ANCONEUS AND POPLITEUS.
 
The limb buds of the embryo
form laterally in the womb,
as if the arms and legs will grow
out to each side. But at two months
the buds point forward.
The upper limbs rotate outward,
and the lower limbs inward.

When we flex the leg at the knee,
the movement is backwards,
but the forearm flexing at the elbow
is a forward movement.

Consider, then, anconeus
and popliteus-two triangular-
shaped muscles-anconeus
at the back of the elbow,
popliteus behind the knee,
structurally similar
and functionally opposite.

Anconeus locks the elbow
in full extension,
while popliteus unlocks
the fully extended knee-
this small stabilizer,
in deep and close to the joint,
overlaid by the big flashy muscles
used in acceleration.
Modest little popliteus keeps
our kneecaps tracking true.

My legs lengthen as my body
gathers speed, stride after stride.
I can run across a field,
but I will never stand on my hands
like the yogis balancing upside down
in the middle of the room.
Locking their elbows,
anconeus makes it possible.

When the radius crosses the ulna,
and I see the back of my hand,
I place my other hand on my elbow
and feel anconeus contract,
and think how often the essential
is small and hidden.