This curved triangular bone at the base of the spine gets its name from the Latin os sacrum, translated as sacred bone. Its position determines the shape of the lumbar curve. It translates the legs and the two sides of the pelvis, via the sacroiliac joint, into the spine. We often think of the pelvis as one bone but really it is three: the two hip bones consisting of the fused ilium, ishium and pubis and the sacrum. The very tip of the sacrum is a different bone. The little coccyx or tailbone. We do actually have a tail even if it is so small that you can’t see it.
The sacrum’s hollow center is home to the base of the spinal cord which is no longer a cord but a network of nerves called the cauda equina. Five pairs of sacral nerves exit through the five foremen or holes in the bone and weave into the sacral plexus. These nerves bring sensory perception and movement to the descending colon, rectum, bladder, reproductive organs, pelvic floor and the legs.
In craniosacral work we often hold the sacrum. It is the perfect shape and size to rest in the palm of one’s hand. Like all the bones in the body it has a palpable motion. It gently rocks anterior and posterior in a relationship to the movement in the cranium. It can be deeply relaxing to have one’s sacrum held. Sometimes it gets stuck and doesn’t want to move in one vector or the other. Sometimes is can be tilted or off center. This can cause problems and be responsible for various pain patterns.
The sacrum and the area of the the pelvic bowl is also the home to Muladhara, the root chakra. To our relationship to ground, home, safety, survival. It is the base, the beginning, the foundation. It is our sense of belonging, to place, family and community.
Take a moment to feel your sacrum. Find a seat on a firm surface so that you can sit on your sits bones and have your feet flat on the floor. Let your attention drop into the contact of your sits bones into the chair. Now reach behind with your hand and place it, with fingers pointing downward, at the base of your spine. The triangle of your hand resting on the triangle of our sacrum. How are you grounded? After a few breaths take your hand away and imagine your sacrum becoming heavy and dropping into the ground. Feel the subtle sense of movement. Now, imagine it becoming light and the your tail lifting up. Again, feel the subtle sense of movement. Slowly repeat the this motion of dropping and lifting, of rocking. Imagine it. Feel it. Notice what arises. Welcome home!