Remember singing Dem Bones when you were a wee tyke? “The hipbone’s connected to the backbone” isn’t a bad beginning to anatomy lessons, but for those who practice asana, a few more details are helpful. The part of the backbone where the hipbones connect is the sacrum, and the connection is the sacroiliac joint, or SI joint for short. Refining your awareness of the SI joint can help you establish an asana practice that is pain-free…and even profound.
The sacrum, a wedge-shaped bone fused from five vertebrae, forms the back of the pelvic bowl, joining with each hipbone (ilium) at a cartilage-lined surface. Though short but strong ligaments limit SI joint movement, many asana students are all too familiar with the feeling of an out-of-whack sacroiliac, an SI joint prone to slipping out of alignment. Generally speaking, due to the shape of the female pelvis, women are more likely to experience what doctors refer to as SI joint dysfunction.
Keeping the SI joints in line begins with knowing where they are. Turn your back to a mirror and look above your bottom for the dimples of Venus, then reach back and slide your fingertips over them. Medial (closer to the spine) to each dimple, you’ll feel a bony landmark, the posterior superior iliac spine (PSIS for short). And just medial to each PSIS is the SI joint.
Signs of SI misalignment may be as subtle as always sitting with the same leg crossed to relieve joint pressure. Or you may feel a dull ache localized at the SI joint or spreading to the back of the thigh. Sometimes SI misalignments are mistaken for sciatica or lumbar disk problems. If you suspect you have an SI issue, check your joint alignment. Lie on the floor face up, and notice if one PSIS feels like it’s larger or pushing harder into the floor. (It helps to rock or circle over the sacrum.) Or stand in your very best Tadasana and have a teacher or partner check to see if one Venus dimple is higher than the other.
Yogis with pelvic hypermobility might notice a popping sensation in one SI joint during a particular asana, a sign that the SI has slipped out of alignment—or back in. The cause and cure may the very same asana, often a deep reclining twist like Jathara Parivartanasana. SI injuries can also occur during seated twists or aggressive forward bends or backbends. Over time, SI misalignment can lead to joint stress and uneven wear or inflammation.
To avoid SI injury, strengthen the muscles around the joints (massage the sacrum by rocking and circling it on the floor) and always practice asana mindfully. Bend from the lower hinge of the pelvis—the hip sockets—and not from the waist. During twisting asanas, spend a few breaths lengthening the spine before rotating. Rotate the spine gradually and evenly from bottom to top, beginning in the navel area. Move on the exhalations, pausing on the inhalations to allow the breath to “inspire” more length.
For those with tricky SI joints, the safest way to twist is with the pelvis firmly in neutral, such as from Vajrasana (Thunderbolt Pose). In twists like Bharadvajasana, turning the hips in the same direction as the chest can help protect the SI joints. Avoid pelvic torque when twisting deeply in a supine position (as in Jathara Parivartanasana), or when beginning a seated twist with one side of the pelvis higher than the other. (In this case, raise the lower hip by placing a folded blanket underneath.) In twists like Ardha Matsyendrasana (Half Lord Of the Fishes Pose), avoid using the upper body or arms to muscle your way into a deeper spinal rotation.
But even when we are armed with knowledge of contraindications and modifications, the delicious release of a deep twist can tempt us to overdo. Here’s a safer way to explore the depths: Go beyond physical anatomy to the esoteric realms. In Latin, sacrum means “sacred,” and in ancient Rome and Greece, the shallow bowl-shaped bone was associated with ceremony. In shamanic traditions, the sacrum was considered the seat of the soul, necessary for resurrection. In energetic anatomy, this is the location of Svadisthana, the second chakra, whose name translates as “one’s own place.” It is where your mother carried you, and where, perhaps, you’ve carried your own babies.
The lesson is that if we approach twists or any asana as something sacred, we are less likely to do harm. Have you triggered or healed an SI misalignment with asana? What have you learned?