Joints of the Skeletal System

Chapter

8

8-1

Chapter 8Joints of the Skeletal System

• Joints/Articulations• Junctions between bones

•Ligaments connect bone to bone

Functions •Bind parts of skeletal system together• Enable body to move in response to skeletal muscle contraction•Make bone growth possible• Permit parts of the skeleton to change shape during childbirth 8-2

Classification of Joints

Joint Composition Classification•Fibrous Joints

• dense connective tissues connect bones• between bones in close contact

• Cartilaginous Joints• hyaline cartilage or fibrocartilage connect bones

• Synovial Joints• most complex•Contains synovial fluid• allow free movement

Movement Classification •synarthrotic

• immovable• amphiarthrotic

• slightly movable• diarthrotic

• freely movable

8-3

Fibrous Joints

3 Types• Syndesmosis• Suture• Gomphosis

Syndesmosis• long fibers connect bones• amphiarthrotic• distal ends of tibia and fibula

8-4

Fibrous Joints

Suture• between flat bones• synarthrotic• thin layer of connective tissue connects bones

Gomphosis• cone-shaped bony process in a socket• tooth in jawbone• synarthrotic

8-5

Cartilaginous Joints

2 Types• Synchondrosis• Symphysis

Synchondrosis• bands of hyaline cartilage unite bones•between manubrium and first rib• amphiarthrotic

8-6

Cartilaginous Joints

Symphysis• pad of fibrocartilage between bones• pubis symphysis• joint between bodies of vertebrae• amphiarthrotic

8-7

Synovial Joints

• diarthrotic•joint capsule•joint cavity• synovial fluid

•lubrication• synovial membrane• bursae

•fluid filled sac•Cushions/aids movement of tendons over things

8-8

Types of Synovial Joints

Ball-and-Socket Joint• moves in all directions• hip• shoulder

Condyloid Joint• moves up/down & left/right• between metacarpals and phalanges

8-9

Types of Synovial Joints

Gliding Joint• sliding or twisting• between carpals• between tarsals

Hinge Joint• flex/extend• elbow• between phalanges

8-10

Types of Synovial Joints

Pivot Joint• rotation• between proximal ends of radius and ulna•atlas and axis

Saddle Joint• back/forth, side/side• between carpal and metacarpal of thumb

8-11

Types of Joint Movements

• abduction/adduction• dorsiflexion/plantarflexion• flexion/extension/hyperextension

8-12

Types of Joint Movements

• rotation/circumduction• supination/pronation

8-13

Types of Joint Movements

• eversion/inversion• protraction/retraction• elevation/depression

8-14

Shoulder Joint

• ball-and-socket• head of humerus• glenoid cavity of scapula• loose joint capsule• bursae• ligaments prevent displacement• very wide range of movement

8-15

Shoulder Joint

8-16

Elbow Joint

• hinge joint• trochlea of humerus• trochlear notch of ulna

• gliding joint• capitulum of humerus• head of radius

• pivot joint•radius, ulna

•flexion and extension, rotation• many reinforcing ligaments• stable joint

8-17

Elbow Joint

8-18

Hip Joint

• ball-and-socket joint• head of femur• acetabulum• heavy joint capsule• many reinforcing ligaments• less freedom of movement than shoulder joint

8-19

Hip Joint

8-20

Knee Joint

• largest joint• most complex• modified hinge joint• menisci separate femur and tibia•medial and lateral condyles of distal end of femur• medial and lateral condyles of proximal end of tibia• femur articulates anteriorly with patella• flexion/extension/little rotation• strengthened by many ligaments and tendons• bursae

8-21

Knee Joint

8-22

Life-Span Changes

• Joint stiffness is an early sign of aging• Regular exercise can prevent stiffness• Changes in symphysis joints of vertebral column diminish flexibility and decrease height • Synovial joints lose elasticity

8-23

Sprains

• damage to cartilage, ligaments, or tendons associated with joints

• forceful twisting of joint

Bursitis

• inflammation of a bursa

• overuse of a joint

Arthritis

• inflamed, swollen, painful joints– Rheumatoid Arthritis

– Osteoarthritis

– Gout

Dislocation

• bones are no longer in their normal position– joint capsule and

ligaments tear

– may be nerve damage