Purposes of Joints Allow movement. Directed not random. Provide stability. Bone growth site. Bone growth site
Joint Nomenclature Common names, i.e. shoulder, elbowCommon names Colloquial names –Colloquial names femorotibial = stifle carpus = knee fetlock, pastern, coffin Scientific, descriptive names. Usually from the bones or region forming the joint.Scientific, descriptive names
Categories of Joints Fibrous Cartilaginous Synovial Synarthrodial i.e. rigid Diarthrodial i.e. moveable Old Terminology Current Terminology
Category Classification 1 1. Fibrous joints – joined by dense white fibrous connective tissue. (syn = union) Sutures – [L. sutura a seam] narrow strips of CT. Found mostly in the skull. Allows the growth of bone plates. Stops as ossification occurs.Sutures Syndesmosis – [Gr. syndesmos band] a type of fibrous joint in which the intervening fibrous connective tissue forms an interosseous membrane or ligament. Between radius and ulna.Syndesmosis Gomphosis – [Gr. a bolting together] tooth attachmentsGomphosis
Category Classification 2 2. Cartilaginous joints Symphysis – divided by a series of tissues, i.e.. cartilage, fibrocartilage, or fibrous tissue in the middle of symmetrical halves. Pubis, mandible.Symphysis Synchondrosis – [Gr. a growing into one cartilage] a union between two bones formed by either hyaline cartilage or fibrocartilage; it is usually temporary, the intervening cartilage being converted into bone before adult life. Skull, hyoid bones.Synchondrosis Physis – between epiphysis and diaphysis.Physis Intervertebral disks.Intervertebral disks
Category Classification 3 3. Synovial joints [Gr. syn with + oon egg]Synovial joints Separated by fluid-filled space. synovial membrane fibrous capsule fibrous bands – ligaments articular surface –hyaline cartilage (fibrocartilage). synovial fluid –lubrication AND nutrition disks or menisci –provide support for bony incongruities –stifle and tmj Periarticular Articular Intraarticular
Movements Translation – sliding without changing orientation Rotation Inward Outward Pendular – angular or swinging about an axis flexion extension adduction abduction circumduction
Flexion and Extension Flexion decrease joint angle Extension increase joint angle In saggital plane Hyper extension / flexion – beyond normal ranges.
Adduction & Abduction Midline Adduction - bring towards median plane. Add 2 numbers – bring together. Abduction – move away from median plane. The child was abducted – taken away. In transverse planes.
Circumduction Flexion +/- Extension +/- Adduction +/- Abduction Infinitely variable number of combinations to form complex actions.
Mechanics of Joint Movement Long head triceps: 1.flex shoulder 2.extend elbow Other triceps: extend elbow only Biceps brachii 1.extend shoulder 2.flex elbow Triceps: Same insertion Different origins What joint surfaces are spanned?
Weight vs non weight bearing. What point is considered fixed or immovable? 1.Standing – leg fixed, head moves. 2.Laying – head fixed, leg moves. Brachiocephalicus m.
Synovial Joints Classified by Geometry Plane Hinge Pivot Condylar Ellipsoidal Saddle Spheroidal