Term
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Definition
-Points where rigid elements of skeleton meet
-Most joints join bone to bone
-Some join bone to cartilage
-Some Join teeth to their bony sockets
-Joint system functions to hold the skeleton together, and enables it to be mobile
-Weakest points in the skeleton; structure allows them to resist crushing, tearing and various forces that may serve to drive them out of alignment |
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Term
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Definition
-Fibrous joints
-Gomphoses
-Cartilaginous joints
-Synovial joints |
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Term
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Definition
-Bones are connected by fibrous tissue
-No joint cavity is present
-Most are immovable or only slightly movable (i.e. synarthotic or ampiarthrotic)
-Subtypes include: sutures(bones in the skull), syndemoses (ligament between the radius and ulna, or tibula and fibula), gomphoses (tooth within a socket) |
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Term
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Definition
-Articulating bones are united by cartilage or combination of cartilage/fibrous tissue
-Lacks joint cavity
-Not highly movable (synarthrotic or ampiarthrotic)
-Sub-types include: synchondroses (epiphyseal plate) and symphysis (intervertebral disks, pubis symphysis) |
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Term
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Definition
-Most common type of joint and most movable joint type
-Each contains a fluid joint cavity which acts as a shock absorber and shock distributor in joint compression (i.e. knee joint, shoulder)
-General structure includes: articular capsule, joint cavity, synovial fluid, articular cartilage, reinforcing ligaments, nerves and vessels, articular disks or menisci, fat pads and bursae |
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Term
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Definition
-Encloses joint cavity with a 2-layered capsule: outer- fibrous capsule that is continuous with the periosteal outer layer from bone; strengthens the joint capsule
inner- synovial membrane of loose CT; covers all internal joint surfaces not covered by hyaline cartilage |
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Term
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Definition
-also called Synovial Cavity
-potential space that holds a small amount of synovial fluid |
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Term
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Definition
-Found within the joint cavity
-Filtrate of blood from capillaries of synovial membrane and glycoprotein molecules secreted from membrane
-acts as lubricating fluid in the joint cavity and gets squeezed into and out of articular cartilage by joint movements (nourishing and lubricating cartilage and removing waste from cartilage) |
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Term
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Definition
-Cartilage that covers the ends of opposing bones
-This spongy cushion absorbs compression of joint articulation |
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Term
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Definition
-Band-like support
-Most often intrinsic or capsular (thickening of capsule outer layer)
-extracapsular/intracapsular (e.g., medial collateral ligament; anterior cruciate ligament) which are external/internal to capsule itself |
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Term
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Definition
-Rich supply of sensory nerve fibers innervate articular capsule
-Pain receptors
-Proprioceptors(position receptors)- to monitor body and joint movements and posture
-rich blood supply- extensive capillary beds in synovial membrane (synovial fluid source)
-overlap of both nerve and blood supply through several major branches to each synovial joint (protective both against injury and compression) |
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Term
| Articular Disks or Menisci |
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Definition
-Fibrocartilage structures that extend internally from joint capsule and divides the joint cavity into 2
-its purpose is to improve "fit" between articulating bone ends, stabilizing joint
-allow 2 different movements at the joint (over the disc surfaces); e.g. knee joint |
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Term
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Definition
-Pads that lie between the opposing bone surfaces near the edge and within the joint
- Protects cartilage and fills spaces as joint cavity changes shape when articulating |
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Term
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Definition
-Small synovial fluid-filled pockets withing CT surrounding most synovial joints
-Either connected to or separate from the joint capsule, but exist wherever tendons or ligaments rub denser tissues
-Serves to reduce friction and absorbs shock
-Similarly, synovial tendon sheaths are bursa sacs that entirely surround tendons where they pass over bony surfaces (e.g. around long tendons at wrists and ankles) |
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Term
| Factors Influencing Synovial Joint Stability |
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Definition
-Articular surface shapes: e.g. shallow or deep connection
-Ligamental support- the more, the greater stability; but, they can only stretch about 6% more than resting before they snap
-Muscle tendon support created by "muscle tone"; most important factor in creating stability at a synovial joint |
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Term
| Functional Types of Joints |
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Definition
-Synarthrosis: immovable joint
-Ampiarthrosis: slightly moveable
-Diarthrosis: movable joint |
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Term
| Diarthrotic Synovial Joints |
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Definition
-Can be broken down further by the functional properties of axial movement
-Monoaxial: when a joint allows movement only along one axis (e.g. only sagitally or coronally, or only rotation around its longitudinal axis; e.g. elbow, ankle)
-Biaxial: movement allowed on 2 axes (but not a combination of 2 at the same time; e.g. wrist)
-Multiaxial: when movement is allowed around multiple axes; e.g. shoulder, hip |
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Term
| Movements seen with the typical Synovial Joint |
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Definition
-Gliding
-Angular motion
-Rotational motion
-Inversion/Eversion of foot
-Dorsiflexion/plantarflexion of foot
-Thumb opposition
-Shoulder protraction/retraction
-Shoulder elevation/depression |
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Term
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Definition
-linear motion where 2 opposing surfaces slide past one another
-movement is slight and very little rotation is allowed due to ligamental and joint capsule restrictions; can be monoaxial or multiaxial
-joints have either flat or slightly curved surfaces
-e.g. articulating carpal/tarsal bones, sterno-clavicular joint |
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Term
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Definition
-movement at an angle with reference to anatomical position
-flexion/extention: occurs in the sagittal plane. Flexion decreases the angle and extension increases the angle between the bones of a joint
-hyperextension: extension beyond anatomical position(not always allowed)
-abduction: moving away from the center of the body
-adduction: moving towards the center of the body
-circumduction: rotation of a limb around axis while reducing or increasing an angle at a joint |
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Term
| Examples of joints in Angular Motion |
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Definition
-Hinge Joints: monoaxial; e.g. elbow, knee
-Ellipsoidal or condyloid joints: oval face or surface sits in small depression on other surface; biaxial (phalangeal/metacarpal) or multiaxial (carpal/radial)
-Saddle joints: each articular face has the shape of a saddle; concave on one side and convex on the other; biaxial (thumb joint) usually
-Ball in socket joints: round head of 1 bone in cup shaped hollow of another; multiaxial (shoulder, hip) |
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Term
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Definition
-Direction: left/right
-Types include: pivot joints- monoaxial (atlas and axis), but can include rotation(allowing rotation of the head to either side)
-Ball in socket joints: multiaxial(shoulder, hip); permits rotation and angular movement |
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