Chapter 9 - Joints

(articulation) any point where two bones meet

the science of joint structure, function, and dysfunction

study of musculoskeletal movement

• bony joints
• fibrous joints
• cartilaginous joints
• synovial joints

synostosis; an immovable joint formed when the gap between two bones ossifies and they become a single bone

ossification of fibrous or cartilagenous 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

• sutures
• gomphoses
• syndesmoses

immovable or slightly movable fibrous joints that closely bind the bones of the skull to each other; occur nowhere else

the attachment of a tooth to its socket

- which consists of collagen fibers that extend from the bone matrix of the jaw into the dental tissue

a fibrous joint at which two bones are bound by longer collagenous fibers than in a suture or gomphosis, giving the bone more mobility

• amphiarthrosis or amphiarthrodial joint
• - two bones are linked by cartilage

• synchondroses
• symphyses

a joint at which the bones are bound by hyaline cartilage

two bones are joined by fibrocartilage

• most familiar type of joint
• -diarthrosis or diarthrodial joint

- a layer of hyaline cartilage usually about 2 or 3 mm thick

the joint (articular) cavity

• synovial fluid
• - rich in albumin and hyaluronic acid

encloses the cavity and retains the fluid

composed mainly of fibroblast-like cells that secrete the fluid, and is populated by microphages that remove the debris from the joint cavity

• 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

attaches a muscle to a bone

attaches bone to bone

• where a tendon passes over a bone, or between bone and skin
• - cushions muscles, helps tendons slide easily over the joints

• elongated cylindrical bursae wrapped around a tendon
• - in the hands and feet

act as levers to enhance the speed or power of limb movement

• 1. first class lever - RFE
• 2. second class lever - FRE
• 3. third class lever - REF

the degree through which a joint can move; joint flexibility

• ball & socket joints
• condylar (ellipsoid) joints
• saddle joints
• plane (gliding) joints
• hinge joints
• pivot joints

movement that decreases a joint angle, common at hinge joints

movement that straightens a joint and generally returns a body part to the zero position

extension of the joint beyond the zero position

movement of a body part in the frontal plane away from the midline of the body

movement in the frontal plane back toward the midline

a movement that raises a body party vertically in the frontal plane

lowers a body part in the same plane

anterior movement of a body part in the transverse (horizontal) plane

posterior movement

one end of an appendage remains fairly stationary while the other end makes a circular motion

movement in which a bone spins on its longitudinal axis

a movement that turns the palms to face anteriorly or upward

movement that turns the palm to face posteriorly or downward

movement to the left or right of the zero position

movement back to the median, zero position

to move the thumb to touch the tip of any of the other four fingers

the return of the thumb to the zero position

a movement in which the toes are elevated

movement of the foot so that the toes point downward

a foot movement that tips the soles medially, somewhat facing each other

movement that tips the soles laterally, away from each other

largest and most complex diarthrosis of the body

patellofemoral joint

lateral meniscus and medial meniscus

a transverse ligament

of the knee is supported by extracapsular ligaments and intracapsular ligaments

prevents hyperextension

prevents the femur from sliding off the front of the tibia and prevents the tibia from being displaced backward

"wear and tear arthritis" normal consequences of years of wear and tear on the joints

results from an autoimmune attack against the joint tissues