Pharynx dr.gosai

Ojvensha E learning Resources-Prepared by Dr.B.B.Gosai

Pharynx

(*****Important Long Question, Short note and Viva)

Introduction:

• It is fibromuscular common passage for respiratory and digestive system

Extent

• Beginning: Base of skull.

• Termination: At the level of lower border of cricoid cartilage (C6 vertebra); continues as esophagus.

Location:

• Behind the nasal cavity, oral cavity and Larynx.

Parts: Pharynx is divided into three parts:

• Nasopharynx communicates anteriorly with Nasal cavity

• Oropharynx communicates anteriorly with Oral Cavity.

• Laryngopharynx communicates anteriorly with Larynx

Draw this Diagram

Nasopharynx

Oropharynx

Laryngopharynx


Length: 12 cms

Width: Upper part wide (5 cms) and lower part narrow (1.5 cms)

Interior of pharynx

Nasopharynx:

• Extent: From base of skull to lower border of soft palate.

• Roof: Supported by sphenoid & occipital bone.

• Floor: Formed by soft palate.

• Ant wall: post nasal aperture

• Post wall: sloping surface of roof

• Features seen in Lateral wall: (*****Short note and Viva)

1. Pharyngeal opening of auditory tube communicates pharynx with middle ear cavity

2. Tubal elevation raised by cartilage of auditory tube

3. Pharyngeal recess (Fossa of Rosenmuller) can be mistaken as auditory opening during procedures to dilate the tube and lateral to this fossa is Internal carotid artery which may be damaged in procedure.

4. Tubal tonsil near tubal elevation.

5. Salpingopharyngeus muscle forms salpingopharyngeus fold.

6. Salpingopalatine fold raised by levator palati muscle

7. Pharyngeal tonsil is present in submucosa.


Draw this Diagram

Oropharynx

• Extent: From lower border of soft palate to upper border of epiglottis.

• Roof: undersurface of soft palate

• Floor: Post 1/3 of tongue & interval between tongue & epiglottis. Lingual tonsil is present in post 1/3 of tongue.

• Ant wall: Oro pharyngeal isthmus

• Post wall: 2nd & upper 3rd cervical vertebra

• Features seen in Lateral wall:

1. Palatoglossal arch raised by Palatoglossus muscle

2. Palatopharyngeal arch raised by Palatopharyngeus muscle

3. Tonsillar fossa between arches contain Palatine tonsil.

1 2 3 5 6

7


Draw this Diagram (same diagram to be used for Nasopharynx and Orapharynx)

Laryngopharynx

• Extent: Upper border of epiglottis to lower border of cricoid cartilage.

• Ant wall: Inlet of larynx & mucosa covering posterior surface of larynx.

• Post wall: 3rd, 4th, 5th & 6th cervical vertebral bodies support it.

• Lateral wall: Supported by thyroid cartilage & thyrohyoid membrane.

• Anteriorly on each side of larynx: Piriform fossa is present. This is common site of lodgment of foreign bodies e.g. fish thorns, metal pins in children etc. This may lead to damage to Internal laryngeal nerve causing loss of sensation of inlet of larynx which in turn may lead to aspiration of food particles in respiratory tract.

1 2

3


No need to raw this Diagram for the short note

Wall of the Pharynx (Structure of Pharynx)

From inside out:

1. Mucous membrane

2. Submucosa

3. Pharyngobasilar fascia

4. Muscles

5. Buccopharyngeal fasca

Muscles of Pharynx Three Transverse (constrictors):

1. Superior constrictor

2. Middle constrictor

3. Inferior constrictor

Three Longitudinal:

1. Stylopharyngeus

2. Palatopharyngeus

3. Salpingopharyngeus


Draw this Diagram for the note on Constrictor muscles

Constrictor muscles of Pharynx: (**** Short note) General Points:

All constrictors are fan shaped.

They overlap with each other which give funnel shaped appearance to Pharynx.

Flower pot arrangement.

All are inserted to Pharyngeal Raphe.


1. Superior constrictor:

• Origin: Medial pterygoid plate, Hamulus, pterygomandibular raphe, side of tongue and mandible behind 3rd molar tooth.

• Fibers fan and inserted to Pharyngeal tubercle and Pharyngeal raphe.

• There is Gap between upper border of Superior constrictor and Base of skull known is Foramen of Morgagni (covered by Fascia)

2. Middle constrictor

• Origin: Hyoid bone.

• Fibers fan and inserted to Pharyngeal raphe.

3. Inferior constrictor

• Two parts:

• Thyropharyngeus:

• Origin: Thyroid cartilage.

• Fibers fan but lower border is straight and inserted to Pharyngeal raphe.

• Cricoopharyngeus:

• Origin: Cricoid cartilage.

• Fibers encircle and form sphincter.

4. Wall of Pharynx is weak just above cricopharyngeaus as in this part there is no overlapping of muscles. This weakness is known as Killian’s Dehiscences which is common site of Pharyngeal diverticulum in neuromuscular incordination of two parts of inferior constrictor.

• Actions of constrictor muscles (***viva): All constrictors are having propulsive action and propel food particles towards esophagus except Cricopharyungeus which is having sphincteric action. (It contract when other constrictor relax and it relax when other constrictor contract)

Three Longitudinal:

1. Stylopharyngeus from styloid process to posterior border of thyroid cartilage.

2. Palatopharyngeus from palate to posterior border of thyroid cartilage

3. Salpingopharyngeus from auditory tube cartlage to posterior border of thyroid cartilage


Action of longitudinal muscles is to elevated larynx during deglutition.

Motor nerve supply of Muscles of Pharynx (***viva): All the muscles of pharynx are supplied by pharyngeal plexus except stylopharyngeus muscle (by glossopharyngeal nerve).

Structures passing between Constrictor muscles: (***viva and short questions):

1. Above superior constrictor: Auditory tube and Palatine vessels

2. Between superior constrictor and middle constrictor: Stylopharyngeus muscle and glossopharyngeal nerve

3. Between middle constrictor and inferior constrictor: Internal laryngeal nerve and Superior laryngeal vessels.

4. Below inferior constrictor muscle: Recurrent laryngeal nerve and inferior laryngeal vessels.

No need to raw this Diagram for the short note


Blood supply of pharynx

• Arterial supply:

• Ascending pharyngeal – ECA.

• Ascending palatine & tonsillar – facial A.

• Dorsal lingual – Lingual A.

• Greater paltine, pharyngeal & pterygoid – from maxillary A.

• Veins: drains in facial & internal jugular.

• Lymphatics: Retropharyngeal & deep cervical nodes.

Sensory supply:

Pharyngeal plexus formed by vagus nerve, Glossopharyngeal nerve and sympathetic fibers.

Motor Nerve supply

All the muscles of pharynx are supplied by pharyngeal plexus except stylopharyngeus muscle (by glossopharyngeal nerve).

Applied Anatomy: (***viva)

• Palatopharyngeal sphincter – Its contraction produces a ridge called passavant’s ridge on the pharyngeal wall at the junction of nasopharynx with oropharynx. It is well developed in patients with cleft palate deformity.

• Enlarged pharyngeal tonsils due to chronic infection – Adenoids.

• Killian’s dehiscence common site of pharyngeal diverticulum.

• Gag reflex: Reflex contraction of muscles of pharynx when the wall of pharynx is touched. This reflex is absent in lesions of Glossopharygeal nerve damage or damage to its nucleus in Medulla oblongata.

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Pharynx dr.gosai

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