Joints TEST Flashcards
What is a joint?
A joint is a functional junction between bones
What is arthrology?
Arthrology is the study of joints
What are the three major types of joints (classified by the type of tissue binding the joint)?
- Fibrous (fibrous connective tissues)
- Cartilaginous (fibrocartilage connective tissue)
- Synovial (synovial membrane, and epithelial tissue)
Describe the characteristics of fibrous joints and give an example of this type of joint
Fibrous joints are immovable. They have a tiny bit of fibrous connective tissue between the bones they join. Examples of fibrous joints are the sutures of cranial bones.
Describe the characteristics of cartilaginous joints and give an example of this type of joint
Cartilaginous joints have tough fibrocartilage connective tissue between the bones they join. They are able to move slightly. Examples of cartilaginous joints include the (1) intervertebral disc and (2) pubic symphysis
Describe the characteristics of synovial joints and give an example of this type of joint.
Synovial joints are the most common type of joint in the body and have synovial membranes (an epithelial tissue) lining the joint and secreting synovial fluid. Synovial joints allow free movement. Examples of synovial are the (1) humerus articulating with the glenoid cavity of the scapula, an d(2) the femur articulating with the acetabulum of the hipbone or coxa.
What is the basic structure of a typical synovial joint?
- Have articular cartilage (hyaline cartilage) at the ends of the two articulating bones
- Have synovial membranes that surround the joint and produce synovial fluid which fills the synovial cavity
- Have a joint capsule made of heavy connective tissue which surrounds the entire joint to protect and stabilize it
- Have bursae (outpockets of membranes) to help cushion the joint
What are the functions of the synovial joint structures?
- Articular cartilage is very smooth and reduces friction between the two articulating bones
- Synovial membranes secrete synovial fluid to fill the synovial cavity and further reduce friction
- Synovial fluid reduces friction, moistens the cartilage, and nourishes the cartilage (necessary because cartilage has no blood vessels). Normal synovial fluid has the consistency of raw egg white
- Joint capsule provides stability and protection for the joint
- Bursae help to cushion the joint
What are two characteristics are used to classify synovial joints?
Shape and movement
What are the four major types of synovial joints?
- Hinge joint
- Ball and socket joint
- Pivot joint
- Saddle joint
Describe the characteristics and functions of hinge joints and give an example of this type of joint
- Hinge Joint Characteristics: the convex surface of one bone fits into the concave surface of another bone; can move in only one phase
- Functions: increases or decreases the angle formed by the joint
- Examples: elbow and knee
Describe the characteristics and functions of ball and socket joints and give an example of this type of joint.
- Ball and Socket Joint
- Characteristics: head of one bone fits into depression of another bone; provides the most movement of any joint
- Functions: provides movement in all planes and provides rotational movement around a central axis
- Examples: hip (femur in acetabulum of coxa); shoulder (humerus in glenoid cavity of scapula)
Describe the characteristics and functions of pivot joints and give an examples of this type of joint.
Pivot Joints
Characteristics: one bone pivots on or around another bones
Functions: provides rotation around a central axis
Examples: head of radius rotating around ulna; atlas
rotating (pivoting) around the dens of the axis)
Describe the characteristics and functions of saddle joints and give an example of this type of joint.
Saddle Joint
Characteristics: both bones have concave and convex surfaces (saddle-shaped); concave surface of one bone articulates with concave surface of another bone
Functions: provides movement in two planes
Examples: first metacarpal articulating with the trapezium (a carpal bone)
What are the five types of joint movement? (If given an examples, be able to tell which of the types of joint movement is involved.)
Flexion
Extension
Adduction
Abduction
Circumduction
Give the function and an example of flexion
Flexion functions to decrease an angle. An example is the biceps contracting and decreasing the angle of the elbow (hinge joint)
Give the function and an example of extension
Extension functions to increase an angle. An example is the triceps contracting and increasing the angle of the elbow (hinge joint)
Give the function and an example of adduction
Adduction functions to bring a limb toward the midline of the body. An example of the medial adductor muscle in the thigh contracting which functions to bring the thigh toward the midline of the body.
Give the function and an example of abduction
Abduction functions to move a limb away from the midline of the body. An example is the deltoid muscle contracting to take the arm away from the midline
Give the function and an example of circumduction
Circumduction functions to make a circular motion. An example is the arm moving in a circle
How does dorsiflexion differ from plantar flexion?
Dorsiflexion involves tilting the foot upward at the ankle while plantar flexion involves titling the foot down and back at the ankle
How does circumduction differ from rotation?
Circumduction involves making a circular movement while rotation involves rotation around a central axis
What are four joint disorders discussed in class?
Osteoarthritis and rheumatoid arthritis
Bursitis
Gout
Sprains
To what does the term arthritis refer?
Inflammation of the joints
What causes osteoarthritis and what are its symptoms?
Osteoarthritis is the most common form of arthritis. It is initially triggered by a trauma (injury). This results in destruction of articular cartilage which causes bone to move against bone. Also, the synovial fluid has decreased viscosity. All this makes it more difficult for the bones associated with the joint to move properly. Symptoms are extreme pain and immobility
What causes rheumatoid arthritis and what are its symptoms?
Rheumatoid arthritis starts with a disorder of the immune system which can be brought about by emotional stress. It results in inflammation of the synovial membrane. The membrane then secretes more synovial fluid, causing joints to swell. Symptoms are swelling, extreme pain, and immobility
What causes bursitis and what are its symptoms?
Bursitis is inflammation of the bursae, or membrane sacs which cushion joints. It commonly occurs in hips, shoulders, and knees when they are overused. Symptoms are extreme pain. (an example is lots of walking can inflame the bursa between the calcaneus bone and the achilles tendon. Another example is tennis elbow cause by inflammation of bursa between the olecranon process of the radius and the skin.)
What causes gout and what are its symptoms?
Gout is an accumulation of uric acid crystals in the joints, commonly the big toe. It occurs due to the inability of the body to break down purines, so diet plays a role in gout. Gout is also more prevalent in males. Symptoms are extreme pain and immobility. Fresh cherries and fresh pineapple are often eaten to relieve the symptoms of gout
What causes sprains and what are their symptoms?
Sprains are caused when connective tissues around the joints (cartilage, ligaments, tendons) become overstretched or torn. It is often caused by twisting. Symptoms are swelling, extreme pain, and immobility
Are disorders of the joints a relatively new occurrence?
No. Fossilized remains of a Tyrannosaurus rex showed signs of gout and a 500,000 year old skeleton with osteoarthritis has been found.
