Chapter 09 Lecture Outline

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Chapter 09

Lecture Outline

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9.1 Classification of Joints

• Joints (articulations)

– Places of contact between bones, bones and

cartilage, or bones and teeth

– Arthrology—study of joints

2


• Range of motion at joints

– Motion ranges from no movement to extensive

movement

– Structure of each joint determines its mobility and

stability

– Inverse relationship (tradeoff) between mobility

and stability

o For example, skull sutures are immobile but very stable

3


• What are the functional classes of joints?

– Synarthroses

o Immobile joints

o Can be fibrous or cartilaginous joints

– Amphiarthroses

o Slightly mobile joints

o Can be fibrous or cartilaginous joints

– Diarthroseso Freely mobile joints

o All synovial joints

4

• What are the structural classes of joints?

– Fibrous joint

o Bones held together by dense connective tissue

– Cartilaginous joint

o Bones joined by cartilage

– Synovial joint

o Bones joined by ligaments with fluid-filled joint cavity

separating bone surfaces


5

Figure 9.16

9.2 Fibrous Joints

• Characteristics of fibrous joints

– Connected by dense regular connective

tissue

– Have no joint cavity

– Immobile or only slightly mobile

– Three most common types

o Gomphoses

o Sutures

o Syndesmoses

7

9.2a Gomphoses

• Gomphoses (peg in a

socket)

– Articulations of teeth with

sockets of mandible and

maxillae

– Tooth held in place by

fibrous periodontal

membranes

– Function as synarthroses

Figure 9.2a

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9.2b Sutures

• Sutures (seams)– Found between some skull bones

o Very short fibers

– Interlocking, irregular edges

o Increase strength and decrease risk

of fracture

– Function as synarthroses

– Allow growth in childhood

– Become ossified synostoses in

older adults

Figure 9.2b

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9.2c Syndesmoses

• Syndesmoses

– Bound by interosseous

membrane, broad

ligamentous sheet

– Found between radius and

ulna and between tibia and

fibula

– Function as amphiarthroses

o Provide pivot for two long

bonesFigure 9.2c

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10

Copyright © 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill EducationCopyright © 2016 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education

What did you learn?

• Where are gomphoses

located?

• Where can I find

syndesmoses joints?

• Functionally, how are

syndesmoses classified? (In

other words, how much

movement do they allow?)

11

9.3 Cartilaginous Joints

• Properties of cartilaginous joints

– Either hyaline cartilage or fibrocartilage

between bones

– Lack a joint cavity

– Immobile or slightly mobile

– Synchondroses or symphyses

12

9.3a Synchondroses

• Synchondroses

– Bones joined by hyaline cartilage

– Immobile (synarthroses)

Figure 9.3a

13

9.3b Symphyses

• Symphyses

– Pads of fibrocartilage between articulating bones

o Resist compression and act as shock absorbers

– Allow slight mobility (amphiarthroses)

Figure 9.3b

14


What did you learn? • What type of cartilage is

found in a synchondrosis?

• What type of cartilage is

found in a symphyses?

15

9.4a Distinguishing Features and

Anatomy of Synovial Joints

• Synovial joints

– Bones separated by a joint cavity

– Include most joints in the body

– Diarthroses (freely mobile)

16

Figure 9.417



All with the basic features

o Articular capsule and joint cavity

o Outer fibrous layer and Inner synovial membrane

o Joint cavity

o synovial fluid lubricates articular cartilage

o Articular cartilage

o Hyaline cartilage (avascular)

o Reduces friction during movement

o Ligaments, nerves, and blood vessels

o Stabilize, strengthen, and reinforce synovial joints

o Numerous nerves detect painful stimuli

18



• Bursae

– Fibrous, saclike structures containing synovial fluid

– Lined internally by synovial membrane

– Found in synovial joints where bones, ligaments, muscles,

skin, or tendons rub together

– Connected to or separate from joint cavity

– Alleviate friction

19



• Other accessory structures

– Tendon sheaths, elongated bursae

o Wrap around tendons where friction is excessive

o Common in wrist and ankle

– Fat pads

o Act as protective packing material in joint periphery

o Can fill spaces when joint shape changes

20

Figure 9.5a

21

Figure 9.5b

22

9.4b Classification of Synovial Joints

• Classified by movements allowed and shapes

of joint surfaces

• Classes by movement– Uniaxial joint

o Bone moves in just one plane or axis

– Biaxial joint

o Bone moves in two planes or axes

– Multiaxial joint

o Bone moves in multiple planes or axes

23


• Classes by shape of joint surfaces (from least to

most mobile)– Plane joints

– Hinge joints

– Pivot joints

– Condylar joints

– Saddle joints

– Ball-and-socket joints

24

Figure 9.625


• Plane joint– Articular surfaces flat

– Simplest, least mobile synovial articulation

– Uniaxial: limited side-to-side gliding movement in a single plane

• Hinge joint– Convex surface within concave depression

– Uniaxial: like the hinge of a door

• Pivot joint– Bone with rounded surface fits into ligament ring

– Uniaxial joint: rotation on longitudinal axis

26


• Condylar joint– Oval, convex surface articulating with concave surface

– Biaxial

• Saddle joint– Convex and concave surfaces resembling saddle shape

– Biaxial

• Ball-and-socket joint– Spherical head of one bone fitting into cuplike socket

– Multiaxial, permitting movement in three planes

– The most freely mobile type of joint

27

9.6b Angular Motion

• Angular motion

– Increases or decreases angle between two bones

– Includes specific types

o Flexion and extension

o Hyperextension

o Lateral flexion

o Abduction and adduction

o Circumduction

28

9.6b Angular Motion

• Flexion

– Movement in an anterior-posterior plane

– Decreases the angle between bones: brings bones closer together

– E.g., bending finger

• Extension

– Also in anterior-posterior plane, but opposite of flexion

– Increases angle between articulating bones

– E.g., straightening your fingers after making a fist

29

9.6b Angular Motion

• Hyperextension

– Joint extended more than 180 degrees

– E.g., glancing up at the ceiling while standing

• Lateral flexion

– Trunk of body moving in coronal plane laterally

– Occurs between vertebrae in the cervical and

lumbar region

30

Figure 9.831

Flexion, Extension, Hyperextension,

and Lateral Flexion

9.6b Angular Motion

• Abduction

– Lateral movement of body part away from midline

– E.g., arm or thigh moved laterally from body

midline

• Adduction

– Medial movement of body part toward midline

– E.g., thigh brought back to midline

32

Figure 9.9 33

Abduction and Adduction

9.6b Angular Motion

• Circumduction

– Proximal end of

appendage

relatively stationary

– Distal end makes a

circular motion

– Movement makes

an imaginary cone

shape

– E.g., drawing a

circle on the

blackboard(both) © The McGraw-Hill Companies, Inc./JW Ramsey, photographer

34Figure 9.10

9.6c Rotational Motion

• Rotation

– Bone pivots on its own longitudinal axis

– Lateral rotation

o Turns anterior surface of bone laterally

– Medial rotation

o Turns anterior surface of bone medially

– Pronation

o Medial rotation of forearm so palm of hand posterior

– Supination

o Lateral rotation of forearm so palm of hand anterior

35

Figure 9.1136

Rotational Movements

9.6d Special Movements

• Depression

– Inferior movement of a body part

– E.g., movement of mandible while opening mouth

• Elevation

– Superior movement of a body part

– E.g., movement of mandible when closing mouth

37

38Figure 9.12a

Special Movements Allowed at Synovial Joints


• Dorsiflexion– Limited to ankle joint

– Talocrural (ankle) joint bent so the

dorsum (superior surface) of foot

moves toward the leg

– E.g., when digging in your heels

• Plantar flexion– Talocrural joint bent so dorsum

pointed inferiorly

– E.g., ballerina on tiptoes in full

plantar flexion

Figure 9.12b39


• Inversion

– Occurs only at intertarsal

joints of the foot

– Sole turns medially

• Eversion

– Occurs only at intertarsal

joints of foot

– Sole turns laterally

Figure 9.12c


• Protraction

– Anterior movement from

anatomic position

– E.g., jutting jaw anteriorly at

temporomandibular joint

• Retraction

– Posterior movement from

anatomic position

– E.g., pulling in jaw

posteriorly at

temporomandibular joint

Figure 9.12d


• Opposition

– Movement of thumb toward

tips of fingers at

carpometacarpal joint

– Enables the thumb to grasp

objects

• Reposition

– Opposite movement

Figure 9.12e

9.7a Temporomandibular Joint

• Features of the temporomandibular joint

(TMJ)

– Head of mandible articulates with temporal bone

– Only mobile joint between bones in the skull

– Has loose articular capsule

• Surrounds joint

• Promotes extensive range of motion

– Hinge, gliding, and some pivot

– Joint moves anterior and inferior during jaw opening

– Has articular disc

• Thick pad of fibrocartilage

• Divides synovial cavity into two chambers

43

Figure 9.13

44

Temperomandibular Joint

Clinical View: TMJ Disorders

• Most common due to alteration in the ligaments

securing the joint

• Possible spasm in the lateral pterygoid muscle

• Articular disc forced out of normal position

• Clicking or popping heard as person opens or

closes mouth

• Possible pain in joint, paranasal sinuses,

tympanic membrane, oral cavity, eyes, and teeth

45

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9.7b Shoulder Joint

• Sternoclavicular Joint

– Saddle joint

– Formed by manubrium and sternal end of clavicle

– Articular disc

o Partitions joint into two parts forming two synovial

cavities

– Elevation, depression, circumduction possible

– Stability provided by fibers and ligaments

o Makes this specific joint very stable and difficult to

dislocate

47

48

Sternoclavicular

Joint

9.7b Shoulder Joint

• Acromioclavicular Joint

– Plane joint

– Formed from acromion and lateral end of clavicle

– Fibrocartilaginous articular disc within joint cavity

– Joint capsule strengthened superiorly by acromioclavicular

ligament

– Clavicle bound to coracoid process by coracoclavicular

ligament

o If torn, acromion and clavicle no longer align (shoulder

separation)

49

9.7b Shoulder Joint

• Glenohumeral (Shoulder) Joint

– Ball-and socket joint

o Formed by head of humerus and glenoid cavity of scapula

– Permits greatest range of motion of any joint in the

body

o Most unstable and most frequently dislocated

– Fibrocartilaginous glenoid labrum

• Encircles the socket in all directions except inferior

– Abundant bursae

o Decrease friction where tendons and muscles extend across

capsule

50

9.7b Shoulder Joint

• Glenohumeral (Shoulder) Joint (continued)

– Supporting ligaments and tendons

o Coracoacromial ligament, coracohumeral ligament,

glenohumeral ligaments

o Tendon of long head of biceps brachii

– Most joint stability due to rotator cuff muscles

o Subscapularis, supraspinatus, infraspinatus, teres minor

o Work as a group to hold head of humerus in glenoid cavity

o Tendons encircle joint and fuse with articular capsule

51

Figure 9.15a

52

Acromioclavicular

and Glenohumeral

Joints

Figure 9.15b-c

53

Acromioclavicular and Glenohumeral Joints

9-54

Shoulder Joint Dislocations

• Shoulder separation refers to

acromioclavicular dislocation

– Pain when arm abducted more than

90 degrees

– Acromion appearing prominent

• Shoulder dislocation

– Downward displacement of the humerus is the most common shoulder dislocation

– Dislocations most often occur when the arm is abducted and then receives a blow from above

• Children especially prone to dislocation

9.7c Elbow Joint

• Elbow is a hinge joint composed of two articulations

- Humeroulnar joint

o Trochlear notch of ulna articulating with trochlea of

humerus

- Humeroradial joint

o Capitulum of humerus articulating with head of radius

- Both enclosed within a single articular capsule

55

Figure 9.16a-b

56

Elbow Joint

9.7c Elbow Joint

• Elbow is very stable because

– Articular capsule is thick

– Bony surfaces of humerus and ulna interlock closely

– Multiple, strong ligaments reinforce articular capsule

o Radial collateral ligament

– Stabilizes joint at lateral surface

– Extends around head of radius

o Ulnar collateral ligament

– Stabilizes medial side of the joint

– Extends from medial epicondyle of humerus to coronoid and olecranon of

ulna

o Anular ligament

– Surrounds the neck of the radius

– Binds head of the radius to the ulna

57

Clinical View: Subluxation of the Head

of the Radius

• Subluxation refers to incomplete dislocation

• Subluxation of the head of the radius

– Head pulled out of anular ligament

– Occurs almost exclusively in children (usually < 5 yrs)

• Nursemaid’s elbow: subluxation when in pronation

– Child’s anular ligament thin and radial head not fully

formed

– Doctor may maneuver radial head back into anular

ligament

58

9.7d Hip Joint

• What are the main components and functional

characteristics of the hip joint?– Articulation between head of the femur and acetabulum of

os coxa

– Acetabular labrum—fibrocartilaginous ring that deepens

socket

– More stable, less mobile than glenohumeral joint

59

Figure 9.17c-d60

Hip Joint

9.7d Hip Joint

• Intracapsular ligaments

– Iliofemoral ligament

o Ligament providing support for anterior articular capsule

– Ischiofemoral ligament

o Intracapsular ligament posteriorly located

– Pubofemoral ligament

o Triangular thickening of capsule’s inferior region

– Become taut when hip extended

• Ligament of the head of femur (ligamentum teres)

– Small ligament from acetabulum to fovea of head of femur

– Provides no strength

– Contains artery supplying head of femur

61

Figure 9.17a-b 62

Hip Joint

Clinical View: Fracture of the Femoral Neck

• Fracture of femur is often incorrectly referred to as

“fractured hip”

• Intertrochanteric fractures

– Extracapsular fractures

– Usually in younger and middle-aged individuals

• Subcapital fractures

– Occur within hip articular capsule

– Usually in elderly people with osteoporosis

– May result in tearing of retinacular arteries

o May have avascular necrosis in the region

63

Figure 9.18a-b 64

Knee Joint

9.7e Knee Joint

• Structures of the knee joint

– Articular capsule

o Encloses only medial, lateral, and posterior knee regions

– Quadriceps femoris muscle tendon

o Passes over knee’s anterior surface, surrounds patella

– Patellar ligament

o Extends from patella to tibial tuberosity

– Fibular collateral ligament

o Reinforces lateral surface of joint

o Extends from femur to fibula

o Prevents hyperadduction

65

9.7e Knee Joint

• Structures of the knee joint (continued )

– Tibial collateral ligament

o Reinforces medial surface of joint

o Extends from femur to tibia

o Prevents hyperabduction

– Medial meniscus and lateral meniscus

o Deep to articular capsule within knee joint

o C-shaped fibrocartilage pads on top of tibial condyles

o Cushioning between articular surfaces

o Change shape to conform to articulating surfaces

o Partially stabilize joint medially and laterally

66

9.7e Knee Joint

• Structures of the knee joint (continued )– Cruciate ligaments—cross each other

o Deep to articular capsule

– Anterior cruciate ligament (ACL)

o Extends from posterior femur to anterior tibia

o Prevents hyperextension and anterior displacement of tibia

– Posterior cruciate ligament (PCL)

o Extends from anteroinferior femur to posterior tibia

o Prevents hyperflexion and posterior displacement of tibia

67

Figure 9.18c-d 68

Knee Joint

Clinical View: Knee Ligament and

Cartilage Injuries

• Tibial collateral ligament injury when leg forcibly abducted

• Fibular collateral ligament injury when medial side of knee is

struck

• ACL injury when leg hyperextended

• PCL injury when leg hyperflexed

• Meniscus injury due to trauma and/or overuse

• Unhappy triad: injury of tibial collateral ligament, medial

meniscus, and ACL

– Occurs due to a lateral blow to the knee that abducts and

laterally rotates leg

69

9.7f Talocrural (Ankle) Joint

• Talocrural joint

– Highly modified hinge joint

– Permits dorsiflexion and plantar flexion

– Includes two articulations within one joint capsule

o Between distal end of tibia and talus

o Between distal end of fibula and lateral aspect of talus

70

Figure 9.19a 71

Talocrural Joint

Figure 9.19b

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 72

Talocrural Joint

9.7f Talocrural (Ankle) Joint

• Anatomical features of talocrural joint

– Medial and lateral malleoli of tibia and fibula

o Prevent talus from sliding medially or laterally

– Articular capsule covers distal tibia, medial malleolus, lateral

malleolus, and talus

– Deltoid ligament binds tibia to foot on medial side

o Prevents overeversion

– Lateral ligament binds fibula to foot on lateral side

o Prevents overinversion

o Prone to sprains and tears

– Anterior and posterior tibiofibular ligaments

73

Clinical View: Ankle Sprains and Pott Fractures

• Sprain

– Stretching or tearing of ligaments without fracture or dislocation

– Results from twisting foot, usually overinversion

– Fibers of lateral ligament stretched or torn

– Localized swelling and tenderness anteroinferior to lateral

malleolus

• Pott fracture

– Occurs with overeversion

– Medial malleolus avulsed off of tibia (fracture)

– Talus moves laterally and fractures fibula

74


What did you learn?

• What direction does the jaw move

when opening?

• What are the three joints that make

up the shoulder?

• What is the common direction for

shoulder dislocation?

• What makes the elbow so stable?

• What are the 3 main ligaments of

the hip?

• What makes up the unhappy triad

of the knee?

75

9.8 Development and Aging of the Joints

• Arthritis

– Rheumatic disease involving damage to articular cartilage

– Osteoarthritis

o Primary problem of aging joint due to wear and tear

• Exercise and joint health

– Increases flow of synovial fluid to chondrocytes

– Strengthens muscles that support and stabilize joints

– In extreme, may aggravate potential joint problems and

may worsen osteoarthritis

76

Clinical View: Arthritis

• Arthritis

– Group of inflammatory or degenerative diseases of the joints

– Symptoms of joint swelling, pain, and stiffness

• Gouty arthritis

– Typically seen in middle-aged or older males

– Due to increased levels of uric acid

• Osteoarthritis

– Degenerative joint condition in older individuals

– Due to wearing down of articular cartilage

– Fingers, knuckles, hips, knees, and shoulders most affected

• Rheumatoid arthritis

– Seen in younger to middle-aged adults, often women

– Autoimmune disorder

– Starts with synovial membrane inflammation77

Chapter 09 Lecture Outline

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