Properties of Joints

Question 1

What is a Joint? (3 points)

Answer 1

An articulation between 2 bones.
An articulation between bone & cartilage.
An articulation between bone & teeth (gomphosis).

Question 2

Functions of Joints. (2 points)

Answer 2

Movement: multiaxial (more than 1 plane) or uniaxial (on a single plane).

Synchondroses allowing for the facilitation of growth: in cartilaginous joints.

Question 3

Movement examples (2): No movement.

Answer 3

Sutures of skull, Synchondroses.

Question 4

Movement example: Slight movement.

Answer 4

Distal ends of long bones - amphiarthrotic.

Question 5

Movement example: Free movement.

Answer 5

Synovial joints associated with articular capsules.

Question 6

Function of Connective Tissue in Joints.

Answer 6

Connects / “binds” to bone.

Question 7

Fibrous Joint classification type: Sutures.

Answer 7

Skull sutures,
Slightly moveable in juveniles,
Immoveable in adults - a bony joint, synostosis (replacement of ligaments with bone at an advanced age).

Question 8

Fibrous Joint classification type: Gomphosis.

Answer 8

Alveolar region & teeth,
No bone-to-bone connection,
Tooth & bone connection,
Example of a Peg-and-Socket joint (tooth = peg, fitting into alveolar region of maxilla or mandible),
Periodontal ligaments - keep tooth within bone.

Question 9

Fibrous Joint classification type: Syndesmosis.

Answer 9

Dense, irregular Connective Tissue,
Wide,
E.g. interosseous membrane, CT connecting the shafts of the radius & ulna, CT connecting the shafts between tibia & fibula.

Question 10

Cartilaginous Joint classification properties in both types (primary & secondary).

Answer 10

Composed of cartilage - generally hyaline cartilage,
Always temporary joints (during bone growth),
bones are joined by solid masses of Connective Tissue.

Question 11

Cartilaginous Joint classification type: Primary.

Answer 11

AKA synchondrosis joints,

Hyaline cartilage attaches to bone.

Question 12

Cartilaginous Joint classification type: Secondary.

Answer 12

AKA symphyses joints (permanent),
No movement allowed,
Hyaline cartilage + fibrocartilaginous disc (typically in the middle of joint for greater strength),
2 types: Pubic Symphyses & Intervertebral discs.

Question 13

Secondary Cartilaginous Joint type: Pubic Symphyses.

Answer 13

Anterior portion during pregnancy to allow movement during birth,
greater movement in these joints.

Question 14

Secondary Cartilaginous Joint type: Intervertebral discs.

Answer 14

Cartilaginous portions between the vertebral bodies.

Question 15

Fibrous Joints: common to all subcategories.

Answer 15

Bones are joined by solid masses of Connective Tissue.

Question 16

Synovial Joints: common description.

Answer 16

Bones are joined by a Connective Tissue capsule surrounding a lubricated cavity.

Question 17

Synovial Joints common structures (3 points)

Answer 17

Synovial Capsule, Synovial Cavity & Articular Cartilage.

Question 18

Synovial Joints common structure: Synovial Capsule.

Answer 18

Connective Tissue portion of joint,
Binds bone to bone,
On the sides of joints / binds on the edges,
Allows for the synovial cavity.

Question 19

Synovial Joints common structure: Synovial Cavity.

Answer 19

The space left because of indirect articulation between Connective Tissue and bones,
Plays a role in movability of synovial joints.

Question 20

Synovial Joints common structure: Articular cartilage.

Answer 20

Hyaline Cartilage,
Shock absorbent,
Allows for smooth movement,
Avascular - if damaged, bone on bone contact occurs (painful: cannot heal sufficiently).

Question 21

Joint movement classification: Synarthrosis.

Answer 21

Immovable joints,

2 types: Sutures (in adult skulls) & Synchondroses (epiphyseal plates).

Question 22

Joint movement classification: Amphiarthrosis.

Answer 22

Slightly moveable joints,
Associated with amphiarthosis membranes between the radius & ulna, as well as the tibia & fibula,
Associated, too, with secondary cartilaginous (symphyses) joints.

Question 23

Joint movement classification: Diarthrosis.

Answer 23

Freely moveable joints,
Ball & Socket joints - multiaxial movement (e.g. glenohumeral & acetabulofemoral joints),
Hinge joints - less moveable but more moveable than other joints.

Question 24

Joint movement classifications

Answer 24

Synarthrosis, Amphiarthrosis & Diarthrosis.

Question 25

Relationship between mobility & stability of joints

Answer 25

More stability = less mobility, | Less stability = more mobility.

Question 26

Apophyseal Joints: description of concept.

Answer 26

A joint where 2 or more bones join in the spinal column, Apophyseal joints - spinal joints - are encapsulated by Connective Tissues, coated with cartilage & lubricated with synovial fluid to enable smooth joint articulation, Each vertebra has a pair of apophyseal joints - one on the left & right sides.

Question 27

Z-Joints (Zygapophyseal Joints)

Answer 27

``` True diarthrodial (diarthrosis) synovial joints, Connects adjacent vertebral bodies. ```

Question 28

Describe Arthritis

Answer 28

Inflammation of Joints.

Question 29

Describe Osteoarthritis.

Answer 29

A degenerative joint disease: joint articular cartilage is gradually lost, allowing for bone-on-bone contact. Any bone-on-bone contact leads to: additional erosion of cartilage around it, friction between bones causing osteoblasts to move faster and thus allowing bony spurs to form. Bony spurs are more common in older adults, runners & athletes.

Question 30

Describe Gouty Arthritis.

Answer 30

Gouty Arthritis is an acute inflammatory arthritis. It is caused by a crystallisation of uric acid. Individuals with a diet high in purines causes a build-up of uric acid. Erosion of articular cartilage and joint-capsules occurs.

Question 31

Where is Gouty Arthritis most common?

Answer 31

Joints more distal of the body. Joints of the hand and foot digits, ankles, knees & wrists. I.e. metatarsophalangeal joints.

Question 32

Describe the diet that causes or exacerbates presentations of Gouty Arthritis.

Answer 32

``` Diets high in purines: processed meats (i.e. deli meats), alcohol, some types of processed seafood. ```

Question 33

Describe Rheumatoid Arthritis.

Answer 33

Autoimmune disease: the human body is sending signals to attack the cartilage in particular joints, causing it to tear apart.

Question 34

In which age groups is rheumatoid arthritis most common?

Answer 34

Most common in patients between 30-50yro. Late-onset RA presents around 60-65yro.

Question 35

In which area/s of the body is Rheumatoid Arthritis most common?

Answer 35

Digits of hands.

Question 36

Name the 6 types of Synovial joints.

Answer 36

``` Ball & Socket/Multiaxial, Plane, Pivot, Hinge/Uniaxial, Saddle, Condylar. ```

Question 37

Describe the features of a Ball & Socket Joint, including an example.

Answer 37

Multiaxial/Spheroidal Joint - the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone. Range of motion along multiple axes (thus, multiaxial). ``` E.g. Glenohumeral Joint: Shallow socket (Scapula), bulbous head (Humerus). Bad fit = greater range of motion. ``` E.g. Coxal Joint (Hip joint).

Question 38

Describe the features of a Plane Joint, including an example.

Answer 38

Flat or almost flat articular surfaces, causing them to slide passed each other. Typically biaxial. E.g. Acromioclavicular Joint: Acromion Process of Scapula & Lateral end of Clavicle form the AC Joint. Slight movement in order for movement up & down, and sometimes anterior and posterior.

Question 39

Describe the features of a Pivot Joint, including an example.

Answer 39

AKA a "Rotary Joint" or "Trochoid Joint". Freely moveable joint (diarthrotic). Allows only rotary movement around a single axis. E.g. Proximal Radioulnar Joint: Slight pivot movement in pronation and supination. Presence of a ligament which allows radial head to pivot.

Question 40

Describe the features of a Hinge Joint, including an example.

Answer 40

Larger joints tend to be Hinge Joints. Range of motion primarily on one plane. E.g. Humeroulnar Joint (Elbow): Uniaxial. Allows flexion & extension on a single axis. E.g. Knee Joint.

Question 41

Describe the features of a Saddle Joint, including an example.

Answer 41

One articulating surface looks like a saddle, while the other sits in it. Allows for a large amount of movement - flexion, extension, adduction, abduction & thus, circumduction. ``` E.g. First Carpal Metacarpal Joint: First digit (thumb) metacarpal articulates with the triquetral bone (a carpal bone). ```

Question 42

Describe the features of a Condyloid Joint, including an example.

Answer 42

Not as bulbous as Saddle Joints. AKA "Condylar", "Ellipsoidal" or "Bicondylar" Joint. Is an ovoid articular surface / the condyle that is received into an elliptical cavity. Allows movement along 2 planes - flexion, extension, adduction, abduction, and thus, circumduction. E.g. Metacarpophalangeal Joint.

Question 43

Define "Range of Motion".

Answer 43

The range through which bones of a joint can be moved. | Measured in degrees in a circle.

Question 44

Name 3 structures present in all Synovial Joints.

Answer 44

Articular Capsule, Articular Cartilage, Synovial Cavity.

Question 45

Describe the structure of Synovial Joints: Articular Capsule.

Answer 45

On the either side edge of the bone. Encloses the synovial cavity. 2 layers: Fibrous (outer) layer & Synovial membrane (inner layer). Fibrous layer - more robust to protect the inner layers, composed of more dense CT. Synovial membrane - secretes synovial fluid.

Question 46

Describe the structure of Synovial Joints: Articular Cartilage.

Answer 46

Hyaline Cartilage. Doesn't bind bone to bone, it's just present to absorb shock - avoids pain caused by bone to bone contact. Present at the ends of bones. Avascular (so won't heal well, if at all). Functions: reduces friction, shock absorbent.

Question 47

Describe the structure of Synovial Joints: Synovial Cavity.

Answer 47

Space between articulating bones. Allows for movement. Lines all components except articular (hyaline) cartilage. ``` Functions: Secretes synovial fluid, Shock absorbent, Reduces friction, includes phagocytic cells, Supplies nutrients to articular cartilage (i.e. oxygen from synovial fluid). ```

Question 48

Describe the structure of Synovial Joints: Articular discs.

Answer 48

Composed of fibrocartilage structure. Divides the synovial cavity. Not large. E.g. Temporomandibular Joint (TMJ): Articular discs in the middle of the TMJ joint.

Question 49

Describe the structure of Synovial Joints: Meniscus.

Answer 49

Incomplete, fibrocartilaginous discs (don't form a complete circle like articular discs). ``` Functions: Improvement of joint fit, Redistributes weight, Shock absorbent, Facilitation of combined movements. ``` E.g. sits on top of distal portion of femur in knee joint.

Question 50

Describe the structure of Synovial Joints: Labrum.

Answer 50

Exclusive to ball-&-socket joints. Extension of CT that forms a lip to allow for a better fit of the ball portion of B&S Joints. Fibrocartilaginous lip. E.g. shoulder & hip joints: Sits in the ball portion, allowing for a better fit into the socket.

Question 51

Describe the structure of Synovial Joints: Bursae.

Answer 51

Not a true component of synovial joints, but often associated with synovial joints. Little CT sac-like structures similar to joint capsules. Contain some fluid. Found in areas with great movement/friction points and areas with more complex movements. (i.e. Shoulder joint). Associated with tendon sheaths (specialised, very long bursae's). E.g. wrist region: Tendons covered by tendon sheaths here, allowing the wrist and digits to flex without pain.

Question 52

Describe the structure of Synovial Joints: Bursae.

Answer 52

Not a true component of synovial joints, but often associated with synovial joints. Little CT sac-like structures similar to joint capsules. Contain some fluid. Found in areas with great movement/friction points and areas with more complex movements. (i.e. Shoulder joint). Associated with tendon sheaths (specialised, very long bursae's). E.g. wrist region: Tendons covered by tendon sheaths here, allowing the wrist and digits to flex without pain.

Question 53

Describe ligaments. Including the 2 main categories.

Answer 53

All joints have ligaments. "Lig" means "to bind" / bone-to-bone, whereas tendons are muscle to bone. 2 main categories: Intrinsic ligaments - connects bone to bone. E.g. sutural ligaments - CT between bones join the two together. Extrinsic ligaments - connects areas of bone to other structures, between the bones in a joint which is separate from the joint capsule. Important in controlling range of motion. E.g. collateral ligaments.

Question 54

How does the structure & shape of articulating bones affect Range of Motion? Glenohumeral Joint

Answer 54

Head of humerus (ball portion) fits into the glenoid cavity (socket region). Glenoid cavity is shallow, so only 1/3 of humeral head fits into socket. Freely moveable joint - great ROM.

Question 55

How does the structure & shape of articulating bones affect Range of Motion? Bones of the Skull.

Answer 55

Bones fit together at suture lines. | No range of motion.

Question 56

Effect of ligaments on ROM. Example: elbow joint.

Answer 56

Ligaments of different strength affect joint movements differently. Elbow joint - 2 ligaments here. With all hinge joints, collateral ligaments are associated. Collateral ligaments play a role in not allowing medial or lateral deviation of joints. Elbow joint ligaments are very strong capsular ligaments that protect the sides of the joint, allowing flexion & extension with very little movement (whether medial or lateral).

Question 57

Effect of muscles on ROM.

Answer 57

Depends on how much a joint is covered with muscles or tendons.

Question 58

Effect of hormones on ROM: E.g. Relaxin.

Answer 58

Particularly during pregnancy and as pregnancy progresses. Pubic symphysis joint is a type of symphyseal joint (cartilaginous). Relaxin relaxes all joints in the body but especially useful around the pubic girdle, pubic symphysis & sacroiliac joints to allow for the widening of the outlet & inlet regions - thus, allowing for childbirth.