L4 - Principles of articulation

Question 1

DEFINITIONS

i) do joints have to have movement?
ii) name three things there can be a point of contact between to form an articulation/joint/arthrosis

Answer 1

i) no
ii) neighbouring bones, bone and cartilage, bone and teeth

Question 2

JOINT CLASSIFICATION - STRUCTURE AND FUNCTION

i) what is structural classification based on pres/absence of? what else?
ii) what are three three structural classifications of a joint?
iii) what is functional classification based on? what are the three groups of this and what does each mean?

Answer 2

i) struc classific based on pres or absence of a synovial cavity
- plus the type of connective tissue

ii) fibrous, cartilagenous or synovial

iii) func classific based on degree of movement joint permits
- synarthrosis = immovable
- amphiarthrosis = partially moveable
= diarthrosis = freely moveable

Question 3

TYPES OF MOVEMENT

i) what movement is allowed by a synarthrosis?
ii) amphiarthrosis?
iii) diarthrosis? what type of joint are these usually?
iv) what type of joint are synarthrosis and amphiarthrosis usually?

Answer 3

i) synarthrosis - immovable
ii) amphithrosis - partially moveable
iii) diarthrosis - freely movable - usually synovial
iv) syn and amphi are usually fibrocart joints

Question 4

FIBROUS JOINTS

i) is there a synovial cavity?
ii) what holds them together?
iii) what amount of movement does it usually permit? give the name of these (2)
iv) what are the three types of fibrous joint?

Answer 4

i) no
ii) held together by fibrous connective tissue
iii) permits little or no movement = syn or amphiarthrosis
iv) suture, syndesmosis, interosseous membrane

Question 5

FIBROUS JOINTS - SUTURE

i) what area of the body are they found and what do they do?
ii) what are they? are they reg or irreg?
iii) what do interlocking edges provide? what type of movement occurs here?
iv) what does ossification of a suture form? give an example of where this may be found and what age it happens

Answer 5

i) unite skull bones
ii) thin layer of dense connective tissue / irregular

iii) interlock edges provide strength
- no movement permitted > synarthrosis

iv) ossification of a suture > synostosis
- L and R frontal bones fuse around 6yrs of age

Question 6

FIBROUS JOINTS - SYNDESMOSIS

i) what is it?
ii) what joint is it similar to? how is it different? (2)
iii) how is the connective tissue typically arranged?
iv) what level of movement does it permit?
v) give two examples of this joint

Answer 6

i) joint held together by ligaments
ii) similar to a suture but has more connective tissue and crosses a greater distance
iii) arranged in bundles which makes it more ligamentous
iv) permits slight movement = amphiarthrosis

v) anterior tibiofibular ligament - between tibia and fibula
- gomphosis/dentoalveolar (between tooth and bone)

Question 7

FIBROUS JOINTS - INTEROSSEOUS MEMBRANE

i) what is it? what does it bring together?
ii) what type of movement is permitted/
iii) what are the two main examples?

Answer 7

i) sheet of dense connective tissue that brings adjacent bones together
ii) slight movement = amphiarthrosis
iii) radius and ulna / tib and fib

Question 8

CARTILAGENOUS JOINTS

i) do they have a synovial cavity?
ii) what two types of cartilage may they be held together by?
iii) what type of movement is permitted? (2)
iv) what are the two types of cartilagenous joint?
v) which type of cartilage is shown in A and B? which has more movement?

Answer 8

i) no
ii) hyaline or fibrocartilage
iii) little (amphi) or no movement (synarthrosis)
iv) two types of joint - synchondrosis and symphysis

v) A - fibrocartilage and B - hyaline
- fibrocartilage has more movement due to lots of fibres

Question 9

CARTILAGENOUS JOINTS - SYNCHRONDOSIS

i) what type of cartilage is present? what type of movement is allowed?
ii) give an example? what is formed when it reaches maturity?

Answer 9

i) hyaline cartilage
- no movement > synarthrosis

ii) epiphyseal plate of bone (growth plate)
- at skeletal maturity the ephiphysis, metaphysis and epiphyseal plate fuse to form a synostosis

Question 10

CARTILAGENOUS JOINT - SYMPHYSIS

i) what type of connective tissue is present?
ii) what type of cartilage lines adjacent bones? what connects the two bones?
iii) what type of movement is allowed here?
iv) where do all symphysis occur? give three examples

Answer 10

i) fibrocartilage
ii) hyaline cartilage lines adjacent bones then a borad disk of fibrocartilage connects the bones
iii) slight movement - amphiarthrosis

iv) all occ in midline of body
- manubrium sternum junction
- IV disks
- pubic symphysis

Question 11

SYNOVIAL JOINTS

i) what does it sit between?
ii) what type of movement does it allow?
iii) what type of cartilage is articular cartilage? where does this sit?

Answer 11

i) sits between articulating bones
ii) allows free movement (diarthrosis)
iii) articular cart is hyaline cart - sits of ends of bones

Question 12

ARTICULAR CARTILAGE/CAPSULE

i) where does it cover?
ii) is it vascular or avascular?
iii) what two main things is it composed of?
iv) what does the orientation of the structure allow? (2)

Answer 12

i) covers end of bones at synovial joints
ii) avascular
iii) mainly composed of collagen and proteoglycan (ECM)
iv) orientation of collagen gives resistance to compression and gives a low resistance surface

Question 13

ARTICULAR CAPSULE

i) what is its role? how many layers does it have?
ii) what is the outermost layer made from? which structure does it connect to?
iii) what does the outer layer allow? how are fibres arranged? what does this result in?
iv) what is the inner layer aka? what type of fibres is it rich in? what does it occassionally contain?

Answer 13

i) encapsulates a synovia joint - 2 layers

ii) outer layer made from fibrous membrane
- connects to the periosteum

iii) outer layer allows flexibility/movement
- fibres are arranged into bundles > high tensile strength

iv) inner layer = synovial membrane
- areolar conn tissue rich in elastic fibres
- occ contains structural articular fat pads

Question 14

SYNOVIAL FLUID

i) what is it secreted by?
ii) what is it rich in? (2) which cells secrete this?
iii) give four main roles

Answer 14

i) secreted by synovial membrane

ii) rich in hyaluronic acid (secreted by fibroblast like cells)
- rich in interstitial fluid from blood plasma

iii) 1) lubrication/reducing friction
2) shock absorber
3) nutrition supply and removal of waste products from avascular artic cartilage
4) phagocytes remove microbes and debris

Question 15

ACCESSORY LIGAMENTS TO SYNOVIAL JOINTS

i) where do intracapsular ligaments lie? how are they seperated from the synovial fluid?
ii) give two examples of intracapsular ligaments
iii) where do extracapsular ligaments sit? give two examples

Answer 15

i) intracapsular sit inside the joint capsule
- sep from synovial fluid by folds in the synovial membrane

ii) intracapsular > anterior and posterior cruciate ligament

iii) extracapsular lie outside the joint capsule
- fibular and tibial collateral ligaments of the knee

Question 16

ACCESSORY ARTICULAR DISKS TO SYNOVIAL JOINTS

i) what type of cartilage make these up? where may they lie?
ii) what may they also be called?
iii) what is the role of these disks? (2)
iv) which group of people are tears common in? what may it lead to if this is not treated?

Answer 16

i) made of fibrocartilage
- lie between articular cartilage of some synovial joints eg knee

ii) artic disks = menisci
iii) help maintain joint stability and direct flow of synovial fluid
iv) tears common in athletes > can progress to OA if not treated

Question 17

NERVE AND BLOOD SUPPLY OF SYNOVIAL JOINTS

i) what do nerve endings that supply the joints also supply?
ii) which two areas are nerves distributed to? which two things do they allow?
iii) are many components of the synovial joint vascular or avascular? what do they therefore rely on?

Answer 17

i) nerve endings also supply the associated muscles

ii) nerves distrib to the articular capule and associated ligaments
- allow pain and proprioception

iii) many components are avascular therefore rely on numerous branching of arteries and veins to supply associated tissue

Question 18

BURSAE AND TENDON SHEATHS

i) what are bursae? what are they lined with?
ii) what is the role of bursae?
iii) what are tendon sheaths? where are they especially found?(2)

Answer 18

i) bursae are fluid filled sacs lined with synovial like membrane
ii) role is to cushion movement between body parts and reduce friction

iii) tendon sheaths are specialised membranes that wrap around tendons
- espec found where many tendons come togther and/por pass through a synovial joint capsule

Question 19

name the six types of synovial joint

Answer 19

planar, hinge, pivot, condyloid, saddle, ball and socket

Question 20

SYNOVIAL JOINTS - PLANAR

i) what type of surfaces come together at this joint? (2)
ii) what type of movment does it permit? (2)
iii) give two examples of this joint

Answer 20

i) flat or slightly curved
ii) back and forth / side to side
iii) intercarpal joints and intertarsal joints

Question 21

SYNOVIAL JOINT - HINGE

i) what two types of surface come together?
ii) what type of motion does it permit?
iii) give two examples of this joint

Answer 21

i) concave surface of one bone fits into convex surface of another
ii) motion in a single axis eg flexion/extension
iii) knee and elbow joint

Question 22

SYNOVIAL JOINTS - PIVOT

i) which two surfaces come togther?
ii) what type of movement does it permit? what axis is this in?
iii) give two examples and the action of each

Answer 22

i) rounded/pointed surface of one bone pivots inside a ring formed by another bone and a ligament
ii) rotation in the longitudinal axis

iii) radioulnar joint - twists forearm
- atlanto axial joint - shaking head

Question 23

SYNOVIAL JOINTS - CONDYLOID

i) which two surfaces come together?
ii) what type of movement does it permit? (2)
iii) give two examples

Answer 23

i) convex oval projection of one bone fits into an oval depression of the other
ii) movement in two axis - flex/exten and abduc/adduc
iii) wrist joint and metacarpophalangeal joints

Question 24

SYNOVIAL JOINTS - SADDLE

i) what two surfaces come together?
ii) what type of joint is it a modified version of?
iii) what movement does it permit? (2) what other movement can it sometimes permit?
iv) give an example

Answer 24

i) one bone fits into the saddle shaped bone it opposes
ii) modified condyloid joint

iii) permits movement in two axis
- flexion/exten and abduc/adduc
- sometimes allows rotation eg thumb

iv) carpometacarpal joint - between trapezium and metacarpal

Question 25

SYNOVIAL JOINTS - BALL AND SOCKET

i) what two surfaces come together?
ii) what movement does it allow? (3)
iii) give two examples
iv) what is a disadvantage of this type of joint? how is this rectified?

Answer 25

i) ball like surface of one bone fits into cup like depression of the other

ii) triaxial movement in three planes
- flex/exten, add/abduc, rotation

iii) shoulder and hip joint
iv) increased motion can decrease stability so more likely to dislocate > accessory muscles are needed to stabilise joint

Question 26

name the six types of synovial joint A-F

Answer 26

A - planar, B - hinge, C - pivot, D - condyloid, E - ball and socket, F - saddle

Question 27

GLENOHUMERAL JOINT

i) what type of joint is it? which two areas does it connect?
ii) why is it the most mobile joint in the body?
iii) what is the glenoid labrum? what does it allow?
iv) what three ligaments is the joint stabilised by?
v) how many bursae are associated with it?
vi) label the diagram

Answer 27

i) synovial ball and socket joint
- connects the proximal humerus to the scapula

ii) most mobile joint because its shallow
iii) glenoid labrum is a narrow rim of fibrocartilage that deepens the glenoid fossa
iv) stabilised by glenohumeral, coracohumeral and transverse humeral ligaments
v) four associated bursae

vi) A - coracohumeral
B - transverse humeral
-C - glenohumeral

Question 28

GH JOINT - ROTATOR CUFF MUSCLES

i) what do the rotator cuff muscles provide?
ii) what two bones do they joint?
iii) what do they encircle?
iv) label diagram

Answer 28

i) provide stability of GH joint
ii) join scap with humerus
iii) encircle the joint and fuse w joint capsule

iv) A - supraspinatus, B - infraspinatus, C - teres minor,
D - subscapularis

Question 29

ACROMIOCLAVICULAR JOINT

i) what type of joint is it? what does it act as?
ii) which three ligaments stabilise it?
iii) what movement does it allow?

Answer 29

i) synovial planar joint but acts like a pivot
ii) acromioclavic, coracoacrom, coracoclavicular
iii) allows movement of scapula allowing greater arm rotation above the head

Question 30

STERNOCLAVICULAR JOINT

i) what type of joint is it?
ii) which two areas foes the medial clavicle articulate with?
iii) what divides the joint into two synovial cavities?
iv) which three ligaments reinforce it?
v) what type of movement is it capable of? is it active or passive?

Answer 30

i) synovial saddle joint
ii) medial clavicle fits into a hollow formed by suplat surface of manubrium and medial costal cart of first rub
iii) fibrocartilagenous articular disk divides the joint
iv) interclavic, anterior and post sternoclavic ligaments

v) triaxial movement
- movement is passive and dictated by movement of the shoulder