Chapter 8: Joints Flashcards
what are joints?
where two bones meet
where is the only point that bones can move?
at joints
what is the function of joints?
allow mobility while preserving bone strength
the amount of movement in a bone is determined by
the anatomical structure
in what two ways are joints classed?
- functionally by the ROM
2. structurally by anatomical organization
describe the movement and strength of synarthrosis joints
no movement, very strong
describe the movement, strength, and structure of amphiarthrosis joints
little movement, middle strength, articulating bones connected by collagen fibers or cartilage
describe the movement and strength of diarthrosis joints
freely movable, weak
what are the 4 structural classes of joints?
- fibrous
- cartilaginous
- bony
- synovial
what are the three types of fibrous joints?
- suture
- gomphosis
- syndesmosis
describe the structure and location of suture joints. What ROM?
synarthrotic joint connected by dense fibrous connective tissue, located between bones of skull. No ROM
describe the structure and location of gomphosis joints. What ROM?
synarthrotic joints binding teeth to bony sockets in maxillae and mandible. No ROM
describe the structure and location of syndesmosis joints. What ROM?
amphiarthotic joint with bones connected by a ligament, distal joint between tibia and fibula and radius and ulna. Little ROM
describe the structure and location of synchondrosis joints
synarthrotic joint formed by rigid cartilaginous bridge between two articulating bones. Between ends of first pair of ribs and sternum. No ROM
describe the structure and location of synostosis joints. What ROM?
synarthrotic joint, totally rigid (bony), immovable. Formed when bones fuse; frontal suture, epiphyseal lines. No ROM
what are the 2 types of cartilaginous joints?
- synchondrosis
2. symphysis
what is the only type of bony joint?
synostosis
what is the structure and location of symphasis joints? ROM?
bones held together by cartilage, between pubic bones, little movement
what is the structure and location of synovial joints? ROM?
diarthrotic joint located at ends of long bones. Full ROM
what are the four components of a synovial joint?
- articular cartilage
- joint capsule
- synovial membrane
- joint cavity
describe the structure and fuction of the articular cartilage in synovial joint
covers bone ends, structure like hyaline cartilage with no perichondrium and its matrix contains more water
describe the structure and function of the joint capsule in synovial joint
sac enclosing ends of bones, reinforced by tendons and ligaments, continous with the periosteum of two bones.
Adds strength and mobility
describe the structure and function of the synovial membrane in a synovial joint
lines internal joint capsule, secretes synovial fluid into joint cavity. Lubricates, cushions, prevents abrasion, and suports chondrocytes
describe the structure of synovial fluid
clear, straw coloured, viscous due to hyaluronic acid (like raw egg whites)
how does the synovial fluid reach the cartilage?
produced by synovial membrane, moves from aereolar tissue to joint cavity, percolates through articular cartilage
what are the 3 main functions of the synovial fluid?
- lubrication
- nutrition distribution
- shock absorption
describe the lubriacation function of synovial fluid
under compression, fluid squeezes out of cartilage into joint cavity to reduce friction between bones
describe the nutrition distribuation function of synovial fluid
fluid circulates constantly, providing nutrients and removing wastes
what assists in circulation of synovial fluid?
compression and expansion of articular cartilage
desrcibe how synovial fluid assists in shock
absorption
viscosity increases with increased pressure
what is the function of the accessory structures supporting the knee?
provide support an additional stability
what are the 5 accessory structures supporting the knee joint?
- quadriceps muscle
- bursa
- fat pads
- meniscus
- accessory ligaments
how does the qudriceps muscle support the knee?
limits ROM and provides mechanical support
what is the bursa and how does it support the knee joint?
small, thin, fluid-filled pocket of synovial fluid, lined with synovial membrane that reduces friction and acts as shock absorber
where does the bursa form?
in connective tissue outside a joint capsule
what are fat pads, and how do they support the knee joint?
localized masses of adipose tissue covered by a layer of synovial membrane. Protect artcular cartilage and fill in spaces created as joint moves and cavity changes shape
where are fat pads located relative to a joint?
superficial to joint capsule
what is the meniscus and how does it support the knee joint?
pad of fibrocartilage between opposing bones in synovial joint. May subdivide synovial cavity or channel synovial fluid flow. It allows variations in shapes of the articular surfaces
what type of ligaments support the knee joint?
extrinsic ligaments (separate from capsule).
what two extrinsic ligaments support the knee? How do they support the joint?
- patellar
- cruciate
support, strengthen and reinforce synovial joints
greater ROM means ____ joints
weaker
another word for dislocation
luxarion
what is dislocation or luxation?
movement beyond normal ROM
what happens to a joint that is dislocated?
articulating surfaces forced out of position, damaging surface of joints
where does joint pain come from?
nerves monitoring capsule and surrounding tissue
are their pain receptors in the joint capsule?
no
flexion and extension refer to movement at what joints?
hinge joints of long bones
flexion
decreases angle of joint
extension
increases the angle of a joint
hypertension
extension past anatomical position
abduction and adduction refer to the movements of the
appendicular skeleton
abduction
movement away from midline of the body
adduction
movement towards the midline of the body
describe the strength and ROM of the joints in the axial skeleton
strong, no to little movement
give 2 examples of joints in the axial skeleton
- atlanto-occipital joint between the atlas and occipital bone
- atlanto-axial joint between C1 and C2
describe the strength and ROM of the joints in the appendicular skeleton
extensive ROM, often weaker than those of axial skeleton
what are the synchondroses of the vertebral column?
intervertebral joints, forming intervertebral disks
intervertebral disks account for how much of the vertebral column?
1/4
what causes the vertebral column to shrink with age?
water content decreases
what is another implication of water content decreasing in vertbral disks?
reduced cushioning, increased risk for injury
what are intervertebral disk diseases (IVDD)?
bulging disk and herniated disk
what causes bulging disk IVDD?
weakened posterior longitudinal ligamnets causes tough outer layer of cartilage to bulge out laterally
what happens in herniated disk IVDD?
nucleus pulposus breaks through anulus fibrosus and protrudes into vertebral canal
what happens to the spinal nerves in herniated disk IVDD?
they compress and can become numb on one side
what is osteopenia?
inadequate ossification leading to loss of bone mass, which may lead to osteoporosis
when does osteopenia typically set in?
30-40 years old
which sex does osteopenia typically affect more severely?
female
what causes osteopenia
- lack of estrogen
- lack of exercise
- excessive alcohol consumption
- smoking
- medications
- radiation
what two causes of osteopenia have a synergistic effect?
excessive drinking and smoking
what is osteoporosis
bone loss suffiecient enough to affect normal function
what are the causes of osteoporosis?
- low estrogen
- diet
- alcoholism
- anorexis
- kidney disease
- medications
- lack of exercise
- smoking
on average, how much do people shrink per decade after 40?
quarter to a third of an inch
which joint in the body has the greatest ROM?
shoulder joint
what is another name for the shoulder joint
glenohumoral joint
what joint in the body is the most frequently dislocated?
shoulder/glenohumoral joint
what joints are ball-and-socket diarthrosis type?
- shoulder (head of humerus and glenoid cavity of scapula)
2. Hip (head of femur and fossa of acetabulum)
the ball-and-socket joint of glenohumoral joint is stabalized by
5 major ligaments, surrounding muscles, and associated tendons
what is the role of the bursae in the shoulder joint?
reduce friction by surrounding tendon of the biceps brachii as it passes through the articular capsule
ball-and-socket joints permit what types of movement?
flexion, extension, adduction, abduction, circumduction, rotation
how is the head of the femur attached to the acetabulum?
acetabular labrum
what is the acetabular labrum? Function?
Rim of fibrocartilage that increases depth of joint cavity and helps seal in synovial fluid
what is the function of the articular capsule of the hip?
encloses head and neck of femur
what reinforces the articular capsule of the hip?
5 ligamnets
the elbow joint is a _____ joint involving the ___, ____, and _____
complex hinge joint, involving radius, ulna, and humerus
2 reasons why the elbow joint is extremely stable
- bony surfaces of hemerus and ulna interlock
2. strong ligaments reinforce the articular capsule
what is the largest and strongest articulation in the body?
humero-ulnar joint
how does the humero-ulnar joint work?
like a door hige
the ____ of the humerus articulates with the ___ of the ulna
trochlea of humerus articulates with trochlear notch of ulna
what determine the plane of movement in the humero-ulnar joint?
shape of the trochlear notch
what limits the degree of extension in the humero-ulnar joint?
shapes of the olecranon fossa and olecranon
the knee contains 3 separate articulations, where are they located?
2 between the femur and tibia and 1 between the patella and patellar surface of the femur
what are the two knee articulations between the femur and tibia?
- medial condyle of tibia to medial condyle of femur
2. lateral condyle of tibia to lateral condyle of femur
what is the functions of the 3 knee articulations?
flexion, extension, very limited rotation
what bone is not part of the knee joint
fibula
what provides laterla support to the knee joint?
fibular collateral ligament (lateral collateral ligament/LCL)
the quadriceps muscle continues as ___ to ___
patellar ligament; anterior tibial surface
what provides medial support to the knee joint?
tibial collateral ligament (medial collateral ligament/MCL)
what are the popliteal ligaments. What is their function?
ligaments that run between femur and heads of tibia and fibula. Support knee
what are the medial and lateral menisci? Location and function?
pair of fibrocartilage pads between femoral and tibial surfaces. Act as cushions and provide lateral stability to knee
what is the anterior cruciate ligament?
ACL. Responsible for locking and unlocking knee
how is the ACL involved in movement of knee?
at full extension, slight lateral rotation of tibia tightens ACL and forces lateral meniscus between tibia and femur
rheumatism
general term indicating pain and stiffness in bones/muscles
what is arthritis?
all rheumatic diseases that affect synovial joints
arthritis always involves
damage to articular cartilage
what are the 3 types of arthritis?
- osteoarthritis
- rheumatoid arthritis
- gouty arthritis
what are 2 other names for osteoarthritis?
degenerative arthritis, degenerative joint disease
what is the most common form of arthritis?
osteoarthritis
what age individuals are most affected by osteoarthritis?
over 60
osteoarthritis affects what % of men/women over 60?
15% men and 25% women
what are the causes of osteoarthritis?
cumulative wear and tear on joints and genetic factors affecting collagen formation
what does normal articular cartilage look like?
smooth slick surface, thick with homogeneous matrix
what does articular cartilage look like after it has been damaged by osteoarthritis?
rough, bristly collagen fibres on the surface
what is the effect of rough collagen fibre on the surface of articular cartilage?
increases friction and inflammation, can cause further degeneration
what is an arthroscope? Function?
narrow, flexible fiberoptic tube with tiny camera that allows exploration of joint without major surgery.
what is arthroscopic surgery?
use of arthroscope and other small flexible tools to conduct surgery with only small incisions
what is MRI and its function?
magnetic resonance imaging. Allows visualization of soft tissue outside joint cavity, not visible with arthroscope
what are 2 benefits of MRI?
cost-effective and noninvasive
what are the benefits of artificial joints?
can restore mobility and relieve pain
what are the pitfalls of artificial joints?
cannot perform high-impact activities, only last about 15 years and can’t really be replaced
what is the best primary method of treatment for joint problems?
keep moving! It will squeeze fluid out of cartilage to lubricate the joint
