Joints

Question 1

Learning Objectives

Answer 1

Understand the structure and function of joints.
Classify joints based on their structure AND their function.
Define the movement(s) possible at different types of joints
Identify joints important for speech and swallowing

Question 2

Joints/Articulators Classification

Answer 2

Structural (3) (type of material binding bones together and whether a joint cavity is present)
- Fibrous, Cartilagenous or Synovial
-Bony/synotosis joints in frontal skull of infant
Functional (3) (amount of movement joint allows)
-Synarthrosis, amphiarthrosis, diarthrosis

Question 3

Fibrous

Answer 3

• Bones joined by collagen fibres, no joint cavity and little to no movement
• E.g. syndemosis, suture, gomphosis

Question 4

Cartilaginous

Answer 4

• Bones joined by cartilage, no joint cvity, little to no movement
• Synchondrosis is a temporary joint that will fuse later in time (growth plates of hyaline cartilage that unites bones)
• Symphaysis (fibrocartilage unites bones such as intervertebral discs and pelvic symphysis)

Question 5

Synovial

Answer 5

• Bones separated by fluid filled cavity
• Further classified into:
• Gliding/plane (flat bones)
• Hinge (e.g. elbow) (cylinder nests in trough)
• Pivot (radius into ulna) (axle into sleeve)
• Ellipsoid/condylar (oval surfaces)
• Saddle (biaxial in a concave/convex area)
• Ball and socket (multiaxial such as hip or shoulder)

Question 6

Synarthrosis

Answer 6

Very little movement

Either bony, fibrous or cartilagenous

Question 7

Amphiarthrosis

Answer 7

Slight movement

Fibrous or cartilaginous

Question 8

Diarthrosis

Answer 8

Freely movable
All diarthroses are synovial
- Nonaxial
- Mono/uniaxial
- Biaxial
- Tri/multiaxial

Question 9

Synovial joints have:

Answer 9

Articular cartilage
Joint cavity
Articular capsule
Synovial fluid
Ligaments
Nerves and blood vessesls

Question 10

Accessories for Joints

Answer 10

Menisci, fat pads, tendons and bursae

Question 11

Joint stability is impacted by:

Answer 11

• Shape of articulating surface
• Menisci and discs
• Ligaments and joint capsule
• Muscle action/tendon tension

Question 12

Joints for Speech + Swallowing

Answer 12

TMJ
costovertebral joints are synovial plane/gliding
2-7 sternocostal joints are synovial gliding
1st sternocostal is cartilaginous synchondrosis
Larynx
Fibrous gomphosis