When was the last time you genuinely looked up? Not the head-tilt-back of yawning. Distributed extension, neck lengthening, eyes climbing through the ceiling. Probably not in a long time.
The desk demands the opposite. Eight to ten hours a day in passive cervical flexion. The lower cervicals — C3 through C7 — lose their contribution to extension entirely. The suboccipitals, four small muscles tucked between the skull and the upper two vertebrae, do everything. So when the practice asks for full extension in Urdhva Dhanurasana, the suboccipitals jam, the chin pokes up, and the back of the skull collides with the atlas.
That collision is the pinching. The fix is not less extension. The fix is to teach the lower cervicals to participate again so that extension becomes distributed rather than hinged.
The drill: sit tall, fist under the chin, eyes level. Press the chin into the fist, hard, for ten seconds. Release. Then actively lift the back of the skull, sliding it up the spine with eyes still level. The lower cervicals extend. The suboccipitals rest. Three rounds. The back of the neck does the work; the front of the neck stays long.
Then drop into Ustrasana and notice. The pinch is quieter. The extension feels spread out. The skull has stopped landing on the same spot. The longer protocol is over here.