1. Chapter 8, Section 1
Joints

2. Joints, also called articulations, are functional junctions
between two bones
The science of joints is called arthrology.
Functions of joints
Bind skeleton together
Enable body movements
Makes growth possible
Permit changes in skeleton for childbirth

3. Classification of Joints
Classifications based on amount of movement
Synarthrotic = immovable
Amphiarthrotic = slightly moveable
Diarthrotic = fully movable
Classifications by types of tissue:
Fibrous joint = dense connective tissue
Cartilaginous joint = bones connected by cartilage
Synovial joint = contains a synovial membrane

4. Fibrous Joints There are three (3) types of fibrous joints:
Syndesmosis
Suture
Gomphosis
1. Syndesmosis:
Bones are connected by a sheet or bundle of fibrous tissue.
Examples include the interosseous membrane and interosseous ligaments between the tibia and fibula.
Interosseous membrane between tibia and fibula is a syndesmosis joint.

5. Fibrous Joints Suture: Thin layer of dense connective tissue
Connects flat bones of the
skull (sutural ligaments)
Synarthrotic
Gomphosis:
Cone-shaped bony process
in a bony socket
Example includes a tooth
anchored into a bony socket

6. Cartilaginous Joints There are two (2) types of cartilaginous joints:
Synchondrosis
Symphysis
Synchondrosis
Bones are united by a band of hyaline cartilage.
Located between manubrium of sternum & 1st rib
Also located at epiphyseal plates of developing bone
Movement is synarthrotic

7. Cartilaginous Joints Symphysis
A pad of fibrocartilage between two bones
Examples include the pubic symphysis and intervertebral discs
Movement is amphiarthrotic.

8. General Structure of Synovial Joints
Synovial Joints are Freely movable (Diarthrotic)
Structures include:
Articular cartilage
Synovial membrane – secretes synovial fluid
Joint cavity – filled with synovial fluid
Joint capsule – dense connective tissue that stabilizes and protects joint
Figure 8.7 The generalized structure of a synovial joint.

9. General Structure of Synovial Joints
Structures include:
Ligaments – bundles of collagenous fibers that reinforce the joint capsule
Menisci (sing. Meniscus) – pad of fibrocartilage that separates some joints.
Bursa – sac filled with synovial fluid.
Bursitis = inflammation of bursa
Figure 8.8 Menisci separate the articulating surfaces of the femur and tibia. Several bursae are associated with the knee joint.

10. Types of Synovial Joints
Ball-and-socket
rounded head + cup-shaped socket.
Movement in all planes (multi-axial).
Allows for rotation
Includes hip joint and shoulder joint.
Condylar joint
Oval condyle + elliptical socket
Movements in most planes (bi-axial)
No rotational movement
Joints between metacarpals and phalanges/

11. Types of Synovial Joints
Plane (Gliding) Joint
Flattened bones slide across each other
Includes carpals and tarsals
ribs 2-7 articulate with sternum
Hinge joint
Increases or decreases angel between bones
Includes elbow joint
Joints between phalanges

12. Types of Synovial Joints
Pivot Joint
Rotation around a central axis (uni-axial)
Joint between radius and ulna
Joint between atlas (C1) and axis (C2).
Saddle Joint
2 concave bones positioned at right angles
Includes metacarpal and carpal of thumb
End of Chapter 8, Section 1

13. Types of Joint Movements
Section 2, Chapter 8
Types of Joint Movements

14. Types of Joint Movements
Movement at a joint occurs when a muscle contracts and its fibers pull its moveable end (insertion) towards its fixed end (origin).
Abduction = movement away from the midline
(think of someone being abducted, or taken away)
Adduction = movement towards the midline
(think of adding together)

15. Types of Joint Movements
Flexion = decreases the angle of a joint
Bend elbow
Extension = increases the angle of a joint
Extend elbow
Hyperextension = extension beyond the anatomical position
bend hand back, bend head back beyond
anatomical position

16. Types of Joint Movements
Rotation = movement around a central axis
Twisting the head from side to side
Circumduction = movement so end follows a circular path
moving the finger in a circular motion
without moving the hand.

17. Types of Joint Movements
Elevation = raising a part
Shrugging the shoulders
Depression = lowering a part
Drooping the shoulders
Protraction = moving a part forward
thrusting head forward
Retraction = moving a part backward
pulling the head backward

18. Types of Joint Movements
Supination = turning the hand so the palm faces upward or anteriorly
Example: turning a doorknob clockwise with your right hand.
Pronation = turning the hand so the palm faces downward or posteriorly
Dorsiflexion = movement at the ankles that points toes towards the sky
Plantar flexion = movement at the ankles that points toes towards the ground

19. Types of Joint Movements
Eversion = turning the foot so the planter surface faces laterally
Inversion = turning the foot so the plantar surface faces medially
End of Chapter 8, Section 2

20. The Knee Joint and Joint Disorders
Chapter 8, Section 3
The Knee Joint and Joint Disorders

21. Knee Joint
The knee joint is the largest and most complex synovial joint in body.
Two distal condyles of the femur articulate with two proximal condyles of the tibia. This is a condylar joint.
The femur also articulates anteriorly with the patella. This is a plane joint.
Figure 8.21
Figure 8.20

22. Knee Joint General structures of a synovial joint in the knee
Synovial Membrane
Secretes synovial fluid
Joint Cavity
Stores synovial fluid
Joint Capsule
Relatively thin support
Reinforced by several ligaments and tendons
Figure 8.20

23. Knee Joint Several ligaments and tendons strengthen the knee joint.
Patellar tendon - The patella is partially enclosed in tendons fused together from the thigh muscle.
Patellar ligament – continuation of patellar tendon. Extends from patella to the tibial tuberosity.

24. Knee Joint Ligaments continued:
Tibial collateral ligament – connects medial condyle of femur with medial condyle of tibia.
Fibular collateral ligament – connects lateral condyle of femur with head of fibula.
Anterior & Posterior Cruciate ligaments – provide additional support to medial surface of tibia and femur
Figure 8.21a Anterior right knee with patella removed.

25. Knee Joint
Two menisci (medial & lateral meniscus) separate the femur and tibia, and align them.
Figure 8.20 (a) sagittal section of the knee joint.
(b) Photograph of the left knee joint (frontal section)

26. Knee Joint Three major bursae surround the knee joint.
Suprapatellar bursa
Largest bursa in body
Prepatellar bursa
Between patella and skin
Housemaid’s knee = prepatellar bursitis
Infrapatellar bursa
Figure 8.20a

27. Joint Disorders
Sprain = overstretching or tearing of connective tissue (tendons, ligaments, or cartilage) associated with a joint.
However, the bones are not disarticulated.

28. Joint Disorders Arthritis = inflamed, swollen, and painful joints.
Osteoarthritis
Most common arthritis
Occurs with aging
Articular cartilage degenerates, causing bone to rub against bone.
Results in stiff and painful joints
Fingers may appear gnarled and knee may bulge.
Osteoarthritic fingers often take on a gnarled appearance.

29. Joint Disorders End of Chapter 8, Section 3 Rheumatoid Arthritis
Autoimmune disorder (immune system attacks tissue)
Synovial membrane thickens & becomes inflamed
Mass of fibrous connective tissue (Pannus) invades synovial space.
Fibrous pannus destroys articular cartilage, and the joints may swell and ossify.
Knuckles may swell as a result of rheumatoid arthritis.
Other symptoms of Rheumatoid Arthritis:
low-grade fever, fatigue, appetite, stiffness.
End of Chapter 8, Section 3