Chapter 9-- Joints

Chapter 9-- Joints

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Famous Quotes• I figured my body always would be able

to repair itself. I think all of us believe that – until you begin to age and get hit with deteriorating joints. Lee Majors

• It had not occurred to me that marriage requires the same effort as a career. And unlike a career, marriage requires a joint effort. Jessica Savitch (1947-1983)

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Ch. 9 (Joints) Study Guide 1. Critically read Chapter 9 pp. 278-297 before 9.3

(Anatomy of selected diarthroses). Study all figures in the PowerPoint slides as well.

2. Comprehend Terminology (those in bold in the textbook) within the reading scope above

3. Study-- Figure questions, Think About It questions, and Before You Go On (section-ending) questions (within the reading scope above)

4. Do end-of-chapter questions—– Testing Your Recall— 1-4, 6-7, 9, 11-16, 18– True or False– 2, 4, 5, 9, 10

5. Review/study review sheet document (4 pages) posted on Blackboard

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I. Overview of the joints

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Figure 9.1– a gymnast and joint flexibility

§ Why Knuckles Crack and Joints Creak

• Some peoples' bodies play a percussive symphony of cracking and creaking, thanks to the large orchestra of noise-making human joints.

• What's behind it all?

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§ Joints and their names1. What are joints?• Arthrology = study of the joints• Kinesiology = study of musculoskeletal

movement (motion of human body)2. How joints are named?• From the names of the bones involved• Ex. The atlantoccipital joint • Ex. The humeroscapular joint

II. Functional classification of joints

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1. Are all joints able to move?– Immovable joints– where? Why?– Less movable– ex. vertebral column; why?– Moveable—shoulder, elbow, knee

2. Functional classification (freedom of movement)– synarthrosis (little/no movement) (“Syn”--

together)– amphiarthrosis (slightly movable)– diarthrosis (freely movable) (‘Dia”– through)

III. Structural classification of joints

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§ Structural classificationHow adjacent bones are joined?

1. Bony joints (synostosis; synarthrosis)– two bones fused

2. Fibrous joints (synarthrosis)—held together by collagen fibers; lack a synovial cavity

3. Cartilaginous joints (amphiarthrosis)– held together by cartilage; lack a synovial cavity

4. Synovial joints (diarthrosis)– having synovial (joint/articular) cavity (Fig. 9.5 next slide)

Fig. 9.5 Synovial Joint• Joint in

which two bones are separated by a space called a synovial (joint) cavity

• Most are freely movable

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§ 1. Bony Joints (Synostosis)A. Gap between “two bones ossify”–

become a single bone• TWO frontal/mandibular bones in infants

B. Can occur in either fibrous joints or cartilaginous as well; Examples:• Aging: cranial sutures (fibrous joints)

destroyed (ex. Parietal bones fuse) in elderly• Aging: attachment of first rib to the sternum

(cartilaginous joint) becomes a synostosis with age

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§ 2. Fibrous Joints (Synarthrosis-Amphiarthrosis)

• Collagen fibers span the space between bones

• Three kinds of fibrous joints– A. Sutures— the fibers are short and

allow for little movement – B. Gomphoses— the fibers are also _____

and allow for little movement; between teeth and the jaw

– C. Syndesmoses—longer fibers and more movable

• Figure 9.2

Fig. 9.2

SutureGomphosis

Syndesmosis9-15

Fibrous Connective Tissue

AB

R. Tibia

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• Immovable fibrous joints– Bind bones together; only in skull

• 3 types— (Fig. 9.3 next slide)• Serrate sutures - interlocking

lines– coronal, sagittal and lambdoid

sutures• Lap sutures - overlapping

beveled edges– Between temporal and parietal

bones; Name the suture? • Plane sutures - straight,

nonoverlapping edges– palatine processes of the maxillae

Fibrous Joint – A. Sutures

Suture

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Serrate suture Lap suture Plane suture

Dovetail joint Miter joint Butt joint

BoneWood

Three types of suture--

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Fibrous Joint – B. Gomphoses• Attachment of a tooth to

its socket • Held in place by fibrous

periodontal ligament– Consisting of collagen

fibers attach teeth to jawbones (which bones?)

• Little movement (Synarthrosis) while chewing Gomphoses

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• Two bones bound by broad fibrous sheet called– Interosseous membrane

• More/less movable than that of sutures/gomphoses

• Examples: radius to ulna (a more movable one, Amphiarthrosis) allow supination and pronation (next slide); tibia to fibula (less movable one)

Fibrous Joint – C. Syndesmosis

Tibia & fibula

Syndesmosis

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Supination and Pronation• For example: In the

forearm• Supination

– rotation of forearm so that the palm faces forward

• Pronation– rotation of forearm so

the palm faces to the rearA BSupine means up. In order to carry a bowl of soup, your hand must be in the supine position

Check point question #1--

• Functionally, why are sutures classified as synarthroses, and syndesmoses as amphiarthroses?

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§ 3. Cartilaginous Joints (amphiarthrosis)

Two bones are linked by cartilage

Two types– A. synchondroses and B. symphyses

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Cartilaginous Joint – A. Synchondrosis

• Bones are joined by hyaline cartilage

• Examples:– First rib attachment

to sternum (A on the right)

– Temporary joint between epiphysis and diaphysis in growing bones: called Epiphyseal ?__________

A

B, next

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Cartilaginous Joint – B. Symphyses• 2 bones joined by

fibrocartilage• Examples:

– See figure at right

• Only slight amount of movement is possible

• Examples– 1 & 2 on the right

1

2

Check point question #2--• What is the structural difference in

histology between a synchondrosis and a symphysis?

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IV. Focusing on synovial joints

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§ 4. Synovial Joint• Most are freely movable;

two bones in fact Do / Do not touch each other

• Two bones are separated by a space called A. _________ cavity (with fluid in it) and a soft tissue called B._____________

• B. Articular cartilage -- hyaline cartilage covering the joint surfaces

• Synovial fluid —a lubricant; feeds cartilages

A B

Next slide

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§ Synovial joints1. Joint (Articular) capsule encloses joint cavity

– (Outer) Fibrous capsule: continuous with periosteum– (Inner) synovial membrane; secretes ____________

2. Articular discs or menisci: cartilage grows inward and forms pads (Fig. 9.29 c-d; 8.39)– jaw, wrist, sternoclavicular and knee joints– absorbs shock, guides bone movements and

distributes forces• Tendon: attaches muscle to bone• Ligament: attaches bone to bone

Knee Joint

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Right Knee Joint – Superior View

• Medial meniscus & lateral meniscus absorb shock and shape joint

Lateral condyle of tibia Medial condyle of tibia

?

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PCL

ACL

9-31Anterior view Posterior view

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§ Tendon Sheaths and Bursae• Bursa = a sac

filled with synovial fluid

• Tendon sheaths = elongated bursae lined with synovial membrane and wrapped around a tendon

Ulnar bursa

Tendon sheaths

Tendons (flexor digitorum)

Tendon Sheaths and Bursae• Bursa = a sac filled with synovial fluid

– (Locations) between muscles or between a tendon & a bone etc.; Good examples– Shoulder joint etc. Fig. 9.24

• Tendon sheaths = elongated bursae – (Locations) where there is considerable friction; such

as the hand, wrist, fingers, the ankle, foot, toes etc.• Functions of bursa and tendon sheaths:

– Reduce friction in joints (such as the shoulder), – Cushion the movement of one body part over

another

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Fig. 9.24 Humeroscapular joint

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Check point question #3--• A) What is the functional

classification of synovial joints?• B) Why is a meniscus in an

interphalangeal joint unnecessary?

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V. Types of synovial joints

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§ 6 Types of Synovial Joints—in descending order of mobility

1.

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1. Ball-and-Socket Joints• Features: Smooth hemispherical head

fits within a cuplike depression• Examples:

– (shoulder) head of humerus into glenoid cavity of scapula

– (hip) head of femur into acetabulum of hip bone

• Type: only multiaxial joints in the body• Demonstration: (next slide)

Planes of movement (A-C) & axes of rotation• Shoulder joint has 3

degrees of freedom = multiaxial joint;

• Other joints – monoaxial or biaxial

• Axis of rotation– Def.--perpendicular to the plane of movement; examples— A, B, C

The arm rises in the frontal plane

The arm moves through the sagittal plane

The arm rotates in the transverse plane

A

B

C

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Planes of movement & axes of rotation• A—Abduction

(away from midline) vs. adduction

• B—Flexion (decreases a joint angle) vs. extension

• C—Medial (internal) rotation vs. lateral rotation

The arm rises in the frontal plane

It moves through the _________ plane

The arm rotates in the ______ plane

A

B

C

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2.

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2. Condyloid (ellipsoid) Joints• Features: Oval convex surface on one

bone fits into a similarly shaped depression on the next

• Examples:– radiocarpal joint of the wrist – metacarpophalangeal joints at the bases of

the fingers• Type: Biaxial joints– why?• Demonstration: index finger (or 2nd - 5th

digits) and Fig. 9.21

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When someone is abducted, they are taken away, just as abduction takes the limb away from the body.

During adduction, the limb is added to the body.

Metacarpophalangeal joints

3.

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Condyloid joint

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3. Saddle Joints• Features: Each articular surface is

shaped like a saddle, concave in one direction and convex in the other bone (like a sitting rider)

• Examples: trapeziometacarpal joint at the base of the thumb

• Type: Biaxial joint (see demo below)• Demonstration:

– A) frontal plane (palmar abduction)– B) sagittal plane (opposition)

primates’ anatomical hallmark: __________Fig. 1.5 & 9.21 c-d

The thumbs became opposable; they made the hands prehensile

Monkey

Human

Primate adaptations:

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Figure 9.21d

ID this movement of thumb 9-50

Figure 9.21e

ID this movement of thumb 9-51

4.

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4. Gliding (plane) Joints• Features: Flat articular surfaces in

which bones slide over each other• Examples: Fig. Z tarsal bones

– between the carpal bones of the wrist, – the tarsal bones of the ankle, – articular processes of the vertebrae

• Type: Biaxial joints• Demonstration: head is tilted side-to-

side and back-and-forth, the vertebrae slide accordingly

Gliding

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TalusCalcaneus

Cuboid(Intermediate)

(Lateral)

Medial cuneiform

Can Talented Naval Medics Interest Lazy Cubs?

5.

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Anterior view

Capitulum

Funny bone

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5. Hinge Joints• Features: One bone with convex surface

that fits into a concave depression on other bone

• Examples:– ulna and humerus at elbow joint (trochlea of the

humerus fits into the trochlear notch of the ulna)– femur and tibia at knee joint (tibiofemoral)– finger and toe joints (interphalangeal)

• Type: Monaxial (uniaxial) joints

• Fig. 9.25b

A hinge joint --the elbow

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(Trochlear notch)

6.

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6. Pivot Joints• Features: One bone rotates on its

longitudinal axis relative to the other• Examples:

– proximal radioulnar joint; the radius pivots during pronation and supination

– atlantoaxial joint (dens of axis to atlas); Fig. 8.24 (rotation of the atlas)

• Type: Monaxial joints• Demonstration: see next 3 slides

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Supination and Pronation• For example: In the

forearm• Supination

– rotation of forearm so that the palm faces forward

• Pronation– rotation of forearm so

the palm faces to the rearA B

9-63of the atlas (the next slide)

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(C1)

(C2)

?

Anterior arch

Check point question #4--• Which of the 6 type of synovial

joints are biaxial?• Give one specific example for each

biaxial synovial joint.

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Questions (muddiest points)?

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