ANATOMY OF PHARYNX : ANATOMY OF PHARYNX 1 INTRODUCTION : INTRODUCTION Pharynx is a wide muscular tube which lies at the crossroads of respiratory and digestive tract 2 EMBRYOLOGY OF PHARYNX : EMBRYOLOGY OF PHARYNX 3 Saggital midline section of 23-25 day embryo showing position of foregut,2 and stomatodaeum,3 . : Saggital midline section of 23-25 day embryo showing position of foregut,2 and stomatodaeum,3 . Endodermal lining of foregut differentiates into :
-Part of nasal cavity
-Endodermal lined part of buccal cavity
-Pharynx, with glands and other structures like thymus
pharyngotympanic tube, tonsils, middle ear etc
-Larynx, tracheobronchial tree
-Oesophagus, stomach, duodenum…… 4 Branchial System : Branchial System Branchial System- 6 pairs of pharyngeal arches separated by endodermally lined pouches and ectodermally lined clefts
Each arch consists of a nerve, artery, and cartilaginous structures
The remaining neck musculature gains contributions from cervical somites 5 Slide 6: Maxillary and mandibular (Meckel’s) process regress to form the malleus and incus
Ossification of maxillary process forms maxilla ,premaxilla ,zygomatic bone and part of temporal bone
Ossification around Meckel’s cartilage gives rise to
Mandible ,sphenomandibular ligament,and anterior malleolar ligaments
.temporalis, .masseter, .pterygoids, .mylohyoid (mus. Of mastication)
.ant belly of digastric,.tensor tympani,.tensor veli palatini
Nerve: - mandibular br of CN. V
Pouch: dorsal part of pouch forms
.Eust tube, middle ear
.EAC/TM 6 First Branchial Arch Slide 7: Reichert’s cartilage contributes to:
superstructure of the stapes
upper body and lesser cornu of the hyoid
styloid process and stylohyoid ligament.
muscles of facial expression
posterior belly of digastric
Nerve- 7th cranial nerve
Artery- stapedial artery
Pouch:dorsal part forms Eust. Tube, ventral part forms palatine tonsil 7 Second Branchial Arch Third Branchial Arch : Third Branchial Arch Lower body of the hyoid and greater cornu
.superior & middle pharyngeal constrictors.
Nerve- 9th cranial nerve(Glossopharyngeal N.)
.proximal portions of the internal and external carotid
. Inferior parathyroids(dorsal part)
. Thymus gland and thymic duct(ventral part) 8 Fourth Branchial Arch : Fourth Branchial Arch 9 Fourth and Sixth Branchial arches fuse to form the laryngeal cartilages.
Muscles- cricothyroid, inferior pharyngeal constrictors
Nerve- Superior Laryngeal Nerve
Artery- Right Subclavian, Aortic arch
- superior parathyoid glands
-parafollicular thyroid cells(along with fifth pharyngeal pouch) Sixth Branchial Arch : Sixth Branchial Arch 10 Muscles- remaining/intrinsic laryngeal musculature
Nerve- Recurrent Laryngeal Nerve
Artery- Pulmonary Artery and ductus arteriosus PHARYNX : PHARYNX Size- 12-13 cm (approx. 5 inches)
The pharynx is divided into three parts:
c] Pharyngiobasilar fascia
d] Muscular coat
e] Buccopharyngeal fascia 11 NASOPHARYNX : NASOPHARYNX - Extends from the bony base of the skull to the soft palate
Anterior wall - choanae, through which the nasopharynx communicates with the nasal cavity
Roof - the lower wall of the sphenoid sinus,base of skull
Posterior wall – arch ofAtlas vertebra and prevertebral M.
Floor – ant. by soft palate , def. post.
Lateral wall - orifices of the Eustachian tubes, bordering on the pharyngeal recess (fossa of Rosenmüller) 12 PHARYNGEAL RECESS(FOSSA OF ROSENMULLER) : PHARYNGEAL RECESS(FOSSA OF ROSENMULLER) Behind the ostium of the auditory tube is a deep recess, the pharyngeal recess
At the base of this recess is the retropharyngeal lymph node (the Node of Rouvier)
Clinical significance: Nasopharyngeal cancer 13 Slide 14: Epithelial lining of Nasopharynx : ciliated columnar epithelium
Nerve supply : pharyngeal br. Of pterygopalantine ganglion
Function of Nasopharynx :
1. Acts as conduit for air
2. Ventilates middle ear
3. Elevation of soft palate against post. Pharyngeal wall and Passavant’s ridge[mucosal ridge raised by fibers of Palatopharyngeus] helps cut of nasopharynx from oropharynx. 14 OROPHARYNX : OROPHARYNX The oropharynx extends from the soft palate to the edge of the epiglottis
Posterior wall- 2nd and 3rd cervical vertebrae
Anteror wall- Oral cavity , through the fauces
Lateral wall- the tonsils surrounded by the pharyngeal arches as well as the two fossa between the root of the tongue and the epiglottis 15 Slide 16: Function of Oropharynx:
1. Common pathway for food and air
2. Speech resonance[articulation of vowels]
3. Deglutition[ 2nd pharyngeal phase of swallo
4. Reflex action[ coughing, sneezing,vomiting]
5. Drainage of mucus from nasopharynx
Epithelium : lined by stratified squamous nonkeratinised epi.
Nerve supply: Pharyngeal plexus 16 LARYNGOPHARYNX(HYPOPHARYNX) : LARYNGOPHARYNX(HYPOPHARYNX) Lowest part of the pharynx, extending from the upper edge of the epiglottis to the lower edge of the lamina of the cricoid cartilage.
Anteror wall- laryngeal inlet and post. Surface of cricoid and arytenoid cartilage.
Posterior wall- 3rd to 6th cervical vertebrae.
Lateral wall- Piriform fossa on both sides 17 Slide 18: Laryngopharynx includes three major sites:
.post-cricoid area (common site of carcinoma in females suffering from Plummer-Vinson syndrome)
.posterior pharyngeal wall 18 Slide 19: Function of Hypopharynx: hypopharynx serves as a passageway for food and air
Epithelium: stratified squamous epithelium
Nerve supply: pharyngeal plexus 19 Relations Of Pharynx : Relations Of Pharynx 20 Slide 21: The Lymphoid Tissue of Pharynx 21 Slide 22: THE PALATINE TONSILS A pair of lymphoid tissue lying on either side of oropharynx
Medial surface covered by mucous membrane showing 8-30 crypts
The largest being CRYPTA MAGNA
EPITHELIUM- Non keratinized stratified squamous 22 Slide 23: Bed of Palatine Tonsil a] The Pharyngobasilar fascia
b] Superior constrictor and palatopharyngeus muscle
c] Buccopharyngeal fascia
d] Styloslossus in lower part
e] Glossopharyngeal nerve 23 Slide 24: Blood supply of Tonsil ARTERIAL DRAINAGE:
. Tonsilar br. Of Facial A.[main source]
. Ascending palatine br. Of Facial A.
. Dorsal lingual br. Of Lingual A.
. Ascending pharyngeal br. Of ECA.
. Decending palatine br. Maxillary A.
VENOUS DRAINAGE: To paratonsillar v. to facial v. to common facial v. to IJV
Drain to Juglodigastric node.
Glossopharyngeal N. and Lesser palatine N.
Paratonsilar V. can be injured during Tonsillectomy. 24 WALDEYER’S RING : WALDEYER’S RING 25 Muscular coat of Pharynx : Muscular coat of Pharynx 26 Slide 27: Outer Circular Layer:
- Superior constrictor
- Middle constrictor
- Inferior constrictor[ Thyropharyngeal and Cricopharngeal part]
. Inner Longitudinal layer:
-palatopharyngeus 27 Applied Anatomy : Applied Anatomy Sinus of Morgagni
Space at the upper back part of each side of the pharynx where the walls are deficient in muscular fibers between the upper border of the superior constrictor and the base of the skull and closed only by the aponeurosis of the pharynx
Prominence on the posterior wall of the nasopharynx formed by contraction of the superior constrictor of the pharynx during swallowing
. at the posterior wall of the pharynx between the diagonal and horizontal inferor constrictor muscle fascicles, a triangular hiatus occurs called killian’s triangle, the place where Zenker’s diverticulum, a diverticulum of the mucosa of the lower pharynx typically occurs 28 Killian’s Dehiscence : Killian’s Dehiscence 29 Structures Entering Pharynx : Structures Entering Pharynx Above superior constrictor and base of skull
Ascending palatine A.
Between middle and superior constrictor
Between middle and inf constrictor
Internal laryngeal N
Sup laryngeal vessels
Below inf constrictor
Recurrent laryngeal N
Inf laryngeal A 30 Slide 31: NERVE SUPPLY OF PHARYNX MOTOR SENSORY Mainly arise from Cranial Division of Acc. Nerve, except stylopharyngeus m. supplied by Glossopharyngeus n. Via Glossopharyngeal Nerve. Autonomic Via Vagus N. 31 …To Conclude : …To Conclude Pharynx: Muscular tube
Specific points to remember
Fossa of rosenmuller
Sinus of morgagni
Killian’s Dehiscence Slide 33: 33