Final answer:
The orientation of angular face muscles pertains to their origin on the skull and insertion into the skin, facilitating facial expressions. An example of muscle orientation indicating function is the sternocleidomastoid, which divides the neck into different triangles.
Step-by-step explanation:
Orientation of Angular Face Muscle
The term 'angular face muscle' generally refers to the muscles of facial expression which are a part of the axial muscles group. These muscles include, but are not limited to, the zygomaticus major and minor, which are responsible for raising the corners of the mouth. Unlike typical skeletal muscles, the muscles of facial expression have their origins on the surface of the skull and insert into the skin, not the bone, leading to a unique orientation that allows for the complex movement of the face necessary for expression. This feature also differentiates them as they can directly move the skin.
The sternocleidomastoid muscle serves as an example of how muscle orientation can reflect function. With an origin on the sternum and clavicle and an insertion on the mastoid process of the temporal bone, it acts to divide the neck into anterior and posterior triangles, thereby aiding in neck movement and head stabilization.