She had her back to him; her shoulders were stiff and her spine was rigid and erect.

Captain Picard tried to keep his spine erect, but his shoulders slumped perceptibly.

The books look robust, their spines erect, their pages warm.

The spines erected behind them and the Chasers looked in dismay at the trails which had been gouged through the camp.

Though she held her spine erect, he could feel the quivering of her muscles, as if the mere act of standing were a strain.

Her back was turned to him, head high, spine erect.

When that animal has its spines erect, it cannot eat.

When escape is not possible, the butterflyfish will sometimes turn to face its aggressor, head lowered and spines fully erect, like a bull about to charge.

Her shoulders were straight enough to please a Marine drill sergeant, and her spine erect enough to parallel a flagpole.

Sitting up straight, as in shoulders back, spine erect, knees together, ankles crossed, hands demurely in your lap.