A&P 8: Joints Flashcards
Joints
Articulations; sites where 2 or more bones meet
Synarthroses
immovable joints
Amphiarthroses
slightly movable joints
Diarthroses
freely movable joints
Fibrous joints
bones joined by fibrous tissue, namely dense fibrous connective tissue; no joint cavity present; 3 types - sutures, syndesmoses, gomphoses
Sutures
“seams”; occur only between bones of the skull
Synostoses
closed sutures; “bony junctions”
Syndesmoses
bones connected exclusively by ligaments, cords or bands of fibrous tissue
Gomphosis
peg-in-socket fibrous joint; only example is the articulation of a tooth with its bony alveolar socket; “nail” or “bolt”
Periodontal ligament
fibrous connection in the case of a tooth in its socket
Cartilaginous joints
articulating bones united by cartilage; lack a joint cavity; not highly movable; 2 types - synchondroses & symphyses
Synchondrosis
junction of cartilage; a bar or plate of hyaline cartilage unites the bones; virtually all of these are synarthrotic
Symphysis
a joint where fibrocartilage unites the bone; “growing together”; limited movement permitted
Synovial joints
“joint eggs”; articulating bones are separated by a fluid-containing joint cavity; substantial freedom of movement
Articular cartilage
glassy-smooth hyaline cartilage covers the opposing bone surfaces; keep bone ends from being crushed
Articular capsule
2-layered joint capsule
Fibrous layer
tough external layer of an articular capsule; composed of dense irregular connective tissue that is continuous with the periostea of the articulating bones; strengthens the joint so the bones are not pulled apart
Synovial membrane
inner layer of an articular capsule; composed of loose connective tissue; covers all internal joint surfaces that are not hyaline cartilage; function: make synovial fluid
Synovial fluid
small amount of this slippery fluid occupies all free spaces within the joint capsule; derived largely by filtration from blood flowing through capillaries in the synovial membrane; has a viscous, egg-white consistency
Ligaments
synovial joints are reinforced and strengthened by a number of bandlike _____
Capsular ligaments
thickened parts of the fibrous layer
Extracapsular ligaments
distinct; ligaments found outside the capsule
Intracapsular ligaments
ligaments found deep to the capsule; covered with synovial membrane; do not actually lie within the joint cavity
Fatty pads
cushioning between the fibrous layer and the synovial membraneor bone
Articular discs
menisci (“cresents”); wedges of fibrocartilage separating articular surfaces; extend inward from the articular capsule and partially or completely divide the synovial cavity in two; improve the fit between articulating bone ends, making the joint more stable and minimizing wear and tear on the joint surfaces; occur in the knee, jaw, and a few other joints
Bursae
flattened fibrous sacs lined with synovial membrane, contain a thin film of synovial fluid; occur where ligaments, muscles, skin, tendons, or bones rub together
Tendon sheath
elongated bursa that wraps completely around a tendon subjected to friction; common where several tendons are crowded together within narrow canals (ex. wrist)
Origin
where the muscle is attached to the immovable (or less movable) bone
Insertion
the end of the muscle attached to the movable bone
Nonaxial movement
slipping movements only, since there is no axis around which movement can occur
Uniaxial movement
movement in one plane
Biaxial movement
movement in 2 planes
Multiaxial movements
movement in or around all 3 planes of space and axes
Gliding
occurs when 1 flat, or nearly flat bone surface glides or slips over another (back/forth & side to side)
Angular movements
increase or decrease the angle between 2 bones; include flexion, extension, hyperextension, abduction, adduction, and circumduction
Flexion
bending movement, usually along the sagittal plane, that decreases the angle of the joint and brings the articulating bones closer together
Extension
reverse of flexion; occurs at the same joints; involves movement along the sagittal plane that increases the angle between the articulating bones and typically straightens a flexed limb or body part
Hyperextension
continuing extension movements beyond the anatomical position
Abduction
movement of a limb away from the midline or median plane of the body, along the frontal plane
Adduction
opposite of abduction; movement of a limb toward the body midline, or in the case of the digits, toward the midline of the hand or foot
Circumduction
moving a limb so that it describes a cone in space; consists of flexion, abduction, extension, and adduction performed in succession
Rotation
turning of a bone around its own long axis; only movement allowed between the 1st 2 cervical vertebrae; common at the hip and shoulder joints; may be directed toward the midline or away from it
Supination
rotating the forearm laterally so that the palm faces anteriorly or superiorly; radius and ulna are parallel in the anatomical position
Pronation
forearm rotates medially and the palm faces posteriorly or inferiorly; moves the distal end of the radius across the ulna so that 2 bones form an X; a weaker movement than supination
Dorsiflexion
corresponds to wrist extension; lifting the foot so that its superior surface approaches the shin
Plantar flexion
corresponds to wrist flexion; depressing the foot (pointing the toes)
Inversion
turning the sole of the foot medially
Eversion
turning the sole of the foot laterally
Protraction
nonangular anterior movement in a transverse plane; ex. jutting out your jaw
Retraction
nonangular posterior movement in a transverse plane; ex. pulling jaw in
Elevation
lifting a body part superiorly; ex. scapula do this when you shrug your shoulders
Depression
moving an elevated part inferiorly; ex. during chewing, the mandible is alternately elevated and _____
Opposition
saddle joint between metacarpal I and the trapezium allows this movement of the thumb; action taken when you touch your thumb to the tips of the other fingers on the same hand; makes the hand a good tool for grasping and manipulating objects
Femoropatellar joint
intermediate joint between the patella and the lower end of the femur
Tibiofemoral joint
lateral and medial joints between the femoral condyles above and the C-shaped menisci (semilunar cartilages) of the tibia below
Patellar ligament
along with the retinacula, ligament that runs from the patella to the tibia; = continuations of the tendon of the bulky quadriceps muscle of the anterior thigh; tapped by doctors to test the knee-jerk reflex
Medial & Lateral Patellar Retinacula
along with the patella, ligaments that run from the patella to the tibia
Fibular & Tipial Collateral Ligaments
extracapsular ligaments critical in preventing lateral or medial rotation when the knee is extended
Oblique Popliteal Ligament
actually part of the tendon of the semimembranosus muscle that fuses with the joint capsule and helps stabilize the posterior aspect of the knee joint
Arcuate Popliteal Ligament
arcs superiorly from the head of the fibula over the popliteus muscle and reinforces the joint capsule posteriorly
Anterior Cruciate Ligament (ACL)
attaches to the anterior intercondylar area of the tibia; passes posteriorly, laterally, and upward to attach to the femur on the medial side of its lateral condyle; prevents sliding of the tibia on the femur, checks hyperextension of the knee
Posterior Cruciate Ligament
stronger than the ACL, ligament attached to the posterior intercondylar area of the tibia; passes anteriorly, medially, and superiorly to attach to the femur on the lateral side of the medial condyle
Glenoid labrum
rim of fibrocartilage that slightly deepens the glenoid cavity
Coracohumeral Ligament
provides the only strong thickening of the capsule and helps support the weight of the upper limb
Glenohumeral Ligaments
3 ligaments that strengthen the front of the capsule somewhat; weak; may be absent
Rotator Cuff
4 tendons and associated muscles; encircles the shoulder joint and blends with the articular capsule; muscles include the subscapularis, supraspinatus, infraspinatus, teres minor
Anular Ligament
ligament that surrounds the head of the radius
Ulnar Collateral Ligament
strong capsular ligament that restricts side-to-side movement of the elbow (medially)
Radial Collateral Ligament
strong capsular, triangular ligament that restricts side-to-side movement of the elbow on the lateral side
Hip Joint
ball and socket joint with a good range of motion (though not as good as the shoulder); movements occur in all possible planes but are limited by the joint’s strong ligaments and its deep socket
Acetabular Labrum
circular rim of fibrocartilage that enhances the depth of the acetabulum
Ileofemoral Ligament
strong, V-shaped ligament anteriorly (of the hip)
Pubofemoral Ligament
triangular thickening of the inferior part of the capsule (hip)
Ischiofemoral Ligament
spiraling posterior ligament of the hip
Ligament of the head of the femur
ligamentum teres; flat intracapsular band that runs from the femur head to the lower lip of the acetabulum; slack during most hip movements, not important in stabilizing the hip; mechanical function unclear (does contain an artery that helps supply the head of the femur)
Temporomandibular joint
jaw joint; modified hinge joint; lies anterior to the ear; condylar process of the mandible articulates with the inferior surface of the squamous part of the temporal bone
Mandibular fossa
concave depression in the mandible posteriorly
Articular tubercle
dense knob of the mandible anteriorly
Lateral ligament
lateral aspect of the loose articular capsule that encloses the tempormandibular joint
Arthroscopic surgery
“looking into joints”; outpatient procedure that removes damaged cartilage so it doesn’t cause a joint to lock or bind
Sprain
ligaments reinforcing a joint are stretched or torn; common sites are the ankle, the knee, and the lumbar region of the spine
Dislocation (luxation)
occurs when bones are forced out of alignment; usually accompanied by sprains, inflammation, and difficulty in moving the joint; may result from serious falls; common contact sports injuries
Subluxation
partial dislocation of a joint
Bursitis
inflammation of a bursa; usually caused by a blow or friction; ex. housemaid’s knee (water on the knee) caused by falling on one’s knee; student’s elbow (olecranon _____)
Tendonitis
inflammation of tendon sheaths, typically caused by overuse
Arthritis
describes over 100 different types of inflammatory or degenerative diseases that damage the joints; most widespread crippling disease in North America (1 in 5)
Osteoarthritis (OA)
most common chronic arthritis; “wear-and-tear arthritis”; most prevalent in the aged; related to the normal aging process
Rheumatoid arthritis (RA)
chronic inflammatory disorder with an insidious onset; usually arises between the ages of 30 and 50, but may occur at any age; affects 3 times as many women as men; affects 1% of all people; autoimmune
Pannus
“rag”; an abnormal tissue that clings to the articular cartilages
Gouty arthritis (gout)
excess uric acid becomes deposited as needle-shaped urate crystals in the soft tissues of joints; more common in men than in women
Lyme Disease
inflammatory disease caused by spirochete bacteria transmitted by the bite of ticks that live on mice and deer; often results in joint pain and arthritis, especially in the knees; characterized by a skin rash, flu-like symptoms, and foggy thinking; if untreated, neurological disorders and irregular heartbeat may ensue
