Exam 5 Part 1 Flashcards
Joints
also called articulations: sites where two or more bones meet
Functions of joints
give skeleton mobility and hold skeleton together
Structural
1.three types based on what material binds the joints and whether a cavity is present
- Fibrous
- Cartilaginous
- Synovial
Functional
2.three types based on movement joint allows
- Synarthroses: immovable joints
- Amphiarthroses: slightly movable joints
- Diarthroses: freely movable joints
Fibrous Joints
- Bones joined by dense fibrous connective tissue
- No joint cavity
- Most are immovable (synarthroses)
–Depends on length of connective tissue fibers
Three types of fibrous joints
–Sutures
–Syndesmoses
–Gomphoses
Suture
Synesmosis
Gomphosis
Cartilaginous Joints
- Bones united by cartilage
- Like fibrous joints, have no joint cavity
- Not highly movable
- Two types
–Synchondroses and Symphyses
Synchondroses
- A bar or plate of hyaline cartilage unites bones
- Almost all are synarthrotic (immovable)
- Examples
–Temporary epiphyseal plate joints
•Become synostoses after plate closure
–Cartilage of 1st rib with manubrium of sternum
Symphyses
•Fibrocartilage unites bone in symphysis joint
–Hyaline cartilage also present as articular cartilage on bony surfaces
- Symphyses are strong, amphiarthrotic (slightly movable) joints
- Examples: Intervertebral joints, pubic symphysis
Synovial Joints
- Bones separated by fluid-filled joint cavity
- All are diarthrotic (freely movable)
- Include almost all limb joints
- Characteristics of synovial joints
–Have six general features
–Have bursae and tendon sheaths associated with them
–Stability is influenced by three factors
–Allow several types of movements
–Classified into six different types
•Synovial joints have six general features:
- Articular cartilage:
1.consists of hyaline
cartilage covering ends of bones
•Prevents crushing of bone ends
- Joint (synovial) cavity:
small, fluid-filled
potential space that is unique to synovial joints
- Articular (joint) capsule:
3.two layers thick
- External fibrous layer: dense irregular connective tissue
- Inner synovial membrane: loose connective tissue that makes synovial fluid
- Synovial fluid
4.viscous, slippery filtrate of
plasma and hyaluronic acid
- Lubricates and nourishes articular cartilage
- Contains phagocytic cells to remove microbes and debris
- Different types of reinforcing ligaments
- Capsular: thickened part of fibrous layer
- Extracapsular: outside the capsule
- Intracapsular: deep to capsule; covered by synovial membrane
- Nerves and blood vessels
- Nerves detect pain; monitor joint position and stretch
- Capillary beds supply filtrate for synovial fluid
•Three factors determine stability of joints to prevent dislocations:
1.Shape of articular surface (minor role)
•Shallow surfaces less stable than ball-and-socket
2.Ligament number and location (limited role)
•The more ligaments, the stronger the joint
3.Muscle tone keeps tendons taut as they cross joints (most important)
•Extremely important in reinforcing shoulder and knee joints and arches of the foot
•All muscles attach to bone or connective tissue at no fewer than two points
–Origin: attachment to immovable bone
–Insertion: attachment to movable bone
•Range of motion allowed by synovial joints
–Nonaxial: slipping movements only
–Uniaxial: movement in one plane
–Biaxial: movement in two planes
–Multiaxial: movement in or around all three planes
•Three general types of movements
–Gliding
–Angular movements
–Rotation
•Gliding movements
–One flat bone surface glides or slips over another similar surface
–Examples
- Intercarpal joints
- Intertarsal joints
- Between articular processes of vertebrae
•Angular movements
–Increase or decrease angle between two bones
–Angular movements include:
- Flexion: decreases the angle of the joint
- Extension: increases the angle of the joint
–Hyperextension: movement beyond the anatomical position
•Flexion and extension occur along sagittal plane (in anatomical position)
3 Types of Angular movements
–Abduction: movement along frontal plane, away from the midline
–Adduction: movement along frontal plane, toward the midline
–Circumduction
- Involves flexion, abduction, extension, and adduction of limb
- Limb describes cone in space
Rotation:
•turning of bone around its own long axis, toward midline or away from it
–Medial: rotation toward midline
–Lateral: rotation away from midline
–Examples
- Rotation between C1 and C2 vertebrae
- Rotation of humerus and femur
Supination and pronation:
Rotation of radius and ulna
•Supination: palms face anteriorly
–Radius and ulna are parallel
•Pronation: palms face posteriorly
–Radius rotates over ulna
Dorsiflexion and plantar flexion
- Dorsiflexion: bending foot toward shin
- Plantar flexion: pointing toes
Inversion and eversion
- Inversion: sole of foot faces medially
- Eversion: sole of foot faces laterally
Protraction and retraction:
- Protraction: mandible juts out
- Retraction: mandible is pulled toward neck
–Elevation and depression
•Elevation: lifting body part superiorly
–Example: shrugging shoulders
•Depression: lowering body part
–Example: opening jaw
Opposition:
–movement of thumb
•Example: touching thumb to tips of other fingers on same hand or any grasping movement
•There are six different types of synovial joints
–Categories are based on shape of articular surface, as well as movement joint is capable of
- Plane
- Hinge
- Pivot
- Condylar
- Saddle
Ball-and-socket
Know joint type (plane joint), movement allowed (nonaxial gliding), and joint example.
Know joint type (hinge joint), movement allowed (uniaxial flexion/extension), and joint example.
Know joint type (pivot joint), movement allowed (uniaxial rotation), and joint example.
Know joint type (condylar joint), movement allowed (biaxial flexion/extension and adduction/abduction), and joint example.
Know joint type (saddle joint), movement allowed (biaxial flexion/extension and adduction/abduction), and joint example.
Know joint type (ball-and-socket joint), movement allowed (multiaxial flexion/extension, adduction/abduction, and rotation), and joint example.
•Five main synovial joints
–Knee
–Shoulder
–Elbow
–Hip
–Jaw
Knee Joint
- Femoropatellar joint
- Plane joint
- Allows gliding motion during knee flexion
- Lateral and 3. Medial tibiofemoral joint
- Joint between femoral condyles and lateral and medial menisci of tibia
- Hinge joint that allows flexion, extension, and some rotation when knee partly flexed
Knee Joint
- Joint capsule is thin and absent anteriorly
- Anteriorly, quadriceps tendon gives rise to three broad ligaments that run from patella to tibia
–Medial and lateral patellar retinacula that flank the patellar ligament
- Doctors tap patellar ligament to test knee-jerk reflex
- At least 12 bursae associated with knee joint
- Capsular, extracapsular, or intracapsular ligaments act to stabilize knee joint
- Capsular and extracapsular ligaments help prevent hyperextension of knee
–Fibular and tibial collateral ligaments: prevent rotation when knee is extended
–Oblique popliteal ligament
–Arcuate popliteal ligament
- Intracapsular ligaments reside within capsule, but outside synovial cavity
- Help to prevent anterior-posterior displacement
–Anterior cruciate ligament (ACL)
- Attaches to anterior tibia
- Prevents forward sliding of tibia and stops hyperextension of knee
–Posterior cruciate ligament
- Attaches to posterior tibia
- Prevents backward sliding of tibia and forward sliding of femur
Common knee injuries involved the 3 C’s:
- Collateral ligaments
- Cruciate ligaments
- Cartilages (menisci)
Shoulder (Glenohumeral) Joint
- Most freely moving joint in body
- Stability is sacrificed for freedom of movement
- Ball-and-socket joint
–Large, hemispherical head of humerus fits in small, shallow glenoid cavity of scapula
- Poor bony fit.
- Articular capsule enclosing cavity is also thin and loose
–Contributes to freedom of movement
•Reinforcing ligaments
–Primarily on anterior aspect
–Coracohumeral ligament
•Helps support weight of upper limb
–Three glenohumeral ligaments
- Strengthen anterior capsule, but are weak support
- Reinforcing muscle tendons contribute most to joint stability
–Tendon of long head of biceps brachii muscle is “superstabilizer”
Four rotator cuff tendons encircle the shoulder joint
Subscapularis
Supraspinatus
Infraspinatus
Teres minor
Shoulder Injuries
- Dislocations – structures reinforcing the joint are weakest anteriorly and inferiorly, allowing the head of the humerus to dislocate forward and downward
- Separations – this is a dislocation of the acromioclavicular joint
Hip (Coxal) Joint
- Movement has been sacrificed for stability
- Ball-and-socket joint
- Large, spherical head of the femur articulates with deep cup-shaped acetabulum of hip bone
- Good range of motion, but limited by the deep socket
Reinforcing ligaments include:
–Iliofemoral ligament
–Pubofemoral ligament
–Ischiofemoral ligament
–Ligament of head of femur (ligamentum teres)
Hip Joint Stability
- Greatest stability comes from deep ball-and-socket joint
- Muscle tendons that cross the hip joint also contribute to its stability
–However, stability comes chiefly from the cupped socket and the capsular ligaments
Temporomandibular Joint (TMJ)
- The jaw joint is a modified hinge joint
- The mandibular condyle articulates with the temporal bone
- Two types of movement
–Hinge: depression and elevation of mandible
–Gliding: side-to-side (lateral excursion) grinding of teeth
•Most easily dislocated joint in the body
Dislocation of TMJ
- most common because of shallow socket of joint
- Almost always dislocates anteriorly, causing mouth to remain open
–To realign, physician must push mandible back into place
Common Joint Injuries
- Cartilage tears
- Sprains
–Reinforcing ligaments are stretched or torn
–Common sites are ankle, knee, and lumbar region of back
–Partial tears repair very slowly because of poor vascularization
•Dislocations (luxations)
–Bones forced out of alignment
–Caused by serious falls or contact sports
•Subluxation: partial dislocation of a joint
•Bursitis
–Inflammation of bursa, usually caused by blow or friction
–Treated with rest and ice and, if severe, anti-inflammatory drugs
•Tendonitis
–Inflammation of tendon sheaths, typically caused by overuse
–Symptoms and treatment similar to those of bursitis
•Arthritis
–>100 different types of inflammatory or degenerative diseases that damage joints
–Most widespread crippling disease in the U.S.
–Symptoms: pain, stiffness, and swelling of joint
–Acute forms: caused by bacteria, treated with antibiotics
–Chronic forms: osteoarthritis, rheumatoid arthritis, and gouty arthritis
•Osteoarthritis (OA)
–Most common type of arthritis
–Irreversible, degenerative (“wear-and-tear”) arthritis
–May reflect excessive release of enzymes that break down articular cartilage
–By age 85, half of Americans develop OA, more women than men
–Treatment: moderate activity, mild pain relievers, capsaicin creams
•Glucosamine, chondroitin sulfate, and nutritional supplements not effective
•Rheumatoid arthritis (RA)
–Chronic, inflammatory, autoimmune disease of unknown cause
•Immune system attacks its own cells
–Usually arises between ages 40 and 50, but may occur at any age; affects three times as many women as men
–Signs and symptoms include joint pain and swelling (usually bilateral), anemia, osteoporosis, muscle weakness, and cardiovascular problems
–Treatment includes steroida and nonsteroidal anti-inflammatory drugs to decrease pain and inflammation
–Disruption of destruction of joints by immune system
- Immune suppressants slow autoimmune reaction
- Some agents target tumor necrosis factor to block action of inflammatory chemicals
–Can replace joint with prosthesis
•Gouty arthritis
–Deposition of uric acid crystals in joints and soft tissues, followed by inflammation
–More common in men
–Typically affects joint at base of great toe
–In untreated gouty arthritis, bone ends fuse and immobilize joint
–Treatment: drugs, plenty of water, avoidance of alcohol and foods high in purines, such as liver, kidneys, and sardines
