What is the least common type of head form characterized by a wide and angular lower jaw and a broad square chin?

The least common type of head form characterized by a wide and angular lower jaw and a broad square chin is the triangular head form. This particular shape is defined by its angular features, which include a wider jaw that tapers towards the forehead. The broad square chin contributes to a more pronounced jawline, giving this head form its distinctive triangular appearance.

In contrast, the square head form typically features a broader forehead and a jawline of similar width, while the oval head form is longer than it is wide, with softer features and a more rounded appearance. The round head form is characterized by equal width and length, producing a circular shape with fuller cheeks. Recognizing the unique attributes of the triangular head form is essential in the field of mortuary science, especially when it comes to restorative work and preparing the deceased for viewing.