Bones and joints Flashcards
What is a joint
Where two or more bones meet
What are the 3 types of joints in the body? how much movement do they permit?
Synovial (allows free movement)
Cartilagenous (semi-moveable)
Fibrous (no movement)
What are the six types of synovial joints, give examples for each and briefly mention how much movement they allow
Ball and socket e.g. hip + knee joint, allows flexion/extension/abduction/adduction/inter and external rotation
Hinge e.g. elbow and knee joint, allow movement in one axis = flexion and extension
Plane/gliding e.g. acromioclavicular and intercarpal joints, allows gliding movements between flat surfaces.
Condyloid e.g. metacarpophalangeal and radoiocarpal joint, allow flexion/extension/abduction/adduction
Saddle e.g. carpometacarpal and sternoclavicular joint, allows flexion/extension/abduction/adduction. 2 articular surfaces are concave-convex and site like a saddle.
Pivot e.g. radioulnar joint and atlantoaxial joint, allow rotation around a single axis.
describe cartilaginous joints
These joints are held together by cartilage between the articulating bones
What are the two types of cartilaginous joints and describe them with examples
Synchondroses: joint where the bones are joined together by hyaline cartilage (mainly found in developing skeleton but can also be founding mature Skeleton) e.g. first sternocostal joint and growth plate
Symphyses: joint where the bones are joined by fibrocartilage, found at the skeletal midline e.g. IV discs, symphysis pubis
describe fibrous joints
these joints are held together by a dense, fibrous connective tissues, consisting mainly of collagen.
What are the 3 types of fibrous joint, give examples
Sutures: e.g. between bony plates of the skull
Gomphoses: between alveolar bone and tooth (bony socket and root of tooth)
Syndesmoses: bones are joined by ligament or fibrous connective tissue (interosseous membrane) e.g. distal tibiofibular joint
Describe/draw the structure of a general synovial joint
Periosteum (tough white fibrous membrane) covers the outer surface of the bone.
Articular/fibrous capsule supports and stabilises the joint and connects the two bones together. It is made up of irregular fibrous connective tissue. It has 2 layers:
outer fibrous membrane and inner synovial membrane.
Synovial cavity is made up of synovial membrane and synovial fluid.
The articulating surfaces fo the bones are covered in hyaline cartilage - which helps to reduce friction and absorb shock.
Additional structures may be present in the joint too, including: menisci/articular discs, bursa, extra and intra capsular ligaments, tendons, fat pads.
What is function of hyaline cartilage on a reticulating surfaces of bone?
helps to reduce friction and absorb shock.
What are the functions of synovial fluid?
Lubricates and reduces friction between articulating bones
Provides nutrients to the cartilage
Removes metabolic waste products
Phagocytic cells remove debris
what are menisci and what is their role?
they are C shaped fibrocartilage pads which provide extra shock absorption and cushioning.
what are articular discs and what is there function?
Small, oval shaped structure which strongly unites bones in a joint
what Is the function of a fat pad?
fat pad acts as a cushion and protects articular cartilage
what Is the function of an extra-capsular ligament?
provide stability, hold joint together, prevent dislocation
Why are bones considered organs?
Because they contain many types of tissues such as blood, nerves, connective tissue and bone tissue.
What are the components of bone? how much do they make up and what do they contain?
Organic component (osteoid): makes up 1/3 - mainly type 1 collagen and ground substance (proteoglycans and extracellular fluid). This gives bones flexibility.
Inorganic component: 2/3 - primarily hydroxyapatite which stores calcium and phosphate salts. These make bones brittle, giving them hardness and strength.
What are the two types of bone?
Cortical/compact
Cancellous/trabeculae
Describe the structure of compact bone and where is it found?
Compact bone is found in the shaft of long bones and on the other surface of all bones.
It is made up of osteons - cylindrical structures which contain a central canal (Haversian canal) through which nerves and blood vessels pass through. The osteons are made up of concentric layers, called lamellae. They contains osteocytes which are connected to each other by canaliculi.
What is the endosteum?
Boundary between compact and cancellous bone
what is a Volkman’s canal?
It connect the Haversian canals in osteons together, at right Angles