Biology Lesson 7.4

Lesson 7.4

Joints – the place where bones join or articulate.

Lesson 7.4 Joints

Three categories based on ability to move:1.immovable – little to no

movment in joint ex. Sutures

2. slightly movable – some movement in joint ex. Vertebrae

3. freely movable or synovial joint – of 3 has most movement ex. Limbs, jaw

Parts of a synovial joint:

1.Articular cartilage - covers the ends of the bones

2. Synovial fluid – lubricates the joint

Parts of a synovial (freely movable) joint:1. Articular cartilage 2. Synovial fluid

3.Ligaments – hold bones together creating the joint capsule

4. Joint capsule – surrounds the joint

5. Synovial membrane – produces the synovial fluid

1. hinge joints

• ex. elbow

• like a door hinge it swings only one way 

Types of synovial joints

Types of synovial joints1. hinge joints

2. Gliding joints • Ex. Carpals• one bone slides across another bone

Types of synovial joints1. Hinge joints2. Gliding joints

3. Ball and socket joints • Ex. hip• greatest range of motion• round head of one bone fits in the hollow socket of another

Types of synovial joints1. Hinge joints2. Gliding joints 3. Ball and socket joints

4. Pivot joints • ex. C1-C2 the atlas and axis

vertebrae• allows only rotation

Types of synovial joints1. Hinge joints2. Gliding joints 3. Ball and socket joints 4. Pivot joints

5. Saddle joints• Found only in the hands • ex. Thumb metacarpal to carpal• Saddle portion of one bone nestles into saddle portion of other

Types of synovial joints1. Hinge joints2. Gliding joints 3. Ball and socket joints 4. Pivot joints5. Saddle joints

6. Ellipsoid joints

• joints between metacarpals and phalanges

• move up/down and left/right

•one bone bulges and fits into indention of other bone

Joint Problems

1. Disease – mainly arthritis

2 types of arthritis

A. osteoarthritis most common joint disorder Is the deterioration of the articular cartilage usually due to age

most serious in hip joint

Joint Problems1. Disease – mainly arthritis

2 types of arthritisA. osteoarthritis

B. Rheumatoid arthritis

Autoimmune disorder Cause unknown Effects hands, ankles, knees,

fingers most often Can affect any age Controlled with medications

Joint Problems

1. Disease – mainly arthritis

2. Injury

A. Sprain most common when ligaments over

stressed and swelling and inflammation occurs

treatment is rest

Joint Problems

1. Disease – mainly arthritis 2. Injury

A. Sprain

B. Dislocation joint overstressed and bone pops out of ligament

treatment - must be relocated

Joint Problems1. Disease – mainly arthritis 2. Injury

A. SprainB. Dislocation

C. Torn Ligaments Ligament is under stress and

tears Treatment: not completely torn then rest

and it will heal completely torn will need

surgery to reattach or sub

Surgery