Joints and associated structures Flashcards
How are joints classified?
- Their structural properties
- Their level of mobility
What are the structual classifications of joints?
Fibrous:- bones connected by fibrous connective tissue, e.g. sutures of skull.
Cartilaginous:- bones connected with cartilage, e.g. pubic symphysis.
Primary (synchondrosis, connected by hyaline cartilage)
Secondary (symphysis, connected by fibrocartilage – mainly in the midline of the body)
Synovial joints:- the articulation is surrounded by an enclosing synovial capsule; bones not directly connected at the joint surfaces but strengthened by surrounding structures. Articular surfaces generally covered in hyaline cartilage.
examples such as interphalangeal joints.
What is the Epiphyseal plate?
It is at the end of bones
It is observed in the bones of babies, children and young adults
They are temporary cartilaginous joints that allow bone growth
These plates remain in cartilaginous joints until the bone growth ceases when they ossify
What are 3 types of Synovial Joints and give examples for each?
Uniaxial- movement in one direction only e.g. the hinge joint
Biaxial-Movement in 2 different planes e.g. saddle joint
Multiaxial-Movement on several axes e.g.ball and socket
What are the 3 joint mobility classifications?
Synarthosis - little or no mobility (mostly fibrous joints like skull sultures)
Amphiarthosis-limited mobility (often fibrocartilaginous such as pubic symphsis)
Diarthosis- freely mobile
If a joint is more mobile what does that usually tell us about the stability of the joint?
The more mobile a joint the less stable it usually is
Why might some joints have poor stability?
the shape of the articulating part of the bones would provide poor stability
What structures can provide stability to joints?
Ligaments – collagenous connective tissue linking bones
Tendons – collagenous connective tissue between bones and muscles.
What are some other important fascial structures near the joints?
Retinacula (reticulum)
Aponeuroses (aponeurosis)
Bursae (Bursa)
singular terms are in brackets
What is the Reticulum?
A thickened band of deep fascia found close to a joint. This band holds the tendons down during muscle contraction to prevent BOW-STRINGING which could compromise function
What is the Aponeurosis?
A flat sheet like structure formed from a tendon or ligament
Can provide a broad attatchment for a muscle which will help distribute the mechanical load over a larger area than a more typical tendon would
They can also provide protection for underlying structures e.g in the palm of the hand and the sole of the foot
What is a bursa?
closed sac of a serous membrane whose interior is similar to that of synovial joints
The membranes of the bursa secrete a lubricating fluid to their interior.
Bursae are found at body sites that are subject to friction where they act as a bearing that allows free movement and prevent friction
Inflammation of Bursa can be real painful
