بسم الله الرحمن الرحيم
The Nose
Presented by
Dr. Sa`ad Y. Sulaiman
Ninevah Collage of Medicine
University of MosulCourse Assessments
Mid-year Exam.Clinical Exam. + Quizzes
Final Exam
20
20
60
Embryology:
The nose develops from a number of mesenchymal processes around the primitive mouth .The nasal cavity is first recognizable in the 4th week of intrauterine life as an ectodermal thickening called olfactory or nasal placode. Any interruption to pregnancy at this time (4th week) will lead to congenital anomaly of the nose.Anatomy:
The external nose Bony part Cartilaginous part # Give shape to the lower part of the nose and nasal tip . # Attached to the cartilages are the muscles for dilating the nares.The vestibule is the dilated passageway leading from the external nares into nasal fossa and is lined by skin bearing coarse hear (vibrissae), sebaceous glands and sweat glands.
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The nasal cavity is divided by the nasal septum into two parts which have similar anatomical structure but may be asymmetrical.
The septum Anteriorly: Cartilage (Quadrilateral Cartilage ) Posteriorly: Bone (1) perpendicular plate of ethmoid (2) Vomer
The lateral wall of the nasal cavity
On the lateral wall .. Turbinates (chonchae)..three.. .. Meatus ( meati) .. three.. The inferior turbinate forms a bone by itself, attached to the lateral wall of the nose .The middle and superior turbinates are part of the ethmoid bone . The turbinates are covered with mucous membrane (columnar ciliated epithelium). Underling the mucous membrane there is erectile tissue.Sup. meathus posterior ethmoidal sinuses.Middle meatus frontal, maxillary & anterior ethmoidal sinuses.Inferior meatus nasolacrinnal duct.`
Most of paranasal sinuses opened into the middle meatus (maxillary, anterior ethmoid and frontal sinuses). Therefore evaluation of the middle meatus and its surrounding is considered the most important step during nasoendoscopy and this entire area is called osteo-meatal complex and pathology in this region is indicative of underlying sinus disease .
Boundaries of nasal cavity (continue)
The floor (the hard palate) The roof The nasal bones. Cribriform plate. The body of sphenoid. Posteriorly. Posterior choanae. The nasopharynx. Eustachian tube. The middle ear.Nerve supply
Sensory nerve Trigeminal nerve maxillary division. ophthalmic division. Secretory nerve Vidian nerve (nerve of pterygoid canal) = greater petrosal nerve, a branch of the facial nerve (parasympathetic) + deep petrosal nerve (sympathetic) derived from the sympathetic plexus on the internal carotid artery . The olfactory nerves.
Arterial supply:
Int.&Ext. carotid arteries An aggregation of poorly supported vessels on the anterior part of the septum just behind the skin margin is known as Little`s area (Kiesselbach`s plexus). This area is a common site of epistaxis and is formed by anastomoses of (1) anterior ethmoid artery. (2) superior labial artery. (3) sphenopalatine artery. (4) greater palatine artery .Physiology of the nose:
The chief functions of the nose are: 1) Olfaction. 2) Filtration. 3) Humidification. There are other functions, such as vocal resonance, self-cleansing and the provision of moisture for the protection of mucous membrane.Paranasal sinuses:
These are air spaces which develop in the bones of the skull and communicate with the nasal cavity. Divided into: 1. Anterior group – frontal, anterior ethmoid and maxillary middle meatus. 2. Posterior group Posterior ethmoid cells superior meatus Sphenoid sinus sphenoethmoidal recess. ྡ?`鐄鐅鐆The maxillary sinus: (The antrum)
Is the largest sinus ( 15 ml in adult) It is pyramidal in shape Apex . malar process of maxilla Base (the medial wall). lateral wall of the nasal cavity Roof . floor of the orbit Floor . tooth roots Posterior wall. pterygopalatine fossa.The floor of the sinus is related to the tooth roots, particularly those of the second premolar and first molar, which may project into the sinus and may be covered only by a thin plate of bone, therefore maxillary sinusitis may be due to apical tooth abscess. Extraction of such poorly covered tooth can result in oroantral fistula.
The frontal sinus:
The sinus is not present at birth but appear at the age of 5 years. Rarely symmetrical and they are separated by a thin bone. The roof of the orbit forms the floor of the frontal sinus.The ethmoid sinus (the ethmoid air cells):
Variable in number and size (6-10 air-containing cells of a total volume of 2-3 ml.) Relatively large at birth. Laterally (lamina papyraceae) Medially is the nasal cavity. Superiorly: anterior cranial fossaThe sphenoid sinus:
This sinus occupies the body of the sphenoid bone and drains into the sphenoethmoidal recess. The pituitary gland is located on its roof The lateral wall is in contact with the cavernous sinus.Relations of sphenoid sinus
Laterally ; The internal carotid artery Optic nerve. Cavernous sinus 3rd cranial nerve. 4th cranial nerve. 5th cranial nerve( ophthalmic and maxillary divisions). 6th cranial nerves. Superiorly ; the frontal lobes and the olfactory apparatus . Posteriorly lie the pituitary fossa. Inferiorly; Vidian nerveFunction of paranasal sinuses:
The physiological role of paranasal sinuses is uncertain. They are a continuation of the respiratory cavity and covered by respiratory mucosa. They may have the following functions; (1) Decrease the weight of the skull. (2) Warming and moistening of the air. (3) Add resonance to the laryngeal voice. (4) Temperature buffer.Symptoms of Nasal Diseases
Nasal obstruction Nasal Discharge Sneezing Pain Epistaxis Disturbance of smellInflammatory conditions of the nose
(1) Inflammations confined mainly to the external nose . (2) Inflammations mainly confined to the nasal cavity .Inflammations confined mainly to the external nose ;
FURUNCULOSIS :(boil) Acute infection of a hair follicle with staphylococcus aureus. The nasal vestibule is a vulnerable site …It starts as a hard tender red nodule which enlarges and becomes more painful and fluctuant . The majority discharge into the nasal vestibule and resolves.
A serious (although rare ) complication is the spread of the infection through the valveless superior ophthalmic veins to the cavernous sinus leading to cavernous sinus thrombosis which characterized by ; (1) Severe illness with fever (2) Prostration (3) Convulsion. (4) Local changes include oedema with cyanosis of the eyelids and base of the nose and chemosis due to obstruction of the ophthalmic vein. Ophthalmoplegia and papillary changes (dilated or small immobile ) are common . Retinal haemorrhage and papilloedema are late events.