Muscles of the Face

Exercise 17.4

Label the muscles of Figure 17.2 as you read.

There are many muscles in the face. We will not concern ourselves with these muscles on the cat, but only on the human.

Underlying the scalp are the frontalis and the occipitalis muscles. These muscles are named for the bones which lie under them. The two muscles are connected by a broad flat tendon, the galea aponeurotica. The frontalis raises the eyebrows and wrinkles the forehead, while the occipitalis pulls the scalp posteriorly.

There are three circular muscles on the face. These muscles are sphincters. They contract with a drawstring-like action. The muscles are the two orbicularis oculi which surround and close the eyes and the orbicularis oris which closes and puckers the lips.

The zygomaticus extends from the zygomatic bone to the corner of the mouth. This muscle pulls the corner of the mouth toward the zygomatic bone, into a smile. Sometimes this muscle is called the zygomaticus major.

The levator labii superioris is a muscle consisting of three parts. Some books label the lateral third of the levator labii superioris as the zygomaticus minor. The levator labii superioris pulls the upper lip up in an expression of disdain.

The depressor labii inferioris pulls the lower lip down.

An antagonist is a muscle which works against another. The antagonist of the zygomatic is the triangularis which pulls the corners of the mouth down as in a sadness.

The platysma is a broad flat muscle covering all of the muscles of the neck. It is listed here with the facial muscles because of its profound effect on facial expression. Contrac tion of the platysma pulls lower lip downward and posteriorly as in horror.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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