![]() Suface of eyeball between superior rectus and lateral rectus Moves eyes down and away from nose rotates eyeball from 6 o’clock to 9 o’clock Surface of eyeball between inferior rectus and lateral rectus ![]() Moves eyes up and away from nose rotates eyeball from 12 o’clock to 9 o’clock Moves eyes down and toward nose rotates eyes from 6 o’clock to 3 o’clock Moves eyes up and toward nose rotates eyes from 1 o’clock to 3 o’clockĬommon tendinous ring (ring attaches to optic foramen) (b) Each muscle inserts onto the eyeball. If you have ever been to a doctor who held up a finger and asked you to follow it up, down, and to both sides, he or she is checking to make sure your eye muscles are acting in a coordinated pattern.įigure 11.4.3 – Muscles of the Eyes: (a) The extraocular eye muscles originate outside of the eye on the skull. These muscles are located inside the eye socket and cannot be seen on any part of the visible eyeball ( Figure 11.4.3 and Table 11.3). The movement of the eyeball is under the control of the extra ocular ( extrinsic) eye muscles, which originate from the bones of the orbit and insert onto the outer surface of the white of the eye. Figure 11.4.2 Muscles in Facial Expression Muscles That Move the Eyes Additional muscles of facial expression are presented in Figure 11.4.2. With these movements, you can feel the action of the corrugator supercilli. Raise your eyebrows as if you were surprised and lower your eyebrows as if you were frowning. ![]() Place your finger on your eyebrows at the point of the bridge of the nose. There are several small facial muscles, one of which is the corrugator supercilii, which is the prime mover of the eyebrows. This muscle allows you to whistle, blow, and suck and it contributes to the action of chewing. The buccinator muscle compresses the cheek. The physicians originally studying human anatomy thought the skull looked like an apple. The two bellies are connected by a broad tendon called the epicranial aponeurosis, or galea aponeurosis (galea = “apple”). In other words, there is a muscle on the forehead ( frontalis) and one on the back of the head ( occipitals). The muscle has a frontal belly and an occipital belly (near the occipital bone on the posterior part of the skull). The occipitofrontalis muscle elevates the scalp and eyebrows. The orbicularis oris is a circular muscle that moves the lips, and the orbicularis oculi is a circular muscle that closes the eye. Because the muscles insert in the skin rather than on bone, when they contract, the skin moves to create facial expression ( Figure 11.4.1).įigure 11.4.1 – Muscles of Facial Expression: Many of the muscles of facial expression insert into the skin surrounding the eyelids, nose and mouth, producing facial expressions by moving the skin rather than bones.Įditor’s note: Replace figure with one that includes all muscles from table for example figure 10.7 from Marieb or 9.8 from Amerman The insertions of these muscles have fibers intertwined with connective tissue and the dermis of the skin. The muscles of facial expression originate from the surface of the skull or the fascia (connective tissue) of the face. AXIAL MUSCLES OF THE HEAD NECK AND BACK Muscles of Facial Expression The first grouping of the axial muscles you will review includes the muscles of the head and neck, then you will review the muscles of the vertebral column, and finally you will review the oblique and rectus muscles. Some of the axial muscles may seem to blur the boundaries because they cross over to the appendicular skeleton. This system reflects the bones of the skeleton system, which are also arranged in this manner. The skeletal muscles are divided into axial (muscles of the trunk and head) and appendicular (muscles of the arms and legs) categories. Appendicular muscles of the pelvic girdle and lower limbs.Muscles of the pectoral girdle and upper limb.Axial muscles of the abdominal wall and thorax. ![]() Axial muscles of the head neck and back.By the end of this section, you will be able to identify the following muscles and give their origins, insertions, actions and innervations:
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