1. Ch. 8 Joints of the Skeletal System

2. Part 1: Classifying Joints & Joint Movements
Interactive pages

3. Types of Joints (AKA: Articulations)
Structural Classification (type of tissue that binds the bones
Fibrous
Cartilaginous
Synovial
Functional Classification (degree of movement)
Synarthrotic
Immovable
Amphiarthrotic
Slightly Moveable
Diarthrotic
Freely Moveable
Types of Joints
(AKA: Articulations)

4. Fibrous Joints
Bones bound by dense connective tissue (collagen fibers)
Types of Fibrous Joints
Syndesmosis
Bound by a sheet (interosseous membrane) or bundle (interosseous ligament) of Dense C.T.
Permits slight movement (amphiarthrosis) such as twisting between the tibia and the fibula
Sutures
Between plates of the skull (fontanels in infancy)
Immovable (synarthrotic)
Gomphosis
Union of a bony process in a socket (root of tooth attached to mandible or maxilla by periodontal ligament)
Immovable

5. Syndesmosis
Suture
Gomphosis

6. Cartilaginous Joints Bones bound by cartilage or fibrocartilage
Types of Cartilaginous Joints
Synchondrosis
Hyaline Cartilage
Most Temporary during growth (ex. Epiphyseal plate)
Becomes synostosis at maturation
Permanent Synchondrosis between manubrium & 1st rib (sternocostal joint)
Symphysis
Articulating bones covered in hyaline cartilage
Connected by a pad of fibrocartilage
Ex. Pubic symphysis & intervertebral joints

7. Symphysis
Synchondrosis

8. Synovial Joints: General Structure
Freely Moveable (Diarthrosis)
Ends of bones covered in hyaline cartilage called Articular Cartilage
Bones held together by joint capsule
Outer layer is Dense C.T. fibers attach to periosteum
Inner layer is Loose C.T.
Synovial membrane
Secretes synovial fluid
Synovial fluid testing may indicate arthritis, gout, or infection
Ligaments reinforce the joint capsule
Accessory Structures of the Joint
Menisci
Pad of fibrocartilage that cushion and distribute weight
Bursae
Fluid filled sacs that cushion tendons that glide over bones

9. Synovial Joint
Structure
Accessory Structures

10. Synovial Joints: Types
Ball & Socket or Spheroidal
Wide range of motion (multiaxial movement)
Rounded head articulates with cup-shaped cavity of another bone
Hip (Acetabulofemoral) & Shoulder (Glenohumeral)
Condylar or Ellipsoidal
Back and forth/Side to Side (biaxial movement)
Oval condyle of one bone fits into the elliptical cavity of another
Metacarpophalangeal joints
Plane or Gliding
Sliding and Twisting (nonaxial movement)
Flat articulating surfaces
Intercarpal & Intertarsal joints

11. Synovial Joints: Types
Hinge
One plane of movement (uniaxial)
Convex/Concave articulating surfaces
Humeroulnar joint and interphalangeal joints
Pivot or Trochoid
Rotation in one plane (uniaxial)
Cylindrical surface of one bone rotates in a ring of bone and ligament
Atlantoaxial joint & proximal radioulnar joing
Saddle or Sellar
Wide range of motion (biaxial)
Both bones have a convex and concave surface
Carpometacarpal 1

13. Types of Joint Movements
Flexion:
Bending at joint to decrease angle
Extension
Moving at a joint to increase angle
Hyperextension
Extension beyond anatomical position
Abduction
Moving part away from midline
Adduction
Moving part towards midline

14. Types of Joint Movements
Dorsiflexion
Movement at ankle that moves anterior foot closer to the shin
Plantar flexion
Movement at the ankle that moves anterior foot farther from shin
Medial rotation
Turning limb toward midline
Lateral rotation
Turning limb away from midline
Pronation
Rotate forearm to palm down
Supination
Rotate forearm to palm up
Circumduction
Moving a part so that the end follows a circular path

15. Types of Joint Movements
Inversion
Turning plantar surface medially
Eversion
Turning plantar surface laterally
Protraction
Moving a part forward
Retraction
Moving a part backward
Elevation
Raising a part
Depression
Lowering a part

16. Part 2: Specific Synovial Joints & Disorders
Interactive pages

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

18. Figure 8.13a Shoulder Joint
AKA Glenohumeral 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.

19. Major ligaments of the shoulder joint: Coracohumeral ligament.
Glenohumeral ligaments.
Transverse humeral ligament.
Left: © Dr. Ronald Bergman

20. Contains 2 articulations: Humeroulnar & Humeroradial Hinge joint:
Elbow Joint:
Contains 2 articulations:
Humeroulnar & Humeroradial
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.

21. Major ligaments of elbow joint:
Radial collateral ligament.
Ulnar collateral ligament.
Anular ligament.

22. Hip Joint:
AKA: Acetabulofemoral
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.

23. Major ligaments of the hip joint:
Iliofemoral ligament (strongest ligament in body).
Pubofemoral ligament.
Ischiofemoral ligament.
Left: © Dr. Ronald Bergman

24. Clinical Application 8.1
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.

25. Knee Joint: AKA: Tibiofemoral 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.

26. 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.

27. 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.

28. Lifespan 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.