Massage Therapy Journal Spring 2024

Spring 2024 • 29

3. Synovial Joints: These joints are characterized by having a joint cavity filled with synovial fluid. The synovial fluid lubricates and brings nutrients to the joint. These joints allow an extensive amount of range of movement and are the most common type of joint in the body. Synovial joints can be further classified based on their shape and movement capabilities. Functional Classification of Joints Functional classification categorizes joints based on the degree of movement they allow. There are three primary types: 1. Synarthroses: These joints offer very little to no movement and instead provide stability. They are often found in areas where protection of the structures inside the bone is important, such as the bones in the skull. 2. Amphiarthroses: These joints allow limited movement. They are found in areas that require both stability and slight flexibility, such as the vertebral discs in the spine. 3. Diarthroses (Synovial Joints): These joints are freely movable joints and include most joints in the body. These joints allow a wide range of movement and are subdivided into six types based on their shape and movement patterns. Each synovial joint has its own individual joint capsule. The capsule has two distinct layers, the outer fibrous capsule and the synovial membrane. The fibrous joint capsule is continuous with the periosteum of the bone and may contain ligaments. This layer is innervated with joint kinesthetic receptors (which report the joint positions) and nociceptors (which indicate pain or danger). The synovial membrane also produces synovial fluid. This layer is highly vascularized and produces fluid that is similar in consistency to egg whites. Synovial joints are further classified into specific types based on their shape and the types of movement they allow. The main types include: • Pivot joint: Allows rotation around a single axis. Some examples are the proximal and distal radioulnar joints in the forearm and the atlantoaxial (C1-C2) joint in the spine. This is

a one-plane movement joint, meaning it only allows gliding movement. • Hinge joint: Allows movement primarily in one plane, similar to a hinge on a door. Examples include the elbow, ankle, interphalangeal and knee joints. • Ellipsoidal (Condyloid) joint: Allows movement in two planes with no rotation. Examples are the radiocarpal (wrist), atlantooccipital (C0-C1), metacarpophalangeal and metatarsophalangeal joints. • Saddle joint: Allows movement in two planes with a wide range of motion. An example is the first carpometacarpal (trapeziometacarpal) joint of the thumb. Some sources also include the sternoclavicular joint in this category. • Ball-and-Socket joint: Allows a wide range of motion in multiple directions. Examples include the glenohumeral and hip (coxal) joints. These joints move in all three planes. • Gliding (Plane) joint: Allows sliding or gliding movements between somewhat flat surfaces. Examples include the intercarpal (wrist), intertarsal (foot), acromioclavicular, proximal tibiofibular, and facet (zygapophyseal) joints of the spine. This type of joint moves in all three planes. Planes of movement reference and define the different ways the human body can move. These planes serve as a useful framework for understanding and describing the three dimensional movement of joints. There are three planes of movement, each perpendicular to the others: 1. The sagittal plane divides the body into a How the Body Moves: Planes of Movement left and right side. Movements that occur within this plane are typically joint flexion and extension. 2. The frontal plane divides the body into anterior (front) and posterior (back) halves. Movements that occur within this plane involve sideways or lateral movements. Lateral flexion of the spine and most abductions and adductions of joints happen in this plane.

Planes of movement reference and define the different ways the human body can move. These planes serve as a useful framework for understanding and describing the three-dimensional movement of joints.

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