Joints Flashcards
What is a joint?
A union or junction between two or more bones or rigid parts of the skeleton
Where do articular arteries (which nourish the joint) arise from?
They arise from the vessels around the joint
Most articular nerves are branches of the nerves that supply the muscles surrounding the joint. T/F?
True
What is the name of the sensation transmitted by joints which provides awareness of the movement and position of parts of the body?
Proprioception
Joints can be classified according to their general morphology into three categories. These are…?
Fibrous joints
Cartilaginous joints
Synovial joints
What are the three classification of joints according to their function?
Synarthrosis - joints which do not provide movement
Amphiarthrosis - joints which provide a small degree of movement
Diarthrosis - joints which provide free movement
What kind of joints do not have a joint cavity?
Fibrous joints and cartilaginous joints
What is a fibrous joint?
A joint which connects bones via fibrous tissue
Fibrous joints can be classified according to the range of movement they permit as…?
Synarhtrotic or amphiarthrotic
Give an example of a fibrous joint.
Sutures of the cranium
What are cartilaginous joints and what range of motion do they offer?
These are joints without a joint cavity which are connected by cartilage. They can be syarthrotic or amohiarthrotic.
What are the two types of cartilaginous joints?
Primary (synchondroses)
Secondary (symphases)
What range of movement is offered by synovial joints?
Synovial joints are diarthrotic joints
What is the general structure of a synovial joint?
Bones are united by a joint capsule which is formed from an outer fibrous membrane and an inner synovial membrane. The articular surfaces of the bones are lined with hyaline cartilage and are separated by synovial fluid.
What is the synovial fluid and what is it composed of?
It is the viscous, clear fluid that exists within the capsule of a synovial joint and is secreted by the synovial membrane. Its main component is hyaluronic acid but it also contains macrophages.
What is the synovial membrane composed of?
Loose areolar connective tissue with two types of cell: type A synoviocytes and type B synoviocytes
What are the functions of the two types of cell within the synovial membrane?
Type A synoviocytes - modified macrophages
Type B synoviocytes - fibroblast-like cells responsible for secreting hyaluronic acid and other proteins of the synovial fluid.
Synovial joints often have additional structures such as articular discs and fat pads associated with them. What are the purpose of these?
Articular discs - absorb compression forces, adjust to changes in the contours of joint interphases and increase range of movement
Fat pads - absorb compression forces
What are bursae, where are the found and what is there function?
They are fibrous, slightly flattened sacks lined with synovial membrane and containing a thin film of synovial fluid.
They are usually found between bone and other tissues such as skin, tendons, ligaments and muscles.
They function to cushion the movement between these structures.
What are tendon sheaths and what are there function?
Tendon sheaths are essentially elongated bursae which wrap around tendons which are particularly subjected to stress and protect them from frictional forces.
What are the six sub-groups of synovial joints?
Plane joints Hinge joints Pivot joints Ellipsoid/condyloid joints Saddle joints Ball and Socket
Which synovial joints are uniaxial?
Plane joints
Hinge joints
Pivot joints
Which synovial joints are biaxial?
Condyloid joints
Saddle joints
Which synovial joint is multiaxial?
Ball and Socket
Give an example of a plane joint.
Acromioclavicular joint between acromion of the scapula and the clavicle
Give an example of a hinge joint.
Elbow joint
Give an example of a pivot joint.
Superior radioulnar joint
Give an example of an ellipsoid joint.
Metacarphophalangeal joints (knuckle joints)
Give an example of a saddle joint.
Carpometacarpal joint at the base of the thumb
Give an example of a ball and socket joint.
Hip joint. Spherical head of femur and socket formed by the acetabulum of the hip bone
What kind of ligaments reinforce a synovial joint?
Accessory ligament
What are the two main forms of ligament found inside the synovial joints?
Intracapsular accessory ligaments
Extracapsular accessory ligaments
What limits the range if motion of a fibrous joint?
The length of the fibrous tissue of the joint. Longer tissue = greater range of motion
Give a description of a synchondroses and provide an example of this type of joint.
It is a joint which unites bines via hyaline cartilage and is almost always synarthrotic. It can occur permanently (between first rib and manubrium) or temporarily ( between epiphyses and diaphyses of long bones in development)
What us synovial fluid drained by?
Lymph vessels
Describe a secondary cartilaginous joint and give an example of this type of joint.
Here the articulating surfaces of the bones of the joint are covered in hyaline cartilage but the bones are united by fibrocartilage. It usually occurs in the midline of the body (e.g. Pubic symphysis and intervertebral discs). They function well as shock absorbers
What are the three sub-sets of fibrous joints? Give a description and provide an example for each
Syndesmosis - units bone with an interosseous filament (amphiarthrotic) e.g.joint between radius and ulna joined by ligamentum flavum
Gomphosis - peg-like process fits into socket between the root of the tooth and the alveolar process of the jaw and the joint is composed of a periodontal ligament (synarthrotic)
Suture - strong, synarthrotic joint in the skull held by a sutural ligament
