Flashcards in Chapter 9: Joints Deck (83)
What are the 2 categories of joint classification?
1) Presence/absence of space between articulating bones and 2) Type of connective tissue binding them together
What are the 6 types of joints?
- Fibrous joints (No synovial cavity. Bones held together by irregular dense connective tissue)
- Cartilaginous joints (No synovial cavity. Bones held together by cartilage).
- Synovial joints (Has a synovial cavity. Bones united by dense irregular connective tissue of an articular capsule and accessory ligaments)
- Synarthrosis (Immovable joint)
- Amphiarthrosis (slightly movable joint)
- Diarthrosis (Freely movable joint. All are synovial joints)
What are the 3 types of fibrous joints?
Sutures, syndesmoses, and interosseous membranes
What are sutures?
Thin layer of dense irregular connective tissue only between bones of the skull. Irregular interlocking edges of sutures give them added strength and decrease chance of fracturing. Synarthroses in adults (immovable) and amphiathroses in infants (slightly movable). Shock absorpion. Synostosis = complete fusion of 2 bones into 1.
What are syndesmoses?
Fibrous join where there's a greater distance between the articulating surfaces and more dense irregular connective tissue then in a suture. Dense irregular conn tissue arranged in a bundle (ligament) so limited movement. Example: Distal tibiofibular joint which permits slight movement. Example 2: Gomphosis (cone-shaped peg fits into a socket)... articulations between roots of teeth and their sockets (alveoli).. permits no movement.
What is the interosseous membrane?
Final category of fibrous joint. Substantial sheet of dense irregular connective tissue that binds neighbouring long bons and permits slight movement (ie betwee radius and ulna, and tibia and fibula)
What are 2 featuers of cartilaginous joints and what are the 2 types?
Lacks synovial cavity and little to no movement. 2 Types: Synchondroses and symphyses
What are synchrondroses?
Cartilaginous joint. Connecting material is hyaline cartilage. Epiphyseal (growth) plate that connects the epiphysis and diaphysis. When bone elongation ceases, bone replaces the hyaline cartilage and the synchondrosis becomes a synostosis (a bony joint). Ie between rib and manubrium of sternum.
What is a symphyss?
Cartilaginous joint. Ends of articulating bones are covered with hyaline cartilage but broad flat disc of fibrocartilage connects the bones. Usually at midline of body. Ie pubic symphysis; junction of manubrium and body of sternum; intervertebral joints between vertebrae. Slightly movable.
What are synovial joints and what is the cartilage called that covers them?
They have a space called a synovial cavity. Freely moveaby and covered by a layer of hyaline cartilage called articular cartilage.
What is the function of articular cartilage on synovial joints?
Reduces friction between bones at joint during movement and helps absorb shock.
What is the articular capsule?
Aka joint capsule. Surrounds synovial joint, encloses synovial cavity and united articulating bones
What are the 2 layers that articular capsules are composed of?
Fibrous membrane (outer) and inner synovial membrane
What does the fibrous membrane of articular capsule do?
Dense irregular connective (mainly collagen fibres)and attaches to periosteum of articulating bones. Helps prevent bones from dislocating due to great tensile stregnth (can stretch), moveable.
What is the synovial membrane of articular capsule?
Composed of areolar connective tissue with elastic fibres. Accumulations of adipose tissue called articular fat pads (ie fat pad in the knee)
How are some people double jointed?
Have a greater flexibility in their articular capsules and ligaments
What does synovial fluid look like?
Viscous, clear or pale yelllow fluid. Consists of hyaluronic acid secreted by synovial cells in synovial membrane and interstitial fluid filtered from blood plasma.
What does synovial fluid do?
Forms a thin film over surfaces within articular capsule. Reduces friction by lubricating joint, absorbing shocks, and supplying O2 and nutrients to and removing CO2 and waste from chondrocytes. Contains phagocytic cells to remove microbes and debris. If immobile, fluid becomes viscous. If mobile, less viscous
What are 2 types of accessory ligaments contained in synovial joints?
Extracapsular ligaments (lie outside articular capsule) and intracapsular ligaments (within articular capsule)
What are articular discs/menisci?
Crescent shaped pads of fibrocartilage that lie between th articular surfaces of the bones are attached to the fibrous capsule. Lateral and medial menisci or knee joint. Divides synovial cavity into 2 spaces, allowing separate movement in each (ie TMJ)
What are the 5 functions of menisci?
1) Shock absorption
2) Better fit between articulating bones
3) Providing adaptable surfaces for combined movements
4) Weight distribution over a greater contact surface
5) Distribution of synovial lubricant across the articular surfaces of the joint
What is the labrum? Functions?
Fibrocartilaginous lip that extends from edge of joint socket. Prominent in ball-and-socket joints of shoulder and hip. Labrum help deepen the joint socket and increase area of contact between the socket and ball-like surface of the head of the humerus or femur
Where do synovial joints get their blood supply?
They contain many nerve endings that are distributed to the articular capsule and associated ligaments. Veins remove CO2 an waste from joints. Chondrocytes in articular cartilage of a synovial joint receive O2 and nutrients from synovial fluid derived from blood
What are bursae and tendon sheaths?
Sac life structures called bursae are situated to aleviate friction in some joints like shoulder and knee joints. Walls consist of outer fibrous membrane of thin, dense connective tissue lined by synovial membrane. FIlled with a small amount of fluid similar to synovial fluid. Located between skin and bones, tendons and bones, muscles and bones, or ligaments and bones... cushions movement of these bony parts against one another.
What do tendon sheaths do?
Reduce friction at joints. Tubelike burssae. Wrap around certain tendons that experience lots of friction. Visceral layer (inner) is atatched to surface of tendon. Parietal layer (out) is attached to the bone.
What are the 4 main categories that synovial joints are grouped in?
1) Gliding 2) Angular 3) Rotation 4)special movements (occur at certain joints)
What are gliding joints and what are examples?
Nearly flat bone surfaces move back and forth and side to side. Examples are intercarpal and intertarsal
What are angular movements and what are the 7 types?
There's an increase/decrease in the angle between articulating bones. THe types are: flexion, extension, lateral flexion, hyperextension, abduction, adduction and circumduction
What is flexion and extension and what are examples?
USUALLY occurs along sagittal plane. Flexion is a decrease in the angle between articulating bones. Extension is an increase in the angle between articulating bones often to restore a part of the body to the anatomical position after being flexed. Examples: Bending head toward chest, bending trunk forward at intervertebral joints (crunches), moving humerus forward at shoulder joint (ie swinging arms), moving forearm toward arm at elbow joint (bending elbow), moving palm toward forearm at wrist or radiocarpal joint, bending digits of hand at the interphalangeal joints between phalanges (ie clenching fingers), moving femur forward at hip joint between femur and hipbone (ie walking) and moving heal toward butt at tibiofemoral joint between tibia ,femur, and patella (ie bending the knee)