New York — That old song ''Dry Bones'' - ''The knee bone's connected to the thighbone'' - doesn't apply to break dancing. Saber Mostafa, a 16-year-old dancer at a New York disco, the Roxie, looks like a jumble of disconnected joints. A graceful robot, he glides across the floor, feet barely seeming to move. His boneless hands swim like fish. Another breaker, Oz, spins on his shoulder, his legs twisting like windmills, turning him in a circle. He stops, midspin, on a dime.
This ''latest'' dance craze - which combines mime and acrobatics, fluidity and great energy - has actually been around for 10 years, being developed on the streets of both the East and West Coasts. Lately it has emerged into the mainstream. A short break-dancing segment in the film ''Flashdance'' catapulted this street art into a worldwide phenomenon.
In the last six months, various groups from the United States have toured London, Rome, and Japan. The New York City Breakers recently performed for an office party at Merrill Lynch, Pierce, Fenner & Smith, the brokerage firm, and have just signed to do a commercial for Burger King. It's midnight at the Roxie, a cavernous brick building, once a warehouse. Red and blue lights slice a jagged path through the darkness as three DJs feed one record after another into an unceasing roar of sound.
Saber, Oz, and other breakers are dancing to the throbbing beat that's overlaid with a rhythmic, rhymed story spoken by a ''rapper.'' (''Stay on the scene like a rubber machine,'' one drones.)
Although most of the breakers are between 13 and 19, break dancing is not kid's stuff. ''I practice two hours a night - and that's when I'm being lazy,'' says Matthew Caban, a breaker who's just returned from a tour in Italy.
''I practice every chance I get, between class, after school,'' says Saber. ''Sometimes I get to perform for school assemblies.''
What draws them to the Roxie and other discos to dance night after night, emerging blinking at 8 in the morning? Matthew says, ''It feels good to do things that are unordinary. I like getting better and better. It's good for your health, and you meet a lotta people.''
Money is a big lure. ''I don't work on the streets anymore,'' says Saber, who's been dancing for two years. ''The cops push you off. I go where the money is.'' Street breakers might each make $20 to $30 a night in on-the-spot donations, while a party engagement can bring a good breaker $300 a night, and a group, $400.
Break dancing is a male-dominated activity. It's designed to show off athletic prowess, command of intricate steps, and inventiveness. Susan Vega, a sweet-faced 16-year-old known to her friends as Miss Susie Q., is one of the few girls who breaks. Why are there so few? ''You know how girls are,'' she says. ''They don't think it's ladylike. They also think it turns the boys off. I don't care about that - I'll spin on my hair.''
Susie says her mother didn't want her to go dancing at first, but ''when she saw how serious I was about dancing, then she began to trust me. She saw I wasn't taking drugs.''
While glittery eyes attest to the use of drugs at the Roxie, many breakers steer clear of them. ''It's not a drug-oriented culture,'' says Michael Holman, manager of the New York City Breakers. ''It's too athletic.''
Saber agrees: ''When you dance, you have to be thinking about your next move every second. You can't let nothin' disturb you.'' Another dancer, however, warns darkly of some particularly dangerous drugs being used.
Break dancing actually merges two types of movement. The robotlike mime is called ''electric boogie,'' which started in Fresno, Calif., in the early '70s and was popularized by the TV show ''Soul Train.'' The acrobatics were developed about the same time by Harlem youths, who called it break dancing. Today, most dancers incorporate both.
Many dancers use the streets as a training ground. Up on 72nd Street, Tron, a grinning beanpole dressed in black, sets the ''box'' (giant cassette player) on the shelf of a bank's outdoor money machine and the breakers start their first of 10 four-minute sets.
To a disco-ized version of the ''Addams Family'' theme, Tron, Edwin, and Ray join hands and appear to send an electric current through them, blasting the end man into a solo. There is an amiable, supportive feeling among them, each allowing the other his solo and stepping in to take over if he runs out of steam or ideas.
Break dancing is seen as a step out of the ghetto. ''A year ago, these kids were on the same corner snatching purses,'' says their manager, Gypsy Lee. Musicians, rappers, and breakers are all practicing to grab a piece of the lucrative break-dance pie that is looming ahead. The New York City Breakers have been on such TV shows as ''Ripley's Believe It Or Not,'' ''That's Incredible!,'' and ''Merv Griffin,'' and will be seen next summer in the film ''16 Candles.''
Break dancing may also be helping to stem gang violence. Last year, the leaders of the 4,000-member Zulu gang and of a 500-member rival gang made a peace treaty, vowing to ''dance it out, rather than fight it out,'' Gypsy Lee says.
Where once switchblades reigned, now ''battles'' are fought through dance. The treaty has been honored for a year, and the Zulu Nation, the name of the organization joining the two gangs, now devotes itself to churning out music and rappers for the growing industry.
Is this a flash in the pan, or will it last? Some are studying jazz or modern dance to continue a dancing career if breaking dies out. Others are studying mime with Marcel Marceau. Gypsy Lee hopes to start a dancing school or to teach breaking in city schools.
But the form is still evolving. ''Break dancing's on its way out,'' one dancer scoffs. ''What we're doing now is the 'pop' - a jerky electric boogie. See, instead of moving my hand smoothly in a wave, I make it jerk, like a cartoon. Now you move your legs like this . . . .''