Range of motion (ROM) describes the full capacity of a joint to move in different directions. Assessing ROM helps determine baseline joint function, monitor recovery, identify limitations, and track rehabilitation progress. This information provides a general understanding of ROM assessment and is not a substitute for professional medical advice or self-diagnosis.
Understanding Joint Motion
Joint motion is categorized into two main types: active range of motion (AROM) and passive range of motion (PROM). AROM refers to the movement an individual can achieve independently by contracting muscles around the joint. This type of motion reflects muscle strength and coordination.
PROM involves movement achieved with assistance from an external force, such as a therapist, a device, or gravity, without muscle engagement from the individual. Comparing AROM and PROM can help differentiate between issues stemming from muscle weakness or pain (affecting AROM) and those related to joint stiffness or structural limitations (affecting PROM).
Assessing joint motion provides objective data to document an injury or condition. This data helps healthcare professionals establish a starting point for intervention and track changes in joint function over time.
Measuring Range of Motion
Measuring range of motion involves using specific tools and consistent techniques to ensure accurate readings. The goniometer is the primary device used for this purpose, functioning much like a protractor. It consists of a stationary arm, a movable arm, and a fulcrum or axis.
To use a goniometer, the clinician positions the patient appropriately, aligning the goniometer’s fulcrum with the joint’s axis of rotation. The stationary arm is aligned with a stable body segment, while the movable arm follows the moving segment. The angle is then read in degrees, indicating the joint’s range of movement. Consistent patient positioning and stabilization of adjacent body parts are essential to obtain reliable measurements.
Another tool, the inclinometer, measures angles relative to gravity and is frequently used for assessing spinal range of motion. This device is placed on the body segment being measured, and its digital display provides the angle. Regardless of the tool, maintaining a standardized approach is important for comparing measurements over time or between different individuals.
Interpreting ROM Measurements
Interpreting range of motion measurements involves comparing the obtained numerical degree values to established “normal” ranges for specific joints. For instance, normal knee flexion typically ranges from 120 to 150 degrees, with extension reaching 0 degrees. Normal elbow flexion is often considered 140-150 degrees, with extension at 0 degrees. For the shoulder, normal abduction can be between 150-180 degrees, and flexion around 180 degrees. These ranges serve as general guidelines, as individual variations exist due to age, gender, and unique anatomical factors.
When ROM measurements fall below the typical range, it indicates limited range of motion, often caused by factors like stiffness, pain, swelling, or structural changes within the joint. A flexion contracture, for example, means the joint cannot fully straighten, while an extension lag indicates a delay in reaching full extension. These limitations can significantly affect daily activities and overall function.
Conversely, excessive range of motion, known as hypermobility, occurs when a joint moves beyond its typical range. While sometimes asymptomatic, hypermobility can contribute to joint instability in some individuals.
Factors Affecting Joint Mobility
Several factors can influence a person’s joint mobility, leading to variations in range of motion. Age is a significant factor, as natural physiological changes can lead to a gradual decrease in flexibility over time.
Injury and trauma frequently impact joint mobility. Swelling, pain, the formation of scar tissue, or direct structural damage to bones, ligaments, or tendons can restrict movement. Medical conditions also play a role, with diseases such as various forms of arthritis, neurological disorders like stroke, or inflammatory conditions often contributing to reduced joint range.
Prolonged immobilization, such as being in a cast after a fracture or extended periods of inactivity, can cause joints to stiffen and lose mobility. Genetic predispositions also influence an individual’s joint structure and the natural laxity of their ligaments. These inherent variations can affect a person’s baseline range of motion.