Yoga Anatomy

Yoga and the Spine 27

Only a true biped requires both pairs of curves; our tree-swinging

and knuckle-walking cousins have some cervical curve but no

lumbar curve, which is why they are not true bipeds.

If we view our evolution from quadruped to biped in yogic

terms, we could say that the lower body developed more sthira

for weight bearing and locomotion, and the upper body more

sukha for breathing, reaching, and grasping. One way to describe

it is that the lower body moves us out into the environment, while

the upper body brings our environment in to us.

OntOgeny: An even Briefer

HistOry Of Our Own spine

After understanding the evolution of our species (phylogeny), it

is useful to study the developmental stages experienced by each

individual human (ontogeny).

Although the developing fetus exhibits—and then loses—

certain characteristics that we share with our ancient ancestors,

such as gills and a tail, the theory that ontogeny recapitulates

phylogeny has long since been discredited. There is, however,

at least one sense in which this is true: how the phyolgenetic

and ontogenetic development of our spines mirror each other.

Consider how our fetal spines exhibit only the primary curve

along their entire length; this remains the case for our entire

intrauterine existence (figure 2.11).

The first time our spine moves out of that primary curve is

when our heads negotiate the hairpin curve of the birth canal,

and the neck experiences its secondary (lordotic) curve for the

very first time (figure 2.12).

As our postural development proceeds from the head downward, the cervical curve con-

tinues to emerge after we learn to hold up the weight of our head at about 3 to 4 months

and then fully forms at around 9 months, when we learn to sit upright.

E5267/Kaminoff/fig2.11/417586/alw/pulled-r2

Cervical

Thoracic

Lumbar

Sacral

Figure 2.10 The curves

of the spinal column.

E5267/Kaminoff/fig2.12/417587/alw/pulled-r2 E5267/Kaminoff/fig2.13/417588/alw/pulled-r2

Figure 2.11 The entire spine exhibiting

the primary curve in utero.

Figure 2.12 The first emergence of the sec-

ondary curve: negotiating the 90-degree turn

from the cervix into the vaginal passage.