A key component of the neurological assessment
includes evaluating the patient’s muscle tone. Normal muscle tone will maintain some residual tension with relaxation. You can assess this by noting the muscle’s resistance to passive stretch. For example, hold the patient’s hand and support their elbow with your other hand. Flex and extend the patient’s fingers, wrist, and elbow, and move the shoulder through a range of motion. Note any resistance (muscle tone) to these movements.
Reduced resistance could be a sign of peripheral nervous system or cerebellum disease, or an acute stage of spinal cord injury. If you sense decreased resistance, hold the forearm, and shake the patient’s hand back and forth. The patient’s hand should move back and forth but should not be completely floppy. Significant floppiness may signify muscle hypotonia or flaccidity typically caused by a peripheral motor system disorder.
With increased resistance, assess for changes as you move the limb, note if it remains the same throughout the range of motion movements, and if it persists in both directions (i.e., during both flexion and extension). Move the limb at a variety of speeds and feel for any jerking in the resistance. When assessing muscle tone in the legs, support the patient’s thigh with one hand, hold the foot with the other, and flex and extend the patient’s knee and ankle on each side. Assess for resistance to the moving limb.
Spasticity is a sustained increase in the tension of a muscle when it is passively lengthened or stretched. It is often velocity-dependent and worsens at extreme ranges of motion. Spasticity may indicate central diseases of the corticospinal tract.
Rigidity is increased muscle tone at rest that remains the same throughout the range of motion, regardless of speed. Rigidity may indicate central disorders affecting the basal ganglia, such as Parkinson disease.
It may be difficult to distinguish between spasticity and rigidity at first, but as you perform more patient assessments, these nuances will become easier to recognize with time.
Bickley, L. S., Szilagyi, P. G., Hoffman, R. M., & Soriano, R. P. (2021). Bate’s Guide to Physical Examination and History Taking (13th ed.). Wolters Kluwer Health: Philadelphia.
Hinkle, J. (2021). Brunner & Suddarth’s Textbook of Medical-Surgical Nursing (15th ed.). Wolters Kluwer Health. https://wolterskluwer.vitalsource.com/books/9781975161057