American drama is full of dysfunctional families — you might even say that it’s nothing but dysfunctional families — but some of those families are more shocking than others.

Take, for instance, the Illinois clan at the center of Sam Shepard’s Pulitzer-winning 1978 drama “Buried Child,” consisting of a sickly, alcoholic father who stares helplessly at the television, a forceful mother who is shamelessly conducting an affair with the local priest, a grown-up son with a missing leg who gives violent haircuts and another son who is so mentally blocked that he can’t recognize his own offspring.

And that doesn’t even include the cardinal sins that the family has repressed for years, which gruesomely come to light by the play’s end.

Some of its shock value has worn off, but “Buried Child” (which has not been seen in New York in two decades) remains a gritty, mysterious, often engrossing portrait of domestic life gone to hell, as demonstrated by Scott Elliott’s well-acted Off-Broadway revival on behalf of the New Group.

Elliott’s cast includes real-life married couple Ed Harris and Amy Madigan, Larry Pine and Rich Sommer (“Mad Men”).

The production’s intimacy, intense physicality and seamless flow keep it vivid and visceral, even when the dialogue gets slow or confounding twists pop up.

Harris is especially absorbing as a father who is essentially a shadow of his former self, alternating bouts of coughing with slugs of alcohol. He is so resigned to powerlessness that, in one of the play’s most arresting images, he is buried in corn husks.