2Joints, also called articulations, are functional junctions between two bonesThe science of joints is called arthrology.Functions of jointsBind skeleton togetherEnable body movementsMakes growth possiblePermit changes in skeleton for childbirth
3Classification of Joints Classifications based on amount of movementSynarthrotic = immovableAmphiarthrotic = slightly moveableDiarthrotic = fully movableClassifications by types of tissue:Fibrous joint = dense connective tissueCartilaginous joint = bones connected by cartilageSynovial joint = contains a synovial membrane
4Fibrous Joints There are three (3) types of fibrous joints: SyndesmosisSutureGomphosis1. Syndesmosis:Bones are connected by a sheet or bundle of fibrous tissue.Examples include the interosseous membrane and interosseous ligaments between the tibia and fibula.Interosseous membrane between tibia and fibula is a syndesmosis joint.
5Fibrous Joints Suture: Thin layer of dense connective tissue Connects flat bones of theskull (sutural ligaments)SynarthroticGomphosis:Cone-shaped bony processin a bony socketExample includes a toothanchored into a bony socket
6Cartilaginous Joints There are two (2) types of cartilaginous joints: SynchondrosisSymphysisSynchondrosisBones are united by a band of hyaline cartilage.Located between manubrium of sternum & 1st ribAlso located at epiphyseal plates of developing boneMovement is synarthrotic
7Cartilaginous Joints Symphysis A pad of fibrocartilage between two bonesExamples include the pubic symphysis and intervertebral discsMovement is amphiarthrotic.
8General Structure of Synovial Joints Synovial Joints are Freely movable (Diarthrotic)Structures include:Articular cartilageSynovial membrane – secretes synovial fluidJoint cavity – filled with synovial fluidJoint capsule – dense connective tissue that stabilizes and protects jointFigure 8.7 The generalized structure of a synovial joint.
9General Structure of Synovial Joints Structures include:Ligaments – bundles of collagenous fibers that reinforce the joint capsuleMenisci (sing. Meniscus) – pad of fibrocartilage that separates some joints.Bursa – sac filled with synovial fluid.Bursitis = inflammation of bursaFigure 8.8 Menisci separate the articulating surfaces of the femur and tibia. Several bursae are associated with the knee joint.
10Types of Synovial Joints Ball-and-socketrounded head + cup-shaped socket.Movement in all planes (multi-axial).Allows for rotationIncludes hip joint and shoulder joint.Condylar jointOval condyle + elliptical socketMovements in most planes (bi-axial)No rotational movementJoints between metacarpals and phalanges/
11Types of Synovial Joints Plane (Gliding) JointFlattened bones slide across each otherIncludes carpals and tarsalsribs 2-7 articulate with sternumHinge jointIncreases or decreases angel between bonesIncludes elbow jointJoints between phalanges
12Types of Synovial Joints Pivot JointRotation around a central axis (uni-axial)Joint between radius and ulnaJoint between atlas (C1) and axis (C2).Saddle Joint2 concave bones positioned at right anglesIncludes metacarpal and carpal of thumbEnd of Chapter 8, Section 1
13Types of Joint Movements Section 2, Chapter 8Types of Joint Movements
14Types of Joint Movements Movement at a joint occurs when a muscle contracts and its fibers pull its moveable end (insertion) towards its fixed end (origin).Abduction = movement away from the midline(think of someone being abducted, or taken away)Adduction = movement towards the midline(think of adding together)
15Types of Joint Movements Flexion = decreases the angle of a jointBend elbowExtension = increases the angle of a jointExtend elbowHyperextension = extension beyond the anatomical positionbend hand back, bend head back beyondanatomical position
16Types of Joint Movements Rotation = movement around a central axisTwisting the head from side to sideCircumduction = movement so end follows a circular pathmoving the finger in a circular motionwithout moving the hand.
17Types of Joint Movements Elevation = raising a partShrugging the shouldersDepression = lowering a partDrooping the shouldersProtraction = moving a part forwardthrusting head forwardRetraction = moving a part backwardpulling the head backward
18Types of Joint Movements Supination = turning the hand so the palm faces upward or anteriorlyExample: turning a doorknob clockwise with your right hand.Pronation = turning the hand so the palm faces downward or posteriorlyDorsiflexion = movement at the ankles that points toes towards the skyPlantar flexion = movement at the ankles that points toes towards the ground
19Types of Joint Movements Eversion = turning the foot so the planter surface faces laterallyInversion = turning the foot so the plantar surface faces mediallyEnd of Chapter 8, Section 2
20The Knee Joint and Joint Disorders Chapter 8, Section 3The Knee Joint and Joint Disorders
21Knee JointThe knee joint is the largest and most complex synovial joint in body.Two distal condyles of the femur articulate with two proximal condyles of the tibia. This is a condylar joint.The femur also articulates anteriorly with the patella. This is a plane joint.Figure 8.21Figure 8.20
22Knee Joint General structures of a synovial joint in the knee Synovial MembraneSecretes synovial fluidJoint CavityStores synovial fluidJoint CapsuleRelatively thin supportReinforced by several ligaments and tendonsFigure 8.20
23Knee Joint Several ligaments and tendons strengthen the knee joint. Patellar tendon - The patella is partially enclosed in tendons fused together from the thigh muscle.Patellar ligament – continuation of patellar tendon. Extends from patella to the tibial tuberosity.
24Knee Joint Ligaments continued: Tibial collateral ligament – connects medial condyle of femur with medial condyle of tibia.Fibular collateral ligament – connects lateral condyle of femur with head of fibula.Anterior & Posterior Cruciate ligaments – provide additional support to medial surface of tibia and femurFigure 8.21a Anterior right knee with patella removed.
25Knee JointTwo menisci (medial & lateral meniscus) separate the femur and tibia, and align them.Figure 8.20 (a) sagittal section of the knee joint.(b) Photograph of the left knee joint (frontal section)
26Knee Joint Three major bursae surround the knee joint. Suprapatellar bursaLargest bursa in bodyPrepatellar bursaBetween patella and skinHousemaid’s knee = prepatellar bursitisInfrapatellar bursaFigure 8.20a
27Joint DisordersSprain = overstretching or tearing of connective tissue (tendons, ligaments, or cartilage) associated with a joint.However, the bones are not disarticulated.
28Joint Disorders Arthritis = inflamed, swollen, and painful joints. OsteoarthritisMost common arthritisOccurs with agingArticular cartilage degenerates, causing bone to rub against bone.Results in stiff and painful jointsFingers may appear gnarled and knee may bulge.Osteoarthritic fingers often take on a gnarled appearance.
29Joint Disorders End of Chapter 8, Section 3 Rheumatoid Arthritis Autoimmune disorder (immune system attacks tissue)Synovial membrane thickens & becomes inflamedMass of fibrous connective tissue (Pannus) invades synovial space.Fibrous pannus destroys articular cartilage, and the joints may swell and ossify.Knuckles may swell as a result of rheumatoid arthritis.Other symptoms of Rheumatoid Arthritis:low-grade fever, fatigue, appetite, stiffness.End of Chapter 8, Section 3