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Pharynx
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The pharynx, more commonly known as the throat, is a 12-14 cm, or 5 inch, long tube extending behind the nasal and oral cavities until the voice box (larynx) and the esophagus. Essentially, it forms a continuous muscular passage for air, food, and liquids to travel down from your nose and mouth to your lungs and stomach.
The functions of the pharynx are accomplished by two sets of muscles which help push the food bolus further down the digestive tract. In addition, they also help with swallowing and speaking.
In this page, we will learn more about the anatomy of the pharynx and its functions, including its main regions and muscles.
| Muscles |
Pharyngeal constrictors: Superior, middle and inferior muscles Longitudinal muscles: Palatopharyngeus, salpingopharyngeus, stylopharyngeus |
| Arteries | Facial artery, lingual artery, maxillary artery (branches of external carotid artery) |
| Nerves | Pharyngeal plexus: receives branches of vagus nerve (CN X), glossopharyngeal nerve (CN IX) and maxillary nerve (CN V2) |
Definition
The pharynx is a muscular column that begins in the head posterior to the nasal cavity, travels inferiorly behind the oral cavity before finally merging with the larynx and esophagus.
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Based on its anterior relations, the pharynx consists of three regions:
- Nasopharynx - posterior to the nasal cavity
- Oropharynx - posterior to the oral cavity
- Laryngopharynx- posterior to the larynx
Pharyngeal constrictors and longitudinal muscles
Attachments
There are six pharynx muscles in total that can be divided into two groups:
- Pharyngeal constrictors
- Longitudinal muscles
| Superior pharyngeal constrictor |
Origins: Pterygoid hamulus, pterygomandibular raphe, posterior end of mylohyoid line of mandible Insertions: Pharyngeal tubercle on basilar part of occipital bone |
| Middle pharyngeal constrictor |
Origins: Stylohyoid ligament, Greater and lesser horn of hyoid bone Insertions: Median pharyngeal raphe, Blends with superior and inferior pharyngeal constrictors |
| Inferior pharyngeal constrictor |
Origins: Oblique line of thyroid cartilage (Thyropharyngeal part), Cricoid cartilage (Cricopharyngeal part) Insertions: Median pharyngeal raphe (Thyropharyngeal part), Blends inferiorly with circular esophageal fibres (Cricopharyngeal part) |
| Palatopharyngeus |
Origins: Posterior border of hard palate, palatine aponeurosis Insertions: Posterior border of thyroid cartilage, blends with contralateral palatopharyngeus muscle |
| Salpingopharyngeus |
Origins: Inferior/cartilaginous part of auditory (Eustachian) tube Insertions: Blends with palatopharyngeus muscle |
| Stylopharyngeus |
Origins: Medial base of styloid process of temporal bone Insertions: Blends with pharyngeal constrictors, lateral glossoepiglottic fold, posterior border of thyroid cartilage |
| Innervation | They are all innervated by the pharyngeal plexus and pharyngeal branch of the vagus nerve, except the stylopharyngeus which is innervated by the glossopharyngeal nerve. |
| Functions | They all act on the pharynx, either constricting or elevating it. |
All the muscles of the pharynx help to push the food bolus towards the esophagus during the act of swallowing; either by contracting, or by shortening the pharynx itself. Some of the muscles also help with speaking.
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Test your knowledge on the muscles of the pharynx with this quiz.
Take a look at the study unit to get a better understanding of how the pharynx muscles are organized and work.
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Arteries
The pharynx is a location with a rich amount of arterial anastomoses, making it a highly vascularized anatomical structure. Four main arteries are responsible for its blood supply, all of them originating from the external carotid artery:
- Ascending pharyngeal artery
- Facial artery (and especially the palatine and tonsillar branches)
- Lingual artery
- Maxillary artery
They supply the pharynx by either passing in close proximity to it, or by sending out ascending and descending pharyngeal arteries. In addition to these arteries, there are others that are closely related to the pharynx but do not necessarily supply it with fresh blood.
The venous drainage of this region is via the external palatine vein which drains into the pharyngeal plexus. In turn, the latter finishes in the internal jugular vein. Watch the following video to learn about all the blood vessels around the pharynx.
Test your knowledge on the blood vessels of the pharynx with this quiz.
Nerves
The main anatomical structure innervating the throat is the pharyngeal nervous plexus. It originates from three major cranial nerves:
The pharyngeal branches of the vagus nerve provide motor innervation to all the structures and muscles of the pharynx, except the stylopharyngeus. The latter receives motor innervation from the glossopharyngeal nerve.
In addition, the pharyngeal branches of the glossopharyngeal nerve provide the majority of the pharynx with sensory innervation. The exception is the nasopharynx; its anterior and superior parts are supplied by the maxillary nerve. In addition, the inferior aspect of the laryngopharynx (surrounding the beginning of the larynx) is innervated by the internal branch of the vagus nerve. Watch the following video to learn all about the nerves of the pharynx.
Test your knowledge on the nerves of the pharynx with the quiz.
Function
If you have been paying close attention, you should be familiar with the functions of the pharynx. The tubular structure of the pharynx makes its main function quite obvious - to facilitate the passage of air, solids, and liquids from the nose and mouth. Therefore, the pharynx functions in both the digestive and respiratory systems. The muscles further provide help by facilitating peristalsis (constrictors), together with swallowing and speaking (longitudinal muscles). Tackle the following custom quiz about the pharynx to test your newly acquired knowledge. It contains all the relevant aspects: muscles (attachments, functions), arteries, and veins; mixed up randomly to offer you the ultimate challenge on pharynx anatomy.
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