Introduction To Joints

Question 1

What are joints?

Answer 1

Regions of the skeleton where bones meet and articulate with each other

• Supported by a variety of soft tissues
• function is either to allow movement or growth
• There is no single best way to classify joints but classification is usually based on either the degree of movement possible or the nature of the sift tissues involved

Question 2

What are the types of joints?

Answer 2

• Fibrous
• cartilage
• joints

Question 3

Differentiate between the types of classifications of joints

Answer 3

Fibrous- bones are only separated by connective tissue with negligible movement

Sutures- initially mobile but become less mobile and finally fuse completely in old age

Cartilage
Primary cartilaginous (synchondrosis)

Secondary cartilaginous (symphysis)

Synovial
-Characterized by 6 criteria

Question 4

Describe synovial joints

Answer 4

• Articulate surfaces covered with hyaline cartilage.
• Has a joint cavity with synovial fluid
• Has a joint capsule
• Has a synovial membrane
• Reinfirced by ligaments internally, externally or both
• Capable of varying degrees of movement

Question 5

What are the joints of axial skeleton?

Answer 5

1. Atlantooccipital
2. Atlantoaxial
3. Intervertebral
4. Zygapophyseal(facet)
5. Inter laminar

Question 6

Where is the Atlantic-occipital joint?

Answer 6

• Between the occipital condyles and the lateral masses of the atlas(C1)
• Allows for the nodding action when indicating ‘yes’

Question 7

What is the atlantoaxial joint?

Answer 7

• Between the atlas and axis (C2)
• Allows fir rotation movement of the head as when saying no
• Pivot joint

Question 8

What are the intervertebral joints?

Answer 8

1. Cartilaginous joint

Example- The intervertebral disc- outer annular fibrous - lamella of Fibrosus-lamella of fibrocartilage
Inner nucleus Pulposus - gel like substance

Synovial joints- Zygapophyseal joints- between superior and inferior Articular facets of adjacent vertebra

Question 9

What causes the vertebral column to be curved?

Answer 9

The shape of the vertebral bodies and position (and orientation) of the joints make the column curved

Question 10

Contrast the primary and secondary curvatures

Answer 10

Primary curvature present at birth - concave anterior (kyphotic)

Secondary curvature- develops over time-covnvex anterior (lordotic)

The curvature allows us to walk fully bipedally

Question 11

Describe the skeleton of the upper extremity

Answer 11

Clavicle attaches limb to torso

Shoulder (glenohumeral) joint
-Scapula, humerus

Elbow joint

• Olecranon process of ulna and trochlea of humerus
• Head of radius and capitulum

Proximal radioulnar joint
-Head of radius and radial notch on ulna

Wrist joint
-Distal end of radius and scaphoid and lunate

Question 12

What is the glenohumoral joint(shoulder)?

Answer 12

Articulation between
-Head of humerus & glenoid cavity

Synovial ball and socket joint

Wide range of movement

Stability sacrificed fir mobility

Stability provided by rotator cuff muscles and bony arch

Question 13

Describe the elbow joint

Answer 13

Synovial hinge type: Humera-radial and humero-ulnar

Flexion and extension movements possible

Synovial pivot type: radio-ulnar

Pronation and supination movement possible

Question 14

Describe lower extremity skeleton

Answer 14

Pelvic girdle

• Pelvic bones
• sacrum

Hip joint
-femur, acetabulum of pelvis

Knee joint

• Condyles of femur and tibia
• Patella (helps with smooth movement of the muscle)

Ankle joint
-Tibia, fibula, talus

Question 15

Describe hip joint

Answer 15

Synovial ball and socket

More stable than shoulder and somewhat less mobile

Weight bearing joint

Femur neck fractures often in elderly

• Osteoporosis
• Can be devastating

Question 16

Describe the knee joint

Answer 16

Between the femoral condyles and tibial condyles

Separated from each other by fibrocartilage menisci

Synovial hinge joint