A&P Chapter 8 Flashcards
Joints are classified by either ______ or ______
Function or structure
What joints are classified based on function?
Synarthroses, Amphiartoses, and Diarthroses
What joints are classified based on structure?
Fibrous, Cartilaginous, and Synovial joints
Motion ranges from ___ movement to _____ movement
No movement to extensive movement
The structure of each joint determines what?
It’s mobility and stability
There is an inverse relationship (trade off) between what?
Mobility and stability
What is an example of the inverse relationship between mobility and stability?
Skull sutures are immobile but very stable
What are fibrous joints?
Bones joined by dense fibrous connective tissue. They have no joint cavity, and most are immovable
Fibrous joints are mostly immovable, but what does it depend on?
The length of connective tissue fibers
What are the three types of fibrous joints?
Sutures, Syndesmoses, Gomphoses
What are sutures?
Rigid, interlocking joints of the skull, which allows for growth during youth
How do sutures allow for growth during youth?
Contains short connective tissue fibers that allow for expansion
What happens to sutures in middle age?
They ossify and fuse. These immovable joints join the skull into one unit that protects the brain
What are syndesmoses?
Bones connected by ligaments, bands of fibrous tissue
Why does movement vary in syndesmoses?
Fiber length varies, so movement varies
The inferior tibiofibular joint is an example of what joint type?
Short fibers in syndesmosis (offers little to no movement)
The interosseous membrane connecting the radius and ulna is an example of what joint type?
Longer fibers in syndesmoses offers a larger amount of movement)
What are gomphoses?
Peg-in-socket joints
What is the only example of gomphoses?
Teeth in the alveolar sockets
What is the fibrous connection of a tooth in the alveolar socket, and what does it do?
The periodontal ligament holds the tooth in socket
What are cartilaginous joints?
Bones united by cartilage, that has no joint cavity, and is not highly movable
What are the two types of cartilaginous joints?
Synchondroses and symphyses
What are synchondroses?
A bar or plate of hyaline cartilage unites bones.
Almost all synchondroses are ______?
Synarthotic (immovable)
What is an example of synchondroses?
Temporary epiphyseal plate joints, which become synostoses after plate closure
What is an example of synchondroses?
The cartilage of the 1st rib that connects to the manubrium of the sternum
What are symphyses?
Fibrocartilage unites bone in symphysis
Hyaline cartilage is also present in the symphysis joint as what?
Articular cartilage on bony surfaces
Symphyses are strong and _____ joints
Amphiarthrotic (slightly movable)
What are 2 examples of symphyses?
Intervertebral joints and the pubic symphysis
What are synovial joints?
Bones separated by fluid-filled joint cavity
All synovial joints are ______
Diarthrotic (freely moveable)
Synovial joints include almost all ____ ______
Limb joints
What are the characteristics of synovial joints?
Classified into 6 different types, has multiple features for support and stability, has bursae and tendon sheaths associated with them, stability is influenced by several factors, and allows several types of movements
What are the 6 synovial joint shapes?
Plane, hinge, pivot, condylar, saddle, and ball-and-socket
Synovial joints have how many general features?
6
What is articular cartilage?
Consists of hyaline cartilage covering ends of bones, this prevents crushing of bone ends
What is the joint/synovial cavity?
Small, fluid-filled potential space that is unique to synovial joints
What is the articular/joint capsule
Has two layers:
External fibrous layer made of dense irregular connective tissue
Inner synovial membrane made of loose connective tissue that makes synovial fluid
What is synovial fluid?
A slippery filtrate of plasma and hyaluronic acid. It lubricates and nourishes articular cartilage. It also contains phagocytic cells to remove microbes and debris
What are the 6 features of synovial joints?
- They have different types of reinforcing ligaments
- They have nerves and blood vessels
- They have synovial fluid
- They have articular cartilage
- They have a joint/synovial cavity
- They have a articular/joint cavity
Some synovial joints have what two features?
Fatty pads and articular discs/menisci
What are fatty pads for?
For cushioning between fibrous layer of capsule and synovial membrane or bone
What are articular discs/menisci?
Fibrocartilage separates articular surfaces to improve “fit” of bone ends, stabilizes joint, and reduces wear and tear
What are bursae and tendon sheaths?
Bags of synovial fluid that act as a lubricating “ball bearing”
Are bursae and tendon sheaths part of synovial joints?
Not strictly, but they are closely associated with synovial joints
What do bursae do?
Reduces friction where ligaments, muscles, skin, tendons, or bones rub together
What are tendon sheaths?
Elongated bursae wrapped completely around tendons subjected to friction
All muscles attach to bone or connective tissue at no fewer than two points, what are they?
Origin and insertion
What is an origin of a muscle?
Attatchment to immovable bone
What is an insertion of a muscle?
Attachment to moveable bone
Muscle contraction causes _____ to move toward _____
Insertion to move toward origin
Movements occur along which three planes?
Transverse, frontal, or sagittal
What are the ranges of motion allowed by synovial joints, and what are they?
Nonaxial = slipping movements only
Uniaxial = movement in one plane
Biaxial = movement in two planes
Multiaxial = movement in or around all three planes
What are the three general types of movements?
Gliding, angular movements, rotation
What are gliding movements?
One flat bone surface glides or slips over another similar surface
What are examples of gliding movements?
Intercarpal joints, intertarsal joints, and between articular processes of vertebrae
What are angular movements?
A movement along the sagittal plane that increases or decreases the angle between two bones
What does angular movements include?
Flexion, extension, hyperextension, abduction, adduction, circumduction
What is flexion?
Decreases the angle of the joint
What is extension?
Increases the angle of the joint
What is hyperextension?
Movement beyond the anatomical position
What is abduction?
Movement along frontal plane, away from the midline
What is adduction?
Movement along frontal plane, toward the midline
What is circumduction?
Involves flexion, abduction, extension, and adduction of limb. The limb describes cone in space
What is rotation?
Turning of bone around its own long axis, toward midline or away from it
What is medial rotation?
Rotation toward midline
What is lateral rotation?
Rotation away from midline
What are two examples of rotation?
Rotation between C1 and C2 vertebrae, and the rotation of humerus and femur
What are the special movements of synovial joints?
Supination, pronation, dorsiflexion, plantar flexion, inversion, eversion, protraction, retraction, elevation, depression, opposition
What is supination and pronation?
Rotation of the radius and ulna
What is supination?
Palms face anteriorly, radius and ulna are parallel (think anatomical position)
What is pronation?
Palms face posteriorly, radius rotates over ulna
What is dorsiflexion?
Bending foot towards shin
What is plantar flexion?
Pointing toes
What is inversion?
Sole of foot faces medially
What is eversion?
Sole of foot faces laterally
What is protraction?
Mandible juts out
What is retraction?
Mandible is pulled towards the neck
What is elevation?
Lifting body part superiorly
What is an example of elevation?
Shrugging shoulders
What is depression?
Lowering body part
What is an example of depression?
Opening jaw
What is opposition?
Movement of thumb
What is an example of opposition?
Touching thumb to fingertips on the same hand
Where is the temporomandibular joint?
The head of mandible articulates with temporal bone
What is the only mobile joint between the bones in the skull?
Temporomandibular joint (TMJ)
What type(s) of joint(s) is the TMJ joint?
Hinge and gliding
What is an example of the TMJ being a gliding joint?
Side-to-side grinding of teeth
What is a TMJ disorder?
Alteration in the ligaments securing the joint, and the articular disc is forced out of normal position
What are symptoms of a TMJ disorder?
Ear and face pain, tender muscles, popping sounds when opening mouth, and joint stiffness
What causes TMJ disorders?
Usually by grinding teeth, but can also be due to jaw trauma or poor occlusion of teeth
What are the treatments for TMJ disorders?
Bite plate (for teeth grinding) and relaxing jaw muscles
What is the most freely moving joint in the body?
Glenohumeral (shoulder) joint
Why is the glenohumeral joint the most freely moving?
Stability is sacrificed for freedom of movement
What type of joint is the glenohumeral joint?
Ball-and-Socket
How is the glenohumeral joint a ball-and-socket joint?
Head of humerus fits in the small, shallow glenoid cavity of scapula
The articular capsule inclosing the cavity of the glenohumeral joint is characterized as what?
Thin and loose, which contributes to movement
What decreases friction in the glenohumeral joint?
Bursa
Due to the mobility of the shoulder, what is a common injury?
Shoulder dislocations
Why are shoulder dislocations common, besides the movement?
Structures reinforcing the glenohumeral joint are weakest anteriorly and inferiorly, so the head of humerus can easily dislocate forward and downward. The glenoid cavity provides poor support when the humerus is rotated laterally and abducted
What are examples of shoulder dislocation mechanisms?
When a football player uses his arm to tackle an opponent, and blows to the top and back of shoulder
What is termed a “shoulder separation?”
Refers to acromioclavicular dislocation
What are signs of acromioclavicular dislocation / shoulder separation?
Pain when the arm is abducted more than 90 degrees, and the acromion appearing prominent
What is a subluxation?
Incomplete dislocation
What is Nursemaid’s elbow?
Subluxation of the head of the radius. The head of the radius is pulled out of the annular ligament
What age group does Nursemaid’s elbow occur in?
Almost exclusively in children, usually <5 years
Why does Nursemaid’s elbow occur in children?
A child’s annular ligament is thin, and the radial head is not fully formed
How can Nursemaid’s elbow be corrected?
A doctor may maneuver the radial head back into annular ligament
What type of joint is the coxal (hip) joint?
Ball-and-socket
Why is the coxal joint a ball-and-socket joint?
The large, spherical head of the femur articulates with the deep cup-shaped acetabulum of the os coxa
The coxal joint has a good range of motion, but it’s limited by what?
The deep socket
Common knee injuries involve the 3 C’s, what are they, and how are they caused?
- Collateral ligaments = struck from side
- Cruciate ligaments: ACL = hyperextended / Cruciate ligaments: PCL = hyperflexed
- Cartilages (menisci) = trauma and/or overuse
What is the “unhappy triad”?
Lateral blows to an extended knee can result in tears in the tibial collateral ligament, medial meniscus, and anterior cruciate ligament
What causes cartilage tears?
Compression and shear stress
Fragments from a cartilage tear can cause the joint to do what?
Lock or bind
Unfortunately in cartilage tears, the cartilage rarely does what?
Rarely repairs itself
How is a cartilage tear repaired?
Arthoscopic surgery
If the menisci is partially removed, what happens to the knee joint?
The joint is less stable, but mobile
If the menisci is completely removed, what happens to the knee joint?
Osteoarthritis can occur
Meniscal transplants are possible in ______ patients
Younger
What is a sprain?
Reinforcing ligaments are stretched or torn
What are common sites for a sprain?
Ankle, knee, and lumbar region of back
Why do partial tears of the reinforcing ligaments repair very slowly?
Poor vascularization
What are three options is the reinforcing ligaments are torn completely?
- Ends of ligaments can be sewn together
- Replacement with grafts
- Allow time and immobilization for healing
What is bursitis?
Inflammation of bursa, usually caused by a blow or friction
How is bursitis treated?
With rest and ice, if it’s severe, anti-inflammatory drugs
What is tendonitis?
Inflammation of tendon sheaths, usually caused by overuse
The symptoms and treatment of tendonitis is similar to what condition?
Bursitis
What is a dislocation?
Bones are forced out of alignment
What accompanies a dislocation?
Sprains, inflammation, difficulty moving joint
What causes dislocations?
Serious falls or contact sports
Dislocations must be ______ to treat
Reduced
What is osteoarthritis (OA)?
The most common type of arthritis. Irreversible, degenerative (“wear-and-tear”) arthritis
What can osteoarthritis reflect?
Excessive release of enzymes that break down articular cartilage. Cartilage is broken down faster than it is replaces. Bone spurs (osteophytes) may form from thickened ends of bones
By age 85, how much of Americans develop OA?
Half
Which sex is more affected by OA?
Women
OA is usually a part of what process?
The normal aging process
What is crepitus in OA?
Joints may be stiff, and may create a crunching noise upon rising, which is called crepitus
What are treatments for OA?
Moderate activity, mild pain relivers, capsaicin creams
What is rheumatoid arthritis (RA?)
Chronic, inflammatory, autoimmune disease of unknown cause
What is an autoimmune disease?
Immune system attacks own cells
When does RA occur?
Usually between the ages of 40 and 50, but can occur at any age
Which sex is more affected by RA, and by how much
Women are three times more affected than men
What are the signs and symptoms of RA?
Joint pain and swelling that is usually bilateral, anemia, osteoporosis, muscle weakness, and cardiovascular problems
What is gouty arthritis?
Deposition of uric acid crystals in joints and soft tissues, followed by inflammation
What sex is more affected by gouty arthritis?
Men
Where does gouty arthritis typically occur?
The joint at the base of the great toe
What happens in untreated gouty arthritis?
Bone ends fuse and immobilize the joint
What are treatments for gouty arthritis?
Drugs, plenty of water, avoidance of alcohol and foods high in purines, such as liver, kidneys, and sardines
