Anatomy of The Nose

Anatomy of The Nose

1. Anatomy of the nose By Dr Nassar Ayoub Zeeshan Ali M-1036

2. External Nose Internal Nose Musculature of Nose Vascular Supply. Nerve supply. Lymphatic Drainage Paranasal Sinuses

3. External Nose It is pyramidal in shape with its root up and the base directed downwards Nares – external opening of nose Choanae - open into the nasopharynx Bony Part : Posterior 1/3 rd is bony Nasal Bone Frontal Process of Maxilla Nasal Part of Frontal Bone Cartilaginous Part : Anterior 2/3 rd is cartilaginous Upper Lateral Cartilage Lower Lateral Cartilage/Alar Cartilage Septal Cartilage

4. (a) Upper lateral cartilages. They extend from the undersurface of the nasal bones above, to the alar cartilages below. (b) Lower lateral cartilages (alar cartilages). (c) Lesser alar (or sesamoid) cartilages. Two or more in number. They lie above and lateral to alar cartilages. (d) Septal cartilage . Its anterosuperior border runs from under the nasal bones to the nasal tip.

5. Internal Nose Nasal Cavity Extends from Nostrils externally to Choanae internally Nasal Septum divides Nasal Cavity into two compartments Nasal Septum Septal Cartilage Perpendicular Plate of Ethmoid Bone Vomer

6. Boundaries of Nasal Cavity Floor Palatine Process of Maxilla Horizontal Process of Palatine Bone

7. Roof Nasal Bone Frontal Bone Cribriform Plate of Ethmoid Bone Sloping body of Sphenoid Bone

8. Medial Wall Septal Cartilage Perpendicular Process of Ethmoidal Bone Vomer

9. Lateral Wall 3 Projections Superior, Middle and Inferior Conchae/Vestibule Space below each Concha is called Meatus Spenoethmoidal Recess – Above superior concha > Sphenoid Air Sinus Superior Meatus – Below superior concha > Posterior ethmoid sinuses Middle Meatus – Below middle concha Bulla Ethmoidalis > formed by Middle ethmoidal air sinuses Hiatus semilunaris – Lies below bulla > Maxillary Sinus Infundibulum – continuous with frontal sinus Inferior Meatus – Below inferior concha > Nasolacrimal Duct

10. Regions of Nasal Cavities Each nasal cavity consists of three general regions Nasal vestibule – small dilated space just internal to the naris that is lined by skin and contains hair follicles Respiratory region Largest part of the nasal cavity Rich neurovascular supply Lined by respiratory epithelium composed mainly of ciliated and mucous cells Olfactory region small, is at the apex of each nasal cavity Lined by olfactory epithelium which contains the olfactory receptors

11. Vestibular Region From anterior nostrils to inferior concha Respiratory Region From inferior concha to the posterior nostril and up to the superior concha Olfactory Region Above the superior concha up to the roof of nose and adjoining part of septum

12. Musculature of Nose Elevator muscle group — which includes the procerus muscle and the levator labii superioris alaeque nasi muscle. Depressor muscle group — which includes the alar nasalis muscle and the depressor septi nasi muscle. Compressor muscle group — which includes the transverse nasalis muscle. Dilator muscle group — which includes the dilator naris muscle that expands the nostrils

13. Innervation and Vasculature of Muscles Facial Nerve Maxillary and Ophthalmic Arteries Anterior facial and Ophthalmic Vein Ophthalmic Vein drains into cavernous sinus – Septic Cavernous Thrombosis Lymphatics – Along Anterior facial vein to Submandibular nodes or Preauricular nodes

14. Nasal Skin The skin over the nasal bones and upper lateral cartilages is thin and freely mobile while that covering the alar cartilages is thick and adherent, and contains many sebaceous glands.

15. Blood Supply Branches from the internal carotid artery , the branch of the anterior ethmoid artery, the branch of the posterior ethmoid artery, which derive from the ophthalmic artery Branches from the external carotid artery, the sphenopalatine artery, the greater palatine artery, the superior labial artery, and the angular artery. The external nose is supplied with blood by the facial artery, which becomes the angular artery that courses over the superomedial aspect of the nose. The sellar region (sella turcica, “Turkish chair”) and the dorsal region of the nose are supplied with blood by branches of the internal maxillary artery (infraorbital) and the ophthalmic arteries that derive from the internal common carotid artery system. Internally , the lateral nasal wall is supplied with blood by the sphenopalatine artery (from behind and below) and by the anterior ethmoid artery and the posterior ethmoid artery (from above and behind). The nasal septum also is supplied with blood by the sphenopalatine artery, and by the anterior and posterior ethmoid arteries, with the additional circulatory contributions of the superior labial artery and of the greater palatine artery. These three (3) vascular supplies to the internal nose converge in the Kiesselbach plexus (the Little area), which is a region in the anteroinferior-third of the nasal septum, (in front and below) Veins follow Arterial Pattern

16. Nerve Supply of Nose • Three cranial nerves – Olfaction - the olfactory nerve [I] – General sensation - the trigeminal nerve [V], • Anterior - ophthalmic nerve [V 1 ] • Posterior - maxillary nerve [V 2 ] – Glands - parasympathetic fibers in the facial nerve [VII] (greater petrosal nerve), • Sympathetic fibers

17. Nerve Supply (a ) Olfactory nerves They carry sense of smell and supply olfactory region of nose. They are the central filaments of the olfactory cells and are arranged into 12-20 nerves which pass through the cribriform plate and end in the olfactory bulb

18. (b) Nerves of common sensation They are: (i) Anterior ethmoidal nerve. (ii) Branches of sphenopalatine ganglion. (iii) Branches of infra-orbital nerve. They supply vestibule of nose both on its medial and lateral side. Most of the posterior two-thirds of nasal cavity (both septum and lateral wall) is supplied by branches of sphenopalatine ganglion which can be blocked by placing a pledget of cotton soaked in anaesthetic solution near the sphenopalatine foramen situated at the posterior extremity of middle turbinate. Anterior ethmoidal nerve which supplies anterior and superior part of the nasal cavity (lateral wall and septum) can be blocked by placing the pledget high up on the inside of nasal bones where the nerve enters.

19. (c) Autonomic nerves Parasympathetic nerve fibres supply the nasal glands and control nasal secretion. They come from greater superficial petrosal nerve , travel in the nerve of pterygoid canal (vidian nerve) and reach the sphenopalatine ganglion where they relay before reaching the nasal cavity. They also supply the blood vessels of nose and cause vasodilation. Sympathetic nerve fibres come from upper two thoracic segments of spinal cord , pass through superior cervical ganglion, travel in deep petrosal nerve and join the parasympathetic fibres of greater petrosal nerve to form the nerve of pterygoid canal (vidian nerve). They reach the nasal cavity without relay in the sphenopalatine ganglion. Their stimulation causes vasoconstriction.

20. Lymphatic Drainage Lymphatics from the external nose and anterior part of nasal cavity drain into submandibular lymph nodes The rest of nasal cavity drain into upper jugular nodes either directly or through the retropharyngeal nodes. Lymphatics of the upper part of nasal cavity communicate with subarachnoid space along the olfactory nerves.

21. Paranasal sinuses four paired paranasal sinuses The paranasal air sinuses are lined with respiratory epithelium 1- Maxillary sinuses , the largest of the paranasal sinuses, are under the eyes, in the maxillary bones (open in the back of the semilunar hiatus of the nose). 2- F rontal sinuses , superior to the eyes, in the frontal bone , which forms the hard part of the forehead . 3- E thmoidal sinuses , which are formed from several discrete air cells within the ethmoid bone between the nose and the eyes. 4- S phenoidal sinuses , in the sphenoid bone .

22. Functions of paranasal sinuses The presence of these sinuses lightens the skull They add resonance to speech