1. Chapter 08 Lecture Outline
See separate PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes.

2. Introduction Joints (Articulations):
Functional junctions between bones
Bind parts of skeletal system together
Make bone growth possible
Permit parts of the skeleton to change shape during childbirth
Enable body to move in response to skeletal muscle contractions

3. 8.1: Types of Joints Structural Classification of Joints: Fibrous
Cartilaginous
Synovial
Functional Classification of Joints:
Synarthrotic—immovable
Amphiarthrotic—slightly movable
Diarthrotic—freely movable

4. Fibrous Joints
Fibrous joints are held together with dense connective tissue containing many collagen fibers; found in bones in close contact
There are 3 types of fibrous joints:
Syndesmosis
Suture
Gomphosis
Syndesmosis:
Bones bound by a sheet of dense connective tissue (interosseous membrane) or a bundle of dense connective tissue (interosseous ligament)
Amphiarthrotic (flexible, may twist)
Lies between tibia and fibula

5. Fibrous Joints Suture: Gomphosis: Between flat bones of skull
Thin layer of connective tissue (sutural ligament) connects bones
Synarthrotic (immovable)
Gomphosis:
Cone-shaped bony process in a socket in jawbone
Tooth in jawbone by periodontal ligament
Synarthrotic (immovable)

6. Cartilaginous Joints
Cartilaginous joints are connected by hyaline cartilage or fibrocartilage
There are 2 types of cartilaginous joints:
Synchondrosis
Symphysis
Synchondrosis:
Bands of hyaline cartilage unite bones
Some are temporary, such as epiphyseal plate (ossification converts this to a synostosis)
Between manubrium and the first rib (costal cartilages, permanent, synarthrotic)

7. Cartilaginous Joints Symphysis: Pad of fibrocartilage between bones
Articular surfaces covered by hyaline cartilage
Amphiarthrotic (limited movement)
Pubic symphysis
Joint between bodies of adjacent vertebrae (intervertebral discs)

8. Synovial Joints Synovial Joints: Most joints are synovial joints
All are diarthrotic joints
Structure of s synovial joint:
Articular cartilage covers articular ends of bones
Joint capsule, consists of 2 layers:
Outer fibrous layer, composed of ligaments
Inner layer, synovial membrane, which secretes synovial fluid

9. General Structure of Synovial Joints
Synovial joints are more complex than other types of joints, and contain the following parts:
Articular cartilage
Joint capsule
Ligaments
Synovial membrane
Synovial cavity
Synovial fluid
Meniscus (-i) in some joints
Bursa (-ae) in some joints

10. General Structure of Synovial Joints
Diagram of the knee joint, showing typical synovial joint structures, as well as less common structures, such as menisci and bursae

11. Types of Synovial Joints
There are 6 types of synovial joints, classified by shape and movements they allow:
Ball-and-Socket Joint:
Also called spheroidal joint
Round head in cup-shaped cavity
Widest range of motion
Multiaxial, plus rotation
Hip, shoulder
Condylar Joint:
Also called ellipsoidal joint
Oval condyle fits into elliptical cavity
Back-and-forth, side-to-side movement
Biaxial movement, no rotation
Joints between metacarpals & phalanges

12. Types of Synovial Joints
Plane Joint:
Also called gliding joint
Almost flat, or slightly curved
Back-and-forth and twisting
Nonaxial movement
Wrist and ankle joints
Hinge Joint:
Convex surface fits into concave surface of other bone
Uniaxial movement (in 1 plane)
Elbow, joints between phalanges

13. Types of Synovial Joints
Pivot Joint:
Also called trochoid joint
Cylindrical surface rotates within ring of other bone
Uniaxial movement
Rotation only
Atlas (C1) and dens of axis (C2)
Saddle Joint:
Also called sellar joint
Both bones have concave and convex surfaces
Biaxial movement (in 2 planes)
Carpal & metacarpal of thumb

14. 8.2: Types of Joint Movements
Action of skeletal muscle produces movement at synovial joints
Relatively fixed end of a skeletal muscle is called the origin
More movable end of a skeletal muscle is called the insertion
Movement at a joint occurs when a muscle contracts, and its fibers pull the insertion towards the origin

15. Types of Joint Movements
Abduction / adduction
Flexion / extension / hyperextension
Lateral flexion

16. Types of Joint Movements
Dorsiflexion / plantar flexion
Circumduction / rotation
Medial rotation / lateral rotation
Supination / pronation

17. Types of Joint Movements
Inversion / eversion
Protraction / retraction
Elevation / depression

18. 8.3: Examples of Synovial Joints
Examples of large, complex synovial (also freely movable) joints:
Shoulder
Elbow
Hip
Knee

19. Shoulder Joint Shoulder Joint: Ball-and-socket
Head of humerus and glenoid cavity of scapula
Loose joint capsule
Ligaments prevent displacement
Glenoid labrum
Several bursae
Very wide range of movement, including rotation, circumduction

20. Shoulder Joint Major ligaments of the shoulder joint:
Coracohumeral ligament
Glenohumeral ligaments
Transverse humeral ligament

21. Elbow Joint Elbow Joint: Hinge joint: Plane (gliding) joint:
Contains 2 articulations:
Hinge joint:
Between trochlea of humerus and trochlear notch of ulna
Flexion / extension only
Plane (gliding) joint:
Between capitulum of humerus and fovea on head of radius
Pronation / supination
Several reinforcing ligaments

22. Elbow Joint Major ligaments of elbow joint: Radial collateral ligament
Ulnar collateral ligament
Anular ligament

23. Hip Joint Hip Joint: Ball-and-socket joint
Head of femur and acetabulum of hip bone
Acetabular labrum
Heavy joint capsule
Many reinforcing ligaments
Variety of movement, yet less than at shoulder joint

24. Hip Joint Major ligaments of the hip joint:
Iliofemoral ligament (strongest ligament in body)
Pubofemoral ligament
Ischiofemoral ligament

25. Clinical Application 8.1 Replacing Joints
Synthetic materials are used to replace joints damaged by arthritis or injury
Steel and titanium replace larger joints, silicone used for smaller joints, some are ceramic
Hip replacements are the most common
New technology for joint replacement:
Use of materials that resemble natural body chemicals, such as coating implant with hydroxyapatite
3D printing technology used to create custom replacement joints

26. Knee Joint Knee Joint: Largest & most complex joint 3 bones:
Femur: Medial and lateral condyles of distal end
Tibia: Medial and lateral condyles of proximal end
Patella: Articulates with anterior surface of femur
Strengthened by many ligaments and tendons
Cushioned by bursae, fat pads
Menisci separate femur and tibia

27. Knee Joint Major ligaments of the knee joint:
Patellar ligament
Oblique popliteal ligament
Arcuate popliteal ligament
Tibial (medial) collateral ligament
Fibular (lateral) collateral ligament
Anterior cruciate ligament
Posterior cruciate ligament
Knee joint characteristics:
Modified hinge joint between condyles
Flexion / extension
Some rotation when knee is flexed
Plane joint between femur & patella

28. Clinical Application 8.2 Joint Disorders Sprains:
Tearing of connective tissue in joint, without bone dislocation
Bursitis:
Inflammation of a bursa, from overuse or stress
Arthritis:
Inflammation, swelling, and pain in a joint
Rheumatoid arthritis: autoimmune disease
Osteoarthritis: degenerative, most common type, occurs with aging
Lyme arthritis: caused by Lyme disease, passed through tick bite

29. 8.4: Life-Span Changes Joint stiffness is an early sign of aging
Many people develop arthritis as they age
Fibrous joints first to change; can strengthen, however, over a lifetime
Cartilage in synchondroses stiffens
Ligaments lose elasticity
Changes in symphysis joints of vertebral column diminish flexibility and decrease height (due to water loss from the intervertebral discs)
Synovial joints lose function, as capillary supply diminishes
Disuse hampers the nutrient supply to joints; speeds up stiffening
Activity and exercise can keep joints functional longer