Stylopharyngeus muscle

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Stylopharyngeus muscle
Musculusstylopharyngeus.png
Muscles of the pharynx and cheek. (Stylopharyngeus visible at center left.)
Details
Origin Temporal styloid process
Insertion Thyroid cartilage
Nerve Glossopharyngeal nerve (CN IX)
Actions Elevates the larynx, elevates the pharynx, dilates the pharynx; facilitates swallowing
Identifiers
Latin musculus stylopharyngeus
TA98 A05.3.01.114
TA2 2190
FMA 46664
Anatomical terms of muscle

The stylopharyngeus muscle is a muscle in the head. It originates from the temporal styloid process. Some of its fibres insert onto the thyroid cartilage, while others end by intermingling with proximal structures. It is innervated by the glossopharyngeal nerve (cranial nerve IX). It acts to elevate the larynx and pharynx, and dilate the pharynx, thus facilitating swallowing.

Contents

Structure

The stylopharyngeus is a long, slender, [1] [2] tapered pharyngeal muscle. [2] It is cylindrical superiorly, and flattened inferiorly. [1]

It passes inferior-ward along the side of the pharynx [1] between the superior pharyngeal constrictor (situated deep to the stylopharyngeus) and the middle pharyngeal constrictor (situated superficial to the stylopharyngeus), [2] before spreads out beneath the mucous membrane. [1]

Origin

It arises from (the medial side of the base of) the temporal styloid process. [2] [1]

It is the only muscle of the pharynx not to originate in the pharyngeal wall. [2]

Insertion

Some of its fibers are lost in the superior and middle constrictor muscles, some merge with the lateral glossoepiglottic fold, while still others join with those of the palatopharyngeus muscle to insert onto the posterior border of the thyroid cartilage. [2]

Innervation

The stylopharyngeus is the only muscle of the pharynx innervated by the glossopharyngeal nerve (CN IX) (all others being instead innervated by the vagus nerve (CN X)) by special visceral motor neurons with their cell bodies in [2] the rostral part of[ citation needed ] the nucleus ambiguus. [2]

Blood supply

The stylopharyngeus receives arterial supply from the paryngeal branch of the ascending pharyngeal artery. [2]

Lymphatic drainage

The lymphatic drainage of the region of the stylopharyngeus muscle is mediated by the middle cervical lymph nodes that drain into the supraclavicular lymph nodes. [2]

Relations

The stylopharyngeus is the medial-most and most vertical of the three styloid muscles. [2]

The muscle is situated in between the external carotid artery and internal carotid artery. [2]

On the lateral pharyngeal wall, it is situated posterior to the superior constrictor muscle, and anterior to the buccopharyngeal fascia. [2]

The glossopharyngeal nerve runs on the lateral side of this muscle, and crosses over it to reach the tongue.[ citation needed ]

Variation

Supernumerary muscles originating from other nearby regions of the skull may be present, and may be clinically significant. [2]

Development

Embryological origin is the third pharyngeal arch. Its development commences between the 4th and 7th week of gestation. [2]

Function

The stylopharyngeus:[ citation needed ]

See also

Additional images

Related Research Articles

Articles related to anatomy include:

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The glossopharyngeal nerve, also known as the ninth cranial nerve, cranial nerve IX, or simply CN IX, is a cranial nerve that exits the brainstem from the sides of the upper medulla, just anterior to the vagus nerve. Being a mixed nerve (sensorimotor), it carries afferent sensory and efferent motor information. The motor division of the glossopharyngeal nerve is derived from the basal plate of the embryonic medulla oblongata, whereas the sensory division originates from the cranial neural crest.

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The superior thyroid artery arises from the external carotid artery just below the level of the greater cornu of the hyoid bone and ends in the thyroid gland.

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The inferior thyroid artery is an artery in the neck. It arises from the thyrocervical trunk and passes upward, in front of the vertebral artery and longus colli muscle. It then turns medially behind the carotid sheath and its contents, and also behind the sympathetic trunk, the middle cervical ganglion resting upon the vessel.

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<span class="mw-page-title-main">Temporal styloid process</span>

The temporal styloid process is a slender bony process of the temporal bone extending downward and forward from the undersurface of the temporal bone just below the ear. The styloid process gives attachments to several muscles, and ligaments.

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References

PD-icon.svgThis article incorporates text in the public domain from page 1143 of the 20th edition of Gray's Anatomy (1918)

  1. 1 2 3 4 5 Standring, Susan (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice (42th ed.). New York. pp. 711–712. ISBN   978-0-7020-7707-4. OCLC   1201341621.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Jain, Prachi; Rathee, Manu (2022), "Anatomy, Head and Neck, Stylopharyngeus Muscles", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID   31613499 , retrieved 2023-01-12