Articulations of bones Functions of joints

◦ All joints hold bones together◦ Allow for mobility

Ways joints are classified◦ Functionally◦ Structurally

Joints

Synarthroses◦ Immovable joints

Amphiarthroses◦ Slightly moveable joints

Diarthroses◦ Freely moveable joints

Functional Classification of Joints

Fibrous joints◦ Generally immovable

Cartilaginous joints◦ Immovable or slightly moveable

Synovial joints◦ Freely moveable

Structural Classification of Joints

[Insert Table 5.3 here]

Summary of Joint Classes

Table 5.3

Bones united by fibrous tissue Example:

◦ Sutures◦ Syndesmoses

Allows more movement than sutures Example: Distal end of tibia and fibula

Fibrous Joints

Bones connected by cartilage Example:

◦ Pubic symphysis Intervertebral joints

Cartilaginous Joints

Articulating bones are separated by a fibrous articular joint cavity

Synovial fluid is found in the joint cavity

Synovial Joints

Include hip, knee, elbow joints

http://www.argosymedical.com/Skeletal/samples/animations/Synovial%20Joints/index.html

Articular cartilage (hyaline cartilage) covers the ends of bones

A fibrous articular capsule encloses joint surfaces

A joint cavity is filled with synovial fluid Ligaments reinforce the joint

Features of Synovial Joints

Bursae—flattened fibrous sacs◦ Lined with synovial membranes◦ Filled with synovial fluid◦ Not actually part of the joint

Tendon sheath◦ Elongated bursa that wraps around a tendon

Ligamento reinforce articular capsule

Structures Associated with the Synovial Joint

http://www.argosymedical.com/Skeletal/samples/animations/Aging%20Bone/index.html

http://www.argosymedical.com/Skeletal/index.html

The Synovial Joint

Figure 5.29

Reinforce articular capsule Covers the ends of bones

Lines the articular capsule

Fluid filled synovial membrane sacs

Types of Synovial Joints

Figure 5.30a–cUlna / RadiusAtlas/axis

Elbow (humerus /ulna)Interphalange (between phalanges)

Intercarpal (between carpal bones)

Sliding movements in one or two planes(uni-or biaxial

Allows movement in one plane (uniaxial)

uniaxial

Types of Synovial Joints

Figure 5.30d–f

Metacarpal bones/ proximal phalanges (knuckles)Forearm bones/ wristSkull/ vertebral columnWrist joint

Shoulder jointHip joint

biaxialbiaxial

Thumb metacarpal and trapezium (a carpal)

multiaxial

Hip joint is more stable than the knee joint

◦ Hip Is a multiaxial joint Allows movement in all directionsKnee

allows movement in one plane (uniaxial)

Hip vs Knee Joint

Five Golden Rules of Skeletal Muscle Activity

Table 6.2

Movement is attained due to a muscle moving an attached bone

Muscles are attached to at least two points◦ Origin

Attachment to a moveable bone◦ Insertion

Attachment to an immovable bone

Muscles and Body Movements

Muscles and Body Movements

Figure 6.12

Flexion◦ Decreases the angle of the joint◦ Brings two bones closer together◦ Typical of hinge joints like knee and elbow

Extension◦ Opposite of flexion◦ Increases angle between two bones

Types of Ordinary Body Movements

Types of Ordinary Body Movements

Figure 6.13b

Rotation◦ Movement of a bone

around its longitudinal axis

◦ Common in ball-and-socket joints

◦ Example is when you move atlas around the dens of axis (shake your head “no”)

Types of Ordinary Body Movements

Abduction◦ Movement of a limb away

from the midline

Adduction◦ Opposite of abduction◦ Movement of a limb toward

the midline

Types of Ordinary Body Movements

Circumduction◦ Combination of flexion, extension, abduction, and

adduction◦ Common in ball-and-socket joints

Types of Ordinary Body Movements

Dorsiflexion◦ Lifting the foot so that the superior surface

approaches the shin Plantar flexion

◦ Depressing the foot (pointing the toes)

Special Movements

Inversion◦ Turn sole of foot medially

Eversion◦ Turn sole of foot laterally

Special Movements

Supination◦ Forearm rotates laterally so palm faces anteriorly

Pronation◦ Forearm rotates medially so palm faces

posteriorly

Special Movements

Opposition◦ Move thumb to touch the tips of other fingers on

the same hand

Special Movements

Bursitis—inflammation of a bursa usually caused by a blow or friction

Tendonitis—inflammation of tendon sheaths Arthritis—inflammatory or degenerative

diseases of joints◦ Over 100 different types◦ The most widespread crippling disease in the

United States

Inflammatory Conditions Associated with Joints

Osteoarthritis◦ Most common chronic arthritis◦ Probably related to normal aging processes◦ Softening, fraying and eventual breakdown of

cartilage leading to bone spurs (excess bone tissue) Rheumatoid arthritis

◦ An autoimmune disease—the immune system attacks the joints

◦ Symptoms begin with bilateral inflammation of certain joints

◦ Often leads to deformities

Clinical Forms of Arthritis

Gouty arthritis◦ Inflammation of joints is caused by a deposition of

uric acid crystals from the blood◦ Can usually be controlled with diet

Clinical Forms of Arthritis

Osteoporosis◦ Bone-thinning disease afflicting

50% of women over age 65 20% of men over age 70

◦ Disease makes bones fragile and bones can easily fracture

◦ Vertebral collapse results in kyphosis (also known as dowager’s hump)

◦ Estrogen aids in health and normal density of a female skeleton

Skeletal Changes Throughout Life

Skeletal Changes Throughout Life

Figure 5.34

Skeletal Changes Throughout Life

Figure 5.35

Dislocation of joint A dislocation is a separation of two bones where they meet at a joint. A dislocated bone is no longer in its normal position, which may result in damage to ligaments, nerves, and blood vessels.

Dislocation of the shoulder joint is common and occurs when the top part of arm bone slips out of its socket

Radial dislocation may be caused by a sudden pull on a child's arm or hand. For first aid, immobilize the arm and take the child to the doctor's office or emergency room.