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Anatomy of Joints

Biology - Anatomy of joints.
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"Gliding" movement of joints:
1 flat bone glides or slides over another (cartilaginous - symphysis: pad or plate of cartilage) *intervertebral discs
"Angular" movement of joints:
changes the angle between 2 joints (synovial joint: made of multiple components) *
""Special" movement of joints:
movement at specific joints (oposites: elevation/depression, protraction/retraction)
3 general catagories of joint movement:
Gliding, Angular, & Special Movements
3 structural categories of joints:
Fibrous, Cartilaginous, Synovial
Fibrous Joints are:
joints composed of collagenous fibers - no joint cavity present (dense CT - white fibers)
Cartilaginous Joints are:
joints connected by hyaline cartilage or fibrocartilage
Synovial Joints are:
joints that allow free movement (most of the joints of the body are this) complex and contain multiple components 5 (diarthrosis - full movement)
Sutures are:
fibrous joints located between the flat bones of the *skull - united by a thin layer of dense CT (synarthrosis- NO movement)
Syndesmosis joints are:
fibrous joints contain bones that are bound or bundled by a sheet of dense CT (amphiathrotic- allows slight movement) *Tibiofibular articulation
Gomphosis joints are:
fibrous joints formed by the union of a cone shaped bony process & a bony socket (synarthrosis- NO movement) *root of tooth united with mandible
Synchondrosis joints are
cartilaginous joints joined by a band or plate of hyaline cartilage (synarthrosis- NO movement) *epiphyseal plate
Symphysis joints are:
cartilaginous joints with articulating surfaces seperated by thin layers of hyaline cartilage attached to a pad of fibrocartilage (amphiathrotic- allows slight movement) *intervertebral discs
5 distinct components of a synovial joint:
articular cartilage, joint capsule, reinforcing ligaments, menisci, & bursa
Synovial joint - articular cartilage:
hyaline cartilage that covers the surface of each bone
Synovial joint - joint capsule:
double layered capsule surrounded by a cavity that holds bones together
Outer layer of joint capsule:
external, tough, flexible, fibrous capsule, continuous with the periosteum of bones
Inner layer of joint capsule:
loose CT that covers all internal joint surfaces that do not contain hyaline cartilage, (secretes synovial fluid that prevents friction)
Synovial joint - reinforcing ligaments:
collagenous fibers that strenghten joint (usually thickened portions of fibrous capslue - intrinsic or capsular) *prevents excess movement
Synovial joint - menisci (or articular discs):
separate the cavity into 2 compartments - discs of fibrocartilage between articular surfaces (knee, jaw, sternoclavicular)
Synovial joint - bursa:
flattened fibrous sacs with a synovial membrane and fluid that prevent friction on adjacent structures during joint activity (between skin & bone or bone & ligaments)
Synovial fluid is:
a clear viscous (thick, sticky consistancy) fluid secreted by a membrane to lubricat joints and prevent friction *contains phagocytes & nourishes cartliage
Ball-and-socket (synovial joint):
most freely movable joints, all angular movement (head of one bone fits into socket of another) * hip & shoulder
6 types of synovial joints:
ball-and-socket, condyloid joints, gliding joints, hinge joints, pivot joints, & saddle joints
Condyloid (synovial joint):
have all motion except rotation, oval condyle of one bone fits into the elliptical cavity of another (metacarpals & phalanges)
Gliding (synovial joints):
have flat or slightly curved articulating sites (carpals & tarsals, and sternum w/ ribs 2-7)
Hinge (synovial joint):
Only flexion & extension - convex surface of one bone fits into a concave surface of another (elbox & knee)
Pivot (synovial joint):
permits rotation - cylindrical surface of one bone rotates within ring formed of bone & ligament (axis (dens) -or- radioulnar joint)
Saddle (synovial joint):
articulating surfaces have both the concave and convex surfaces (carpal & matacarpal of the THUMB)
Origin:
the part of a muscle that is attached to the immovable bone ("fixed point")
Insertion:
part of the muscle attached to the movable bone (when a muscle contracts across a joint it's _________ pulls toward the origin)
Types of Angular movement:
Flexion, extension, abduction, adduction, circumduction, & rotation
Types of Special movement:
supination/pronation, inversion/eversion, elevation/depression, & protraction/retraction
Types of Flexion (angular movement):
dorsiflexion & plantar flexion
Flexion is:
bending parts at a joint so that the angle between them decreases and the parts come closer together (bending the knee)
Dorsiflexion is:
flexion of the foot - the ankle movement that brings the foot closer to the shin
Plantar flexion is:
flexion of the foot - movement at the ankle that brings the foot farther from the shin
Extension is:
straightening parts at a joint so that the angle between them increases and the parts move further apart
Abduction is:
moving a part away from the midline (lifting arm to form 90 degree angle -or- spreading fingers or toes)
Adduction is:
moving a part toward the midline (putting arm down to your side -or- closing fingers or toes)
Circumduction is:
moving a part so that it's ends follow a circular path (moving finger in circular pattern without moving hand)
Rotation is:
moving a part around an axis (moving head from side to side) *can be medial or lateral
Supination is:
turning the hand so that the palm is upward or facing anteriorly
Pronation is:
turning the hand so that the palms are facing downward or posteriorly
Inversion is:
turning the foot so that the plantar surface faces medially (inward)
Eversion is:
Turning the foot so that the plantar surface is facing laterally
Elevation is:
raising a part (shugging the shoulders)
Depression is:
lowering a part (drooping the shoulders)
Protraction is:
moving a part forward (thrusting head forward)
Retraction is:
moving a part backwards (pulling head back)
Ligaments in the shoulder:
coracohumeral, glenohumeral, transvers humeral
The shoulder joint is:
2 joints a ball-and-socket (synovial) joint called the glenohumeral joint & a syndesmosis (fibrous) joint called the acromioclavicular joint
The ball-and-socket in the shoulder is:
surrounded by many reinforcing ligaments and tendons collectively called the rotator cuf
The 4 bursa that lubricate the shoulder:
subscapular, subdeltiod, subacromial, & subcoracois
Shoulder movement can:
occur in any angular plane - flexion, extension, adduction, abduction, rotation and circumduction
The elbow joint is:
2 joints hinge (trochlear notch of ulna/trochlea of humerus) & gliding joint (capitulum of humerus/head of radius)
Ligaments of the elbow:
"Ulnar collateral" ligament medially, "radial collateral" ligament laterally, & "anular" ligament encircles the head of the radius
The elbow joint is a very:
stable joint with many reinforcing ligaments.
The elbow only allows for:
movement by-- flexion and extension
The hip (coxal) joint:
Contains many large reinforcing ligaments & allows same movements as shoulder, but with less range due to bony limitations
(flexion, extension, adduction, abduction, rotation and circumduction)
Ligaments in the hip (coxal) joint:
Iliofemoral ligament, pubofemoral ligament, & ischiofermoral ligament
The knee consists of:
3 joints (2 condyloid joints at the medial and lateral condyles) & (1 gliding joint between the patella and the patellar surface of the femur)
Extracapsular ligaments in the knee:
(strong, on the outside) patellar, tibial collateral, & fibular collateral
Intrascapular ligaments of the knee:
(weaker ligaments on the inside) anterior cruciate & posterior cruciate
Your epiphyseal plates harden:
between the ages of 14-20
With age fibrocartilage loses water, which:
decreases flexibility of intervertebral joints
Collagen starts to change and:
stiffen at the age of 30
Articular cartilage:
(hyaline) resists wear and minimizes friction *and acts asa shock absorber for spoungy bone