Arthrology Flashcards

Question

How does articular cartilage help mechanically?

Answer 1

* Biomechanically the PG’s and collagen are the important components * Collagen provides tensile strength whilst PG’s provide compressive strength * Subchondral bone also helps as a shock absorber * The fluid component of the cartilage is also important Cartilage acts similarly to a sponge full of water * Water will be squeezed out or absorbed dependent upon the loading of the tissue * Usually only a very small area of cartilage is actually loaded * May have to withstand forces up to several times an animal’s bodyweight

Answer 2

* Synovial fossae appear in the articular cartilage of many species (areas of endochondral bone which are ‘naked’ of cartilage and covered only by a thin layer of connective tissue) * Their role is unclear (?distribution of synovial fluid)

Answer 3

Articular capsule and the ligaments contain many nerve endings * Innervated by the nerves that supply the voluntary striated muscles * Innervated parts of the joint can sense pain and responds to the amount of movement and stretch of a joint All structures are supplied by the circulatory system except articular cartilages * Supplied by capillaries from arteries located adjacent to them * Adjacent veins are responsible for removal of waste products Articular cartilage is avascular and reliant upon synovial fluid for nutrition • Lack of nerve supply means lesions usually become severe before an animal exhibits any outward signs

Answer 4

Extra and intracapsular ligaments Articular discs / menisci Bursae

Answer 5

provide stability reduce friction maintain joint health and physiology

Answer 6

* Extracapsular = outside the articular capsule * Stabilise joints e.g. medial and lateral collateral ligaments of the horses’ hock joint * Intracapsular = inside the joint * Provide added stability * Folds in the synovial membrane mean that these ligaments, whilst lying inside the articular capsule, are not actually inside the synovial cavity * E.g. cruciate ligaments within the stifle joint.

Answer 7

Some synovial joints contain fibrocartilage discs / menisci • Located between the articular surfaces • Attach to the joint capsule • Often divide the synovial cavity in two • Purpose is to modify the shape of a bone’s surface to enable bones to more tightly fit together • Also help to stabilise joints and to distribute synovial fluid E.g. the stifle joint

Answer 8

Fluid filled sacs located between skin and bone, tendon and bone, muscle and bone, and ligament and bone • Found in any area where there may be friction (‘rubbing’) between bone and soft tissues • Not part of joints but are located near to them • Structure resembles that of the articular capsules

Answer 9

``` categorised on the type of movement they allow • arthrodial (planar) • trochoid (pivot) • ellipsoid (condyloid) • sellaris (saddle) • spheroid (ball and socket) • ginglymus (hinge) ```

Answer 10

‘gliding and sliding’ movements Also referred to as nonaxial joints as the movements produced do not occur about an axis Bones forming arthrodial joints have generally fairly flat articular surfaces Examples include the carpus and tarsus

Answer 11

One bone provides a protrusion that fits into the ring of another bone Allows rotational movements about an axis in one direction (also called monaxial) Main example is the atlanto-axial joint

Answer 12

Formed where one bone has a convex-oval shaped articular surfaces that articulates with a concave-oval shaped articular surface of another Biaxial allowing side to side and back and forth movements Examples include the radiocarpal and midcarpal joints

Answer 13

Formed where one bone has a ‘saddle’ shaped surface which articulates with another bone that fits into it like a rider would Really modified ellipsoid joints Biaxial Examples include the inter and distal interphalangeal joints

Answer 14

Formed when one bone forms a ‘ball’ that articulates into a ‘socket’ of another • Mulitaxial (enable movement in 3D) • Examples include the shoulder and hip joints

Answer 15

Uniaxial Enable ‘opening and closing’ movements Examples include the elbow and fetlock joints

Answer 16

* Gliding * flexion * extension * adduction * abduction * rotation

Answer 17

* Takes place in arthrodial joints ,e.g. the carpometacarpal joint * Side-to-side, back-and-forth movement * Bones do not change angle.

Answer 18

* Flexion results in a decrease in joint angle * Usually occurs in a sagittal plane * Can occur in spheroid, ginglymus, ellipsoid and sellaris joints * Some joints can dorsiflex or plantar flex * Dorsiflexion = foot bends towards the dorsum * Plantar flexion = foot bends towards the ground surface / sole of the foot

Answer 19

* Opposite of flexion * Increase in joint angle * Some joints may hyperextend (extend beyond their ‘normal’ anatomical position) * Hyperextension can commonly occur at the horses’ fetlock joint

Answer 20

* Movement of a joint towards the midline * Usually in the frontal plane * Shoulder and hip joints are capable of adduction

Answer 21

* Opposite of adduction | * Movement of a joint away from the midline

Answer 22

Movement of a bone around a longitudinal axis • Where rotation occurs in the limb it may be described as lateral or medial rotation • Example is the radioulnar joint of the elbow in humans and canines

Answer 23

The range of motion (ROM) = distance in which joint can be moved in degrees

Answer 24

ROM is affected by the:- structure / shape of bones involved strength of associated ligaments associated muscles use

Answer 25

Structure / Shape of Bones Involved • How closely articulating bones fit together determines the type and range of movement possible • Spheroid joints allow greatest ROM. Strength of Associated Ligaments • The greater the tension in the ligaments associated with a joint, the smaller the ROM. Associated Muscles • Tension within muscles restricts ROM Use • Lack of use of a joint leads to a loss of ROM

Answer 26

* Age has a number of effects on joint structure and function * Articular cartilages undergo thinning * There is a reduction in the amount of synovial fluid produced * Shortening / tightening of ligaments * Combination of these factors leads to a loss of ROM and a gradual degeneration of the joint structures * Speed of change will be affected by use (‘wear and tear’), gender and genetics.

Answer 27

• Lesion of the cartilage • Loose portion of cartilage breaks off leaving loose tissue in the joint; joint mouse. • X-rays or arthroscopy are needed for diagnosis • Causes pain from joint mouse and/or exposed bone • Usually the joint is flushed to remove fragments, anti- imflammatories and pain relief needed • More often seen in younger animals

Answer 28

Most common form of arthritis in humans and companion animals • Characterised by progressive deterioration and loss of articular cartilage • Affects load-bearing synovial joints causing pain, inflammation and loss of mobility • Osteophytes (bone spurs) can form

Answer 29

* Age * Obesity * Joint trauma * Joint instability * Genetics * Metabolic disease * Endocrine disease

Answer 30

* Inflammation in the synovial membrane * Can be a secondary condition of osteoarthritis * Can also be caused by excess of joint fluid (effusion) or trauma to the joint

Answer 31

• Usually only caused by trauma when the integrity of the joint is compromised allowing dirt and bacteria into the joint capsule.

Arthrology Flashcards

(55 cards)