Practicality and Grace.

You can see that current pockets are located completely outside the area where there is potentially space; the hips and butt of modern pants, for both women and men, are closely fitted. If there’s any ease, it starts just above the knees.

Conveniently, the point where the vastus lateralis starts to curve back in towards the knee, creating space, is also right around the lowest point your arms can reach without bending over, giving us a well-defined

Sam Blackley: On Trouser Pockets