Joints Flashcards
Arthrology
= study of joints
What are the 3 functional classifications of joints?
- Synarthroses
- Amphiarthroses
- Diarthroses (synovial)
Synarthroses joint
- no movement
- bones are close together and may overlock
- extremely strong joints (located where movement between bones must be prevented)
What are the 5 major types of synarthroses joint?
- Sutures
- Fibrous joints
- Gomphoses
- Synchondroses
- Synostoses
Sutures
edges of bones are interlocked and bound together at the suture by dense connective tissue
(e.g.: bones of skull)
Fibrous joint
- bone ends held together by fibrous or collagenous connective tissues
- no synovial cavity between bone ends
- strong joints that inhibit movement
- generally synarthroses
Gomphoses
fibrous joint
(e.g.: gomphoses joint binds to teeth by the bony sockets in the maxillary bone and mandible)
Synchondroses
- a rigid, cartilaginous bridge between two bones
- the epiphyseal cartilage is a synchondrosis that connects the diaphysis of a long bone with an epiphysis
- cartilaginous joints are connected by cartilage (fibrocartilage or hyaline)
Synostoses
totally rigid and immovable joint created when two separate bones fuse and the boundary between them disappears
(e.g.: the epiphyseal lines of mature bones)
Amphiarthroses
- permits little movement (more than synarthroses)
- much stronger than a freely movable joint
- articulating bones are connected by collagen fibres or cartilage (cartilaginous joints)
What are the two types of amphiarthroses?
- Syndesmosis
- Symphysis
Syndesmosis
the articulating bones are connected by a ligament
(e.g.: distal articulation between the tibia and fibula)
Symphysis
the articulating bones are separated by a wedge or pad of fibrocartilage
(e.g.: connection between the two pubic bones)
Diarthrosis
- known as a synovial joint
- permit a wider range of motion
- typically located at the ends of long bones
What is the purpose of synovial fluid?
- nourishes and lubricates the articular cartilage
- shock absorber to distribute compressive forces
What is the purpose of articular hyaline cartilage?
reduce friction during movement of the joint
Describe structures of a synovial joint
- joint cavity/joint capsule
- joint (articular) capsule
- fibrous capsule
- synovial membrane
- synovial fluid
- articular hyaline cartilage
- may contain intra-articular structures: such as menisci (knee), articular disc (TMJ) and articular labrum (shoulder)
- fat pad
- ligaments
- tendons
- fascia
- bursae
What is the purpose of synovial membrane?
lines the articulatory cavity
What are the 6 types of synovial joints?
- ball & socket
- hinge
- ellipsoid/condyloid
- saddle
- pivot
- plane
Hinge joint
permits movement in one plane, usually flexion and extension (e.g: knee joint)
Ellipsoid/Condyloid joint
contains a convex surface which articulates with a concave elliptical cavity (e.g: metatarsophalangeal joint)
Saddle joint
opposing articular surfaces with a reciprocal concave-convex shape (e.g: carpometacarpal joints)
Pivot joint
allows rotation only (e.g: distal radioulnar joints)
Plane joint
articular surfaces are relatively flat, allowing the bones to glide over one another (e.g: subtalar joint)
What are the 3 classifications of joints?
- fibrous
- cartilaginous
- synovial
Cartilaginous joints
- cartilage holds together bone ends
- no synovial cavity between bony ends
- strong joints with minimal movement only
- most are amphiarthrotic, but some are synarthrotic
Synovial joints
- bone ends separated by synovial cavity, which allows lots of movement
- all are diarthrotic
- predominate the limbs
- has synovial cavity, articular cartilage, synovial capsule or articular capsule and reinforcing ligaments; same has articular discs, menisci, and bursae
Fat pad
commonly superficial to the joint capsule, protect the articular cartilages
Tendons
may limit range of motion and provide mechanical support
Fascia
help to maintain shape and position of muscles and allow adjacent muscles to move past each other
What are the 3 types of ligaments?
- accessory ligaments
- extracapsular ligaments
- intracapsular ligaments
Accessory ligaments
localised thickenings of the capsule
Extracapsular ligaments
interconnect the articulating bones and pass across the outside of the capsule
Intracapsular ligaments
help to prevent excessive movement that might damage the joint
