GROSS ANATOMY OF THE NASAL CAVITY & THE PHARYNX

External Nose The External Nose includes: The root (area between the eyebrows) The bridge The dorsum nasi terminating at the apex Just inferior to the apex is the philtrum. The external openings of the nose: nostrils or nares are bounded laterally by the flared alae. It is covered with the skin and contains two nasal bones, several cartilages and muscles of facial expression The External Nose contains the most anterior part of the Nasal Cavity and Nasal Vestibule.

External Nose Dorsum Root Bridge Philtrum Apex Ala Ala Septum Nasal vestibule Ala Septum Philtrum

Nasal Cartilages Nasal bone Nasal bone Nasal bone

External Nose, Nasal Bones & Cartilages

Nose, Nasal Bones & Cartilages

Nose & Nasal Cartilages Muscles of Facial Expression Vibrissal Hairs

Main Functions of Nasal Cavity It provides an airway for respiration It filters and cleans inspired air It moistens and warms (cools) the entering air It serves as a resonating chamber for speech It houses the olfactory (smell) receptors

Functions of Nasal Cavity It is also filtered & cleaned there.

Walls of Nasal Cavity The Nasal Cavity is divided by its septum into the right and left halves and each half has 4 walls: Superior (Roof) Inferior (Floor) Lateral Medial (Nasal Septum)

Bones of Nasal Cavity Walls: Nasal Roof Nasal Floor Lateral Wall Frontal Ethmoid (cribriform plate) Sphenoid (anterior & inferior surfaces of body) Nasal Floor Intermaxillary (incisive) bone Palatine process of Maxilla Horizontal plate of Palatine bone Lateral Wall Maxilla Lacrimal Ethmoid (labyrinth) Inferior concha Palatine (vertical lamina) Sphenoid (medial lamina of pterygoid process) Medial Wall (Nasal Septum) Vomer Ethmoid (perpendicular plate)

Bones Of Facial Skeleton

Individual Cranial Bones Frontal Parietal Occipital Ethmoid Temporal Sphenoid Nasal Lacrimal Maxilla Zygomatic Inferior Nasal Concha Mandible Vomer

Bones of Nasal Cavity Nasal Cavity

Ethmoid Bone – Coronal Cross Section Cribriform Plate Right Labyrinth Left Labyrinth Right Middle Concha Left Middle Concha Perpendicular Plate

Areas of Lateral Nasal Wall Vestibule of nose Atrium of middle meatus It is above and posterior to vestibule and anterior to middle meatus Agger nasi – Additional concha close to nasal bone Inferior concha Inferior meatus – below concha Middle concha Middle meatus – below concha Superior concha Superior meatus – below concha Spheno-ethmoidal recess Above superior concha

Nasal Vestibule Is a slight dilation inside the nostril, limited by a ridge (limen nasi) over which skin is continuous with the mucosa It is surrounded by cartilage It is lined with the skin containing coarse hairs sebaceous glands and sweat glands

Lateral wall & Openings of Paranasal Sinuses Superior Meatus Sphenoethmoidal Recess S Atrium of Middle Meatus Middle Meatus Nasopharynx Inferior Meatus Nasal Vestibule Oral Cavity

Bones of Lateral Nasal Wall

Bones of Nasal Roof & Floor Frontal Nasal Roof Nasal Ethmoid Sphenoid Inferior Nasal Concha Maxilla Palatine Nasal Floor

Bones of Nasal Floor

Components of Inferior Nasal Wall in Adult View from Oral Cavity Interpalatine suture Secondary Palate or Incisive bone (primary palate)

Nasal Septum Components: Vomer Perpendicular plate of ethmoid bone Nasal crest of maxilla Nasal crest of palatine bone Nasal crest of sphenoid bone Vertical crest of nasal bone Nasal spine of frontal bone Nasal septal cartilage

Components of Nasal Septum Vertical Crest of Nasal Bone Nasal Spine of Frontal Bone Nasal Crest of Sphenoid Bone Perpendicular plate of Ethmoid bone Septal Cartilage Vomer Nasal Crest of Palatine Bone Nasal Crest of Maxilla

Paranasal Sinuses These are air-filled cavities, which develop in facial and cranial bones. The paranasal sinuses are paired and are named for the bone in which they are located: Frontal bone – 2 Frontal sinuses Sphenoid bone – 2 Sphenoidal sinuses Ethmoid bone – 2 Labyrinths with Ethmoidal sinuses (groups of air cells) 2 Maxillary bones – 2 Maxillary sinuses Spaces of sinuses communicate with the nasal cavity via their openings. The sinuses are lined with mucous membrane, which has mucous glands, and it is continuous with that of the nasal cavity Sinuses drain into the nasal cavity due to coordinated ciliary activity. This movement of mucus which is known as muco-ciliary clearance is not random but rather programmed so that mucus moves along in a pattern. This secretion keeps the nose and sinuses moist. The sinus does not “drain” by gravity-it is an active process

Location of Paranasal Sinuses Frontal- Paired, in the frontal bone. One sinus per side located in the forehead. They are separated from each other by a bony septum which deviates from the median plane. Usually asymmetrical, and roughly in shape extending upward above the medial end of the eyebrow and backward into the medial part of the roof of the orbit. Ethmoidal- Contained within the labyrinths of the ethmoid bone. Approximately 6-12 small sinuses per side, located in the lateral wall of nasal cavity between the orbit and nasal cavity. Sphenoidal- Paired, in the body of sphenoid bone. One sinus per its side, located behind the ethmoid sinuses, beside the midline of the body. Pituitary fossa of Sella Turcica projects into this space. Each sinus opens into the spheno-ethmoidal recess above the superior concha. Maxillary (Antrum) - Paired, in maxilla. One sinus located in each side of the face. It is pyramidal in shape with the base forming the lateral wall of the nose and the apex in the zygomatic process of the maxilla. Inferiorly related to tooth-bearing area of maxilla. The roof is formed by the floor of the orbit while the floor is formed by the alveolar process of maxilla. The roots of the first, second premolars, the molar and sometimes the root of the canine project up into the sinus.

Location of Paranasal Sinuses

Location of Paranasal Sinuses

Location of Paranasal Sinuses

Frontal Sinus (Sagittal Section)

Right Frontal Sinus – Diploe is removed Orbit Nose

Extension of Frontal Sinuses in Upper Orbital Walls Anterior Cranial Fossa Frontal Sinus Frontal Sinus

Paranasal Air Sinuses Ethmoid Air Sinuses Sagittal Cross Section Sphenoid Air Sinus Maxillary Air Sinus Sagittal Cross Section

Sphenoidal Sinus – Sagittal Cross Section

Sphenoidal Sinus – Coronal Cross Section (Posterior View)

Ethmoidal Sinuses (Air Cells) Coronal Cross Section

Roof of Ethmoidal Sinuses in Labyrinths Horizontal Cross Section

Left Maxilla – Medial View Maxillary Sinus

Small Right Maxillary Sinus – Coronal Section Right Orbit Palate

Left Maxillary Sinus – Coronal Section From Behind Infraorbital Canal Inferior Orbital Wall Roof Base Maxillary Sinus Floor Apex Hard Palate Molar Tooth

External Nose & Left Maxillary Sinus

Knife Entering Left Maxillary Sinus

Paranasal Sinuses: Site of Drainage to Nasal Cavity Maxillary It drains into the middle nasal meatus through the hiatus semilunaris Frontal It drains into the middle meatus via frontonasal duct, infundibulum and hiatus semilunaris Sphenoidal It drains into the sphenoethmoidal recess Ethmoidal Anterior Group of air cells They drain into the Infundibulum and into the middle nasal meatus Middle Group of air cells They drain into the Middle nasal meatus on or above bulla ethmoidalis Posterior Group of air cells They drain into the Superior nasal meatus

CLINICAL SIGNIFICANCE Sinuses frequently become infected due to obstruction of normal drainage, and negative pressure in a sinus can cause headaches. Blockage of the sinus ostium results in reduction of ventilation and drainage. If the ostium is smaller than 2.5 mm, sinus is predisposed to development of disease. Obstruction interrupts the self-cleaning mechanism of the affected sinus therefore secretion stagnates and changes composition. Neoplasms which arise in the sinuses can be occult for quite a long time, so that they are usually very advanced at the time of diagnosis.

Water’s View of Paranasal sinuses

Drainage of Nasolacrimal Duct into Inferior Nasal Meatus

Nerves of Nasal Septum Olfactory nerves Medial nasal branches of anterior ethmoidal nerve (anterior & upper part of septum) Nasal Branches from pterygopalatine ganglion Nasopalatine nerve Medial posterior superior nasal branches Nasal branches of Infraorbital nerve (movable part of nasal septum) Nasal branch of Anterior superior alveolar nerve Near anterior nasal spine Nasal branches from nerve of pterygoid canal

NERVES OF NASAL SEPTUM

Nerves of Nasal Walls

Nerves of Lateral Nasal Wall Olfactory nerves External nasal branch of anterior ethmoidal nerve Lateral nasal branches of anterior ethmoidal nerve Branches from pterygopalatine ganglion Lateral posterior superior nasal branches Lateral posterior inferior nasal branches of greater palatine nerve Infratrochlear nerve (side of the nose) Infraorbital nerve (maxillary sinus, nasal vestibule) Nasal branch of Anterior superior alveolar nerve (floor and lateral wall up to semilunar hiatus) Facial nerve (nasal muscles)

Nerves of Lateral Nasal Wall

Autonomic Nerves of Nasal Cavity

Arteries of Nasal Septum Septal branches of Sphenopalatine artery Septal branches of anterior ethmoidal artery Septal branches of posterior ethmoidal artery Septal branch of superior labial artery Terminal nasal part of greater palatine artery

Nasal Arteries

Arteries of Lateral Nasal Wall Lateral branches of Sphenopalatine artery Terminal nasal branch of Greater palatine artery Lateral branches of anterior Ethmoidal artery Lateral branches of posterior Ethmoidal artery Nasal branches of Infraorbital artery Superior (anterior & posterior) Alveolar arteries Lateral branch of superior Labial artery Lateral nasal branch of Facial artery

Arteries of Lateral Nasal Wall

Arteries of External Nose

Venous Drainage of Nasal Cavity Drainage is via veins accompanying arteries. Veins form rich submucosal cavernous plexus, which is dense in lower part of septum and in middle and inferior conchae – swell bodies Arteriovenous anastomoses occur there. A few veins pass through cribriform plate to drain into intracranial veins of anterior cranial fossa. When foramen caecum is patent it transmits a vein from nasal cavity to superior sagital venous sinus.

Nasal Veins

Swell Bodies Every 20-30 minutes, swell bodies on one side of nasal cavity become engorged with blood, resulting in swelling of conchal mucosa and decrease in the flow of air, which is directed to other side of nasal cavity. These periodic intervals of occlusion allow respiratory epithelium to recover from over chilling, overheating or over drying (desiccation).

Venous Drainage from External Nose

GROSS ANATOMY OF THE PHARYNX

The Pharynx Is located behind nasal cavities, mouth & larynx Is a musculocutaneous tube, 12 – 14 cm long Extends from cranial base to level of C6 & lower border of cricoid cartilage of the larynx Has its width greatest superiorly (3.5 cm) and it is reduced up to 1.5 cm at junction with esophagus Is attached from above downwards on each side to: Base of skull has strong liner attachment of pharyngobasilar fascia to basilar occipital & petrous temporal bones: From pharyngeal tubercle - laterally, to external carotid foramen and then anteromedially, to base of medial pterygoid plate Posterior Border of Medial Pterygoid Plate Pterygomandibular Raphe Posterior end of Mylohyoid line of Mandible Side of Tongue Hyoid bone Thyroid & Cricoid cartilages

The Pharynx Is subdivided into three parts: Nasopharynx: behind choanae From base of the skull in front of C1 & C2 It communicates with Tympanic Cavity via Auditory tube Oropharynx: behind the mouth In front of C3 Laryngopharynx: behind the larynx In front of C4, C5, C6 Pharyngeal wall has the following layers: Mucous membrane Pharyngobasilar fascia Muscular coat Buccopharyngeal fascia

The Pharynx Nasopharynx Oropharynx Pharynx C3 Laryngopharynx

Skull – Attachment of Pharyngobasilar Fascia Line of Attachment Pharyngeal Tubercle

Skull – Attachment of Pharyngobasilar Fascia

Anterior Pharyngeal Wall from Behind

Pharyngeal Musculature It includes three Constrictor and three Elevator muscles. Constrictor muscles: Superior Pharyngeal Constrictor Middle Pharyngeal Constrictor Inferior Pharyngeal Constrictor Elevator muscles: Stylopharyngeus  Glossopharyngeal nerve Palatopharyngeus Salpingopharyngeus Motor innervation is from cranial part of Accessory nerve through Vagus: its branches forming Pharyngeal plexus (Exception: Stylopharyngeus) Sensory innervation: Pharyngeal plexus, which is formed by pharyngeal branches of Vagus, Glossopharyngeal and rami of Sympathetic trunk. Nasopharynx is supplied by branches of the Maxillary nerve.

Attachments of Pharyngeal Constrictors Middle Superior Inferior

Pharyngeal Muscles from Behind

Pharyngeal & Palatal Muscles from Behind

Pharyngeal Muscles from the Side

View of Pharynx from Behind

Naso & Oropharynx C2 Nasopharynx Oropharynx Pharyngeal Tonsil S.S. Middle Concha Inferior Concha Torus tubarius Opening of Auditory Tube Nasopharynx Palatopharyngeal fold Tubal Tonsil Palatoglossal fold C2 Tongue Palatine Tonsil Oropharynx Lingual Tonsil Epiglottis

Right Auditory Tube (Cartilaginous Part)

Pharyngeal Blood Supply Branches of Ascending Pharyngeal Artery Branches of Facial Artery Ascending palatine Tonsillar rami Branches of Maxillary Artery Greater Palatine Pharyngeal Artery of Pterygoid Canal Branches of Lingual Artery Dorsal Lingual Rami Venous Drainage: Pharyngeal plexus of veins to Pterygoid Plexus, Internal Jugular Vein & Facial vein

Structures of Naso & Oropharynx

Pterygoid Plexus of Vein Pterygoid Plexus of Veins

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