateral Joint �One bone rotates around one axis Example: �atlantoaxial joint �Radioulnar joint

Ellipsoid (Condyloid) Joints �Bilateral �(flexion-extension, abduction-adduction) �One surface is a ovular convex shape, and the other is a reciprocally concave surface.

Saddle Joint �Bilateral �(flexion-extension, abduction-adduction) �Bone are set together as in sitting on a horse Example �Carpometacarpal joint

Ball and Socket Joint �Trilateral �A rounded bone is fitted into a cup-like receptacle Examples: �Iliofemoral joint �Glenohumeral joint

Gliding Joint �Unilateral �Joint permits gliding movements �The bone surfaces are nearly flat, so the only movement allowed is a gliding action

Types of Synovial Joints