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joint
(articulation) any point where two bones meet
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arthrology
the science of joint structure, function, and dysfunction
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kinesiology
study of musculoskeletal movement
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joints (listing)
- bony joints
- fibrous joints
- cartilaginous joints
- synovial joints
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bony joint
synostosis; an immovable joint formed when the gap between two bones ossifies and they become a single bone
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bony joints can form by:
ossification of fibrous or cartilagenous joints
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fibrous joints
- synarthrosis or synarthrodial joint
- -the point at which adjacent bones are bound by collagen fibers that emerge from one bone, cross the space between them, and penetrate into the other
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three kinds of fibrous joints
- sutures
- gomphoses
- syndesmoses
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sutures
immovable or slightly movable fibrous joints that closely bind the bones of the skull to each other; occur nowhere else
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gomphosis
the attachment of a tooth to its socket
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the tooth is held tightly in place by a fibrous periodontal ligament
- which consists of collagen fibers that extend from the bone matrix of the jaw into the dental tissue
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syndesmosis
a fibrous joint at which two bones are bound by longer collagenous fibers than in a suture or gomphosis, giving the bone more mobility
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cartilaginous joint
- amphiarthrosis or amphiarthrodial joint
- - two bones are linked by cartilage
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two types of cartilaginous joints:
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synchondrosis
a joint at which the bones are bound by hyaline cartilage
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symphysis
two bones are joined by fibrocartilage
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synovial joint
- most familiar type of joint
- -diarthrosis or diarthrodial joint
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in synovial joints, the facing surfaces of the two bones are covered with articular cartilage
- a layer of hyaline cartilage usually about 2 or 3 mm thick
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these surfaces are seperated by a narrow space,
the joint (articular) cavity
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the joint (articular) cavity contains a slippery lubricant called
- synovial fluid
- - rich in albumin and hyaluronic acid
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joint (articular) capsule
encloses the cavity and retains the fluid
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synovial membrane
composed mainly of fibroblast-like cells that secrete the fluid, and is populated by microphages that remove the debris from the joint cavity
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meniscus
- crescent shaped
- absorbs shock and pressure, guides the bone across each other, improve the fit between the bones and stabilizes the joint, reduces the chance of dislocation
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tendon
attaches a muscle to a bone
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ligament
attaches bone to bone
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bursa
- where a tendon passes over a bone, or between bone and skin
- - cushions muscles, helps tendons slide easily over the joints
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tendon sheaths
- elongated cylindrical bursae wrapped around a tendon
- - in the hands and feet
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longs bone:
act as levers to enhance the speed or power of limb movement
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types of levers (resistance, effort, fulcrum)
- 1. first class lever - RFE
- 2. second class lever - FRE
- 3. third class lever - REF
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range of motion ROM
the degree through which a joint can move; joint flexibility
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6 types of synovial joints
- ball & socket joints
- condylar (ellipsoid) joints
- saddle joints
- plane (gliding) joints
- hinge joints
- pivot joints
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flexion
movement that decreases a joint angle, common at hinge joints
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extension
movement that straightens a joint and generally returns a body part to the zero position
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hyperextension
extension of the joint beyond the zero position
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abduction
movement of a body part in the frontal plane away from the midline of the body
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adduction
movement in the frontal plane back toward the midline
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elevation
a movement that raises a body party vertically in the frontal plane
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depression
lowers a body part in the same plane
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protraction
anterior movement of a body part in the transverse (horizontal) plane
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retraction
posterior movement
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circumduction
one end of an appendage remains fairly stationary while the other end makes a circular motion
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rotation
movement in which a bone spins on its longitudinal axis
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supination
a movement that turns the palms to face anteriorly or upward
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pronation
movement that turns the palm to face posteriorly or downward
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lateral excursion
movement to the left or right of the zero position
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medial excursion
movement back to the median, zero position
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opposition
to move the thumb to touch the tip of any of the other four fingers
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reposition
the return of the thumb to the zero position
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dorsiflexion
a movement in which the toes are elevated
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plantar flexion
movement of the foot so that the toes point downward
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inversion
a foot movement that tips the soles medially, somewhat facing each other
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eversion
movement that tips the soles laterally, away from each other
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tibiofemoral (knee) joint
largest and most complex diarthrosis of the body
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the patella and patellar ligament articulate with the femur to form a gliding:
patellofemoral joint
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the joint cavity contains two C-shaped cartilages called:
lateral meniscus and medial meniscus
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the lateral meniscus and the medial meniscus are joined by:
a transverse ligament
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popliteal region
of the knee is supported by extracapsular ligaments and intracapsular ligaments
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Anterior Cruciate Ligament (ACL)
prevents hyperextension
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Posterior Cruciate Ligament (PCL)
prevents the femur from sliding off the front of the tibia and prevents the tibia from being displaced backward
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osteoarthritis (OA)
"wear and tear arthritis" normal consequences of years of wear and tear on the joints
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rheumatoid arthritis
results from an autoimmune attack against the joint tissues
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