Cow pharynx

The cow pharynx is a musculomembranous sac common to the digestive and respiratory systems. Here, I will describe the location, parts, topography, and opening of the cow’s pharynx with a hand-drawing diagram and real pictures.

Quick answer: The cow pharynx is a rough funnel-shaped space having 3 parts and 7 openings for communication with other structures of the head and neck.

However, I will also describe the structure of the wall of the cow’s pharynx with diagrams.

What is the pharynx of a cow?

Figure 1 presents the hand-drawing diagram of the cow’s pharynx. It presents the location, extension, and different parts of the cow’s pharynx.

Thus, the above-mentioned hand-drawing diagram helps you to understand the  pharynx –

• Pharynx: The cow’s pharynx is a rough funnel-shaped common passage for the digestive and respiratory systems.
• Location: It is located at the base of the cranial cavity of the cow, and behind the posterior nasal apparatus.

Here, the broad rostral extremity of the cow’s pharynx communicates with the mouth cavity and nasal cavity. However, the narrow caudal extremity opens into the cow’s esophagus.

It is believed that the rostral extremity of the pharynx communicates to the mouth through the isthmus faucium.

What is isthmus faucium in a cow?

Figure 2 shows a wide tubular aperture through which the cow’s mouth cavity communicates with the pharynx. It is the isthmus faucium in a cow.

The cow’s isthmus faucium extends from the rostral pillar of the soft plate to the epiglottis. Let’s see the boundaries of the cow’s isthmus faucium –

• Dorsally: soft palate,
• Ventrally: dorsum of the cow tongue, and
• Laterally: the rostral pillar of the soft palate.

This tubular passage is small except during deglutition. It dilates enough to allow large blouses to pass from the mouth to the pharynx.

How pharynx works for common tube to digestive and respiratory passages?

Figure 3 shows the hand-drawing/schematic diagram of the pharynx, esophagus, trachea, mouth, and nasal cavities. It presents the contribution of the pharynx during normal respiration and swallowing conditions.

Air and feed passages cross each other while passing through the pharynx. During respiration, air passes from the rostro-dorsal to the caudal-ventral way and vice versa. Whereas, during feed intake by the cow, the boluses take their route from rostro-ventral to caudo-dorsal.

Cow pharynx anatomy

So, what should you explain about the anatomy of the cow’s pharynx? You should explain the following while writing the pharynx anatomy in your examination’s manuscript –

• Location and extension of the pharynx (Figure 1),
• Topographic relationship of the pharynx,
• Opening of the pharynx to communicate with other structures,
• Parts of the pharynx, and
• Structures of the pharynx with emphasis on the muscles and mucous membrane,

I will help you to learn these topics from the bovine pharynx clearly. However, this might be a good note on the cattle/bovine pharynx for your upcoming exam preparation.

Topographic relationship of the pharynx

The cow’s pharynx is placed behind the soft palate, caudal nares, and the isthmus faucium. It is located obliquely caudad and ventrad by means of the muscles with pterygoid, palatine, and hyoid bones dorsally.

However, ventrally, it connects with the thyroid and cricoid cartilage of the cow’s larynx. Here, Figure 4 shows the relationship of the pharynx with the soft palate, caudal nares, and different bones of the skull.

Thus, the bovine/cattle/cow’s pharynx is related dorsally to the base of the cranium and ventrally to the larynx. However, you will find the relationship of the pharynx with the suprapharyngeal lymph glands dorsally.

On the right and left lateral, different organs/structures have a close relationship with the pharynx –

• Pterygoid muscles,
• Great cornu of the hyoid bones,
• External carotid and external maxillary arteries,
• Glossopharyngeal, hypoglossal, and rostral laryngeal nerves,
• Mandibular salivary gland, and
• Para pharyngeal lymph glands.

Opening of the cattle’s pharynx

Figure 5 shows the hand-drawing diagram that presents the seven openings of the cattle’s pharynx.

Here, the pharyngeal cavity presents seven openings to communicate with the various organs/structures of the head and neck regions. Followings are the openings of the cattle/cow’s pharynx –

• 1-2: Two openings for the caudal nares,
• 3-4: Two openings for the eustachian tube (eustachian orifice),
• 5: One for the esophagus (aditus esophagius),
• 6: One for the mouth cavity (isthmus faucium), and
• 7: One for the larynx (aditus laryngis)

Here, the caudal nares are located at the rostro-dorsal part of the pharyngeal cavity. Again, the isthmus faucium is located below the caudal nares and communicates with the mouth cavity.

The eustachian orifice is located behind the caudal nares at the dorsolateral part of the cavity. It communicates with the cow’s eustachian tube.

However, the aditus laryngis occupies the greater part of the floor and opens into the larynx. Finally, the aditus esophagus is located dorsal to the aditus laryngis and opens into the esophagus.

Parts of the pharynx in the cow

Figure 6 presents the various parts of the pharynx of a cow. From the diagram, the nasopharynx, oropharynx, and laryngopharynx are identified.

What is the naropharynx in a cow?

Nasopharynx: The dorsal part of the pharynx above the soft palate of the cow is known as the nasopharynx. Here, the conchae/posterior nares are separated dorsally by the crest of the vomer bone. However, the mucous membrane covers the vomer bone here.

What are the oropharynx and laryngopharynx in a cow?

Oropharynx: The oropharynx is the part of the cattle’s pharynx located between the soft palate and the root of the tongue.  

Laryngopharynx: The dorsal and lateral parts of the larynx are the laryngopharynx.

Structure of the wall of the cow’s pharynx

The pharyngeal muscles, fibers/aponeurosis, glands, and mucous membrane form the wall of the cattle’s pharynx.

Cow’s pharyngeal muscles: The different pharyngeal muscles form the main core of the wall. These muscles are described separately as the muscles of the head and neck under the cow’s muscular system.

Figure 7 shows the schematic diagram/presentation of the muscles from the wall of the pharynx.

Followings are the muscles from the wall of the pharynx –

• Palato pharyngeal muscle,
• Thyropharyngeal muscle,
• Hyopharyngeal muscle,
• Circopharyngeus muscle,
• Arytenopharyngeal muscle,
• Pterygopharyngeal muscle, and
• Stylopharyngeal muscle.

These pharyngeal muscles are mainly responsible for sending the food particles from the pharynx to the esophagus through their successive contraction. There are three successive contraction occurs through the pharyngeal muscles in a cow –

• Anterior contraction: It is formed by the pterygopharyngeal muscle,
• Middle contraction: It is formed by the hypophrayngeal muscle, and
• Caudal contraction: It is formed by the thyropharyngeal muscle.

Aponeurosis and mucous membranes of the pharynx

The cow’s pharyngeal aponeurosis is the fibrous layer of the pharyngeal wall. It is placed between the muscle and mucous membranes of the pharyngeal wall.

However, the aponeurosis begins at the base of the cranium and passes beneath the muscular layer of the pharyngeal layer.

The mucous membrane lines the pharyngeal cavity and continues with the mucous membrane of the different organs. Here, it continues with the mucous membrane of the mouth, the nasal cavity, the larynx, the eustachian tube, and the esophagus.

The ciliated epithelium lines the rostral part of the mucous membrane of the pharynx. However, the ventral part of it is lined by the stratified epithelium.

You will also find that the submucosal layer lies between the muscular and mucosal layers. There are plenty of mucosal glands in the submucosal layer of the pharynx.

FAQ’s on cow’s pharynx

Conclusion

So, the cow’s pharynx is the common passage for the respiratory and digestive systems. It is located caudal to the mouth and nasal cavities and lined by the mucous membrane and surrounded by various muscles.

Here, the cow’s pharynx is divided into nasopharynx, oropharynx, and laryngopharynx. However, it has seven openings for communication with the external ears, nasal passages, esophagus, mouth cavity, and the larynx.

References

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• Gupta, S. K. eta al., (2015). Anatomy of Oropharyngeal Cavity of Fowl (Gallus domesticus). Ind journal of vet anatomy., 27(1).
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• Gomez, D. E., et al., (2019). Pharyngeal trauma in dairy cattle. Journal of Veterinary Internal Medicine, 33(4), 1833–1839.

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