Articulations and Joints
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Transcript of Articulations and Joints
Articulations and Joints
Muse lecture #9 6/7/10
JointsChapter 9
Joint Classifications Fibrous Joints Cartilaginous Joints Synovial Joints Types of Movements at Synovial Joints Types of Synovial Joints Factors Affecting Contact and Range of Motion at
Synovial Joints Selected Joints of the Body Aging and Joints Arthroplasty
Muse Lecture #6
An Introduction to Articulations
Articulations Body movement occurs at joints
(articulations) where two bones connect
Joint Structure Determines direction and distance of
movement (range of motion) Joint strength decreases as mobility increases
Classification of Joints
Two methods of classification
Functional classification is based on range
of motion of the joint
Structural classification relies on the
anatomical organization of the joint
Classification of Joints
Functional Classifications Synarthrosis (immovable joint)
No movement Fibrous or cartilaginous connections May fuse over time
Amphiarthrosis (slightly movable joint) Little movement Fibrous or cartilaginous connections
Diarthrosis (freely movable joint) More movement Also called synovial joints Subdivided by type of motion
Party on Arth!
Classification of Joints
Classification of Joints
Classification of Joints
Structural Classifications
Bony
Fibrous
Cartilaginous
Synovial (capsulated)
Classification of Joints
Classification of Joints
Functional Classifications Synarthroses (immovable joints)
Are very strong Edges of bones may touch or interlock Four types of synarthrotic joints:
– suture
– gomphosis
– synchondrosis
– synostosis
Classification of Joints
Synarthrotic Joints
Suture Bones interlocked
Are bound by dense fibrous connective tissue
Are found only in skull
Gomphosis Fibrous connection (periodontal ligament)
Binds teeth to sockets
Yah can’t chomp without the gomph
Joints (Fibrous Joints) Sutures
Occur only between bones of the skull
Syndesmoses Permits slight movement Interosseous membrane
Between the tibia and fibula in the leg
Gomphoses Immovable joint Joint in which a cone-shaped
peg fits into a socket Articulations of the teeth with the
sockets of the maxillae and mandible
Figure 8.1b
Fibula
Tibia
Ligament
(b) Syndesmosis
Joint held together by a ligament.Fibrous tissue can vary in length, but
is longer than in sutures.
Joints (Fibrous Joints) Lack a synovial cavity The articulating bones are held very closely
together by dense irregular connective tissue Fibrous joints permit little or no movement Three types of fibrous joints
Sutures Syndesmoses Gomphoses
Classification of Joints
Synarthrotic Joints Synchondrosis
Is a rigid cartilaginous bridge between two bones:– epiphyseal cartilage of long bones– between vertebrosternal ribs and sternum
Synostosis Fused bones, immovable:
– metopic suture of skull– epiphyseal lines of long bones
Classification of Joints
Functional Classifications Amphiarthroses
More movable than synarthrosis
Stronger than freely movable joint
Two types of amphiarthroses
– syndesmosis:
» bones connected by ligaments
– symphysis:
» bones separated by fibrous cartilage
Classification of Joints
Functional Classifications
Synovial joints (diarthroses) Also called movable joints
At ends of long bones
Within articular capsules
Lined with synovial membrane
Synovial Joints
Components of Synovial Joints
Articular cartilages Pad articulating surfaces within articular
capsules:
– prevent bones from touching
Smooth surfaces lubricated by synovial fluid:
– reduce friction
Figure 8.3
Periosteum
Ligament
Fibrouscapsule
Synovialmembrane
Joint cavity(containssynovial fluid)
Articular (hyaline)cartilage
Articularcapsule
Synovial Joints
Components of Synovial Joints Synovial fluid
Contains slippery proteoglycans secreted by fibroblasts
Functions of synovial fluid:– lubrication
– nutrient distribution
– shock absorption
Synovial Joints Components of Synovial Joints
Accessory structures Cartilages:
– cushion the joint:» Fibrous cartilage pad called a meniscus
(articular disc) Fat pads:
– superficial to the joint capsule– protect articular cartilages
Ligaments:– support, strengthen joints – sprain: ligaments with torn collagen fibers
Synovial Joints
Components of Synovial Joints
Accessory structures Tendons:
– attach to muscles around joint
– help support joint
Bursae:
– pockets of synovial fluid
– cushion areas where tendons or ligaments rub
Figure 8.4b
Coracoacromialligament
Subacromialbursa
Cavity inbursa containingsynovial fluid
Bursa rollsand lessensfriction.
Humerus headrolls medially asarm abducts.
(b) Enlargement of (a), showing how a bursaeliminates friction where a ligament (or otherstructure) would rub against a bone
Humerusresting
Humerusmoving
Synovial Joints
Factors That Stabilize Synovial Joints
Prevent injury by limiting range of motion
Collagen fibers (joint capsule, ligaments)
Articulating surfaces and menisci
Other bones, muscles, or fat pads
Tendons of articulating bones
Synovial Joints
[INSERT FIG. 9.1a]
Figure 9–1a The Structure of a Synovial Joint.
Synovial Joints
Figure 9–1b The Structure of a Synovial Joint.
Synovial Joints
Injuries
Dislocation (luxation)
Articulating surfaces forced out of position
Damages articular cartilage, ligaments, joint capsule
Subluxation A partial dislocation
Movements
Types of Dynamic Motion Linear motion (gliding)
Angular motion
Rotation
Planes (Axes) of Dynamic Motion Monaxial (1 axis)
Biaxial (2 axes)
Triaxial (3 axes)
Movements
Figure 9–2 A Simple Model of Articular Motion.
Movements
Figure 9–2 A Simple Model of Articular Motion.
Movements
Types of Movements at Synovial Joints
Terms describe
Plane or direction of motion
Relationship between structures
Movements
Types of Movements at Synovial Joints
Linear motion
Also called gliding
Two surfaces slide past each other:
– between carpal or tarsal bones
Movements
Angular Motion Flexion
Angular motion Anterior–posterior plane Reduces angle between elements
Extension Angular motion Anterior–posterior plane Increases angle between elements
Movements
Angular Motion Hyperextension
Angular motion
Extension past anatomical position
Angular Movements
Movements
Figure 9–3a Angular Movements.
Movements
Angular Motion Abduction
Angular motion Frontal plane Moves away from longitudinal axis
Adduction Angular motion Frontal plane Moves toward longitudinal axis
Think adding
Think kidnapping
Movements
Figure 9–3 Angular Movements.
Movements
Figure 9–3 Angular Movements.
Movements
Angular Motion
Circumduction
Circular motion without rotation
Angular motion
Movements
Figure 9–3 Angular Movements.
Movements
Types of Movement at Synovial Joints Rotation
Direction of rotation from anatomical position Relative to longitudinal axis of body Left or right rotation Medial rotation (inward rotation):
– rotates toward axis
Lateral rotation (outward rotation): – rotates away from axis
Movements
Figure 9–4a Rotational Movements.
Movements
Types of Movements at Synovial Joints
Rotation
Pronation:– rotates forearm, radius over ulna
Supination:– forearm in anatomical position
Movements
Figure 9–4b Rotational Movements.
Movements
Types of Movements at Synovial Joints Special movements
Inversion:– twists sole of foot medially
Eversion:– twists sole of foot laterally
Dorsiflexion: – flexion at ankle (lifting toes)
Plantar flexion:– extension at ankle (pointing toes)
Plant your feet
Movements
Special Movements at Synovial Joints Opposition
Thumb movement toward fingers or palm (grasping)
Protraction Moves anteriorly In the horizontal plane (pushing forward)
Retraction Opposite of protraction Moving anteriorly (pulling back)
Movements
Special Movements at Synovial Joints Elevation
Moves in superior direction (up)
Depression Moves in inferior direction (down)
Lateral flexion Bends vertebral column from side to side
Movements
Figure 9–5 Special Movements.
Movements
Figure 9–5 Special Movements.
Movements
Classification of Synovial Joints by Shape Gliding Hinge Pivot Ellipsoid Saddle Ball-and-socket
A Functional Classification of Synovial Joints
Movements
Gliding Joints Flattened or slightly curved faces
Limited motion (nonaxial)
Hinge Joints Angular motion in a single plane (monaxial)
Pivot Joints Rotation only (monaxial)
Movements
Figure 9–6 Movements at Synovial Joints.
Movements
Ellipsoid Joints Oval articular face within a depression Motion in two planes (biaxial)
Saddle Joints Two concave, straddled (biaxial)
Ball-and-Socket Joints Round articular face in a depression (triaxial)
Movements
Figure 9–6 Movements at Synovial Joints.
Movements
A joint cannot be both mobile and strong The greater the mobility, the weaker the
joint Mobile joints are supported by muscles
and ligaments, not bone-to-bone connections
Intervertebral Articulations
Intervertebral Articulations
C2 to L5 spinal vertebrae articulate
At inferior and superior articular processes (gliding
joints)
Between adjacent vertebral bodies (symphyseal
joints)
Intervertebral Articulations
Intervertebral Articulations C2 to L5 spinal vertebrae articulate
Intervertebral discs:– pads of fibrous cartilage– separate vertebral bodies– anulus fibrosus:
» tough outer layer» attaches disc to vertebrae
– nucleus pulposus:» elastic, gelatinous core » absorbs shocks
Intervertebral Articulations
Figure 9–7 Intervertebral Articulations.
Intervertebral Articulations
Vertebral Joints Also called symphyseal joints As vertebral column moves
Nucleus pulposus shifts
Disc shape conforms to motion
Intervertebral Ligaments Bind vertebrae together
Stabilize the vertebral column
Intervertebral Articulations
Six Intervertebral Ligaments Anterior longitudinal ligament
Connects anterior bodies
Posterior longitudinal ligament Connects posterior bodies
Ligamentum flavum Connects laminae
Intervertebral Articulations
Six Intervertebral Ligaments Interspinous ligament
Connects spinous processes
Supraspinous ligament Connects tips of spinous processes (C7 to sacrum)
Ligamentum nuchae Continues supraspinous ligament (C7 to skull)
Intervertebral Articulations
Damage to Intervertebral Discs
Slipped disc Bulge in anulus fibrosus
Invades vertebral canal
Herniated disc Nucleus pulposus breaks through anulus fibrosus
Presses on spinal cord or nerves
Intervertebral Articulations
Figure 9–8a Damage to the Intervertebral Discs.
Intervertebral Articulations
Figure 9–8b Damage to the Intervertebral Discs.
Intervertebral Articulations
Movements of the Vertebral Column Flexion
Bends anteriorly
Extension Bends posteriorly
Lateral flexion Bends laterally
Rotation Turning
Articulations of the Axial Skeleton
Articulations of the Axial Skeleton
Articulations of the Axial Skeleton
Joints (Selected Joints of the Body)
Temporomandibular Joint Combined hinge and planar joint formed by the
mandible and the temporal bone Only movable joint between skull bones Only the mandible moves
Figure 8.13c
Lateral excursion: lateral (side-to-side) movements of the mandible
Outline ofthe mandibularfossa
Superior view
Figure 8.13a
Zygomatic process
Mandibular fossaArticular tubercle
Infratemporal fossa
Externalacousticmeatus
Articularcapsule
Ramus ofmandible
Lateralligament
(a) Location of the joint in the skull
Figure 8.13b
Articularcapsule
Mandibularfossa
Articular discArticulartubercle
Superiorjointcavity
Inferior jointcavity
Mandibularcondyle
Ramus ofmandible
Synovialmembranes
(b) Enlargement of a sagittal section through the joint
The Shoulder Joint
Also called the glenohumeral joint
Allows more motion than any other joint
Is the least stable
Supported by skeletal muscles, tendons, ligaments
Ball-and-socket diarthrosis
Between head of humerus and glenoid cavity of
scapula
The Shoulder Joint
Socket of the Shoulder Joint Glenoid labrum
Deepens socket of glenoid cavity
Fibrous cartilage lining
Extends past the bone
Processes of the Shoulder Joint Acromion (clavicle) and coracoid process (scapula)
Project laterally, superior to the humerus
Help stabilize the joint
The Shoulder Joint
Shoulder Ligaments Glenohumeral Coracohumeral Coraco-acromial
Coracoclavicular Acromioclavicular
Shoulder Separation Dislocation of the shoulder joint
The Shoulder Joint
Shoulder Muscles (also called rotator cuff) Supraspinatus Infraspinatus Subscapularis Teres minor
Shoulder Bursae Subacromial Subcoracoid Subdeltoid Subscapular
The Shoulder Joint
Figure 9–9a The Shoulder Joint.
The Shoulder Joint
Figure 9–9b The Shoulder Joint.
The Elbow Joint
A stable hinge joint
With articulations involving humerus,
radius, and ulna
The Elbow Joint
Articulations of the Elbow
Humero-ulnar joint Largest articulation
Trochlea of humerus and trochlear notch of ulna
Limited movement
Humeroradial joint: Smaller articulation
Capitulum of humerus and head of radius
The Elbow Joint
Figure 9–10a The Elbow Joint.
The Elbow Joint
Supporting Structures of the Elbow Biceps brachii muscle
Attached to radial tuberosity Controls elbow motion
Elbow Ligaments Radial collateral Annular Ulnar collateral
The Elbow Joint
Figure 9–10b The Elbow Joint.
The Hip Joint
Also called coxal joint
Strong ball-and-socket diarthrosis
Wide range of motion
The Hip Joint Structures of the Hip Joint
Head of femur fits into it Socket of acetabulum Which is extended by fibrocartilaginous acetabular
labrum Ligaments of the Hip Joint
Iliofemoral Pubofemoral Ischiofemoral Transverse acetabular Ligamentum teres
The Hip Joint
Figure 9–11a The Hip Joint.
The Hip Joint
Figure 9–11b The Hip Joint.
The Hip Joint
Figure 9–11c The Hip Joint.
The Knee Joint
A complicated hinge joint
Transfers weight from femur to tibia
Articulations of the knee joint
Two femur–tibia articulations
At medial and lateral condyles
One between patella and patellar surface of femur
The Knee Joint
Menisci of the Knee Medial and lateral menisci
Fibrous cartilage pads At femur–tibia articulations Cushion and stabilize joint Give lateral support
Locking knees Standing with legs straight:
– “locks” knees by jamming lateral meniscus between tibia and femur
The Knee Joint
Seven Ligaments of the Knee Joint
Patellar ligament (anterior)
Two popliteal ligaments (posterior)
Anterior and posterior cruciate ligaments (inside joint
capsule)
Tibial collateral ligament (medial)
Fibular collateral ligament (lateral)
The Knee Joint
Figure 9–12a The Knee Joint.
The Knee Joint
Figure 9–12b The Knee Joint.
The Knee Joint
Figure 9–12c The Knee Joint.
The Knee Joint
Figure 9–12d The Knee Joint.
Figure 8.14
Tornmeniscus
The Knee Joint
The Knee Joint
Aging
Rheumatism A pain and stiffness of skeletal and muscular
systems Arthritis
All forms of rheumatism that damage articular cartilages of synovial joints
Osteoarthritis Caused by wear and tear of joint surfaces, or
genetic factors affecting collagen formation Generally in people over age 60
Developmental Aspects of Joints
By embryonic week 8, synovial joints resemble adult joints
A joint’s size, shape, and flexibility are modified by use
Advancing years take their toll on joints: Ligaments and tendons shorten and weaken Intervertebral discs become more likely to herniate Most people in their 70s have some degree of OA
Exercise that coaxes joints through their full range of motion is key to postponing joint problems
Aging
Rheumatoid Arthritis An inflammatory condition Caused by infection, allergy, or autoimmune
disease Involves the immune system
Gouty Arthritis Occurs when crystals (uric acid or calcium
salts) Form within synovial fluid Due to metabolic disorders
Rheumatoid Arthritis
RA begins with synovitis of the affected joint Inflammatory blood cells migrate to the
joint, release inflammatory chemicals Inflamed synovial membrane thickens into a
pannus Pannus erodes cartilage, scar tissue forms,
articulating bone ends connect (ankylosis)
Figure 8.15
Gouty Arthritis
Deposition of uric acid crystals in joints and soft tissues, followed by inflammation
More common in men Typically affects the joint at the base of the
great toe In untreated gouty arthritis, the bone ends
fuse and immobilize the joint Treatment: drugs, plenty of water,
avoidance of alcohol
Aging
Joint Immobilization Reduces flow of synovial fluid Can cause arthritis symptoms Treated by continuous passive motion
(therapy) Bones and Aging
Bone mass decreases Bones weaken Increases risk of hip fracture, hip dislocation,
or pelvic fracture
Joints (Arthroplasty)
Arthroplasty Joints may be replaced surgically with artificial joints Most commonly replaced are the hips, knees, and
shoulders Hip Replacements
Partial hip replacements involve only the femur Total hip replacements involve both the acetabulum and
head of the femur Knee Replacements
Actually a resurfacing of cartilage and may be partial or total
Potential complications of arthroplasty include infection, blood clots, loosening or dislocation of the replacement components, and nerve injury
Joints (Arthroplasty)
Joints (Arthroplasty)
Osteoarthritis (OA)
Common, irreversible, degenerative (“wear-and-tear”) arthritis
85% of all Americans develop OA, more women than men
Probably related to the normal aging process
Osteoarthritis (OA)
More cartilage is destroyed than replaced in badly aligned or overworked joints
Exposed bone ends thicken, enlarge, form bone spurs, and restrict movement
Treatment: moderate activity, mild pain relievers, capsaicin creams, glucosamine and chondroitin sulfate
Lyme Disease
Caused by bacteria transmitted by the bites of ticks
Symptoms: skin rash, flu-like symptoms, and foggy thinking
May lead to joint pain and arthritis Treatment: antibiotics
Integration with Other Systems
Bone Recycling Living bones maintain equilibrium between
Bone building (osteoblasts) And breakdown (osteoclasts)
Factors Affecting Bone Strength Age Physical stress Hormone levels Calcium and phosphorus uptake and excretion Genetic and environmental factors
Integration with Other Systems
Bones Support Body Systems The skeletal system
Supports and protects other systems Stores fat, calcium, and phosphorus Manufactures cells for immune system
Disorders in other body systems can cause Bone tumors Osteoporosis Arthritis Rickets (vitamin D deficiency)
Integration with Other Systems
Figure 9–13 Functional Relationships between the Skeletal System and Other Systems.
Integration with Other Systems
Figure 9–13 Functional Relationships between the Skeletal System and Other Systems.