Chapter 9 - Joints Flashcards
Define a joint (articulation)
Any point where two bones meet, whether or not the bones are movable at that interface
Define arthrology
The science of joint structure, function, and dysfunction
Define kinesiology
The study of musculoskeletal movement
Kinesiology is a branch of biomechanics, which deals with what?
A broad variety of movements and mechanical processes
Define synarthrosis
- Type of joint which permits very little or no movement
- Most synarthroses joints are fibrous
Define amphiarthrosis and give examples
- A slightly movable joint
- Examples are symphyses and syndesmoses
Describe diarthrosis and give an example
- Freely movable joints (has a joint capsule)
- Synovial joints are diarthrotic
How are joints named?
Their names are typically derived from the names of the bones involved (example: radioulnar joint)
How are joints classified?
They’re classified according to the manner in which the bones are bound to each other
What are the four major joint categories based on structure?
- Bony joints
- Fibrous joints
- Cartilaginous joints
- Synovial joints
Describe synostosis (bony joint) and give examples
- When a joint becomes immobile because the gap between two bones ossifies (becomes one bone)
- Can occur in either fibrous or cartilaginous joints
- Examples: Left and right mandibular bones in infants, cranial sutures in elderly, attachment of first rib and sternum with old age
Define a fibrous joint
Bones bound by collagen fibers that emerge from one bone and penetrate into the other
What are the three types of fibrous joint?
1) Sutures
2) Gomphoses
3) Syndesmoses
Describe sutures
- A type of fibrous joint that’s immobile or slightly mobile
- Uses short collagen fibers
Describe gomphoses
- The attachment of a tooth to its socket
- Held in place by fibrous periodontal ligament (collagen)
- Allows the tooth to move a little under the stress of chewing
- A type of fibrous joint
Describe syndesmoses
- Two bones are bound by long collagen fibers
- Can be very mobile or less mobile
- A type of fibrous joint
Give an example of a very mobile syndesmosis and an example of a less mobile syndesmosis
- Very mobile syndesmosis: interosseus membrane joining radius to ulna (allows supination & pronation)
- Less mobile syndesmosis: joint between tibia to fibula
Define cartilaginous joints
Two bones that are linked by cartilage
What are the two types of cartilaginous joints?
- Synchondroses
- Symphyses
Define synchondroses and give examples
- Bones are joined by hyaline cartilage
- Examples: Epiphyseal plates in children (temporary joints), first rib attachment to sternum
Costal cartilages are joined to the sternum using what two mechanisms?
The first rib is attached with synchondroses, and other costal cartilages are joined to the sternum by synovial joints
Describe symphyses (singular symphesis) and give examples
- Defined as two bones joined by fibrocartilage
- Examples:
1) Pubic symphysis
2) Bodies of vertebrae joined by intervertebral discs, which allows for only slight movements between adjacent vertebrae. The collective effect of all 23 discs gives the spine considerable flexibility
Describe synovial joints (diarthrosis)
- Defined as two bones are separated by a joint cavity
- The most familiar and most structurally complex type of joint
- Most are freely mobile
- Most likely to develop painful dysfunction
- Most important joints for physical and occupational therapists, athletic coaches, nurses, and fitness trainers
- Their mobility makes them important to quality of life
Describe the general anatomy of synovial joints
1) Articular cartilage (usually 2 or 3 mm thick) made of hyeline cartilage absorbs shock
2) Joint (articular) cavity
3) Synovial fluid—slippery lubricant in joint cavity
Rich in albumin and hyaluronic acid
4) Joint (articular) capsule
-The outer fibrous capsule is continuous with periosteum
-The inner, cellular, synovial membrane has
fibroblast-like cells that secrete synovial fluid and macrophages that remove debris from the joint cavity
Describe synovial fluid
The slippery lubricant in synovial joint cavities; rich in albumin and hyaluronic acid
Describe the two parts of a joint (articular) capsule of synovial joints
1) Outer fibrous capsule: continuous with periosteum
2) Inner, cellular, synovial membrane:
fibroblast-like cells that secrete synovial fluid and macrophages that remove debris from the joint cavity
Describe the accessory structures of synovial joints
1) Articular disc between articulating bones
- Ex: temporomandibular joint
2) Meniscus: moon-shaped cartilage in each knee
- Absorbs shock and pressure
- Guide bones across each other and improve their fit together
- Stabilize the joints, reducing the chance of dislocation
Describe the meniscus of the knee
- A moon-shaped cartilage in each knee
- Absorbs shock and pressure for the synovial joint
- Guide bones across each other and improve their fit together
- Stabilize the joints, reducing the chance of dislocation
Ligaments attach ____ to ____, whereas tendons attach _____ to _____
Ligaments attach bone to bone, whereas tendons attach muscle to bone
Describe bursa and describe its purpose
- A fibrous sac filled with synovial fluid, located between muscles, where tendons pass over bone, or between bone and skin
- Cushions muscles, helps tendons slide more easily over joints, modifies direction of tendon pull
Describe a tendon sheath and where it’s found
- Elongated cylindrical bursa wrapped around a tendon
- In hand and foot
Describe how exercise can benefit your cartilage
- Exercise warms synovial fluid, which makes it become less viscous, and more easily absorbed by cartilage
- Cartilage then swells; becomes a more effective cushion
- Repetitive compression and decompression of cartilage (during exercise) moves synovial fluid in and out of the cartilage like a sponge.
- Oxygen and nutrients are brought to chondrocytes; wastes are taken away
- Without exercise, cartilage deteriorates more rapidly from inadequate nutrition and waste removal
True or false: A warm-up period before vigorous exercise helps protect cartilage from undue wear and tear
True
Define and describe range of motion (ROM)
- The degrees through which a joint can move
- Describes an aspect of joint performance and is a physical assessment of a patient’s joint flexibility
What three elements determine range of motion?
1) Shape of the articular surfaces
2) Strength and tautness of ligaments and joint capsules
3) Action of the muscles and tendons
Describe the three elements of range of motion in detail
1) Shape of the articular surfaces
- Elbow—olecranon of ulna fits into olecranon fossa of humerus
2) Strength and tautness of ligaments and joint capsules
- Stretching of ligaments increases range of motion
- Double-jointed means people have long or slack ligaments
3) Action of the muscles and tendons
- Nervous system monitors joint position and muscle tone
- Muscle tone—state of tension maintained in resting muscles
Define muscle tension
The state of tension maintained in resting muscles
Describe axes of rotation
A moving bone has a relatively stationary axis of rotation that passes through the bone in a direction perpendicular to the plane of movement
Describe a multiaxial joint and give an example
- A joint that has multiple axes of rotation
- Ex: shoulder joint has three degrees of freedom or axes of rotation
Define monoaxial and biaxial joints
Monoaxial joint: rotates on one axis
Biaxial joint: rotates on two axes
What are the six classes of synovial joints? Give examples for each.
1) Ball-and-socket joint (humeroscapular)
2) Hinge joint (humeroulnar)
3) Pivot joint (radioulnar)
4) Plane joint (intercarpal)
5) Saddle joint (trapeziometacarpal)
6) Condylar joint (metacarpophalangeal)
Describe ball-and-socket synovial joints and give an example
- The only multiaxial joints in the body
- Ex: shoulder joint
Describe condylar (ellipsoid) synovial joints and give examples
- Oval convex surface of one bone fits into a complementary-shaped depression on the other
- Biaxial joints: movement in two planes
- Examples: radiocarpal joint, metacarpophalangeal joints, atlanto-occipital joint
Describe plane (gliding) synovial joints and give examples
- Flat articular surfaces, bones slide over each other
- Usually biaxial joints
- Examples: intercarpal; intertarsal; between articular processes of vertebrae
Describe saddle synovial joints and give an example
- Both bones have an articular surface that is shaped like a saddle, one concave, the other convex
- Biaxial joints
- Example: trapeziometacarpal (opposable thumb)
Describe hinge synovial joints and give examples
- One bone with convex surface fits into a concave depression of another bone
- Monoaxial joints—move freely in one plane
- Examples: elbow, knee, joints within fingers, toes
Describe pivot synovial joints and give examples
- A bone spins on its longitudinal axis
- Monoaxial joints
- Examples: atlantoaxial joint (C1 and C2), radioulnar joint at the elbow
Define zero position and describe when it’s used
- The position of a joint when a person is in the standard anatomical position
- Joint movements described as deviating from the zero position or returning to it
What are the two special movements of the thumb?
Opposition and reposition
Define opposition and reposition
Opposition: moving thumb to touch tip of a finger
Reposition: returning thumb to the zero position
Describe the temporomandibular jaw joint (TMJ)
- The articulation of the condyle of the mandible with the mandibular fossa of the temporal bone
- Combines elements of condylar, hinge, and plane joints
- Synovial cavity of the TMJ is divided into superior and inferior chambers by an articular disc
- Deep yawn or strenuous depression can dislocate the TMJ
- Condyles pop out of fossa and slip forward
- TMJ Syndrome common problem
Describe the problems with the TMJ
- A deep yawn or strenuous depression can dislocate the TMJ
- Condyles pop out of fossa and slip forward
- Relocated by pressing down on molar teeth while pushing the jaw backward
Describe TMJ syndrome (how many people does it affect, what are the symptoms, what are the causes, and what are the treatments?)
Temporomandibular joint (TMJ) syndrome:
-May affect as many as 75 million Americans
Signs and symptoms:
-Clicking sounds in the jaw, imitation of jaw movement
-Pain radiating from jaw down the neck, shoulders, and back
-Can cause moderate intermittent facial pain, or severe headaches, vertigo (dizziness), tinnitus (ringing in the ears)
Cause of syndrome:
-Caused by combination of psychological tension and malocclusion (misalignment of teeth)
Treatment:
-Psychological management, physical therapy, analgesic and anti-inflammatory drugs, corrective dental appliances to align teeth properly
What is the name for the shoulder joint?
Glenohumeral (humeroscapular) joint
Describe the glenohumeral (humeroscapular) joint
- Most freely mobile joint in body
- Sacrifices stability for freedom of movement
- Glenoid labrum: fibrocartilage ring that deepens glenoid cavity
- The joint is stabilized by the tendons fused to joint capsule:
- Biceps brachii tendon and Rotator cuff tendons
- Stabilized in all directions except inferiorly
Describe dislocations of the glenohumeral joint
- Very painful and sometimes causes permanent damage
- Dislocations most often occur when the arm is abducted and then receives a blow from above
- Children especially prone to dislocation
Describe the elbow joint
- A combination of a hinge and a pivot joint
- Both articulations are enclosed in one joint capsule
Describe the pivot joint portion of the elbow joint
- Pivot Joint consists of the proximal radioulnar joint
- Head of radius fits into radial notch of ulna
- Held in place by anular ligament encircling radial head
- Allows for pronation and supination
Describe the hinge joint portion of the elbow joint
Hinge joint includes two articulations:
1) Humeroulnar joint: trochlea of the humerus joins trochlear notch of the ulna
2) Humeroradial joint: capitulum of humerus meets head of radius
Describe the coxal (hip) joint
- The head of the femur inserts into the acetabulum of the hip bone
- More stable than shoulder joint
- Acetabular labrum: horseshoe-shaped ring of fibrocartilage that deepens socket
- Dislocations are rare
Describe dislocations of the hip joint
- Dislocation of hip is rare
- Some infants suffer congenital dislocation
- Acetabulum is not deep enough to hold head of femur in place
- Harness, worn for 2 to 4 months can assist with proper positioning
Describe the tibiofemoral (knee) joint
- The largest and most complex diarthrosis of the body
- Primarily a hinge joint
- Capable of slight rotation and lateral gliding when knee is flexed
- Patellofemoral joint: gliding joint
What stabilizes the knee joint?
- The quadriceps tendon in the front
- The tendon of semimembranosus muscle on rear of thigh
Describe the popliteal (posterior) portion of the knee joint
- Extracapsular ligaments
- Intracapsular ligaments cross each other to form X
- Anterior cruciate ligament (ACL) prevents hyperextension of knee when ACL is pulled tight; common site of knee injury
- Posterior cruciate ligament (PCL) prevents femur from sliding off tibia
Describe the jobs of the ACL and the PCL
- Anterior cruciate ligament (ACL) prevents hyperextension of knee when ACL is pulled tight; common site of knee injury
- Posterior cruciate ligament (PCL) prevents femur from sliding off tibia
Describe knee joint injuries
- Highly vulnerable to rotational and horizontal stress
- Most common injuries are to the menisci and anterior cruciate ligament (ACL)
- Heal slowly due to scanty blood flow
Define arthroscopy and describe its use in repairing knee joints
- Arthroscopy: a procedure in which interior of joint is viewed with a pencil-thin arthroscope inserted through a small incision
- Less tissue damage than conventional surgery
- Recover more quickly
- Arthroscopic ACL repair: about 9 months for healing to be complete
Describe the two articulations of the talocrural (ankle) joint
- Talocrural (ankle) joint—includes two articulations:
1) Medial joint: between tibia and talus
2) Lateral joint: between fibula and talus - Both articulations enclosed by one joint capsule
Describe what supports the ankle joint
- Malleoli of tibia and fibula overhang the talus on either side and prevent side-to-side motion
- Calcaneal (Achilles) tendon: extends from the calf muscles to the calcaneus
Sprains (torn ligaments and tendons) are common at the _____ joint
ankle
True or false: the ankle has a more restricted ROM than the wrist
True
Define and describe the prevalence of arthritis
- A broad term for pain and inflammation of joints
- Most common crippling disease in the United States
Describe osteoarthritis
- The most common form of arthritis
- “Wear-and-tear arthritis”; results from years of joint wear
- Articular cartilage softens and degenerates
- Accompanied by crackling sounds called crepitus
- Bone spurs develop on exposed bone tissue causing pain
Define and describe rheumatoid arthritis
- An autoimmune attack against the joint tissues
- Misguided antibodies (rheumatoid factor) attack synovial membrane, enzymes in synovial fluid degrade the articular cartilage, joint begins to ossify
- Ankylosis: solidly fused, immobilized joint
- Remissions occur, steroids and aspirin control inflammation
Define ankylosis
A solidly fused, immobilized joint
Define arthroplasty
The replacement of diseased joint with artificial device called a prosthesis
The synovial cavity of the TMJ is divided into superior and inferior chambers by what?
An articular disc
The only type of joint with a labrum is what?
Ball and socket joints
Describe labrum
A type of cartilage found in the shoulder (glenohumeral) and hip joint (coxal joint)
What is always found in synovial joints?
A joint capsule
In what position does the radius cross over the ulna?
Pronation
True or false: abducting the knee is an abnormal movement
True
