Joint Structure and Function Flashcards
What are the components of a synarthroses joint?
They have essentially no movement.
Function to bind and transfer forces between bones.
Describe a diarthroses joint.
A joint that allows for moderate to extensive motion. They have a synovial fluid-filled cavity.
EX: GH Joint
What are the elements that are always associated with synovial joints?
- Synovial fluid
- Articular cartilage
- Joint capsule
- Synovial membrane
- Ligaments
- Blood vessels
- Sensory nerves
What are other features that are sometimes noted in synovial joints?
- Intra-articular disc = increase congruency and improve force dispersion
- Peripheral labrum = deepen concave joint and support attachment of joint capsule
- Fat pads = reinforce internal aspects of capsule and fill non-articulating joint spaces.
- Bursa = extension of synovial membrane; absorb force and protect CT
- Synovial plica = overlapped pleats of tissue
What are the 3 functions of joints?
- Allow for motion
- Bear body weight
- Provide stability
What are the 7 types of synovial joints?
- Hinge
- Pivot
- Ellipsoid
- Ball and Socket
- Plane joint
- Saddle joint
- Condyloid joint
What is an instantaneous axis of rotation?
Axis of rotation for a specific arc of motion.
Define what connective tissue (CT) forms. What are the three different components of CT?
Connective tissue forms capsules, ligaments, tendons, articular cartilage, and fibrocartilage
Components:
- Fibrous protein = collagen & elastin
- Ground substance = water, solutes, glycosaminoglycans
- Cells = fibroblast and chondrocytes
What are the 3 different types of periarticular connective tissue?
- Dense connective tissue
- Articular cartilage
- Fibrocartilage
What are some examples of dense connective tissue?
Ligaments, fibrous layer of joint capsules, and tendons
Describe dense irregular connective tissue.
Irregular = irregular and haphazard orientation of collagen within ground substance.
Best suited to resist tensile force in multiple directions.
EX: joint capsule
Describe dense regular connective tissue
Regular = more orderly/near parallel orientation of collagen fibers.
EX: Ligaments and tendons
What are the primary functions of dense connective tissue?
Resist tension!
Ligaments and joint capsules protect and bind the joint.
Tendons transfer forces b/w muscle and bone.
*Limited blood supply
What is the primary function of articular cartilage?
Distributes and absorbs joint forces and reduces joint friction.
*Receives nutrition with compression!
How is articular cartilage classified?
Avascular and aneural
What are some examples of fibrocatilage?
Menisci, labrum, and disc
What is fibrocartilage made of?
A mixture of dense and articular cartilage
What is fibrocartilage main function?
Supports and mechanically stabilizes joints, dissipates loads across multiple planes, and guides complex arthrokinematics.
*Aneural and limited blood supply
What does bone consist of?
Type 1 collagen, osteoblast, and hard ground substance
What is the primary function of bone?
Rigid support to the body and systems of levers for muscles.
Can accept tremendous compressive loads.
*Richly vascularized and innervated.
What is compact bone and cancellous bone?
Compact = outer cortex of long bones
Cancellous bone = end of long bones with thinner layer of compact bone surrounded by a network of cancellous bone.
What does Wolff’s Law state?
“Bone is laid down in areas of high stress and reabsorbed in areas of low stress.”
What are 3 different effects of immobalization?
- Immobilized joint will demonstrate changes in structure and function of connective tissues if immobilized for prolonged time.
- Rate of decline is dependent on metabolic activity of the tissue.
- Rapid loss of strength occurs with prolonged reduced loading and recovery is slower.
