Naziha Sultan Ahmed, BVMS, MSc Scientific degree (Prof. Assis.), Department of Anatomy College of Veterinary Medicine, University of Mosul, Mosul, Iraq https://orcid.org/0000-0002-2856-8277 https://www.researchgate.net/profile/ Anatomy | Part 9 | 2nd year 2019

Digestive System

The openings of the pharynx:

1=Paired chonae: rostrodorsally; connect the nasopharynx with the nasal cavity.

2=Paired openings of auditory tubes (Eustachian tube) dorsolaterally; connect the nasopharynx with the middle ear.

3=Aditus pharyngeus (isthmus faucium): connect the oral cavity with the oral pharynx.

4=Aditus laryngeus: caudoventrally, opened in therespiration and closed in the Swallowing.

5=Aditus esophageus: at the caudal end of the laryngopharynx; connect oropharynx with the esophagus.

CouAnatomy | Digestive system | Prof. Assis. Naziha Sultan Ahmed Page | 1 Muscles of the pharynx:

Pharyngeal muscles are striated, bilateral muscles, their function under the swallowing reflex.

The constrictor muscles of the pharynx are:

1-Pterygopharyngeus muscle: originate from pterygoid bone, its fibers are longitudinal assist in shortening the pharynx .It inserts in pharyngeal raphe.

2-Palatopharyngeus muscle: lie immediately under the mucosa, act as sphincter for the nasopharynx and intrapharyngeal opening. It originates from the palatine aponeurosis and inserts in the pharyngeal raphe, act to shorten the pharynx.

3-Stylopharyngeus rostralis: originates from the rostral border of the ventral half of the stylohyoid bone and epihyoid and inserts in the pharyngeal raphe.

4-Hyopharyngeus muscle: originates from thyrohyoid and keratohyoid and inserts in the pharyngeal raphe.

5-Thyropharyngeus muscle: originates from the oblique line of thyroid cartilage of the larynx and inserts in the pharyngeal raphe.

6-Cricopharyngeus muscle: originates from the cricoid cartilage and inserts in the pharyngeal raphe.

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The dilator muscle of the pharynx:

Stylopharyngeus caudalis: originates from the medial surface of the proximal half of stylohyoid bone and inserts in the lateral wall of the pharynx. The action of this muscle is to dilate the pharynx for receiving the bolus while swallowing.

Lymphatic organs of the pharynx: 1-Lingual tonsil: present in the mucosa of the root of the tongue. 2-Palatine tonsil: in or on the lateral wall of the oropharynx. 3-Pharyngeal tonsil: in the roof of the nasopharynx. 4-Paraepiglottic tonsil: on the base of the epiglottis. 5-Tubal tonsil: in the lateral wall of the auditory tube opening.

رسم توضيحي لالطالع

The muscles of mastication: Mastication done by the aid of the teeth, gum, tongue, tempromandibular joint, symphysial joint of the jaw and masticatory muscles.

Muscles of mastication are:

1-Temporalis muscle: occupy the temporal fossa, originates from the lateral surface of the cranium and inserts in coronoid process of the mandible.

2-Masseter muscle: lie laterally to mandible, originates from maxillary region of the skull and zygomatic arch, and inserts in the caudal part (ramus) of mandible.

3-Pterygoideus medialis: lie medially to mandible ramus, originates from the pterygopalatine region and insert on the medial surface of the ramus.

4-Pterygoideus lateralis: lie medially to mandible ramus, originate from pterygopalatine region and insert in pterygoid fovea of mandible ramus.

5-Digastricus: originates from the jugular process caudal to the tempromandibular joint and inserts in the angle of the mandible.

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