A&P CH 8 Joints

elevation and depression, opposition

elevation - means lifting a body part superiorly depression - means to move an elevated body part inferiorly opposition - occurs when you touch your thumb to the fingers on the same hand

hyperextension/flexion

extension - backwards flexion - forwards

Temporomandibular Joint (jaw)

look at page Movement: the temp. joint allows both hinge-like movement and side to side lateral excursion Characteristics: contains an articular disc that divides the synovial cavity into compartments that support each type of movement Ligs: the lateral aspects of the fibrous capsule contains a lateral lig that reinforces the joint

gliding movements

one flat, or nearly flat, bone surface glides or slips over another

Supination, pronation

supination- rotating the forearm laterally so that the palms faces anteriorly or superiorly protation - rotating the arm medially so that the palm faces posteriorly or inferiorly in anatomical position, the hand is supinated and the radius and ulna are parallel

bursae and tendon sheaths

-BAGS OF LUBRICANT THAT REDUCE FRICTION AT SYNOVIAL JOINTS -not part of the syn joints, but are often found closely associated with them -Bursae- flattened fibrous sacs lined with synovial membrane and containing a thin film of synovial fluid. Found in regions where ligaments,muscles,skin rub together. -Tendon sheath- essentially an elongated bursae that wraps around a tendon subjected to friction

synovial joints

-articulating bones are separated by a fluid containing joint cavity -this permits substantial freedom of movement -all syn are freely movable diarthroses -all joints of the limbs

Arthritis

-describes many inflamm or degen diseases that damage the joints, resulting in pain, stiffness, and swelling of joint -acute forms of arth usually result from bacterial invasion and are treated with antibiotics -the syn mem thickens and fluid production decreases, causing increased friction and pain -chronic forms of arth include osteo, rheumatoid, and gouty

Common knee injury

-hit to popliteal (anterior) -by separating femur from tibia medially, such blows to lat side tear both tibia collateral ligament and medial meniscus bc the two are attached anterior cruciate lig also tears

RA continued

-inflamm cells (lymphocytes and neutrophils) migrate into the joint cavity from the blood and release excessive amounts of inflamm chemicals, destroying body tissues -syn fluid accumulates, causing joint swelling and gradually the inflamed syn mem thickens into a pannus, an abnormal tissue that clings to the articular cartilages -pannus erodes the cartilage and underlying bone and forms scar tissue and connects bone ends -later this scar tissue ossifies and the bone ends fuse, immobilizing the joint, this end condition (ankylosis) ("stiff condition") often produces bent, deformed fingers -not all cases of RA result in crippling ankylosis stage, but all cases do involve restriction of joint movement and extreme pain

Bursitis

-inflammation of the bursa, may be caused by a blow or friction -falling on knee can cause a painful bursitis called "water on the knee" due to inflamm of bursae or synovial mem -prolonged leaning on elbow may cause damage to the bursa close to olecranon process, producing students elbow or olecranon bursitis -severe cases treated by injection of anti inflamm drugs into bursa -if excessive fluid accumulates, removing some fluid by needle aspiration may relieve the pressure

Sprains

-ligs or tendons reinforcing a joint are damaged by excessive stretching, or they are torn away from the bone healing -since both ligs and tens are cords of dense fibrous conn tissue with a poor blood supply, sprains heal slowly and are extremely painful common sprain sites -lumbar regions of spine, ankle, knee

Osteoarthritis

-most common, slow and irreversible form of chronic arth, rarely crippling -result of breakdown of articular cartilage and subsequent thickening of bone tissue forming bone spurs, which may restrict joint movement -OA is most prevalent in aged, and probably related to the normal aging process (sometimes seen in younger people and may be genetic) -affected joints may make a crunching noise (crepitus) as they move and roughened articular surfaces rub together -most common in cervical and lumbar spine, fingers, knuckles, knees, hips -can be controlled with pain relievers and moderate activity to keep joints mobile

Cartilage injuries

-most involve tearing of the knee menisci -overuse damage to the articular cartilages of other joints is becoming increasingly common in competitive athletes healing -cartilage is avascular, cannot obtain sufficient nourishment to repair itself, usually stays torn -cart fragments (called loose bodies) can interfere with joint function by causing the joint to lock or bind

Dislocations

-occurs when bones are forced out of alignment -usually accompanied by sprains, inflammation, and joint immobilization -may result from serious falls -are common contact sports injuries -jaw, shoulders, thumbs, and fingers commonly dislocated -repeat dislocations of the same joint are common bc the initial dis stretched the joint capsule and ligs, resulting loose capsule provides poor reinforcement for the joint

Gouty Arthritis

-results when uric acid is deposited in the soft tissues of the joints -an inflamm response follows, leading into an agonizingly painful attack of GA, or gout. -initial attack typically affects one joint, often at the base of the great toe -uric acid, a normal waste product of nucleic acid metabolism, is ordinarily excreted in urine without any problems, however, when blood levels of uric acid rise excessively (due to its excessive production or slow excretion) it may be deposited as needle shaped urate crystals in the soft tissues of joints -much more common in males, bc males naturally have higher blood levels of uric acid (estrogens increases the rate of its excretion) -seems to run in families, genetic factors definitely implicated -untreated gout can be very destructive, the articulating bone ends fuse and immobilize the joint

Fibrous joints

-sutures - made of short connective tissue fibers, immovable joints >ex. between bones of the skull -syndesmoses >made up of ligaments (cords/bands of fibrous tissue) >fibers vary in length (are longer than those of sutures) >slightly movable (the amount of movement allowed depends on the length of the connecting fibers) >ex. joint connecting the distal ends of the tibia and fibula -gomphosis - peg in socket joint, fibrous tissue is the periodontal ligaments >ex. joint of a tooth with its bony alveolar socket

Rheumatoid Arthritis

-usually between ages 40-50, but any age, 3 times as many women -many joints, particularly small joints of fingers, wrists, ankles, and feet are afflicted at the same time and bilaterally (left and right foot) -no wonder drug yet -current RA therapy includes pain killers (like aspirin), anti inflamms, long term antibiotic therapy, physical therapy, progressive treatment course using immunosuppressants -joint prostheses if available also used as last resort for severely crippled RA patients -autoimmune disease in which the bodys immune system attacks its own tissue -in early stages, joint tenderness and stiffness are common -RA begins with inflamm of the syn mem of the affected joints -may include anemia, osteoporosis, muscle atrophy, and cardiovas problems

Factors Influencing Stability of Synovial Joints

1) articular surfaces -shapes of the articular surfaces of bones found at a synovial joint, but play a minimal role in stabilizing the joint -many joints have a shallow sockets or noncomplementary articulating surfaces (misfits), but when articular surfaces are large and fit snuggly together, or when the socket is deep, stability is vastly improved, EX hip joint 2) Ligaments -ligaments at a synovial joint prevent excessive or unwanted movements and help to stabilize the joint, the more ligaments the greater the stability 3) Muscle tone- muscle tone keeps tendons crossing joints taut, which is the most important factor stabilizing joints

types of syn joints (1)

1. Plane joints are the only examples of nonaxial joints. They have flat articular surfaces and allow gliding movements. 2. Hinge joints consist of a cylindrical projection that rests in a trough shaped structure, and allow movement along a single plane. These uniaxial joints permit flexion and extention only 3. Pivot joints consist of a rounded structure that protrudes into a sleeve or ring and allow uniaxial rotation of a bone around its own long axis. example is the joint between the atlas and dens of the axis, which allows you to move your head from side to side "no"

general structure of a synovial joint contains:

1.Articular Cartilage- thin,glassy-smooth hyaline cartilage covers the ends of the articulating bones. Its spongy cushions absorb compression and prevent the bone from being crushed. 2.The Joint (synovial cavity) is a space that is filled with synovial fluid 3. The bilayer articular capsule encloses the joint cavity. The external layer is composed of dense irregular fibrous connective tissue, that is continuous with the periostea of the articulating bones. It stengthens the bones so they do not get pulled apart.The inner later is a synovial membrane composed of loose connective tissue. It lines the fibrous capsule internally and covers all internal joint surfaces that are not hyaline cartilage. 4. Synovial fluid is a slippery fluid that fillas all free space in joint cavity, fluid is derived largely by filtration from blood flowing thru capillaries in the synovial mems, has viscous egg white consistency due to hyaluronic acid (proteoglycan) secreted by cells in the syn mem, but it thins becoms less viscous as it warms during activity 5. Reinforcing ligaments cross synovial joints to strenghten thte joint

types of syn joints (2)

4. condyloid/ellipsoid consist of an oval articular surface that nests in a complementary depression and permit all angular movements - flexion, extension, ab/adduction, circum. Biaxial joints.mEx radiocarpal (wrist) joints and the metacarpophalangeal (knuckle) joints 5. Saddle joints consist of each articular surface bearing complementary concave and convex areas. These biaxial joints allow more freedom of movement than condyloid joints. EX carpometacarpal joints of the thumbs and the movements allowed by these joints are clearly demonstrated by twiddling your thumbs 6.Ball and socket joints consist of a spherical or hemispherical structure that articulate with a cup like structure. They are the most freely moving joints and allow multiaxial movement (in all axes and planes, including rotation). EX shoulder and hip joints

abduction, adduction, circumduction, rotation

Abducation- is the movement of a limb or fingers away from the midline or the hand adduction - the opposite, towards Circumduction - moving a limb so that it makes a cone in the air rotation - turning of a bone along its own long axis

dorsiflexion and plantar flexion

Dorsiflexion - decreases the angle between the top of the foot (dorsal surface) and the anterior surface of the tibia Plantar flexion - decreases the angle between the sole of the foot (plantar surface) and the posterior side of the tibia

flexion and extension

Flexion- decreases the angle of the joint and brings the articulating bones closer together Extension - increases the angle between the articulating bones

Hip (coxal) joint

Movement: is a ball and socket, provides a good range of motion Ligs: several strong ligs reinforce the capsule of the hip joint 1) iliofemoral between the iliac and femur bones 2) ischiofemoral between the ischium and femur bones 3) pubofemoral between the pubis and femur bones Tendons: the muscle tendons that cross the joint contribute to the stability and strength of the joint, but the majority of the stability of the hip joint is due to the deep socket of the acetabulum and the ligaments

Knee Joint

Movement: largest and most complex joint in body, allows extension, flexion, and some rotation Characteristics: enclosed in 1 joint cavity, knee joint is actually 3 joints in one: -femoropatellar joint (an intermediate one between the patella and lower end of femur) -lateral tibiofemoral joint between the femoral condyles and the menisci of the tibia (located laterally) -medial tibiofemoral joint between the femoral condyles, and the menisci of the tibia (located medially) Ligaments: many diff types of ligs stabilize and strengthen capsule of knee joint Tendons: knee capsule reinforced by muscle tendons such as strong tendons of the quad muscles and tendon of the semimembranosus

Elbow Joint

Movement: provides stable and smoothly operating hinge joint that allows flexion and extension only Ligs: ligs involved in providing stability to the elbow joint are the annular lig, the ulnar collateral lig, and the radial collateral lig Tendons: tendons of several arm muscles, the biceps and triceps, also provide additional stability by crossing the elbow joint

Shoulder joint

Movement: stability has been sacrificed to provide the most freely moving joint in the body Ligaments: the ligs that help to reinforce the shoulder joint are the coracohumeral ligs and the three glenohumeral ligs Tendons: the tendons that cross the shoulder joint and provide the most stabilizing effect on the joint are the tendon of the long head of the biceps brachii and the four tendons that make up the rotator cuff

Cartilaginous joints

Synchondroses -Bar or plate of hyaline cartilage unites the bones -Are synarthrotic (immovable joints) -Example: The epiphyseal plate connecting the diaphysis and epiphysis regions in long bones of children Symphyses -articular cartilage fused to an intervening pad or plate of fibrocartilage -fibro is compressible and resilient and acts as a shock absorber and permits a limited amount of movement at the joint -are amphiarthrotic joints designed for strength and flexibility -ex. intervertebral joints, pubic symphysis

Functional classifications of joints

based on the amount of movement allowed at the joint -synarthroses - immovable joints -amphiarthroses - slightly movable joints >(both above) axial skeleton, provide firm attachments and protection of internal organs -diarthroses - freely movable joints >limbs, provide mobility

Structural Classification

based on the material binding the bones together and whether or not a joint cavity is present -fibrous joints: immovable joints, bones joined by fibrous tissue, lack a joint cavity -cartilaginous joints: may be immovable or slightly movable, bones joined by cartilage, lack a joint cavity -synovial joints: freely movable, bones separated by fluid containing joint cavity

angular movements

increase or decrease the angle between two bones

Tendonitis

inflamm of tendon sheath, usually caused by overuse

inversion and eversion

inversion - turns the sole of the foot so that it faces medially eversion - turns the sole of the foot so that it faces laterally

protraction and retraction

protraction - moves the mandible anteriorly, juts jaw forward retraction - returns the mandible to its original position

Memorize

the freakishly long table