Anatomy Chapter 8: Joints
Terms
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- Structural Classifications of Joints
- Fibrous, Cartilaginous, Synovial
- Functional Classification of Joints
- Synarthroses, amphiarthroses, diarthroses
- Synarthroses
- Immovable Joints
- Amphiarthroses
- Slightly movable joints
- Diarthroses
- Freely movable joints
- Fibrous Joints
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Bones joined by fibrous tissue. No joint cavity present.
Amount of movement allowed depends on length of connective tissue fibres.
Mostly synarthroses. Some amphiarthroses.
Includes sutures, syndesmoses, and gomphoses. - Sutures
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Fibrous joints occurring only in the skull.
Wavy articulating bone edges interlock and the junction is completely filled by a minimal amount of very short connective tissue fibres. - Synostoses
- Sutures which are ossified, fused.
- Syndesmoses
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Fibrous joint in which bones are connected by a ligament.
Synarthroses and amphiarthroses. - Gomphoses
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Articulations of the teeth with bony alveolar sockets.
Fibrous joints joined by the periodontal ligaments.
Synarthroses. - Cartilaginous Joints
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Articulating bones are united by cartilage. Lack joint cavity.
Synarthroses and amphiarthroses.
Includes synchondroses and symphyses. - Synchondroses
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Cartilaginous joints joined by a bar or plate of hyaline cartilage.
Almost all synarthrotic. - Symphyses
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Cartilaginous joints in which the articular surfaces of the bones are covered with articular cartilage, which in turn is fused to an intervening plate of fibrocartilage.
Amphiarthrotic. - Synovial Joints
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Joints in which the articulating bones are separated by a fluid-containing joint cavity.
All are diarthroses. - Distinguishing Features of Synovial Joints (5)
- Articular cartilage, joint cavity, articular capsule, synovial fluid, reinforcing ligaments.
- Articular Cartilage
- Glassy-smooth hyaline cartilage which covers the opposing bone surfaces in a synovial joint.
- Joint Cavity
- Potential space of synovial joint that contains a small amount of synovial fluid.
- Articular Capsule
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Two-layered capsule enclosing the synovial joint cavity.
Consists of the fibrous capsule and the synovial membrane. - Fibrous Capsule
- External layer of the articular capsule of a synovial joint, composed of dense irregular connective tissue. Strengthens the joint.
- Synovial Membrane
- Inner layer of the synovial joint capsule which is composed of loose connective tissue. Covers all internal joint surfaces that are not hyaline cartilage and secretes synovial fluid.
- Synovial Fluid
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Lubricating fluid derived by filtration from blood flowing through the capillaries in the synovial membrane of a synovial joint.
Provides a weight-bearing film that reduces friction between cartilages.
Also contains phagocytic cells that rid the joint cavity of microbes and debris. - Reinforcing Ligaments
- Bandlike structures which reinforce and strengthen synovial joints.
- Bursae
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Flattened sacs lined with synovial membrane and containing a thin film of synovial fluid.
Common where parts of synovial joints rub together. - Factors Effecting the Stability of a Synovial Joint
- Shapes of the articular surfaces, number/positioning of ligaments, muscle tone
- Skull Joints
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Articulate cranial and facial bones.
Fibrous--suture
Synarthotic. - Temporomandibular Joint
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Articulates temporal bone of skull and mandible.
Synovial--modified hinge
Diarthotic. - Atlanto-occipital Joint
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Articulates occipital bone and atlas.
Synovial--condyloid.
Diarthotic. - Atlantoaxial Joint
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Articulates atlas and axis.
Synovial--pivot
Diarthotic - Intervertebral Joints (Between Bodies)
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Articulates adjacent vertebral bodies.
Cartilaginous--symphysis
Amphiarthrotic - Intervertebral Joints (Between Articular Processes)
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Articulation between articular processes of vertebrae.
Synovial--plane
Diarthotic - Vertebrocostal Joints
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Articulate vertebrae and ribs.
Synovial--plane
Diarthotic. - Sternoclavicular
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Articulates sternum and clavicle
Synovial--shallow saddle
Diarthrotic - Sternocostal (rib 1 only)
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Articulation between sternum and rib 1
Cartilaginous--synchondrosis
Synarthrotic - Sternocostal (ribs 2-7)
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Articulates sternum with ribs 2-7
Synovial--double plane
Diarthrotic - Acromioclavicular
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Articulates acromion of scapula and clavicle
Synovial--plane
Diarthrotic - Glenohumeral Joint
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Articulates scapula and humerus.
Synovial--ball and socket
Diarthrotic. - Elbow Joint
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Articulates ulna (and radius) with humerus.
Synovial--hinge
Diarthrotic - Proximal and Distal Radioulnar Joints
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Articulate radius and ulna.
Synovial--pivot
Diarthrotic - Radiocarpal Joint
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Articulates radius and proximal carpals.
Synovial--condyloid
Diarthrotic - Intercarpal Joint
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Articulates adjacent carpals
Synovial--plane
Diarthrotic - Carpometacarpal (Digit 1)
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Articulates trapezium and metacarpal 1
Synovial--saddle
Diarthrotic - Carpometacarpal (Digit 2-5)
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Articulates carpals and metacarpals.
Synovial--plane
Diarthrotic - Metacarpophalangeal Joint
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"Knuckle." Articulates metacarpals with proximal phalanges.
Synovial--condyloid
Diarthrotic. - Interphalangeal Joint
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Articulates adjacent phalanges
Synovial--hinge
Diarthrotic - Sacroiliac Joint
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Articulates sacrum and coxal bone
Synovial--plane
Diarthrotic - Pubic Symphysis
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Articulates pubic bones
Cartilaginous--symphysis
Amphiarthrotic - Coxal Joint
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"Hip joint" Articulates hip bone and femur
Synovial--ball and socket
Diarthrotic - Tibiofemoral Joint
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"Knee Joint" Articulates femur and tibia.
Synovial--modified hinge
diarthrotic - Femoropatellar Joint
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"Knee Joint" Articulates femur and patella
Synovial--plane
Diarthrotic - Proximal Tibiofibular Joint
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Articulates tibia and fibula, proximally
Synovial--plane
Diarthrotic - Distal Tibiofibular Joint
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Articulates the tibia and fibula distally
Fibrous--syndesmosis
Synarthrotic - Ankle
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Articulates tibia and fibula with talus
Synovial--hinge
diarhtrotic - Intertarsal Joint
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Articulates adjacent tarsals
Synovial--plane
Diarthrotic - Tarsometatarsal Joint
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Articulates tarsals and metatarsals
Synovial--plane
Diarthrotic - Metatarsophalangeal Joint
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Articulates metatarsal and proximal phalanx
Synovial--condyloid
Diarthrotic - Nonaxial Movements
- Slipping movements which have no axis around which movement can occur.
- Uniaxial Movements
- Movement in one plane
- Biaxial Movement
- Movement in two planes
- Multiaxial Movement
- Movement in or around all three planes of space and axes.
- Gliding Movements
- Translations. One flat bone glides or slips over another.
- Angular Movements
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Movements which increase or decrease the angle between two bones.
Flexion/extension/hyperextension, dorsiflexion/plantarflexion, abduction/adduction, circumduction - Flexion
- A bending movement that decreases the angle of the joint and brings the articulating bones closer together.
- Extension
- Movement along the sagittal plane that increases the angle between articulating bones.
- Hyperextension
- Movement along the sagittal plane that increases the angle between articulating bones past 180 degrees.
- Dorsiflexion
- Lifting the foot so that its superior surface approaches the shin (toes up).
- Plantarflexion
- Depressing the foot so that the toes point down.
- Abduction
- Movement of a limb away from the midline or median plane of the body, along the frontal plane. Spreading the digits apart.
- Adduction
- Movement of a limb toward the body midline or bringing the digits into parallel, touching position.
- Circumduction
- Moving a limb so that it describes a cone in space. The distal end of the limb moves in a circle while the proximal end is more or less stationary.
- Rotation
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Turning of a bone around its own long axis.
Medial--moves toward median plane of the body
Lateral--moves away from median plane of the body - Supination
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Turning the palm to face anteriorly or superiorly.
Anatomical position for the hands. - Pronation
- Turning the palm to face posteriorly or inferiorly.
- Inversion
- Turning the sole of the foot medially.
- Eversion
- Turning the sole of the foot out laterally.
- Protraction
- Jutting out the jaw.
- Retraction
- Pulling in the jaw.
- Elevation
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Lifting a body part superiorly
(Closing mouth or shrugging shoulders) - Depression
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Moving a body part inferiorly.
(Opening mouth, rounding shoulders down) - Opposition
- Movement taken to touch the thumb to the fingers of the same hand.
- Plane Joints
- Synovial joints in which the articular surfaces are essentially flat and allow only short gliding or translational movements.
- Hinge Joints
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Synovial joints in which a cylindrical projection of one bone fits into a trough-shaped surface on another.
Motion is along a single plane and resembles that of a mechanical hinge.
Flexion/extension only. - Pivot Joints
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Synovial joint in which the rounded end of one bone protrudes into a sleeve or ring composed of bone of another.
Allows only uniaxial, rotational movement. - Condyloid Joints
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"Ellipsoidal Joints"
Synovial joints in which the oval articular surface of one bone fits into a complementary depression in another.
Biaxial--permit all angular motions (flexion/extension, abduction/adduction, circumduction) - Saddle Joints
- Synovial joints that resemble condyloid joints but allow greater freedom of movement due to each articular surface having both concave and convex areas.
- Ball-and-Socket Joints
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Synovial joints in which the spherical or hemispherical head of one bone articulates with the cuplike socket of another.
These joints are multiaxial and the most freely moving synovial joints.
Universal movement is allowed. - Types of Synovial Joints
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(Purple Helicopters Save Big Cheerful People)
Plane, hinge, saddle, ball-and-socket, condyloid, pivot