3Joints And Their Classification A joint, or articulation, is any point at which two bones meet, regardless of whether they are movable at that pointThe science of joint structure, function, and dysfunction is called arthrologyThe study of musculoskeletal movement is kinesiology
4Joints And Their Classification Kinesiology is a branch of biomechanics, which deals with a broad range of motions and mechanical processes in the body, including the physics of blood circulation, respiration, and hearing.
5About Joints Tendons Ligaments bind a muscle to boneLigamentsbind bone to boneBoth are dense regular connective tissueAbout Muscles (acting at a joint)origininsertionaction
6Characterizing Joints What type of movement does the joint allow?No movement, limited movement, free movementWhat tissue joins the bones?Fibrous JointsFibrous connective tissue (suture, ligament, tooth)Cartilaginous JointsFibrocartilage (pubic symphysis)Hyaline cartilage (epiphyseal plate, costal cart)Synovial
7Types of Movement Synarthrotic Amphiarthrotic Diarthrotic immoveable, allows no movementAmphiarthroticallows only limited movementDiarthroticfreely moveable
8Types of tissue between bones Suture (dense CT between bony plates)Syndesmosis (ligament)Gomphosis (tooth socket)Symphysis (fibrocartilage)Synchondrosis (hyaline cartilage)Synovial (fluid filled joint)
9Fibrous JointsA fibrous joint is two bones joined by fibrous connective tissue.It is immovable so it is categorized as a synarthrotic joint.No joint cavity
14Cartilaginous JointsA cartilaginous joint is two bones joined by cartilage. The cartilage is either fibrocartilage (a symphysis joint) or hyaline cartilage (a synchondrosis).Fibrocartilage joints (symphyses) are amphiarthrotic (slightly moveable).Examples are intervertebral discs and the pubic symphysisHyaline cartilage joints (synchondroses) are synarthrotic (immovable).Examples are epiphyseal plates and costal cartilages
15In a symphysis, two bones are joined by fibrocartilage (A symphysis is amphiarthrotic: slightly moveable)Symphysis
16A synchondrosis is a joint in which the bones are bound by hyaline cartilage (A synchondrosis is synarthrotic: not moveable)SynchondrosisA synchondrosis is a synarthrosis
17Synovial JointsThe most familiar type of joint and the most common. It allows a wide range of motion so it is functionally classified as a diarthrotic joint (a diarthrosis)Examples include the elbow, knee, knuckles, the joints between the wrist and ankle bonesSynovial joints are the most structurally complex type of joint, (having a joint cavity) and are the most likely to develop uncomfortable and crippling dysfunctions
18Synovial Joints Characteristics Enclosed chamber, flexible fibrous capsuleA cavity filled with fluid, synovial fluidAn inner membrane that produces lubricating fluid, synovial membraneArticular cartilages covering ends of bonesReinforcing ligaments to stabilizeInnervated and vascular
19Synovial Joint Structure These surfaces are separated by a narrow space, the joint (articular) cavity, containing a slippery lubricant called synovial fluid. This fluid is rich in albumin and hyaluronic acid, which give it a viscous, slippery texture. It nourishes the articular cartilages, removes their wastes, and makes movements at synovial joints almost friction-freeIn synovial joints, the facing surfaces of the two bones are covered with articular cartilage, a layer of hyaline cartilage about 2 mm thick
20Synovial Joint Structure In several synovial joints, fibrocartilage grows inward from the joint capsule and forms a pad between the articulating bonesWhen the pad crosses the entire joint capsule it is called an articular disc
21CapsuleA connective tissue membrane (articular capsule) encloses the cavity and retains the fluid.It has an outer fibrous capsule, which acts like a sleeve; it is continuous with the periosteum of the adjoining bones, and an inner, cellular synovial membrane
22BursaeA bursa is a fibrous sac filled with synovial fluid, located between adjacent muscles or where a tendon passes over a bone.Bursae cushion muscles, help tendons slide more easily over the joints, and sometimes enhance the mechanical effect of a muscle by modifying the direction in which its tendon pulls.
23Bursae and Tendon Sheaths The knee joint has at least 13 bursaeFigure 9.4a, b
24Synovial JointBursitis is inflammation of a bursa, usually due to overexertion of a joint.Tendinitis is a form of bursitis in which a tendon sheath is inflamed
25Types of Synovial Joints There are six types of synovial joints, characterized by the motion allowed by the shapes of the bones.PlaneHingePivotCondyloidSaddleBall and socket
26Plane JointsThe carpal and tarsal bones, between the articular processes of the vertebrae, and at the sternoclavicular joint
27Hinge JointsThe elbow, knee, and IPJ = interphalangeal (finger and toe) joints
28Pivot JointsThe atlantoaxial joint between the first two vertebrae and proximal radioulnar joint, where the annular ligament on the ulna encircles the head of the radius
29Condyloid Joints Metacarpal-phalangeal joints: these are biaxial condyloid joints
30Saddle JointsAt the base of the thumb (between the trapezium and metacarpal I) and sternoclavicular joint between the clavicle and sternum.Saddle joints are biaxial joints; in primate anatomy, allows for the opposable thumb
31Ball and Socket JointsShoulder and hip joints are ball and socket. This type of joint is multiaxial.
32Three Important Synovial Joints Knee JointHip JointShoulder Joint
33The Knee Joint Tibiofemoral joint and patellofemoral joint The largest and most complex diarthrosisof the bodyHinge joint, but has movements of gliding, rolling and rotation3 articulations: lateral and medial articulations of femur and tibia; intermediate articulation of patella and femur. Note: Fibula does not articulate with the femur, only with the tibia.
34Extracapsular ligaments Patellar ligament (patellar tendon)Passes from the apex and margins of the patella distally to the tibial tuberosityMedial collateral ligamentExtends from the medial epicondyle of the femur to the medial condyle of the tibiaAt its midpoint, its fibers are attached to the medial meniscus,Lateral collateral ligamentExtends inferiorly from lateral epicondyle of femur to lateral surface of the fibular head
35Two ligaments lie outside the joint capsule: tibial (medial) collateral ligament.fibular (lateral) collateral ligamentThe two collateral ligaments prevent the knee from rotating when the joint is extended.
36Cruciate ligamentsThere are two ligaments that lie inside the joint capsule. They are deep within the joint cavity, but they are not inside the fluid-filled synovial cavity.These ligaments cross each other in the form of an X:the anterior cruciate ligament (ACL)posterior cruciate ligament (PCL)
37Intracapsular ligaments Cruciate ligaments join proximal tibia with distal femur, crisscrossing in the articular capsuleAnterior cruciate ligament (ACL)Weaker of the two cruciatesArises from anterior intercondylar area of tibia, attaches at the posteromedial side of the femoral lateral condyle.Slack when knee is flexed, taut when fully extendedPrevents posterior displacement of femur and hyperextension of knee jointPosterior cruciate ligament (PCL)Arises from posterior intercondylar area of tibia, attaches to the anterolateral surface of the medial condyle of femur.Taut during flexion, prevents anterior displacement of femur on the tibiaIs the main stabilizing factor when weight-bearing during flexed knee position (ie. Walking downhill.)
39Menisci Medial and Lateral Menisci Crescent (C-) shaped plates of fibrocartilage located over the medial and lateral tibial condylesThicker laterally, thinner inside the joint capsuleAct like shock absorbersThicker laterally, taper to thin unattached edges at interior of the joint.
40In the knee, two fibrocartilages extend inward from the left and right but do not entirely cross the jointEach is called a meniscusMenisci absorb the shock of the body weight jostling up and down on the knee and prevent the femur from rocking from side to side on the tibia
42The ACL and PCL are named according to whether they attach to the anterior or posterior side of the tibia, (not for their attachments to the femur.)When the knee is extended, the ACL is pulled tight and prevents hyperextension.The PCL prevents the femur from sliding off the front of the tibia and prevents the tibia from being displaced backward.
43Knee JointBe able to label the drawing with the names of all of the structures of the knee joint, including the bones, ligaments, cartilage, membranes, capsule, menisci, etc.Know the movements allowed and the movements prevented by the anatomy of the knee.
4410 pt Essay Question: Label this (1/2 point each)
52Hip JointStrong, stable ball and socket joint, most moveable of all jointsTransverse acetabular ligament (which bridges the acetabular notch) holds head in beyond its equator.
53Hip Joint Ligaments Iliofemoral ligament Y shaped; Attaches to ant infer iliac spine and acetabular rim proximally and inferior intertrochanteric line distallyPrevents hyperextension of the hip during standingPubofemoral ligamentRuns from the superior ramus of the pubis and passes laterally and to the intertrochanteric line (passing deep to the iliofemoral ligament.)Prevents overabduction of the hip jointIschiofemoral ligamentRuns from ischial part of acetabular rim, to the neck of femur (best seen from posterior view.)Prevents hyperextension of the hip by screwing the femoral head deeper into the acetabulumLigament of the head of the femur (ligamentum teres)Weak, little importance in strengthening hip jointRuns from the transverse acetabular ligament and attaches to the pit(fovea capitis) of head.
59Diarthrotic, ball and socket joint: Humeral head in glenoid cavity The Shoulder JointDiarthrotic, ball and socket joint:Humeral head in glenoid cavity
60Shoulder Joint (Glenohumeral Joint) Ligaments:Glenohumeral ligaments : 3 fibrous bandsFrom the anterior glenoid labrum to the anatomical neck of humerusReinforce the anterior part of the articular capsule (and are inside the capsule, not visible from outside.)Coracohumeral ligamentFrom base of coracoid process to anterior aspect of greater tubercle of humerusTransverse humeral ligamentRuns from greater to lesser tubercle of humerusCreates a channel , bridging over the intertubercular grooveSite for tendon of long head of biceps brachiiCoracoacromial ligamentFrom inferior aspect of acromion to coracoid processForms a protective “arch” preventing superior displacement of the headSupraspinatus muscle passes under this arch.