The Daniels scale is a scale used to measure and classify muscle strength in a joint movement. It can be used for an isolated muscle, but it is generally used to evaluate joint movement, that is, the set of muscles that when contracted allow the movement of a joint.
It is relevant when determining muscle strength and function in people who have suffered some type of injury or to evaluate patients with neuromuscular or neurological injuries, especially central injuries in the spinal cord or central nervous pathways of the motor system.
The evaluation allows, through the patterns of muscular weakness, to locate lesions in a particular region of the cerebral cortex, the spinal cord, a nerve root, a peripheral nerve or a local muscle lesion.
The scale includes a score from 0 to 5, with 6 grades that allow a manual assessment of muscle strength. It is widely used in physical therapy, kinesiology, and trauma to assess the extent or extent of some injuries.
The use of manual muscle estimation scales includes objective and subjective parameters. The subjective ones are those that are related, for example, with the value that the examiner gives to the manual resistance that he imposes on the movement or the force exerted by the patient to overcome it.
These parameters are obviously subjective and depend on the clinical experience of the examiner. Objective parameters include, but are not limited to, the patient’s ability to complete the indicated movement, being able to hold a certain position against gravity, or not being able to perform a certain movement.
Description of the scale
The scale includes 6 grades ranging from muscle paralysis to normal condition. This is described as follows:
0 = The muscle does not contract, complete paralysis.
1 = The muscle contracts, but there is no movement. The contraction can be palpated or visualized, but there is no movement.
2 = The muscle contracts and performs all the movement, but without resistance, it cannot overcome gravity (the joint is tested in its horizontal plane).
3 = The muscle can move against gravity as the only resistance.
4 = The muscle contracts and performs the full movement, in full range, against gravity and against moderate manual resistance.
5 = The muscle contracts and performs the movement in full range against gravity and against maximum manual resistance.
Criteria for assigning the grade within the scale
The patient is first asked to perform the movement to be observed, without external resistance or mechanical assistance. At this point it is determined whether or not the patient can perform the movement. If the patient can perform the movement, it is necessary to discriminate whether or not to complete the movement to its full extent.
Active movement informs the examiner of the patient’s ability to make movement, the range or amplitude of movement for a joint, if there is any limitation due to pain, excess tone, or weakness.
Each movement must be observed and thus each muscle or muscle group is evaluated in each joint range of motion. Classifying muscle function requires acute clinical judgment and a lot of experience.
Accurately locating the function of a muscle or muscle group in a particular scale grade is not only important for functional diagnosis, but also allows one to appreciate the progress made throughout the recovery and treatment process.
Performing a full active movement without external resistance rates the muscle or muscle group at grade 3 on the scale. From there, the application of different degrees of resistance and whether or not the patient can overcome them, allows classification in the following ascending degrees.
The absence of contractions or muscle weakness that limits or prevents movement throughout the entire joint range, causes the corresponding muscle function to be located at a score of less than 3 on the scale.
Preparation to do a muscle test
The examiner and patient must work in harmony if the session is to be successful. This means that certain principles and procedures must be followed that ensure, as far as possible, the comfort or well-being of the patient. These may include the following:
1- The patient must be pain free during each test. This may require that some patients be allowed to move or position themselves in different positions in the interim period between tests.
2- The environment where the test is carried out must be calm and without distractions. The temperature should be comfortable, especially if the patient needs to remove their clothes.
3- The surface of the table where the test is performed must be firm to help stabilize the body segment to be examined, so that the trunk or extremities do not sink into it. The friction between the surface and the patient’s body should be minimal.
4- The examination table must be wide, wide and must have a system that allows its height to be easily adjusted so that the examiner uses the appropriate height to perform the appropriate mechanical maneuvers.
5- Patient position changes must be done in an orderly manner so that the test is carried out sequentially without unnecessarily bothering the patient. The position used must allow adequate stability of the part of the body to be examined by means of one’s own body weight or with the help of the examiner.
6- All the necessary materials for the test must be at hand, near the examiner. This is particularly important in patients who are anxious or for some reason too weak to be left unattended.
– Printed forms to document the muscle test or a computer / tablet that can fulfill the same function.
– Pen, pencil, eraser or computer / tablet.
– Pillow, towels, pads and wedges for positioning.
– Sheets or other covers.
– Some equipment to evaluate specific muscular functions, such as goniometers, stopwatches, etc.
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