From the podcast she states:

• Joints are only where bones meet, and joints facilitate body movement.

• Movements can only occur at joints as our bones are inflexable.

• Each Joint Reflects a compromise between the need for strength & stability against the need for mobility.

• The characteristics of a joint determines the type & amount of movement that will take place.

• Another name for joints is articulations.

• Joints provide strength, support and protection.

Lu also says, Joints are categorized according to their structure or range of motion. The 2 main classification schemes - Structural (Anatomy of Joint) or Functional (Range of motion).

There are 4 structural classifications: Fibrous, cartilaginous, synovial & bony.

There are 3 functional classifications: Synarthrosis (Immovable, Over time bones may fuse together making a bony joint) Amphiarthrosis (Slightly movable) Diarthrosis (Freely movable).

• Synovial joints are the most common within the human body.

• Synarthrosis joints can only be found between the bones in skull.

• A Synostosis joint is one formed when two bones fuse becoming immovable.

Amphiarthrosis joints - little movement, two types:

• Sinchodrosis - Bones are connected by a ligament E.g. Distal joint between tibia & fibia.

• Symphysis - In which the articulating bones are connected by a wedge of fibrocartilage E.g. Between 2 pubic bones.

Diarthrosis joints can be subdivided functionally according to their planes of movement - Freely movable, 3 main planes of movement:

• Moniaxial - Movement in one plane, E.g. Elbow & Ankle, only move in one anatomic plane.

• biaxial - Movement in two planes, E.g. Ribs & Wrist.

• triaxial - Movement in three or more planes, E.g, Shoulders & Hibs.

Synovial Joints provide a far wider range of movement than Synarthrotic & Amphiarthrotic joints. Synovial joints are typically located at the end of long bones.

Synarthrotic & Amphiarthrotic joints are larger found within the axial skeleton system, whereas diarthrotic joints predominate the appendicular skeleton system.

As seen Lu breaks the podcast within different categories making it easier to understand each component of the joints. All of the important areas where covered even with this podcast only being a brief overview off the joint types & classifications. One things in particular I learned from Lu was how to remember the 3 major joints, using a word (SAD), as each letter stands for a particular joint type.

The first YouTube video gives a well-rounded insight to joint classification & joint types in the human body especially the fibrous and cartilaginous joints, as well as breaking down the information making it easy to follow & to learn. He focuses on the different types of joints highlighting their structural differences & how these aids in their specific roles in movement of the skeletal system and also their overall function. The second video provides a more specific detailed explanation of the synovial joints talking through their shape, structure and how this also leads to their overall function aiding the body in its specific movements.

Key Points

§  Firstly, there is three key terms to learn when talking about joints and how freely movable these are synarthrotic/synarthrosis which means the joint is completely immobile, then you have amphiarthrotic/amphiarthrosis which means the joint can partially move and lastly, we have diarthrotic/diarthrosis which means the joint is freely movable.

§  Theres three main types of joints that are found in the human body. There is fibrous, cartilaginous, and lastly the main joint that is found in our body synovial joints.

§  Fibrous joints have no joint cavity & the bones are connected by dense regular connective tissue, Cartilaginous joints also have no joint cavity while this time have pad-like cartilage helping connect the bones together and lastly the synovial joints however do have a joint cavity along with a synovial membrane and synovial both which help protect and cushion the joint.

§  Then there are subdivisions of each joint type for fibrous joints you have a suture joint (synarthrosis) that help’s hold and protect the skull from damage. Next syndesmosis joints (amphiarthrosis) usually found between the tibia and fibula, or the radius and ulna help bind the two bones together.

§  Subdivisions of the cartilaginous joint are synchondrosis (synarthrosis) which is the epiphyseal plate or other wide known as the “growth plate” this helps are long bones especially to grow when we are younger. Second one is symphysis (amphiarthrosis) e.g pubic symphysis.

§  Lastly there is 6 main synovial joints. Firstly, the hinge joint, this structure allows only for flexion and extension preventing abduction and adduction (e.g the elbow joint).

§  Secondly the pivot joints (e.g. radioulnar joint) allow rotation on one axis.

§  Thirdly the ball and socket joint allow for a full range of movement in all axis allowing for flexion, extension, abduction, adduction, and circumduction (e.g. the hip).

§  Fourthly the condyloid joint (e.g. the radoiocarpal joint/wrist joint) allows for rotation on 2 axis and enables most range of motions like flexion, extension, abduction, adduction, and circumduction.

§  Fifthly the saddle joint, the rotation off this joint is restricted due to its bone structure as they have both have a concave and convex face on their surfaces (e.g. carpal-metacarpal joint of the thumb) allowing for flexion, extension, abduction, adduction, and little circumduction.

§  Lastly the gliding joint usually come in groups and are held together by ligaments (e.g. carpals in the hand/ tarsals in the foot) allowing some limited rotation and gliding.

Key Points

v The fibrous joints are bones connected by fibrous tissue which is strong, and this type of joint does not require range of movement as much as the other joints, but rather strength and stability. The cartilaginous joints are bones that are connected by cartilage, and they are also similar to the fibrous joints but they shock absorbers as well. The synovial joint is the end of bones that come together to form a joint, and it is surrounded by a protective capsule filled with a liquid called synovial fluid, and it’s job is to allow smooth movement and reduce friction between the bones.

v There are then 3 sections of the fibrous joints which is the suture joint, gomphses joint and the syndemosis joint. The suture joint is synarhtosis, which means it is immovable, and it is found in the skull where it is fixed and immovable. The gomphses joint is also synarthrosis, and it is found in where the teeth articulate with the socket. The final joint is the syndemosis joint and it is amphiarthrosis, which means it is slightly moveable, and they are used to connect two bones together like the tibia and the fibula.

v There are two main types of cartilaginous joints, and they are synchondroses and symphyses. In a synchondrosis, hyaline cartilage are the connectors and it is synarthrosis. In a symphysis, the bones are connected by fibrocartilage and it is amphiarthrosis.

v The final of the joints is the synovial joints, and it is specified by a fluid filled joint cavity contained in a capsule. The synovial joint is diarthrosis, which means it is freely moveable, and it is the most common type of joint in the body. There are 6 different types of synovial joints that all have their own structure and function.

-              The first joint is the hinge joint, and this allows only flexion and extension as it permits movement in a single place. An example of this joint would be the ankle joint.

-              The next joint is the saddle joint, and it allows movement in two directions due to it’s concave and convex surface. It allows flexion, extension, abduction, abduction and some circumduction, and an example of this joint would be the carpometacarpal joint in the thumb.

-              The plane joint allows bones to glide over one another, and it allows extension and lateral flexion.

-              The pivot joint is a joint that only allows rotation, and an example of it would be the first and second vertebrae in the neck.

-              The condyloid joint allows movement in two directions and it lets you use your bones up and down and side to side. It allows flexion, extension, adduction, abduction and circumduction, and an example of this would be the wrist joint.

The final joint is the ball and socket joint, and this type of joint allows for movement in near every direction. It has a round end of one bone, which is the ball, that fits into the cup-like socket of the other bone. It allows flexion, extension, adduction, abduction and circumduction, and a great example of this socket would be the shoulder joint.