Yoga practice teaches us to find our MIDLINE-- physically, psychically, metaphysically and metaphorically.
Yoga ASANA teaches us how to draw into the midline PHYSICALLY in order to draw from our deep internal musculature. Practicing poses on and off the midline, teaches us to hone the CENTER point of strength and balance.
MEDITATION + PRANAYAMA teaches us to PSYCHICALLY find our center. We develop our ability to concentrate and return again and again to the source of THIS moment. The MIDLINE here is the balance between presence and absence.
Through continued effort and practice, we may begin to explore our experiences METAPHYSICALLY. What is your subtle body suggesting? How is your energetic experience changing according to different postures/breathing/meditation techniques? How does it feel in there?
And finally, the MIDLINE provides great metaphor for the TRUTH. Your center-line, your true authentic being is YOUR midline --your true north for decision-making, intuition and deep understanding. The innate sense of knowing that makes you who you are.