Clinical case: Pharyngeal diverticula

Author: Prof. Joel A. Vilensky, PhD • Reviewer: Carlos Suarez-Quian, PhD
Last reviewed: May 25, 2023
Reading time: 15 minutes

In this article we describe a case of a man suffering from progressive dysphagia and odynophagia, both of them literally caused by two pockets that developed in the walls of his pharynx. Do you want to find out more about these outpouchings and how they develop? Read this article to find out how they manifest, their diagnosis, imaging, management, and anatomy.

Key facts
Pharyngeal constrictors	There are three: superior, middle, and inferior pharyngeal constrictors. They are all innervated by the pharyngeal plexus and pharyngeal branch of the vagus nerve. They all act on the pharynx, either constricting or elevating it.
Stages of deglutition	1st stage (voluntary) - the purpose of this stage is to form a bolus and pass it into oropharynx, an act initiated by the tongue. 2nd stage (involuntary) - this stage consists of a series of reflexes of the pharyngeal mucosa, soft palate, and larynx that ultimately push the bolus towards the esophagus. 3rd stage (involuntary) - the purpose of this stage is to push the bolus into the esophagus, especially through the action of the inferior pharyngeal constrictor.

After reviewing this case you should be able to describe the following:

The attachments, innervation, function and intervening spaces of the pharyngeal constrictors.
The phases and mechanisms of deglutition (swallowing).

This article is based on a case report published in the Journal "Case Reports in Surgery" in 2015, by Caroline C. Jadlowiec, Beata E. Lobel, Namita Akolkar, Michael D. Bourque, Thomas J. Devers, and David W. McFadden.

Contents

Case description
Surgical and anatomical considerations
Explanations to objectives
Sources

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Case description

History

A 65-year-old male presented with a 12-month history of progressive dysphagia (difficulty in swallowing) and odynophagia (painful swallowing) for solids. The patient indicated that typically his swallowing pain was at the level of the sternal notch.

Imaging

In order to diagnose the patient’s problem, a radiographic with barium swallow exam was performed that revealed bilateral moderately sized pharyngeal diverticuli that changed in size during the different phases of swallowing (Figure 1A).

Figure 1. Radiographic images from barium swallow exam showing bilateral diverticuli (white circles) before (A) and after (B) surgery. Although reduced, the left diverticulum was still evident. Note that most of the labeling in this image is approximate because the contrast material obscures many of the bony landmarks.

The diverticuli were higher and more lateral than expected for the known types of diverticuli, prompting a CT scan of the neck (Figure 2).

Figure 2. Axial CT scan showing bilateral pouches (diverticuli).

The CT scan revealed the pharyngeal pouches to be 17mm in diameter and arising between the hyoid bone and thyroid cartilage (Figure 3&4).

Figure 3. Dissection image showing the hyoid and thyroid cartilages and also the thyrohyoid membrane being penetrated by the internal laryngeal nerve.

Management and evolution

After discussion with the patient, definitive surgery was planned. The mouth of the diverticulum on the right side was packed from the pharyngeal side, just above the level of the superior border of the thyroid lamina.

Figure 4. Dissection image like (figure 3) but more lateral orientation, the left thyroid lamina has been reflected forward to revealing the underlying membrane and muscle.

The pouch was subsequently found to be herniating through the superior constrictor muscle and related closely to the superior laryngeal neurovascular bundle (Figure 5). This right-sided diverticulum had a narrow base and was readily excised. The left-sided pouch had a broader base and was sutured closed. A nasogastric tube was inserted and the patient remained in the hospital for five days until oral intake was resumed.

At a two month follow-up there was significant improvement of symptoms. Unfortunately, swallowing deteriorated again at three months, and a repeat barium swallow was done (Figure 1B), Results of this barium swallow suggested that the diverticuli were reduced in size and no longer the cause of the new pain. Instead, this more recent dysphagia was thought likely due to cricopharyngeal muscle spasm. The patient then underwent injection of botulinum toxin into the cricopharyngeus, which alleviated the dysphagia.

Figure 5. Cadaver image of the posterior pharyngeal wall.

Surgical and anatomical considerations

This case depicts a unique diverticulum that occurred bilaterally and originated between the hyoid bone and thyroid cartilage. This patient thus represents a unique case of pharyngoesophageal diverticulum that is similar in symptoms to the more commonly described diverticuli, Zenker’s, Killian-Jamieson’s, or Laimer’s diverticuli (see below).

Figure 6. Sagittal section of head and neck showing the three divisions of the pharynx.

The pathogenesis of pharyngoesophageal diverticuli is explained by peristaltic forces acting against an obstruction, usually a dysfunctional cricopharyngeus, resulting in increased intraluminal pressure and herniation of the pharyngeal mucosa through weakened areas of the pharyngo-esophagus. The present case, however, involves bilateral diverticuli located between the hyoid bone and thyroid cartilage, and thus not directly related to the cricopharyngeus muscle. A possible explanation for the occurrence of this pouch is that a weakness existed in the thyrohyoid membrane that was associated with the passage of the internal laryngeal nerve (branch of the superior laryngeal nerve) and vessels through the membrane (Figure 7).

Figure 7. An image showing the passage of the internal laryngeal nerve through the thyroid membrane.

The fact that the patient’s symptoms fully resolved with treatment of the cricopharyngeus muscle suggests that the diverticuli were manifestations of the swallowing problem and not the basic cause, which is a situation that is similar to that in Zenker’s diverticulum. The surgery used here involved an external approach, which allowed for accurate identification and closure of the pouches, with preservation of the neurovascular bundle. It is likely that the sternal discomfort was associated with inflammation of the mediastinum, which can be associated with motility abnormalities, including diffuse spasm.

The most common pharyngeal diverticulum is a Zenker’s diverticulum, which is characterized by a posterior outpouching originating from Killian’s dehiscence (a triangular area in the pharyngeal wall between the thyropharyngeal and cricopharyngeus parts of the inferior constrictor of the pharynx (Figure 5). The Killian-Jamieson diverticulum is much less common and is an anterolateral herniation located superolateral to the longitudinal muscle of the esophagus and inferior to the cricopharyngeal muscle. The rarest variant of pharyngeal diverticulum is often referred to as Laimer’s or Laimer-Haeckerman’s diverticulum. Similar to the Killian-Jamieson diverticulum, a Laimer’s diverticulum originates between cricopharyngeus and the longitudinal muscle of the esophagus; however, it is located posteriorly and midline.

Explanations to objectives

Objectives

The attachments, innervation, function and intervening spaces of the pharyngeal constrictors.
The phases and mechanisms of deglutition (swallowing).

Pharyngeal constrictors

Superior constrictor: (figure 8: A) Arises from the pterygoid hamulus, pterygomandibular raphe, posterior end of mylohyoid line of mandible. The muscle fibers curve around the pharynx to unite with its counterpart in the median raphe of the posterior wall of the pharynx. The upper fibers of this muscle reach the occipital bone (pharyngeal tubercle). Lowest fibers curve downward deep to the middle constrictor. The curved upper border of the superior constrictor is separated from the base of the skull by an interval occupied by the pharyngobasilar fascia. Through this interval pass the auditory tube and levator veli palatini. Between the inferior border of the superior constrictor, the superior border of the middle constrictor, and the posterior border of the hyoglossus, is another muscular gap filled with fascia through which pass the stylopharyngeus, the glossopharyngeal nerve and the stylohyoid ligament.
Middle constrictor: (figure 8: B) arises from the inferior part of stylohyoid ligament and from the greater and lesser horns of the hyoid bone. Its fibers curve backwards around the pharynx to be inserted with the muscle of the opposite side into the posterior median raphe. The upper fibers of the middle constrictor overlap the superior constrictor, and the lower fibers of the middle constrictor are overlapped posteriorly and laterally by the inferior constrictor. Between the anterior part of the lower border of the middle constrictor and the upper border of the inferior constrictor there is another muscular gap bounded by the thyrohyoid muscle anteriorly. Through this gap passes the superior laryngeal vessels and the internal laryngeal nerve.
Inferior constrictor: (figure 8: C) Arises from both the thyroid and cricoid cartilages. The fibers from the thyroid (known as thyropharyngeus) run posterosuperiorly with the superior fibers running more superiorly than the inferior fibers. The superior fibers overlap the middle constrictor. The fibers from the cricoid (known as cricopharyngeus) run more horizontally and blend inferiorly with the circular fibers of the esophagus. The fibers from the left and right parts of the muscle insert together into the median raphe.

Figure 8. An image showing the pharyngeal constrictors (superior, middle, and inferior).

The constrictor muscles are innervated by the pharyngeal plexus - with the vagus nerve carrying fibers that emerged from the brainstem as CN XI. The cricopharyngeus also receives innervation from the external and recurrent laryngeal nerves. See Explanation 2 for function.

Phases and mechanisms of deglutition

The act of swallowing (deglutition) is initiated voluntarily and consists of closing the mouth, holding the breath, and forcing the bolus into the esophagus. In order to propel food from the mouth into the esophagus three opening must be closed, the nasal cavity, the oral cavity, and the larynx. During the process of swallowing muscular action closes these openings. There are three primary stages in swallowing;

1st Stage: voluntary

The purpose of the first stage is to form bolus and pass it into oropharynx. The anterior part of tongue is pressed against the hard palate and bolus is pushed posteriorly - these movements are affected by intrinsic tongue muscles. At the same time the hyoid bone is raised and moved anteriorly (geniohyoid, mylohyoid, digastric, stylohyoid). The palatoglossal arches are then approximated (palatoglossus) forcing the bolus into the oropharynx and the 2nd or involuntary stage is initiated.

2nd Stage: Involuntary

This stage is initiated by contact of the bolus with mucosa in certain parts of the mouth and pharynx that act as a stimulus to a series of reflexes that function to ensure that the bolus descends into esophagus rather than entering the trachea or nasopharynx. The soft palate is elevated and tightened (levator and tensor veli palatini) and is firmly approximated to the posterior pharyngeal wall by contraction of upper fibers of the superior constrictor, thus preventing the bolus from passing upwards into the nasopharynx.

At same time, the larynx is drawn upwards posterior to the hyoid bone, and the pharynx ascends with it (stylopharyngeus, salpingopharyngeus, thyrohyoid, and palatopharyngeus). The aryepiglottic folds are approximated by action of laryngeal muscles. These actions close the entrance to the larynx by decreasing the size of its entrance and forcing the entrance against epiglottis, which, in turn, is forced against base of tongue. In addition, the tip of the epiglottis is pulled inferiorly by some of the laryngeal muscles (aryepiglottic muscles). But the epiglottis does not descend over the entrance to the larynx in a manner akin to a trap door. In fact, mainly, the larynx moves up against the epiglottis. Although the epiglottis appears to prevent some food from entering larynx, its precise function remains unclear because its removal (because of carcinoma) does not result in any swallowing difficulty.

Finally, because the breath is held during swallowing, the larynx is also closed by the vestibular and vocal folds. During this stage, the bolus descends, this descent being facilitated by both gravity (when erect or sitting) and by successive contractions of the superior and middle constrictors. In this descent the aryepiglottic folds provide lateral food channels leading from the sides of the epiglottis through the piriform recesses to the esophagus.

3rd Stage: Involuntary

The purpose of the last (3rd) stage is to force the bolus down the esophagus. This stage is facilitated by the inferior constrictor, which compresses the bolus and forces it into the esophagus. The swallowing of fluid is essentially similar to that of solids except that in the initial stages the tongue is made to form a tube with the palate through the action of the styloglossus and intrinsic tongue muscles. The fluid is then forced posteriorly in the same way as solid food and cascades down the sides of the epiglottis avoiding the entrance to the larynx.

Gravity is important in helping food descend through the pharynx, but the pharyngeal constrictors can still force food into the esophagus in the individual standing on his (her) head. The cricopharyngeal part of the inferior constrictor acts differently from the other constrictors. It maintains a tonic contraction until swallowing is initiated and thus acts as a sphincter between the pharynx and the esophagus. This normally prevents regurgitation of materials from the esophagus into pharynx unless there is active vomiting. The muscle relaxes during swallowing.

If the innervation of the soft palate or pharynx is damaged, the whole process of swallowing becomes difficult or impossible and food may flow out the nose after ingestion. In such cases, tube feeding may be necessary. Furthermore, in addition to difficulty swallowing, paralysis of the soft palate makes it impossible to develop any pressure on blowing through the mouth, as the nasal and oral parts of the pharynx cannot be closed off. Thus, upon blowing or whistling air escapes through the nose. Paralysis of the soft palate also results in a nasal tone of voice.

During swallowing, the salpingopharyngeus helps to open the orifice of the auditory (Eustachian, pharyngotympanic) tube and is probably assisted by the levator and tensor veli palatini. This equalizes pressure on both sides of tympanic membrane (airline passengers can relieve differential pressure on eardrums by swallowing).

Sources

All content published on Kenhub is reviewed by medical and anatomy experts. The information we provide is grounded on academic literature and peer-reviewed research. Kenhub does not provide medical advice. You can learn more about our content creation and review standards by reading our content quality guidelines.

Reference:

Oh L, Chan L, Veivers D. Atypical Pharyngeal Pouch Arising Bilaterally between the Hyoid Bone and Thyroid Cartilage. Case Reports in Otolaryngology Volume 2017, Article ID 3515438, 4 pages.
Modified by Joel A. Vilensky PhD, Carlos A. Suárez-Quian PhD, Aykut Üren, MD.

Authors:

Joel A. Vilensky
Carlos A. Suárez-Quian
Aykut Üren

Layout:

Abdulmalek Albakkar
Adrian Rad

Illustrators:

Internal laryngeal nerve (lateral-left view) - Paul Kim
Pharyngeal constrictors (posterior view) - Yousun Koh

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