The most astonishing and moving footage in the generally astonishing and moving documentary "The Body Human: The Body Beautiful" comes in the opening credits.

We see the movie film of a 40-day-old human fetus inside the womb. We watch it grow. We are shown the little circle in the head that will become an eye, the curious stub that will turn into a foot, the fingers eerily wiggling at age 3 months.

That alone is worth the price of admission to this latest hour in the Body Human series, on Channel 9 at 8 tonight.

But there is more. A brave 31-year-old woman allows us to witness the comestic surgery that replaces the breast she lost to cancer. A teen-age girl, her face misshapen by a genetic miscoding that gave her a grotesque hanging, underslung jaw, shares her feelings as she learns what can be done for her and as she sees her new face after the incredibly complex operation.

The surgery is depicted with care and taste, and a minimum of blood. And just as the viewer is beginning to grumble that all the patients are women and all the doctors men, we are introduced to a garage mechanic whose skull has been virtually shattered beneath the face, and we watch a team of surgeons make him a new eye socket from a piece of his rib.

Surely plastic surgery is the most emotionally satisfying of operations, and the samples we are shown here are the success stories.

The whole process is supersimplified for us, and the show is marred by some of the most inane gushing one has heard in years: "the tension-packed world of facial surgery," crashing cliches like "behive of activity." patronizing comments about how wonderful it is to get old and wrinkled and not to put too much faith in cosmetics: "then . . . time . . . and the fickle moment fleet (sic) away . . . ."

This silly bathos contrastly nicely with the businesslike remarks of the surgeons at their work.

Quibbling aside, it is a completely absorbing hour. Even if it doesn't tell you much you didn't know already, its exploration of the human body is endlessly interesting.