12 Arthrology F16-2 - Lecture notes Arthology/Ch. 12 PDF

Preview

Summary

Professors: Mark Cook and Vincent Barnett...

Description

Arthrology

ANAT 3001

Arthrology (Joints) Chapter 9 ANAT 3001 Fall 2016 Dr. Barnett

•1

Joints • Rigid elements of the skeleton meet at joints or articulations • Greek root arthro means joint • Structure of joints o Enables resistance to crushing, tearing, and other forces

2

Barnett (2016)

1

Arthrology

ANAT 3001

Mobility vs. Stability

3

Classifications of Joints • Structural classification is based on: o Material that binds bones together o Presence or absence of a joint cavity o Structural classifications include: • Fibrous – multiple dense fibrous connective tissue strands • Cartilaginous – joined by gel-like cartilage connections • Synovial – surfaces of bones covered with cartilage and enclosed in a fluid-filled capsule

• Functional classification is based on: o

The amount of movement • Synarthroses — immovable; common in axial skeleton • Amphiarthroses — slightly movable; common in axial skeleton • Diarthroses — freely movable; common in appendicular skeleton (all synovial joints)

4

Barnett (2016)

2

Arthrology

ANAT 3001

Table 9.1 Summary of Joint Classes

5

Fibrous Joints • • • •

Bones are connected by fibrous connective tissue Do not have a joint cavity Most are immovable or slightly movable Types o Sutures o Syndesmoses o Gomphoses

Sutures

Syndesmoses

Gomphoses 6

Barnett (2016)

3

Arthrology

ANAT 3001

Sutures • Bones are tightly bound by a minimal amount of fibrous tissue • Occur only between the bones of the skull • Allow bone growth so the skull can expand with brain during childhood • Fibrous tissue ossifies in middle age o Synostoses—closed sutures

Joint is held together with very short, interconnecting fibers, and bone edges interlock. Found only in the skull.

7

Syndesmoses • Bones are connected exclusively by ligaments • Amount of movement depends on length of fibers o Tibiofibular joint—immovable synarthrosis o Interosseous membrane between radius and ulna • Freely movable diarthrosis

Joint is held together by a ligament. Fibrous tissue can vary in length but is longer than those found in sutures.

Fibula

Tibia

8

Barnett (2016)

4

Arthrology

ANAT 3001

Gomphoses • Tooth in a socket • Connecting ligament—the periodontal ligament

Peg-in-socket fibrous joint. Periodontal ligaments holds tooth in socket.

9

Cartilaginous Joints • Bones are united by cartilage • Lack a joint cavity • Two types o Synchondroses o Symphyses

10

Barnett (2016)

5

Arthrology

ANAT 3001

Synchondroses • Hyaline cartilage unites bones o Epiphyseal plates o Joint between first rib and manubrium

Figure 9.3a

11

Symphyses • Fibrocartilage unites bones; resists tension and compression • Slightly movable joints that provide strength with flexibility o Intervertebral discs o Pubic symphysis

• Hyaline cartilage—present as articular cartilage

Figure 9.4a

12

Barnett (2016)

6

Arthrology

ANAT 3001

Synovial Joints • Most movable type of joint • All are diarthroses • Each contains a fluid-filled joint cavity

Articular capsule

Synovial membrane

Fibrous layer Ligament

Articular Cartilage

Joint cavity (containing synovial fluid)

13

Structure of a synovial joint •

•

•

•

Articular cartilage •

Ends of opposing bones are covered with hyaline cartilage

•

Absorbs compression

Joint (articular) cavity •

Unique to synovial joints

•

Cavity is a potential space that holds a small amount of synovial fluid

Joint cavity (contains synovial fluid)

Articular capsule—joint cavity is enclosed in a two-layered capsule •

Fibrous layer —dense irregular connective tissue, which strengthens joint

•

Synovial membrane —loose connective tissue •

Lines joint capsule and covers internal joint surfaces

•

Functions to make synovial fluid

Articular (hyaline) cartilage Fibrous layer

Synovial fluid •

•

Barnett (2016)

Ligament

Synovial membrane

A viscous fluid similar to raw egg white •

A filtrate of blood • Arises from capillaries in synovial membrane

•

Contains glycoprotein molecules secreted by fibroblasts

Weeping lubrication—Pressure on joints squeezes synovial fluid into and out of articular cartilage

Articular capsule

Periosteum

see Figure 9.4 14

7

Arthrology

ANAT 3001

Synovial Joints with Articular Discs • Some synovial joints contain an articular disc o Occur in the temporomandibular joint and at the knee joint o Occur in joints whose articulating bones have somewhat different shapes Tendon of quadriceps femoris Femur

Suprapatellar bursa

Articular capsule

Patella

Posterior cruciate ligament

Subcutaneous prepatellar bursa

Lateral meniscus

Lateral meniscus

Synovial cavity Infrapatellar fat pad

Anterior cruciate ligament

Deep infrapatellar bursa

Tibia

Patellar ligament

Sagittal section through the right knee joint

Anterior Anterior cruciate ligament Articular cartilage on medial tibial condyle Medial meniscus Posterior cruciate ligament

Articular cartilage on lateral tibial condyle

Lateral meniscus

Superior view of the right tibia in the knee joint, showing the menisci and cruciate ligaments

Figure 9.15 Marieb Human Anatomy 6th edition

15

How Synovial Joints Function • Synovial joints—lubricating devices o Friction could overheat and destroy joint tissue o Are subjected to compressive forces • Fluid is squeezed out as opposing cartilages touch • Cartilages ride on the slippery film

16

Barnett (2016)

8

Arthrology

ANAT 3001

Synovial Joints Classified by Shape • Pivot joints o Classified as uniaxial—rotating bone turns only around its long axis o Examples • Proximal radioulnar joint • Joint between atlas and axis Uniaxial movement

Pivot joint

Vertical axis Sleeve (bone and ligament) Ulna

Axle (rounded bone) Rotation

Radius

Examples: Proximal radioulnar joints, atlantoaxial joint

17

Movements Allowed by Synovial Joints • Three basic types of movement o Gliding—one bone across the surface of another o Angular movement—movements change the angle between bones o Rotation—movement around a bone's long axis Angular movement

adduction

abduction

Gliding

Rotation 18

Barnett (2016)

9

Arthrology

ANAT 3001

Bursae and Tendon Sheaths • Bursae and tendon sheaths are not synovial joints o Closed bags of lubricant o Reduce friction between body elements

• Bursa—a flattened fibrous sac lined by a synovial membrane • Tendon sheath—an elongated bursa that wraps around a tendon

Acromion of scapula Subacromial bursa

Joint cavity containing synovial fluid

Fibrous layer of articular capsule

Articular cartilage

Tendon sheath

Synovial membrane

Tendon of long head of biceps brachii muscle

Humerus

Fibrous layer

Frontal section through the right shoulder joint Figure 9.5a

19

Special Movements • Opposition—thumb moves across the palm to touch the tips of other fingers

Opposition

Opposition Moving the thumb to touch the tips of the other fingers

Barnett (2016)

Figure 9.7d 20

10

Arthrology

ANAT 3001

Angular Movements • Increase or decrease angle between bones • Movements involve: o Flexion and extension o Abduction and adduction o Circumduction

21

Figure 9.6d Movements allowed by synovial joints.

Flexion

Extension

Flexion Extension

Angular movements: flexion and extension at the shoulder and knee 22

Barnett (2016)

11

Arthrology

ANAT 3001

Figure 9.6e Movements allowed by synovial joints.

Abduction

Adduction

Circumduction

Angular movements: abduction, adduction, and circumduction of the upper limb at the shoulder 23

Special Movements • Elevation—lifting a body part superiorly • Depression—moving the elevated part inferiorly

24

Barnett (2016)

12

Arthrology

ANAT 3001

Rotation • Involves turning movement of a bone around its long axis • The only movement allowed between atlas and axis vertebrae • Occurs at the hip and shoulder joints

25

Special Movements

• Protraction—nonangular movement anteriorly • Retraction—nonangular movement posteriorly

Protraction of mandible

Retraction of mandible

26

Barnett (2016)

13

Arthrology

ANAT 3001

Special Movements • Supination—forearm rotates laterally, palm faces anteriorly • Pronation—forearm rotates medially, palm faces posteriorly

Pronation (radius rotates over ulna)

Supination (radius and ulna are parallel))

o Brings radius across the ulna

27

Special Movements • Inversion and eversion o Special movements at the foot • Inversion—turns sole medially • Eversion—turns sole laterally

Inversion

Eversion

28

Barnett (2016)

14

Arthrology

ANAT 3001

Special Movements • Dorsiflexion and plantar flexion

Dorsiflexion

o Up-and-down movements of the foot o Dorsiflexion—lifting the foot so its superior Plantar flexion surface approaches the shin o Plantar flexion— depressing the foot, elevating the heel 29

End of Joints

30

Barnett (2016)

15...