![]() ![]() Rectus comes from the Latin rectos, meaning straight 1. If the eye is adducted by the medial rectus, the orbital axis runs almost perpendicular to the optical axis, so the inferior rectus no longer produces effective ocular depression, and instead produces external rotation and adduction. Thus, when the physician testing eye movements first asks the patient to follow their finger laterally then inferiorly in the familiar H-shape, the inferior rectus muscle (and the oculomotor nerve that supplies it) are being directly tested. If the eye is abducted by the lateral rectus such that the optical axis lines up with the orbital axis, the inferior rectus produces ocular depression only, and is solely responsible for this movement. This means that the inferior rectus has secondary actions of adduction and external rotation (see figures 2 and 3). However, because the apex of the orbit is placed medially in the skull, the orbital axis that the inferior rectus runs in does not correspond with the optical axis of the eye in its neutral position. It is well known that three external circular muscles (superior constrictor SC, middle constrictor MC, inferior constrictor IC) act as the sphincter, and three internal longitudinal muscles (the stylopharyngeus STP, palatopharyngeus, and salpingopharyngeus) elevate the. The primary action of the inferior rectus is to depress the eye (see figure 1) 1. The pharynx, a tube-like structure, is a part of the digestive system and is composed of six muscles. These muscles make up the inner layer of musculature - they act to elevate (shorten and widen) the pharynx and larynx during swallowing and speaking. It is innervated by the pharyngeal branch of the vagus nerve via the pharyngeal plexus. superior pharyngeal constrictor muscle middle pharyngeal constrictor muscle inferior pharyngeal constrictor muscle Inner/longitudinal muscles. Innervated by the oculomotor nerve, which also supplies medial rectus, superior rectus, and inferior oblique muscles. The muscle is inserted into the pharyngeal raphe and pharyngeal spine. Arterial supplyīranches of the ophthalmic artery, itself a branch of the internal carotid artery. Inferior rectus is crossed by the inferior oblique muscle, which runs inferior to it as it crosses the floor of the orbit. Inferior rectus runs anteriorly on the inferior surface of the eye and inserts into the inferior surface of the sclera just posterior to the junction of cornea and sclera 2. Inferior rectus, along with the other rectus muscles, arises from the annulus of Zinn, the common tendinous ring at the apex of the orbit that surrounds the optic canal 1. tertiary function: one of the three ocular adductors.secondary function: one of the two ocular external rotators.primary function: one of two ocular depressors.insertion: globe (anterior, inferior surface).origin: annulus of Zinn (tendinous ring).innervation: inferior branch of the oculomotor nerve (CN III).These findings suggest that the superior pharyngeal constrictor muscle may also play an important role in the expression of smooth coordinated movements associated with ingestion, from mastication to swallowing. The present study found that the superior pharyngeal constrictor muscle is attached to the buccinator muscle (which plays an important role in mastication) with mucosa and originates from the mandible and root of the tongue. Morphology of the origin of the muscle at the buccopharyngeal part could be divided into three types: type A, membranous. Morphology of the origin of the muscle at the mylopharyngeal part could be divided into two types: type A, tip of the origin on the mylohyoid line and type B, tip of the origin away from the mylohyoid line. To clarify the morphologic characteristics of the superior pharyngeal constrictor muscle, which plays an important role in swallowing, the gross anatomy of the pterygopharyngeal, buccopharyngeal, mylopharyngeal, and glossopharyngeal parts of the muscle was examined. In all three types, the muscle at the buccopharyngeal part transitionally originated from the buccinator muscle. Palatopharyngeus muscle assists deglutition as it shortens the pharynx by elevating it superiorly, anteriorly and medially.This action closes the laryngeal airway and prevents aspiration of food. Morphology of the origin of the muscle at the buccopharyngeal part could be divided into three types: type A, membranous morphology from superior to inferior areas type B, membranous only in superior area and type C, complete lack of membrane. ![]() To clarify the morphologic characteristics of the superior pharyngeal constrictor muscle, which plays an important role in swallowing, the gross anatomy of the pterygopharyngeal, buccopharyngeal, mylopharyngeal, and glossopharyngeal parts of the muscle was examined. ![]()
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