Chapter 8 Joints Flashcards
Joints are classified based on amount of movement
- synarthroses = immovable joints
- amphiarthroses = slightly moveable
- diarthroses = freely moveable
Join movement: Synarthroses
synarthroses = immovable joints
Join movement: Amphiarthroses
amphiarthroses = slightly moveable
Join movement: Diarthroses
diarthroses = freely moveable
Fibrous joints characteristics
- Fibrous joints = bones joined by collagen fibers of connective tissue and no joint cavity is present
- most immoveable- sutures – interlocking junction with minimal amount of very short connective tissue fibers
- cranial bones of skull
- syndesmosis = bones connected by ligaments, cords or bands of fibrous tissue
- radius and ulna
Fibrous joints: Suture
Sutures – interlocking junction with minimal amount of very short connective tissue fibers
-cranial bones of skull
Fibrous joints: Syndesmosis
Syndesmosis = bones connected by ligaments, cords or bands of fibrous tissue
-radius and ulna
Fibrous joints: Gomphosis
Gomphosis = tooth in bone alveolar socket – connected by periodontal ligament
Cartilaginous joints
- synchondrosis = immovable joints joined by hyaline cartilage
- epiphyseal plate
- symphysis = limited movement designed for strength and flexibility and joined by fibrocartilage
- intervertebral discs, pubic symphysis
Cartilaginous joints: Synchondrosis
Synchondrosis = immovable joints joined by hyaline cartilage
-epiphyseal plate
Cartilaginous joints: Symphysis
Symphysis = limited movement designed for strength and flexibility and joined by fibrocartilage
-intervertebral discs, pubic symphysis
Synovial joints: Classification and Features
- articular cartilage
- joint cavity
- articular capsule
- fibrous layer
- synovial membrane - synovial fluid
- reinforcing ligaments
- capsular ligaments
- intracapsular ligaments
- nerves and blood vessels – in the capsule
Synovial joints: Articular cartilage
Articular cartilage = hyaline cartilage that covers opposing bone surfaces
Synovial joints: Joint cavity
Space that contains small amount of synovial fluid
Synovial joints: Articular capsule
Articular capsule – two-layer
* fibrous layer = outer layer of dense regular connective tissue * synovial membrane = inner layer of loose connective tissue and makes synovial fluid
Synovial joints: Synovial fluid
Synovial fluid – contains hyaluronic acid = slippery weight-bearing film
Synovial joints: Reinforcing ligaments
- reinforcing ligaments
- capsular ligaments = thickenings of fibrous layer of capsule
- intracapsular ligaments – covered with synovial membrane so do not lie within capsule
Synovial joints: Nerves and blood vessels
-Nerves and blood vessels – in the capsule: provide sensory information and nourish synovial membrane
Synovial joints: Other features
–Cushion structures and improve fit of joint
* fat pads * articular discs or menisci
Synovial joints: Stability depends on?
Stability depends on
* shapes of articular surfaces * number and positioning of ligaments * muscle tone
Synovial joints: Types of movement
- gliding
* angular- rotation
- special movements (Fig 8.6)
Synovial joints - Types of movement: Gliding
*gliding – bony surfaces slip over one another
Synovial joints - Types of movement: Angular
Angular – increases or decreases the angle between two bones
* flexion – along sagittal plane - decreases angle of joint – brings articular bones closer together
* extension – increases angle of joint or straightens
- hyperextension = increase in joint angle beyond anatomical position
* abduction – movement away from midline along frontal plane
* adduction – movement toward midline
* circumduction – movement that describes a cone in space - distal end of a limb moves in a circle while proximal portion remains stationary
Synovial joints - Types of movement: Rotation
Rotation = turning a bone around its own long axis
-first two cervical vertebrae, shoulder, hip
Joints diseases: Bursa and Tendon sheaths
• Bursa and Tendon sheaths – often associated with synovial joints
*Bursa = flattened fibrous sacs lined with synovial membrane and small amount of synovial fluid
*Tendon sheath = elongated bursa that wraps completely around a tendon subject to friction
Knee Joint
- largest and most complex joint of body
- one joint cavity but have femoropatellar and tibiofemoral joints
- tibial surface = articular cartilage plus C-shaped medial and lateral menisci (fibrocartilage)
- articular capsule present on sides and posterior aspects of knee
- anteriorly – three broad ligaments run from patella to tibia
- many bursae – subcutaneous prepatellar bursa often damaged when knee bumped anteriorly
- capsular and extracapsular ligaments act to prevent hyperextension of knee and are stretched tight when knee is extended
- cruciate ligaments = intracapsular ligaments cross each other forming an X between the femoral condyles
- most susceptible to sports injuries – can absorb vertical force nearly 7 x body weight but very susceptible to HORIZONTAL blows
- most ACL injuries occur when a runner changes direction quickly, twisting a hyperextended knee
Knee Joint: Menisci
Menisci = shock absorbers that deepen articular surface and prevent side-to-side rocking of bones
* tears when subjected to compression and shear (twisting) stress at the same time * avascular so repairs poorly * cartilage fragments (loose bodies) can interfere with joint function * arthroscopic surgery – small instrument with tiny lens and fiber-optic light source that allows surgeon to remove cartilage fragments or repair a ligament through one or more small slits
Knee Joint - Anteriorly three broad ligaments run from patella to tibia:
- Patellar ligament, and
* Medial and lateral retinacula (merge with articular capsule)
Knee Joint: Capsular and Extracapsular ligaments
*capsular and extracapsular ligaments act to prevent hyperextension of knee and are stretched tight when knee is extended
Knee Joint: Cruciate ligaments
Intracapsular ligaments cross each other forming an X between the femoral condyles
* anterior cruciate ligament (ACL)– prevents forward sliding of tibia on femur * posterior cruciate ligament – prevents backward displacement of tibia
Shoulder (Glenohumoral) joint
- glenoid cavity shallow – deepened by glenoid labrum (rim of fibrocartilage)
- few ligaments reinforce joint and mainly located on anterior surface
- rotator cuff = four tendons that encircle shoulder joint and blend in with articular capsule
- dislocations (luxations) – fairly common due to shallow joint cavity and weak anterior and inferior reinforcements
Shoulder (Glenohumoral) joint: Rotator cuff
- Four tendons that encircle shoulder joint and blend in with articular capsule
- can be severely stretched or torn when arm is vigorously circumducted – pitchers, tennis players
Shoulder (Glenohumoral) joint: Dislocations (luxations)
Fairly common due to shallow joint cavity and weak anterior and inferior reinforcements
* forward and downward into axillary area * usually accompanied by sprains, inflammation and difficulty moving joint
Temporomandibular joint (TMJ)
- Modified hinge joint just anterior to ear
- hinge-like depression and elevation of mandible
- gliding from side to side – grinding = lateral excursion
-Dislocations common – shallow joint that dislocates anteriorly
Temporomandibular joint (TMJ): Dislocation
Dislocations common – shallow joint that dislocates anteriorly
TMJ disorders
- Often found in people who grind their teeth, following jaw trauma, poor occlusion of teeth
- symptoms: pain in the ear and face, tenderness of jaw muscles, popping sounds when mouth opens and joint stiffness
- treatment – relaxation of jaw muscles using massage, muscle-relaxants, heat or cold, stress reduction techniques, and bite plate for use during sleep for teeth grinders
Joints Diseases: Sprains
Sprains – occur when ligaments reinforcing a joint are stretched or torn
* most common sites = ankle, knee, and lumbar area of spine * pain, immobilizing and heal slowly
Joints Diseases: Bursitis
Inflammation of a bursa – usually caused by a blow or friction
*severe cases treated by injection of anti-inflammatory drugs into bursa
Joints Diseases: Tendonitis
Inflammation of tendon sheath – typically caused by overuse
* symptoms: pain, swelling and may getting tingling (if compresses sensory nerves) * treatment: rest, ice, anti-inflammatories
Joints Diseases: Arthritis
100 different types of inflammatory or degenerative diseases that damage joints
* symptoms: pain, stiffness, and swelling of joint * acute forms usually result from bacterial infection and are treated with antibiotics * chronic forms include: osteoarthritis, rheumatoid arthritis, and gouty arthritis * osteoarthritis (OA) = most common chronic arthritis = chronic degenerative * rheumatoid arthritis * gouty arthritis
Joints Diseases - Arthritis: Osteoarthritis
- Most common chronic arthritis = CHRONIC DEGENERATIVE CONDITION
- wear-and-tear disease as most common in elderly
- produces softened, roughened, pitted and eroded articular cartilages
- exposed bone thickens and forms osteophytes – bony spurs that enlarge bone ends and may restrict movement
- most affected joints = cervical and lumbar spine, fingers, knuckles (juntas), knees and hips
- most controllable with mild pain relief (aspirin, acetaminophen) and moderate activity
- can be crippling when knees or hips are involved
- total knee and hip replacements with metal and plastic prostheses last about 10-15 years
- done to reduce pain and restore about 80% of original joint function
Joints Diseases - Arthritis: Rheumatoid arthritis
- Chronic inflammatory AUTOIMMUNE DISORDER
- usually occurring between 30-50 years of age
- many joints – especially small joints of fingers, wrists, ankles and feet bilaterally affected
- in addition to pain and swelling – can include anemia, osteoporosis, muscle weakness and cardiovascular disease
- *pannus = thickened synovial membrane that clings to and degrades articular cartilage
- scar tissue forms and connects bone ends
- ANKYLOSIS = fusion of bone ends that deform and immobilize joint
- steroidal and non-steriodal anti-inflammatory drugs, immune suppressants
Joints Diseases - Arthritis: Rheumatoid arthritis
Pannus = thickened synovial membrane that clings to and degrades articular cartilage
- scar tissue forms and connects bone ends - ANKYLOSIS = fusion of bone ends that deform and immobilize joint
Joints Diseases - Arthritis:
Gouty arthritis
Resulting from excessive uric acid production (waste product of nucleic acid metabolism) and deposition of uric acid crystals (needle-shaped crystals) into soft tissues of joints
* inflammatory response accompanied with pain – usually starting in one joint – base of great toe * more common in men * several drugs that terminate or prevent gout attacks available and patients advised to drink plenty of water, avoid alcohol consumption (promotes uric acid overproduction) and foods high in purine-containing nucleic acids (liver, kidneys, sardines)
