Our bodies are complex machines designed for movement, and many systems work harmoniously to achieve this. Among the most important are your joints. These articular surfaces connect bones and other structures to link the whole skeletal system to the locomote.
While we have between 250 to 350 of them, depending on several variables, including definition, inclusion and age, our joints are categorized according to function and structure. There are the three main types of joints in the body, which include fibrous, cartilaginous and synovial. Each type of joint connects the tissue to the body.
Let’s learn about the ten different types of joints and how they work in the human body.
Type #1: Diarthroses Joints
These synovial joints in the body allow for walking, running, and other wide ranges of motion. Diarthroses joints slide over each other with full rotation, and they further split into six types:
- Ball and socket
Synovial joints have space between them and are filled with synovial fluid that lubricates the joint and allows free movement between the connecting parts. Most of your joints are these types. Examples are the shoulder and knee. These joints may grow sore or fatigued as you age, but you can alleviate the symptoms with regular physiotherapy Toronto.
Type #2: Amphiarthroses Joints
This type of joints is less moveable, also known as a cartilaginous joint and holds bones together tightly so that only limited movement is possible. The connection is where bones are made of either hyaline cartilage or fibrocartilage.
Synchondroses are the joints in the developing skeleton of children, made up entirely of hyaline cartilage. In contrast, symphysis joints are permanent and composed of fibrocartilage, which is found midline in the skeleton. Examples are the spine vertebrae and the ribcage.
Type #3: Synarthroses Joints
The synarthroses joint is immovable and serves as a fixed point where two bones come into close contact with no space between and do not have movement. The bones in the skull are an example of this fibrous joint, as they can fuse and become a new structure. There are three types of fibrous joints: sutures, syndesmoses, and gomphoses.
- Sutures Joints: Hold bones together with short fibres, as in the skull.
- Syndesmoses Joints: Hold bones together with connective tissue for a small amount of movement, like the tibia and fibula in the ankle.
- Gomphoses Joints: Hold with the periodontal ligament, connective tissues in the teeth and their sockets.
Type #4: Ball and Socket Joints
A ball and socket joint consists of two bones that come together. One has a rounded end that hooks into the cup-shaped end of the other bone. Rotatory movement in all directions is permitted, including rotation, extension, adduction and abduction. Your shoulder joint and hip joint have this type.
Type #5: Pivot Joints
This rotary or trochoid joint also freely rotates but only on one axis. You get sideways and back and forth movement with the limited range as in a swivel in a ring pattern, out from another bone. Examples include your ulna, radius bones in your forearm, and the atlantooccipital joint in the neck vertebrae between the base of the skull and the cervical spine.
Type #6: Hinge Joints
A hinge joint is characterized by movements similar to a door opening and closing along one plane. This back and forth, flexion and extension movement happens in your elbow, knee and ankle joints.
Type #7: Saddle Joints
A saddle joint involves two bones, one with a convex surface and one with a concave surface. One bone articulates within the other to give a limited rotational movement area, side to side and back and forth. The carbo-metacarpal joint at the base of your thumb is an example.
Type #8: Ellipsoid Joints
The ellipsoid or gliding joint is similar to the ball and socket but without rotation. This means it can move on two axes but has smooth surfaces to slip over one another. Your wrist has this joint.
Type #9: Condyloid Joints
Another free-moving joint is condyloid. There is movement but without rotation, and it can be found in your fingers and jaw.
Besides these typical movements, there are special movements that don’t fit the other classifications like angular, gliding or rotational. These include:
- Plantar flexion
Type #10: Other Joints
To make the body flexible and facilitate movement, we need joints; without them, we would be immobile. Understanding the different types of joints and their function help us appreciate the mechanics of our biological system and gives us a newfound respect for the wondrous body our spirit inhabits.
Here are some other classifications of joints in our bodies:
- mono-articular – one joint
- oligo-articular – 2 to 4 joints
- poly-articular – 5 or more joints
- Simple joints – two articulation surfaces
- Compound joints – three or more articulation surfaces
- Complex joints – two or more articulation surfaces plus a meniscus or articular disc