T3 L4: The principles of articulation

Question 1

What is a fibrous joint?

Answer 1

It has no synovial cavity and is held together by fibrous connective tissue

It permits little or no movement (synarthrosis/amphiarthrosis)

Question 2

What does Synarthrosis mean?

Answer 2

Immovable

Question 3

What does Amphiarthrosis mean?

Answer 3

Partially moveable

Question 4

What does Diarthrosis mean?

Answer 4

Freely moveable

Question 5

What are the 3 types of fibrous joint?

Answer 5

1. Suture
   - irregular thin layer of connective tissue Eg. cranial bones
2. Syndesmosis
   - more connective tissue than in a suture joint
   - Typically permit slight movement Eg. anterior tibiofibular ligament, dentoalveolar
3. Interosseous membrane
   - Sheet of dense connective tissue that binds adjacent bones Eg. tibia and fibula

Question 6

What is a synostosis?

Answer 6

Ossification at a suture

Question 7

What is a cartilaginous joint?

Answer 7

A joint with no synovial cavity that is held together by fibrocartilage of hyaline cartilage

It permits little or no movement

Question 8

What are the 2 types of cartilaginous joint?

Answer 8

1. Synchondrosis
   - Hyaline cartilage Eg. epiphyseal plate
2. Symphysis
   - Fibrocartilage
   - They only occur in the midline of the body Eg. Pubis, sternum, and intervertebral joints

Question 9

What is the difference between hyaline cartilage and fibrocartilage?

Answer 9

Hyaline is softer and contains less fibres

Question 10

What is a synovial joint?

Answer 10

A cavity between articulating bones

Freely moveable (diarthosis)

Contain a later of hyaline cartilage called articular cartilage

Question 11

What is the articular cartilage composed of?

Answer 11

Collagen and proteoglycan

The orientation of collagen structure causes resistance to compression

Question 12

What are the 2 layers of a articular capsule?

Answer 12

Outer fibrous membrane: connects to the periosteum

• Flexibly permits movement
• Fibres are arranged into fibres which allows for high tensile strength

Inner layer (synovial membrane): Areolar connective tissue rich in elastic fibres
-It occasionally contains structural articular fat pads

Question 13

What forms the synovial fluid?

Answer 13

Rich in hyaluronic acid secreted by fibroblast-like cells and interstitial fluid from blood plasma

Question 14

What is the function of synovial fluid?

Answer 14

• Lubricates the articular surface to reduce friction
• Shock-absorbing properties
• Phagocytes remove microbes and debris

Question 15

What are the 2 accessory ligaments of synovial joints?

Answer 15

-Intracapsular ligaments lie within the capsule
Eg. Anterior and posterior cruciate ligaments of the knee

-Extrascapular ligaments lie outside the joint capsule
Eg. Fibular and tibial collateral ligaments of the knee

Question 16

What is the function of accessory articular discs?

Answer 16

Fibrocartilage pads lie between articular cartilage of some synovial joints Eg. meniscus of the knee

• Called menisci or articular discs
• Help with joint stability
• Direct the flow of synovial fluid

Question 17

In what people are meniscal tears common?

Answer 17

Athletes that use their joints a lot

Question 18

What is the nerve and blood supply to synovial joints?

Answer 18

Same nerve endings that supply associated muscles

Many components of joints are avascular but those that aren’t rely on numerous branching arteries and veins supplying the associated areas

Question 19

What are bursae and what is their function?

Answer 19

Fluid filled sacs lined with synovial-like membrane that cushion movement between body parts

Question 20

What are tendon sheaths and what is their function?

Answer 20

They are specialised membranes that wrap around tendons especially where many tendons come together

They protect against damage

Question 21

What are the 6 types of synovial joints?

Answer 21

Planer
Hinge
Pivot
Condyloid
Saddle
Ball and socket

Question 22

What are planer joints?

Answer 22

A type of synovial joint between flat or slightly curved surfaces

Permit back and forth, and side to side movements
Eg. intercarpal joints or intertarsal joints

Question 23

What are hinge joints?

Answer 23

When a rounded surface fits a curved surface

Permits movement in a single axis
Eg. knee joint, elbow joint

Question 24

What is a pivot joint?

Answer 24

When a rounded or pointed surface of one bone pivots inside a ring of another bone

It permits rotation on it’s longitudinal axis
Eg. radioulnar joints, atlanto-axial joint

Question 25

What is the dens of the axis bone?

Answer 25

The bit that sticks up and allows pivoting of the atlas bone above it

Question 26

What is a condyloid joint?

Answer 26

A convex oval projection of one bone fits into an oval depression of another

Permits movement around 2 axis: biaxial flexion and extension, and adduction and abduction
Eg. Wrist joint, metacarpophalangeal joint

Question 27

What is a saddle joint?

Answer 27

A specialised form of saddle joint where one bone fits into a saddle shaped bone is opposes

Allows movement in 2 axis: flexion and extension, and abduction and adduction
Eg. Carpometacarpal joint of the thumb

Question 28

What is a ball and socket joint?

Answer 28

A ball-like surface of one bone fits into a cup-like depression of another

Allows triaxial movement: flexion and extension, abduction and adduction, and rotation
Eg. Shoulder joint, hip joint

Question 29

What is the glenoid labrum?

Answer 29

A narrow rim of fibrocartilage that deepens the glenoid joint

Question 30

What are the 3 ligament that stabilise the glenohumeral joint?

Answer 30

Glenohumeral
coracohumeral
transverse humeral

And has 4 associated bursae

Question 31

Which 3 ligaments stabilise the acromioclavicular joint?

Answer 31

Acromioclavicular
Coracoacromial
Coracoclavicular