The principle of the mandibular sculpture is simple, that is, to minimize the prominent part of the bone to both sides, or to properly cut the prominent part to create a beautiful arc.
 
The mandibular bone is a skeleton of a three-dimensional U-shaped structure. The detailed structure includes: the lower arch, chin, jaw body, jaw angle, jaw branch and temporomandibular joint condyle. Among them, the closely related part to the face shape: chin, jaw angle and the jaw body.
(Anatomical illustration of the jaw bone)
 
The jaw angle can be divided into many different types, including: oblique square, round square, square, and square.
Jaw angle can also be in accordance with its three-dimensional structure tendency to divide into "outer type" and "inverted type."

Jaw angle is the place where the masticatory muscles are attached, will be affected by the chewing habits and change the shape, so people who like to chew or like to eat beef jerky and other food, in addition to masticatory muscles will become hypertrophy and make face wide, But, also make the jaw angle more developed, so that the face is more prominent.
 
The shape of the jaw angle determines the lower arc of the face shape side view; the outer degree of the jaw angle also affects the lower part width of the face. Therefore, the removal of the jaw angle is one of the important steps to improve the face shape; however, facial nerve and jaw angle is very close, unskilled surgical techniques may hurt the facial nerve, causing serious sequelae, so the choice of physicians is very important. Jaw angle is divided into two layers of internal and external bone layer, the middle of the bone marrow cavity, surgical methods also do not need to remove the jaw angle, and only remove the jaw angle outside bone layer, to retain the bone marrow cavity and internal bone layer; some people jaw angle is not particularly developed, hoping to keep the arc of the jaw angle, and want to reduce the width, can use this method. The distance between both side jaw bodies (that is, the width of the U-shape) determines the width of the lower face, but it cannot be changed. However, the jaw body is divided into two layers, the middle sandwiched bone marrow cavity, you can use the surgical method to remove the outer layer, for more space to reduce or change the curvature of the jaw body.
 
The chin is one of the very important elements of the face shape, although it belongs to the part of the jaw bone.
The distance between the two temporomandibular joint condyle (that is, the width of the both side temporal jaw joint) also affects the width of the face shape (which is different from the width of the head shape), which cannot be changed, and the place has been cover by hair sideburns, affect the visual effect of face shape is not large.
 
Zygomatic arch is an important factor affecting the width of face shape.

The jaw bone also has an important structure, that is, "chin nerve." From the inner side close to the upper part of the lower jaw bone through bone marrow cavity, along the bone marrow cavity all the way forward and supply the lower row of teeth perception, now, it is called "lower alveolar nerve". Until close to the canine it through the nerve hole again, into the lower lip, responsible for the lower lips perception, known as the "chin nerve." It is the most important culprit caused postoperative pain after surgery, surgery will often pull it, causing lips consciousness temporary numb; if the surgery hurt it, may cause permanent perception numbness. (This is the perception of nerve, not facial nerve kind of motor nerve, after the injury will only cause numbne
ss of consciousness, and different than facial nerve injury will cause the mouth crooked and eyes oblique.)