practise well
Body of knowledge
Understanding your tailbone
By Amy Matthews and Leslie Kaminoff
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PHOTO: RICK CUMMINGS; MODEL: JEANIE MANCHESTER; STYLIST: EMILY CHOI;HAIR/MAKEUP: BETH WALKER. ILLUSTRATION: MICHELE GRAHAMANATOMY
YOU’VE PROBABLY HEARDmany a teacher say,
“Tuck your tail,” in asana class, making it
seem like a widely understood and accepted
cue. But the phrase can be interpreted many
different ways, often resulting in a chain
reaction of unintended movement. We can
tuck in a way that is efficient and effective, or
in a way that leads to overwork and injury. In
fact, what seems to be a single movement (tail
tucking) can be three different anatomical
actions, acting independently or in
combination, each with its own sensations.
Learning to feel these subtle differences in
your body will help you find a place for your
tail that feels right, whether you are standing
in Tadasana or seated at your desk.
Before we get into tucking the tail, it’s
important to know what the tail is. The
anatomical name for the tail is coccyx, from
the Greek word for a cuckoo’s beak. It is the
“caudal,” meaning tail, section of the spine,
below the triangular-shaped sacrum bone
that lies between the two iliac hipbones
of the pelvis at the sacroiliac joints. The
number and mobility of vertebrae in
the coccyx vary widely from person to
person: you can have three, four, or even
five vertebrae, and some may be naturally
fused together while others are not. Although
small, the coccyx is a site for muscle, ligament,
and tendon attachments, and functions
together with the two sitting bones as a tripod
of bony landmarks at the base of the pelvis.
Every coccyx has a moveable joint at the
bottom of the sacrum, appropriately named
the sacrococcygeal joint. Its main movements
are flexion and extension, with a little bit of
side-bending and rotation possible as well.
These movements are not very large, but the
muscular actions that create them can have a
significant effect on your pelvic floor. Chronic
tension in the pelvic floor can affect the range
of motion available in the hip joints, thehealthy functioning of the rectum, anus, and
bladder, and can lead to pain and overwork in
the lower back (lumbar spine and sacroiliac
joints). Finding your healthiest and most
functional movement in the tail can infl uence
pain patterns throughout the spine, from the
sacrum to the head.
There are three distinct actions that result
in tucking the tail: sacrococcygeal fl exion;
counter-nutation (nutate means “to nod”),
which is when the top of your sacrum tilts
backward and the bottom of the sacrum and
tailbone move forward at the sacroiliac joints;
and posterior or backward tilting of the entire
pelvis including the sacrum and tailbone. You
can explore each of these movements
separately, sequentially, or simultaneously
using the exercises outlined in “A Practice of
Discovery” in the box on the right. Each will
move the tail forward, but only sacrococcygeal
flexion involves the independent movement of
the coccyx. Counter-nutation and posterior
tilting might carry the tail forward in space,
but only as a consequence of moving the
sacrum or pelvis.
There are certainly times on the mat when
it’s useful to play with the interrelatedness of
these three actions. In Child’s Pose, for
example, you may fi nd a deepening of the
flexion of your spine and hip joints when you
also tuck your tail. On the other hand, because
the muscles that fl ex your coccyx are distinct
from the muscles you use to counter-nutate
the sacrum and posteriorly tilt your pelvis, a
teacher’s “Tuck your tail” cue meant to change
your pelvic position may excessively engage
your pelvic-fl oor muscles (which fl ex the
coccyx but don’t tilt the pelvis posteriorly).
Surplus effort can radiate into the muscles of
your hips, pelvis, and spine and get in the way
of finding your ideal combination of stability
and ease in the posture.
With so much room for interpretation-—Healthy movement in your tailbone may
Influence your whole spine.80
august/september 2015yogajournal.com.au