T2 L10 Principles of articulation Flashcards
A joint is a point of contact between what?
Neighbouring bones
Bone and cartilage
Bone and teeth
What are the 2 ways joints can be classified?
Structural classification
Functional classification
What are the examples of shoulder articulation?
Glenohumeral
Sternoclavicular
Acromioclavicular
What is structure classification based on?
Presence or absence of synovial cavity and type of connective tissue
What is functional classification based on?
Degree of movement permitted
What is synarthrosis?
Immovable
What is amphiarthrosis?
Partially moveable
What is diarthrosis?
Freely moveable
Describe fibrous joints
No synovial cavity
Held together by fibrous connective tissue
Permits little or no movement
What are the 3 types of fibrous joints?
Suture
Syndesmosis
Interosseous membrane
Describe suture fibrous joints
Unite skull bones Thin layer of dense connective tissue Irregular Interlocking edges to provide strength & permit no movement Ossification of suture forms synostosis
Give an example of a synostosis
Left and right sides of frontal bone which fuse around 6 years of age
Describe a syndesmosis fibrous joint
More connective tissue than a suture joint
Crosses greater distance than suture
Connective tissue typically arranged into bundles
Typically permits slight movement
Give examples of syndesmosis fibrous joint
Distal tibiofibular joint connected by anterior tibiofibular ligament
Gomphosis - mobile peg and socket joint
Describe an interosseous membrane joint
Sheet of dense connective tissue Binds adjacent long bones Partially moveable (amphiparthrosis)
What are some examples of interosseous membrane joints?
Between radius and ulna
Between tibia and fibia
Describe cartilaginous joints
No synovial cavity
Held together by fibrocartilage or hyaline cartilage
Permits little or no movement
What are the 2 types of cartilaginous joints?
Synchrondosis
Symphysis
What type of cartilage is in a synchrondosis joint?
Hyaline cartilage
Give an example of a synchrondosis joint
Epiphyseal plate
What type of cartilage is in a symphysis joint?
Fibrocartilage
Describe a symphysis joint
Connective tissue is fibrocartilage
Adjacent bones lined with hyaline cartilage but with broad disc of fibrocartilage connecting the bones
Partially moveable
Give examples of symphysis joints
Junction of manubrium and sternum
Intervertebral discs
Pubic symphysis
Describe articular cartilage
Covers bones at synovial joints
Avascular
Composed of collagen and proteoglycans
Orientation of collagen structure imparts resistance to compression and an extremely low-resistance surface
What does the articular capsule surround?
Encapsulates synovial joint
What are the 2 layers of the articular capsule?
Outer fibrous membrane
Inner layer of synovial membrane
Describe the outer fibrous membrane of the articular capsule
Connects to periosteum
Flexibility permits movement
Fibres arranged into bundles giving high tensile strength
Describe the inner synovial membrane of the articular capsule
Areolar connective tissue
Rich in elastic fibres
Occasionally contains structural articular fat pads which stop the 2 surfaces rubbing together
What is synovial fluid secreted from?
From fibroblast cells in synovial membrane and interstitial fluid from blood plasma
What are the functions of the synovial fluid?
Lubricates articular surface to reduce friction
Provides some shock-absorbing properties
Supplies nutrition to and removes waste products from avascular articular cartilage
Phagocytes remove microbes and debris
What are the 2 types of accessory ligaments in synovial joints?
Intracapsular ligaments
Extracapsular ligaments
Where are the intracapsular ligaments?
Lie within joint capsule
Give examples of intracapsular ligaments
Anterior and posterior cruciate ligaments of knee
Where are extracapsular ligaments?
Lie outside joint capsule
Give an example of an extracapsular ligament
Fibular and tibial collateral ligaments of knee
What are accessory articular discs?
Fibrocartilage pads that lie between articular cartilage of some synovial joints
Give an example of an accessory articular disc
Meniscus of knee
What is the function of the accessory articular discs?
Help maintain joint stability
Direct flow of synovial fluid
What are bursae and what is their function?
Fluid filled sacs lined with synovial-like membrane
Function: cushion movement between body parts
What are tendon sheaths?
Similar to bursae
Specialised membranes that wrap around tendons
Common where many tendons come together and pass through synovial joint capsule
What movements does a planar joint allow?
Back and forth
Side to side movements
What are some examples of planar joints?
Intercarpal joints
Intersarsal joints between tarsal bones at ankle
what movements does a hinge joint allow?
Motion in a single axis e.g. flexion and extension
What are some examples of hinge joints?
Knee joints
Elbow joints
What movements does a pivot joint allow?
Rotation in its longitudinal axis (monomial)
Give an example of pivot joints
Radioulnar joint
Atlanto-axial joints (C1 to C2 axial joints)
What movements does a condyloid joint allow?
Movement around 2 axis
- flexion and extension
- abduction and adduction
Give an example of a condyloid joint
Wrist joint
Metacarpophalangeal joint
What movement does a saddle joint allow?
Movement around 2 axis
- flexion and extension
- abduction and adduction
Give an example of a saddle joint
Carpometacarpal joint
What movement does a ball and socket joint allow?
Triaxial movement around 3 planes
- flexion and extension
- abduction and adduction
- rotation
Give examples of a ball and socket joint
Shoulder joint
Hip joint
What type of joint is the glenohumeral joint?
Synovial ball and socket joint
What 3 ligaments stabilise the glenohumeral joint?
Glenohumeral
Coracohumeral
Transverse humeral
What are the 4 rotator cuff muscles>
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
What are the functions of the rotator cuff muscles?
Provide most of strength for glenohumeral joint
Join scapula with humerus
Encircle joint and fuse with joint capsule
What type of joint is the acromioclavicular joint?
Synovial gliding joint (planar) but acts like a pivot
What 3 ligaments stabilise the acromioclavicular joint?
Acromioclavicular
Coracoacromial
Coracoclavicular
What type of joint is the sternoclavicular joint?
Synovial saddle joint capable of triaxial movement
What are the 3 ligaments that stabilise the sternoclavicular joint?
Interclavicular
Anterior sternoclavicular
Inferior sternoclavicular
