Range of motion can be measured in a variety of ways.  Visual ROM is the doctor's best guess of ROM achieved by the patient through different planes of motion as the doctor observes these movements.  

A more accurate way to measure ROM is with an Inclinometer.  You will need two inclinometers for certain planes of motion. Allow the inclinometers to remain in contact with the body and move with the patient. 

You can find ROM measurements in this parameter here: Ideal Range of Motion

Cervical ROM
FLEXION (2 Inclinometers): 
1. Have the patient seated with the head in a neutral position.  Place one inclinometer over the T1 spinous process in the sagittal plane.  Place the second inclinometer on top of the head, also in the sagittal plane. Both inclinometers should be zeroed out in these positions.  
2.  Instruct the patient to flex the head and neck forward. Record both angles.  You will subtract the thoracic measurement from the head inclinometer measurement.
3.  Cranial angle - T1 angle = Degrees of flexion ROM

EXTENSION (2 Inclinometers):
1. Place the inclinometers in the same position as you had them for measurement of flexion. Zero out the inclinometers.  
2. Instruct the patient to extend the head and neck.  Record both angles.  You will again subtract the thoracic measurement from the head measurement.
3.  Cranial angle - T1 angle = Degrees of extension ROM

LATERAL FLEXION (2 Inclinometers):
1. With the patient still in the seated position, now place the T1 and cranial inclinometers in the coronal plane.  Make sure they are zeroed out. 
2.  Instruct the patient to lateral flex the head to one side and record the measurement.  Repeat for the opposite side.  
3.  You will again subtract the thoracic measurement from the cranial measurement to determine lateral flexion for each side. 
4.  Cranial angle - T1 angle = Degrees of lateral flexion ROM

ROTATION (1 Inclinometer):
1. Have the patient lay supine and place the inclinometer at the top of the head in the coronal plane.  You should have a reading of zero.
2. Instruct the patient to rotate the head to one side. Record the angle indicated on the inclinometer, this is the degrees of cervical rotation. 
3. Repeat and record this measurement for the opposite side. 

Lumbar ROM
FLEXION (2 Inclinometers):
1. The patient should be in a standing position.  Place one inclinometer over the T12 spinous process in the sagittal plane. The second inclinometer is also placed in the sagittal plane, but at the region of the sacrum.  Make sure the inclinometers are zeroed out. 
2.  Instruct the patient to bend forward, making sure the movement comes from the lumbar spine and not the hips or thoracic spine.
3.  Record the measurements.  The sacral measurement will be subtracted from the T12 measurement. 
4.  T12 angle - Sacral angle = Degrees of lumbar flexion ROM

EXTENSION (2 Inclinometers):
1. Place the inclinometers in the same position as you had them for measurement of flexion. Zero out the inclinometers.
2.  Instruct the patient to extend the lumbar spine and record the measurements of the inclinometers.  The sacral measurement will be subtracted from the T12 measurement.
3.  T12 angle - Sacral angle = Degrees of lumbar extension ROM

LATERAL FLEXION (2 Inclinometers):
1.  With the patient in the standing position, place one inclinometer at the T12 level in the coronal plane.  Place the second inclinometer top of the sacrum, also in the coronal plane. Make sure the inclinometers are zeroed out. 
2. Instruct the patient to slide a hand down the leg on the side they leaning to, making sure the patient does not bend forward.
3. Note the measurements of the inclinometers. The sacral measurement will be subtracted from the T12 measurement.
4. T12 angle - Sacral angle = Degrees of lumbar lateral flexion ROM
5. Repeat this procedure for the opposite direction of lateral flexion for the other side. 

Reference:  Illustrated Orthopedic Physical Assessment (2nd ed) by Ronald C. Evans