Articulations (Ch 9) Flashcards
What’s another name for joints?
articulations
What are the functions of joints?
support and movement
Joints
- bones articulate (come in contact) at joints
- skeletal muscles cross over joints in order to achieve movement
- more mobile = less stable
- classified by function or structure
Functional classification of joints
relates to amount of movement allowed at the joint
- Synarthrosis
- Amphiarthrosis
- Diarthrosis
Synarthrosis
- functional classification
- immovable joint (ex. skull sutures, epiphyseal plates)
Amphiarthrosis
- functional classification
- slightly movable joint (ex. pubic symphysis)
Diarthrosis
- functional classification
- freely movable (ex. joints in limbs)
Structural classification of joints
based on CT that binds bonds together (fibers/cartilage) and presence or absence of joint cavity
- Fibrous
- Cartilaginous
- Synovial
Fibrous
- structural classification of joints
- connected by fibrous CT (ex. skull sutures)
Cartilaginous
- structural classification of joints
- connected by cartilage tissue (ex. pubic symphysis)
Synovial
- structural classification of joints
- connected by a fluid-filled joint cavity within a capsule (ex. most joints like shoulder/elbow/knee)
- most movable (diarthrosis)
What are the types of cartilaginous joints?
- Synchondroses
2. Symphyses
Synchondroses
type of cartilaginous joint where bones are joined by hyaline cartilage (ex. costochondrial joints, epiphyseal plates)
Symphyses
type of cartilaginous joint where there is fibrocartilage between articulating joints (ex. intervertebral joints, public symphysis)
What are the parts of typical synovial joints?
- Articular (fibrous) capsule
- Joint (articular) cavity
- Synovial fluid
- Articular (hyaline) cartilage
- Ligaments
Articular (fibrous) capsule
- synovial joint
- two parts: outer fibrous layer continuous with periosteum and inner synovial membrane that secretes synovial fluid
Joint (articular) cavity
- synovial joint
- space filled with synovial fluid
Synovial fluid
- synovial joint
- liquid in joint cavity/cartilages that provides lubrication
Articular (hyaline) cartilage
- synovial joint
- absorbs forces on the joint and protects the bone
Ligaments
- synovial joint
- connects bone to bone, strengthens joints (can be internal or external to articular capsule
- have blood supply/are innervated
Bursae
*synovial joint
saclike structure with synovial fluid
Tendon Sheaths
*synovial joint
wrap around tendons to reduce friction where bones/ligaments/tendons rub
Knee Joint
- largest/most complex joint
- acts as hinge (may rotate slightly)
- 2 condyloid joints (lateral/medial)
- both femur and tibia have two condylar surfaces
- strong ligaments to help knee from moving wrong way (LCL, MCL, ACL, PCL)
- 12 bursa to reduce friction
- menisci made of fibrocartilage (aka articular discs) help even out weight distribution/stabilize joint
- ->prevent side to side rocking o femur on tibia
What are the ligaments of the knee?
- Lateral (fibular) Collateral Ligament (LCL)
- Medial (tibial) Collateral Ligament (MCL)
- Anterial Cruciate Ligament (ACL)
- Posterior Cruciate Ligament (PCL)
The unhappy triad
when knee is hit while foot is planted
–> tears multiple ligaments and menesci
Temporomandibular Joint
TMJ
- divided by articular disc (meniscus) into superior and inferior compartments
- superior: gliding
- inferior: hinge
- saggital section through joint –> movement back and forth (opening/closing mouth)
- lateral excursion (side to side)
The Glenohumeral Joint
- ball and socket
- highly mobile = not stable
- glenoid cavity is not deep
- dislocates easily
The Hip Joint
- ball and socket
- less mobility = more stable
- deep acetabulum for herd of femur
- ligamentum teres extend from acetabulum –> fovea captius (on head of femur) which may add stability
The Elbow Joint
- hinge joint (humerus/ulna)
- -> annular ligament forms pivot at proximal radioulnar join
Rheumatoid Arthritis
autoimmune disease
- symptoms: pain, stiffness, weakness
- begins with inflammation of synovial membrane (joint swells)
- chronic inflammation of joint capsule deteriorates CT around joint
Arthritis in Knee
- most common is osteoarthritis –> affects articular cartilages
- “wear and tear” = stiffening, pain, swelling
- extreme solution is complete replacement of knee
hinge
allows flexion/extension (ex. elbow)
pivot
allows rotation (ex. proximal radioulnar)
ball and socket
very flexible, allows flexion/extension, adduction/abduction, and rotation (ex. hip)
gliding
Two opposing articular surfaces slide past each other in almost any direction; the amount of movement is slight (ex. wrist)
abduction
movement of bone away from midline
protraction
Anterior movement of a body part from anatomic position
retraction
Posterior movement of a body part from anatomic position
adduction
movement of bone towards midline
oppostion
moving dumb to touch tips of other fingers
