Transcript Articulations

Articulations
Anatomy and Physiology
I. Classification of joints
• Articulation – point where 2 bones meet (joint)
• Joints are classified according to amount and type of movements
• 3 general types of joints
• Immovable (synarthrosis)
• Slightly immovable ( amphiarthrosis)
• Freely movable (diarthrosis)
II. Immovable joints (synarthrosis)
• Joints fused together
• 4 types
a.
b.
c.
d.
Sutures
Gomphoses
Synchondroses
synostoses
a. Sutures
• Between bones of skulls
• Interlocked
• Bound together by dense connective tissue
b. gomphoses
• teeth to bony sockets
• held into socket by periodontal ligament
c. Synchondroses
• cartilage bridge between 2 articulating bones
• ex. Ends of vertebrosternal rib and sternum
d. synostosis
• rigid immovable
• bones fused together with no line of demarcation as to where it starts
or ends.
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• Ex. Hip, coccyx
III. Slightly movable (amphiarthrosis)
• Permits more movement than syntarthrosis, but stronger than freely
movable joints
• 2 types
1. syndesmosis
2. symphysis
a. Syndesmosis (sin-dez-MO-sis)
• bones connected by a ligament
•
• ex. Tibia and fibula
b,. symphysis
• bones separated by wedge or pad of fibrocartilage
• ex. Vertebrae – vertebral disks
• pubic bones – pubic symphysis
IV. Freely Movable (diarthroses)
• a. Aka – synovial joints
• Allow large range of motion
• Synovial joint surrounded by capsule and synovial membrane lines
the cavity
• Found end of long bones
• Surface slippery and smooth which decreases friction
• Contains synovial fluid
b. 3 functions of synovial fluid
• i. lubricant
the viscous fluid acts to lubricate the joints
ii. nutrient distribution
circulates to provide nutrients and rids waste products
moves every time joint moves
iii. shock absorption
cushions
distributes pressure across the joint which lessens shock on the
surfaces of joint
c. arthritis
• affects syovial joints
damages to articulating cartilages
caused by injury, virus, bacteria, physical stress
2 types arthritis
i. Osteoarthritis –
• Degenerative
• Results from cumulative wear and tear of joint surfaces
• Genetic factors
• 60 + older
ii. Rheumatoid arthritis
• Inflammation
• Due to immune system mistakenly attacking joint tissue
• Allergies, bacteria, virus, and genetics contribute to triggering
iii. Treatment of arthritis
• Exercises
• Physical therapy
• Meds (anti-inflamatory)
• Replacement of joint
V. Accessory Structures of synovial joints
a.
b.
c.
d.
e.
Fat pads
Cartilage pads
Ligaments
Tendons
bursea
a. Fat pads
structure:
• adipose tissue covered by layer of synovial membrane
• superficial to joint capsule
function –
• protect articulating cartilage
• act as packing material for joint by filling in spaces created as joint
cavity moves.
b. Cartilage pads
structure:
• fibrocartilage pad situated between bones within synovial joint
ex. Meniscus
function :
• channel synovial fluid flow
• absorb shock
• subdivide synovial cavity
c. ligaments
i.
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Accessory:
thickenings of capsule
reinforces and strengthens capsule
limits rotation at joint
ii. extracapsular
• connect articulating bones
• passes across outside of capsule
• support wall of joint
ex. Lateral collateral and medial collateral ligaments of knee
iii. Intracapsular
• inside capsule
• prevents extreme movements that could hurt joint
ex. ACL , PCL
iv. other (ligaments of knee)
• popliteal
• patellar
d. tendons
• Connect muscle to bone
• Across and around joints to provide strength to joints
• Tendonitis – inflammation of tendon
e. bursea
structure
• Small fluid filled sacs in connective tissue
• Contain synovial fluid and lined by synovial membrane
• Found where tendons and ligaments rub against other tissues
•
Function –
• Decrease friction
• Absorb shock
Bursitis – inflammation of bursae
• Pain when move tendon or ligament
• Associated with repetitive motion
Golfers, swimmers, pitchers, tennis
VI. Types of Movements
a.
b.
c.
d.
Gliding
Angular
Rotation
Special movements
a. gliding
• Sliding past one another
• Carpal bones
• B/t tarsal bones
• b/t clavicle and sternum
• movement in any direction – but very slight
Ex:
• touch process on clavicle and turn shoulders in – feel sliding
b. angular
Change in angle between shaft and joint
1. Flexion – decrease in angle
ex. Chin to chest, touch toes, bend wrist
2. Extension – increase in angle
Ex. Straightening leg or arm
3. Hyperextension – extension beyond anatomical position
ex. Look at ceiling (hyperextend neck)
4. Abduction – movement of appendage AWAY from long axis of body
(along frontal plane)
ex. Moving arm away from body, spreading fingers
5. Adduction – movement appendages TOWARD long axis of body (along
frontal plane)
Ex. Moving arm toward body, fingers together
6. Circumduction –
Distal end of appendage moves in circle
Ex. Baseball wind up
c. Rotation
• in referent to anatomical position
• depends on part moving
• ex. Head rotation – move chin to right or left (say NO)
• ex. Limb rotation – medial – inward
lateral – outward
Lower arm rotation
• pronation – move palm toward back
• supinate – move palm from back toward front
d. Special movements
FOOT:
inversion
• twisting motion of foot that turns sole inward
eversion
• twisting motion of foot that turns sole outward
dorsiflexion
• flexion of ankle and elevation of sole of foot (dig heel into ground)
plantar flexion
• extend ankle and elevate heel (stand on tip toes)
Special mvmts. cont….
opposition
• thumb to fingers
protraction
• moving body part anteriorly in horizontal plane
• ex. Sticking out tongue
retraction
• opposite of protraction
elevation
• structure moves superiorly
• ex. Shrug shoulders, close mouth,
depression
• structure move inferior
• open mouth
lateral flexion
• vertebral column bends to one side
• ex. Side stiches, move ear toward shoulder
VII. Types of Synovial Joints
Each synovial joint permits different type and range of motion
a.
b.
c.
d.
e.
f.
Gliding
Hinge
Pivot
Ellipsoidal
Saddle
Ball and socket
a. Gliding
• Aka planar joints
• Flattened or slightly curved faces
• Flat articulating surfaces
• Slight movement
Ex. Clavicle, carpals, tarsals, between vertebrae
b. Hinge joint
• Angular movement in single plane (monaxial joint)
• Monaxial joint (only flexes or extends in one plane)
• Ex. Occipital condyle and atlas
•
Elbow, knee, interphalangeal joints , wrist
c. Pivot
• Monaxial
• Permits rotation only
• Ex. Atlanto-axial joint (atlas and axis)
Radioulnar joint
d. Ellipsoidal
• Aka condyloid joint
• Nestles with in a depression
• Angular motion in 2 planes – biaxial
(flexion/extension and abduction/adduction
• ex. Metacarpal phalangeal joint
metatarsalphalangeal joint
wrist – radiocarpal joint
e. Saddle
• Aka sellaris joint
• Articulating faces look like saddles
• Angular motion – biaxial
Circumduction and angular motion (flexion /extension, etc)
• Ex. Carpometacarpal joint (base of thumb – twiddle thumbs)
f. Ball and socket
• round head of bone fits in cup shaped depression of another bone
• multiaxial – rotate, circumduction, angular movements)
• ex. Shoulder , hip
VIII. Major Joints in Human Body
a. Shoulder joint:
• greatest range of motion
• also most frequently dislocated
• most stability provided by ligaments and muscles around joint
• contain bursae to decrease friction between tissue
Shoulder joint cont…
rotator cuff:
• supraspinatus
• infraspinatus
• subscapularis
• teres minor
• primary support for shoulder joint and limits range of motion.
• Injury to rotator cuff usually due to severe stress on shoulder, repetition
(pitchers, swimmers, quarterbacks , etc..)
b. elbow
• olecranon joint
• hinge (flexion and extension)
• diarthrosis
• muscles that extend elbow attach at olecranon process (triceps)
• muscles that flex elbow – attach at radial tuberosity
• stable joint due to the fact that humerus and ulna interlock
• has thick articular capsule and ligament reinforcement
c. hip
• diarthrosis
• flexsion / extension, abduction/adduction, circumduction and rotation
• contains large muscles to help with stability of joint
• ligaments around the hip include
iliofemoral
pubofemoral
ischiofemoral
transverse acetabular ligament
ligamentum teres
d. knee
• Hinge joint
• Flexion / extension (monaxial)
• Limited rotation
• Medial and lateral menisci lie between femoral and tibial surface
Cushions, gives lateral stability,
Knee cont.
Ligaments of knee
Patellar ligament
• Patella is within patellar tendon, continuation of this tendon = patellar ligament which attaches to anterior surface of tibia (tuberosity)
Popliteal ligaments (2)
• Between femur and heads of tibia and fibula
• Supports posterior surface
Anterior and Posterior Cruciate
• Inside joint capsule
• Criss cross inside capsule
• Limit anterior and posterior movement of femur and maintain alignment of femoral and tiaeal condyles.
Tibial (medial ) collateral (MCL)
• Reinforces medial surface of knee
Fubular (lateral) collateral (LCL)
• Reinforces lateral surface of knee
IX. Male vs. Female Skeleton
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General differences:
Males bones larger than female
Males have larger muscle attachment surfaces
Males have larger Joint surfaces
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Skull :
Males have shorter forehead
Males mandible and maxillae larger
Males facial area is more pronounced
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Pelvis:
Males pelvis narrower
Males pelvis deeper
Males pelvic outlet smaller
Males subpubic angle less than 90 degrees
X. Common Disorders of Skeletal System
1. Arthritis – inflammation of joint, pain stiffness
• Osteoarthritis – wear and tear
• Rheumatoid -
2. Bunion
• Bony bump that forms on the joint at the base of your great toe.
• Wearing tight or narrow shoes can form bunions. Sometimes just inherent structural
defect.
3. Bursitis
• Inflammation of fluid filled sac
• Overuse or repetitive movement
4. Gout
• Missing enzyme causes uric acid build up in joints
• Common in toe, knee
5. Herniated disc
• When vertebral disk “pops” out from between vertebrae
Disorders cont…..
6. Luxation
• Full dislocation of a joint
• Usually from fall or unusual movement
• Shoulder, knees, shoulder, fingers, jaw
7. Subluxation
• Partial dislocation of a joint
8. Sprain
• Overstretching or tearing of connective tissue, ligaments and tendons
9. Strain
• Overstretching or over use of muscle