Cross contour brings elliptical curves within the boundaries of form to map the surface.
Cross contour can be applied in one direction or in any mix of directions as long as the mark follows the surface of the form.
Cross-hatching refers to a softer, woven application often used to build up tonal areas of shadow.
Cross contour uses line to map the curved surface of depicted forms in a drawing, but instead of dealing with the profile of the form, it moves within the outer boundaries and maps the surface facing the viewer. In a sense, you could think of cross contour as the multiple profiles of the form actually drawn onto its skin. Although cross contour on rectangular surfaces can be useful, the most prevalent form of this technique involves curved contours to describe rounded organic form. There are many strategies for applying cross contour to the surface of forms. It can be useful to mix and overlap cross contours, to let them fade in and out of application, or to use them in a "broken" manner. Layering cross-contour strokes in different directions is sometimes called cross hatching.
Draw your hand using cross contour.
After laying out the hand position with a few simple lines, start by defining each joint of the fingers as a form bounded by elliptical edges.
Then work into the fingers using cross contour spanning the width of the form.
In the palm or back of the hand, use short strokes laying on the surface of the bumps and depressions of the "skin" of the form in your drawing.
Then try to connect them into longer bands.
Experiment with different levels of looseness or tightly connected cross contour.
Before attempting to draw you hand, practice drawing a round ball.Try to imply the curvature of the ball as you apply your contour hatching marks, turning the ball back at its edges with a greater density of strokes.
The first three drawings are student work then examples after the student work are artists from multiple centuries ago:
Drawing of hand using ink or graphite on 18x24 drawing paper from bond sketch pad
assignment source: Drawing Structure and Vision / Fritz Drury & Joanne Stryker - p. 68
image source: ARTstor database