Joints of the Skeletal System

2

JointsFunctions • Childbirth• Movement• Bone growth possible

3

Classification of Joints - Function

**How much movement they allow**

•Synarthrotic joints• Immovable

• Amphiarthrotic joints• Slightly movable

• Diarthrotic joints• Freely movable

4

Classification of Joints – Structure

(1) Fibrous joints• Dense connective tissues • Between bones in close contact

(2) Cartilaginous joints• Hyaline or fibrocartilage

(3) Synovial joints• Most complex• Allow free movement

(1) Fibrous Joints

• synarthrotic• flat bones• thin layer of CT

• Skull

* Synostoses

Margin ofsuture

Parietalbone

Suture

Suturalbones

Occipitalbone

(a)

• 3 types

1. Suture

(1) Fibrous Joints

2. Syndesmosis:• Amphiarthrotic• Fibrous tissue connection• Interosseous membrane

• Tibia/Fibula• Radius/Ulna

Fibula

Interosseusmembraneof leg

Tibia

7

(1) Fibrous Joints

3. Gomphosis:• Synarthroses

• Tooth in jawbone

Periodontalligament

Alveolarprocess ofmandible

Root oftooth

Crown oftooth

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(2) Cartilaginous Joints

2 types 1. Synchondrosis

• Synarthrotic• Hyaline cartilage

• Sternum & first rib• Epiphyseal line

Thoracicvertebra

Costal cartilage

Manubrium

First rib

9

(2) Cartilaginous Joints2. Symphysis:

• Amphiarthrotic• Fibrocartilage + Hyaline• Pubic Symphysis and Intervertebral Discs

Gelatinouscore

Spinous process

Band offibrocartilage

Pubis

Fibrocartilage disc of symphysis pubis

Intervertebraldiscs

(a) (b)

Body ofvertebra

10

(3) Synovial Joints

• Diarthrotic• 5 distinguishing features:

• Articular cartilage (hyaline)• Joint (articular) capsule• Joint cavity

• Synovial fluid• Ligaments

Spongybone

Joint cavityfilled withsynovialfluid Synovial

membrane

Articularcartilage

Jointcapsule

Figure 5.28

• Tendon attaches muscle to bone• Ligament attaches bone to bone

Odds and Ends: - Bursae - Tendon sheaths

12

Synovial Joints: Movement

Factors that affect synovial joint stability (3)1. Articular Surfaces2. Ligaments3. Muscle Tone

Types of synovial joint movement1. Non-axial

2. Uniaxial3. Biaxial4. Multiaxial

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Types of Synovial Joints

• Gliding (Plane)• Non-axial• Between carpals• Between tarsals

Carpals

• Hinge• Uniaxial• Elbow joint• Femur and tibia (**modified)• Between phalanges

Humerus

Ulna

Radius

Types of Synovial Joints

• Pivot Joint• Uniaxial • Between atlas (C1) & axis (C2)

(e) Pivot joint

Dens

Transverseligament

Atlas

Axis

• Condylar Joint• Biaxial• Between metacarpals and phalanges• Between radius and carpals

Metacarpal

Phalanx

Types of Synovial Joints

• Saddle Joint• Biaxial• Between carpal and 1st metacarpal (of thumb)

Firstmetacarpal

Trapezium

• Ball-and-Socket Joint• Multiaxial• Hip joint• Shoulder joint

Hip bone

Head of femurin acetabulum

Femur

9-16

Shoulder JointCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Head of humerus

Joint cavity

Joint capsule

Articular cartilage

Scapula

Humerus

Clavicle

(a)

Humerus

Articular cartilage

Scapula

Acromion process Subdeltoid bursa

Synovial membrane

Joint capsule

Joint cavity

20

Hip JointCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

(b)

Joint cavity

Articularcartilage

Hip bone

Head of femur

Joint capsule

Femur

© Paul Reimann

Ilium

IliofemoralligamentGreatertrochanter

Femur

Lessertrochanter

Pubis

Pubofemoralligament

Ischium

IliofemoralligamentIschiofemoralligament

Femur

Ilium

(a) (b)

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

21

Elbow Joint

Radius

Tendon of bicepsbrachii muscle

Anular ligament

Humerus

Medialepicondyle

Ulnar collateral ligamentCoronoid processUlna

Humerus

Lateral epicondyle

Anular ligament Radius

Olecranon process Radial collateral ligament Ulna

(b)(a)

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

24

Knee Joint

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Anterior cruciateligament

Femur

(b)

Lateral condyle

Lateral meniscus

Articularcartilage

Lateralcondyle

Head of fibula

Tibia

Fibula

© Paul Reimann

Gastroc-nemiusmuscle(cut)

Popliteusmusclecut)

Obliquepoplitealligament

Arcuatepoplitealligament

Fibula Tibia

Femur

Jointcapsule

Fibularcollateralligament

Plantarismuscle(cut)

Tibialcollateralligament

Tendon ofsemimembranosus(cut)

(a) (b)

Femur

Lateralcondyle

Lateralmeniscus

Lateralcondyle

Fibularcollateralligament

Fibula

Tibia

Medialcondyle

Anteriorcruciateligament

Medialmeniscus

Medialcondyle

Tibialcollateralligament

Patellarligament(cut)

Posteriorcruciateligament

Tendon ofadductormagnus (cut)

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Anterolateral Ligament (ALL)

25

26

Types of Joint Movements

4 general movements1. GlidingGliding

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Types of Joint Movements

9-28

Abduction (away from the midline)Adduction (towards the midline)

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Movement in which one end

of an appendage remains

stationary while the other

end makes a circular motion

9-30

Turning around long

axis

◦ rotation of trunk,

thigh, head or arm

Medial (inwards)

Lateral (outwards)

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◦Forearm

◦Supination

palm faces anterior

◦Pronation

palm faces posterior

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Dorsiflexion - raising of the toes

Plantarflexion -toes point downward

Inversion - soles are turned medially

Eversion - soles face laterally

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Protraction - movement

anteriorly on transverse

plane

◦ thrusting the jaw forward

◦ shoulders or pelvis forward

Retraction - movement

posteriorly

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Elevation – upward vertical movement ◦ mandibles are elevated during biting

◦ clavicles during a shrug

Depression – downward vertical movement

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When you touch your finger to your thumb

Grasping

Manipulation of objects

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Bones pulling apart Stretching synovial joint capsule = increasing volume Increase volume = decrease pressure Decrease in volume means gasses lose solubility and form

bubbles◦ Cavitation

When pressure gets low enough, bubbles pop and that is the cracking sound

Takes about 25-30 minutes for gas to redissolve into joint. During this time you cannot crack that joint (it won’t make the sound)

Only 1 study done◦ Results – does not cause arthritis, may cause soft tissue damage and

decreased grip strength Due to repeated stretching of ligaments around joint

◦ Does show increased mobility9-41

SIGNS OF HYPERMOBILITY Can you touch the floor with the palms of your hands flat while the knees are straight? Can your elbows go beyond straight? Can your knees move beyond straight? Can you move your thumb to touch your forearm as shown? Can your little fingers be moved so they are perpendicular to the upper arm as shown?

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• Girls• Genetic• Disease• Issues

Sprains

Cartilage

Dislocation

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Musculoskeletal disorders 3 main types

◦ Osteoarthritis◦ Rheumatoid◦ Juvenile

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