Shoulder dystocia is an obstetric emergency where the fetal anterior shoulder lodges behind the maternal pubic symphysis after the head delivers. Management proceeds in escalating steps (the $HELPERR$ mnemonic), and the very first physical action is non-invasive.
The McRoberts manoeuvre sharply flexes the mother's thighs against her abdomen. This rotates the pubic symphysis anteriorly and flattens the sacral promontory, enlarging the functional outlet and often releasing the shoulder. Adding suprapubic pressure (Rubin I) over the fetal anterior shoulder pushes it into the oblique diameter to complete the disimpaction.
If these fail, one escalates to internal rotational manoeuvres (Wood's corkscrew, Rubin II, delivery of the posterior arm). Only when everything else fails does one resort to the Zavanelli cephalic replacement or symphysiotomy.
\[\boxed{\text{McRoberts manoeuvre with suprapubic pressure}}\]