Burning, numbness, tingling, and pain can be felt in the back, lower back, legs, and into the feet. A lot of times these symptoms spread out/radiate from one part of the body into another area. Sciatica is an example of pain that radiates into an extremity, in this case, the back of the leg. Nerves originate from the spine and are divided/separated into sensory and motor nerves. The sensory nerve/s give the sensation to the skin known as dermatomes. Dermatomal patterns act as a map on the body.
Example: Dermatomes on the torso of the body react to the thoracic spinal nerve roots, the arms react to the cervical spine nerve roots, and the legs react to the lumbar spinal nerve roots.
Dermatome Location - Corresponding Spine Level
- Shoulders - C4, C5
- Inner/Outer Forearms - C6, and T1
- Thumbs and Little Fingers - C6, C7, C8
- Front of Thighs - L2
- Middle, Sides of Both Calves - L4, L5
- Little Toes - S1
Tendon Reflexes
Most individuals have experienced a physician tapping the knees with a rubber hammer. The normal response is a kick. This is a reflex, which is an involuntary muscular response generated by the hammer tapping the tendon. When the reflex responses do not present, this could mean that the spinal cord, nerve root, peripheral nerve, or muscle has been injured/damaged in some way. Absent reflexes are also clues to other conditions/injuries. An abnormal reflex response could also be caused by a disruption of the sensory (feeling) or motor (movement) nerves and sometimes both. Determining where the neural problem might be, a physician will test reflexes in various parts of the body.Reflex Tested Areas - Corresponding Spine Level
- Upper Arm Biceps - C5-C6 Cervical Spine
- Forearm Distal Radius - C6-C7
- Elbow Triceps - C7
- Abdominal - T8, T9, T10, T11, T12, Thoracic
- Knees/Thighs Patellar, Quadriceps - L3, L4 Lumbar
- Ankles - S1 Sacral
Neurological Exams for Neck/Back Pain
Muscle Strength/Tone
Muscle strength and tone measurements are another way to diagnose nerve deficits. Depending on the symptoms/condition/injury/s there are different ways to evaluate muscle strength:- Stepping on a stool
- Standing on the heels
- Standing on the toes
- Hopping in place
- Performing knee bends
- Gripping an item in each hand
A physician will test the body's muscle tone by passively flexing and extending the arms and legs. Normal muscle tone will respond with a slight resistance to passive motion. Other movements test for proximal (trunk/torso) and distal (distant) weakness. Muscle symmetry is also taken into account.