The body scan is a simple technique, where you lie down in a relaxed state and simply give attention to each part of your body. Body scan is used in Hatha Yoga, often in sitting position before the asana practice. After the asana, body scan is used again in the position called Savasana (pronounced shavasan).
The first practice helps to direct the attention more inward and prepare for the practice with mind looking inwards. In the end of the practice, body scan helps to restore the energy and notice the difference the body achieved with the practice.
Body Scan can also be used on its own and is an integral part of Mindfulness-Based Stress Reduction and Mindfulness-Based Cognitive Therapy programs. Like other mindfulness practices, it requires a quiet room with no one disturbing you as you practice.
You will be practicing body scan lying on the floor or another flat surface, with the body totally relaxed.
You can assume Savasana pose, when you lie flat on your back, feet falling apart in its natural manner and hands placed alongside the body with the palms facing up.
Make sure you do not tense any muscle to maintain the pose, your attention should not be distracted with the inconvenient posture.