Ch.9 - JOINTS Flashcards
What is a joint?
point of contact between:
- Two or more bones
- Cartilage and bone
- Teeth and bone
Structural classifications of joints.
Anatomical criteria:
- presence or absence of a space between the articulating bones (joint cavity)
- type of CT
Functional classification of joints.
Functional criteria:
-degree of movement permitted
Structural classification subcategories:
fibrous joints, cartilaginous joints, and synovial joints.
Fibrous joints
bones held together by dense collagen fibers
cartilaginous joints
bones held together by cartilage
synovial joints
synovial cavity, bones held together by ligaments.
Freely moveable
Functional classification subcaterogies of joints
- synarthrosis
- amphiarthrosis
- diarthrosis
synarthrosis
immovable joint; immoveable joints, like the fibrous joints of the skull (sutures)
amphiathrosis
slightly movable joint; slightly movable joints like the cartilaginous pubic symphysis, intervetebral discs
diarthrosis
freely movable joint; freely moveable joints like the big “ball and socket” synovial joints of the shoulder and hip.
fibrous joints
lack cartilage and a synovial cavity.
- bones are held closely together by dense irregular CT
- little/no movement.
ex) suture joints in the skull and the teeth joints.
fibrous joints- suture
occur only between bones of the skull
fibrous joints- Syndesmosis
permit slight movement, such as the interosseous membrane between the tibia and fibula
Fibrous joints - gomphoses
occur between the teeth and the periodontal ligament
cartilaginous joints
They lack a synovial cavity and provide little or no movement.
Pubic symphysis, the intervertebral disks of the spine
synchondroses
type of cartilaginous joint.
made of hyaline cartilage, like the epiphyseal growth plates
symphyses
type of cartilaginous joint.
have hyaline cartilage sandwiching a disc of fibrocartilage; like the pubic symphysis and the intervertebral discs
synovial joint
Ligaments hold bones together to form a synovial cavity Nerve and blood supply -A two layered capsule encloses the synovial cavity: -An outer fibrous capsule -An inner synovial membrane
synovial fluid
Reduces friction by lubricating the joint Absorbs shock Supplies oxygen and nutrients to cartilage Removes carbon dioxide and metabolic wastes
synovial joints examples
Freely movable joints of the
arms, hips, and legs
Accessory structures of synovial joint
Joint capsule Ligaments Bursae Tendon sheaths Menisci
joint capsules
composed of dense irregular C.T., lined by a synovial membrane. They encompass the joint cavity and the synovial fluid within it.
ligaments (w/ ACL example)
bands of dense regular C.T. (like tendons) that join one bone to another bone. Ligaments can blend with other C.T. to become part of a joint capsule, or they can run inside or outside the joint.
example: The ACL (ligament) lies inside the knee joint, whereas the patellar ligament is outside the joint.
bursae
fluid-filled structures strategically placed to minimize friction in some joints.
tendon sheaths
tube-like bursae that
wrap around tendons
menisci
pads of dense fibrocartilage found between articular surfaces where hyaline cartilage predominates
These “articular discs” provide superior strength and allow bones of different shapes to fit together more tightly.
Nerve and blood supply of synovial joints: arterial branches
Arterial branches from several different arteries merge around a joint before penetrating the articular capsule.
Nerve and blood supply of synovial joints: nerve endings
Nerve endings respond to the degree of movement and stretch, and convey information about pain from the joint to the spinal cord and brain.