Bony skeloton of external nose: The upper part of the maxilla borders the nasal bone , and its frontal process projects upward to the frontal bone. frontal bone frontal process of maxilla nasal bone
The shape of the external nose is defined by the nasal bones, a pair of rectangular bones in the upper nasal dorsum, and by the paired lateral cartilages ( upper nasal cartilages ) and alar cartilages ( major alar cartilages ) in the central and lower portions of the nose. The lateral portions of the nasal alae also contain several small accessory cartilages, called the minor alar cartilages.
Nasal cavity: Nasal vestibule; Nasal fossa proper The nasal cavities begin anteriorly at the nasal vestibule, which is bordered posteriorly by the internal nasal valve (limen nasi) located between the posterior border of the alar cartilage and the anterior border of the lateral cartilage. This valve area is the narrowest portion of the upper respiratory tract and, as such, has a major bearing on the aerodynamics of nasal airflow.
Nasal cavity: Nasal vestibule; Nasal fossa proper The anterior bony opening of the nasal cavity, called the piriform aperture , is bounded laterally and inferiorly by the maxilla and superiorly by the nasal bone.
Lateral nasal wall: Superior turbinate;Middle turbinate; Inferior turbinate
Inner nasal wall: Nasal septum Septal cartilages Perpendicular plate of ethmoid bone Vomer Palatal process of maxilla
The maxillary sinus borders the nasal cavity laterally, and the orbital floor separates the upper part of the sinus from the orbit. Behind the maxillary sinus is the pterygopalatine fossa , which is traversed by the maxillary artery along with branches of the trigeminal nerve and autonomic nervous system . The floor of the maxillary sinus is closely related to the roots of the second premolar and first molar teeth . This creates a potential route for the spread of dentogenic infections, and a tooth extraction may create a communication between the oral cavity and maxillary sinus (oroantral fistula). Nasal sinus The maxillary sinus
The frontal sinus is located in the frontal bone, its floor forming the medial portion of the orbital roof . The sinus, which is highly variable in its extent, is bounded behind by the anterior cranial fossa . Inflammations of the frontal sinus can give rise to serious complications because of its close proximity to the orbit and cranial cavity (orbital cellulitis, epidural or subdural abscess, meningitis). Nasal sinus The frontal sinus
The ethmoid air cells are a labyrinthine system of small, pneumatized sinus cavities that are separated from one another by thin bony walls and extend posteriorly between the middle turbinate (medial border) and orbit to the sphenoid sinus. The orbital plate of the ethmoid bone , called also the lamina papyracea , forms the lateral bony wall that separates the ethmoid air cells from the orbit. Paranasal sinus inflammations can spread through this lamina to involve the orbit (orbital complications). The posterior ethmoid cells are closely related to the optic nerve . The ethmoid roof and cribriform plate ( 1.2) form the bony boundary that separates the ethmoid cells from the anterior cranial fossa. Nasal sinus The ethmoidal sinus
The sphenoid sinus is located at the approximate center of the skull above the nasopharynx. Its posterior wall is formed by the clivus . It relates laterally to the cavernous sinus, the internal carotid artery, and cranial nerves II–VI , and it is very closely related to the optic canal . The optic nerve and internal carotid artery may run directly beneath the mucosa of the lateral wall of the sphenoid sinus, without a bony covering. The sphenoid sinus is bordered superiorly by the sella turcica and pituitary and by the anterior and middle cranial fossae . Nasal sinus The sphenoid sinus
Nasal mucosa Olfactory mucosa Respiratory mucosa The epithelium of the respiratory mucosa is composed of ciliary cells, goblet cells, and basal cells and provides an initial, mechanical barrier against infection. The ciliary cells dominate the surface of the respiratory epithelium. Each ciliary cell has approximately 150–200 cilia, which are composed of microtubules and are interlinked by “dynein arms.”
Nasal mucosa Each ciliary cell has approximately 150–200 cilia, which are composed of microtubules and are interlinked by “dynein arms.” Ciliary cell 动力蛋白臂 Dynein arm 成对纤丝 Peripheral doublet 纤毛杆 Central singleton 中央鞘 Central Sheath 轮辐 radial spokes 连接桥 接键 nexin link
Nasal mucosa Respiratory mucosa This cytoskeleton of the ciliary cells and the activity of dynein, a specialized protein, enable the typical, synchronous beating of the cilia in the respiratory epithelium. This ciliary action propels a blanket of mucous secretions (from the goblet cells) and serous secretions (from the nasal glands) toward the nasopharynx, mechanically cleansing the inspired air in a mechanism called mucociliary transport .
Nasal mucosa Olfactory mucosa The olfactory mucosa covers the olfactory region , which occupies the anterior superior part of the nasal septum and adjacent areas of the lateral nasal wall. Usage subject to terms and conditions of license. including the side of the superior turbinate facing the septum and part of the middle turbinate.
The external nose derives most of its blood supply from the facial artery , which arises from the external carotid artery , and from the ophthalmic artery , which springs from the internal carotid artery . The internal nose receives blood from the territories of the external and internal carotid arteries: the terminal branches of the sphenopalatine artery , which arises from the maxillary artery , and the anterior and posterior ethmoid arteries , which arise from the ophthalmic artery . Vascular supply
A detailed knowledge of the vascular supply is particularly important in the management of intractable epistaxis (nosebleed), which requires vascular ligation or angiographic embolization as a last recourse. The venous drainage of the facial region is handled by the facial vein, retromandibular vein, and internal jugular vein . The regional lymphatic drainage of the face and external nose is handled mainly by the submandibular lymph nodes, while the nasal cavity is additionally drained by the retropharyngeal and deep cervical lymph nodes. Vascular supply
The facial skin receives its sensory innervation from terminal branches of the trigeminal nerve that enter the facial region through the supraorbital, infraorbital, and mental foramina. Only the skin over the mandibular angle and the lower portions of the auricle are supplied by the great auricular nerve . Nerve supply
The facial muscles are classified as mimetic or masticatory, each of these groups receiving different motor innervation. While the mimetic muscles of the face develop from the blastema of the second branchial arch (the hyoid arch) and accordingly are supplied by the facial nerve , the masticatory muscles trace their embryonic development to the first branchial arch (the mandibular arch) and are therefore supplied by mandibular nerve branches arising from the trigeminal nerve. Nerve supply
Ventilation :conditioning the inspired air to warm and humid Olfaction Defense: mechanical defenses and immune response Speech production Function of nose
Physical principles of nasal airflow Function of nose Laminar flow and turbulent flow
The “nasal cycle” is a physiologic phenomenon marked by an alternation between luminal narrowing and widening of the nasal cavities. This alternate congestion and decongestion of the nasal mucosa is effected mainly through reactions of the venous capacitance vessels of the inferior and middle turbinates, which are regulated by the autonomic nervous system. Nasal cycle
The mucociliary transport system consists of the cilia of the respiratory epithelium and a mucous blanket composed of two layers: a deeper, less viscid “sol layer” in which ciliary motion occurs, and a superficial, more viscid “gel layer”. Mucociliary clearance
Disturbances of mucociliary transport can have various causes, such as increased viscosity and thickness of the periciliary sol layer, hampering ciliary movements, or changes in the viscoelasticity of the gel layer resulting in ineffectual mucus transport. Finally, various pathogenic mechanisms can produce changes in the cilia themselves, regardless of the viscosity of the mucous blanket. Mucociliary clearance
Allergic rhinitis Allergic rhinitis (AR) is a common manifestation of allergic diseases, affecting approximately 500 million people worldwide. AR is increasing in prevalence . For example, the prevalence of AR in Japan increased from 29.8% in 1998 to 39.4% in 2008. The prevalence of pollinosis, the typical seasonal AR, has been increased from 19.6% in 1998 to 29.8% in 2008.
Allergic rhinitis AR is increasing in prevalence
Allergic rhnitis and its impact on asthma (ARIA) Global guideline for AR management
Definition AR is defined as a symptomatic disorder of the nose induced after allergen exposure by an IgE-mediated inflammation. It is an inflammation of the lining of the nose and is characterized by nasal symptoms including anterior or posterior rhinorrhoea, sneezing, nasal blockage and/or itching of the nose. These symptoms occur during two or more consecutive days for more than 1 h on most days.
Allergen Most causal antigens for AR are inhalant allergens. House dust mite, animal dander, pollens and fugus are the principal allergens. Other inhalant allergens include feather, insect and grass pollen. Food allergens inckude peanut, egg, milk etc.
Onset of three major AR symptoms Sneezing (consecutive) Sensory nerves containing substance P (SP) and calcitonin gene-related peptide (CGRP) are distributed throughout the epithelial and subepithelial layers of the nasal mucosa. Sensory nerve terminals are located in the epithelial junctions and subepithelial layers. When various chemical mediators are applied to the nasal mucosa, histamine is the only mediator that induces a significant sneezing reflex.
Sneezing The sneezing reflex following allergen challenge is a respiratory reflex induced by the interaction between histamine and the H1 receptor at the sensory nerve terminals containing SP and CGRP and might be a sensory stimulation response amplified by hyperreactivity in the nasal mucosa. Onset of three major AR symptoms
Onset of three major AR symptoms Itching nose Also, sensory nerve terminals are located in the epithelial junctions and subepithelial layers. When various chemical mediators are applied to the nasal mucosa, histamine is the only mediator that induces the sensory nerve terminals to be itching.
Onset of three major AR symptoms Rhinorrhoea (Watery) Synchronously with the sneezing reflex, sensory stimulation on the nasal mucosa induces excitation reflexively in the parasympathetic centre.After allergen challenge on the hemilateral nasal mucosa of patients with allergic rhinitis, the weight of rhinorrhoea induced in both sides of nasal cavities is correlated with the number of sneezes. In addition, the weight of rhinorrhoea in the nasal cavity with allergen challenge is correlated with that on the opposite side. Therefore, rhinorrhoea can be regarded as the secretion from the mucous glands by parasympathetic stimulation.
Onset of three major AR symptoms Rhinorrhoea Therefore, rhinorrhoea can be regarded as the secretion from the mucous glands by parasympathetic stimulation. Furthermore, allergic inflammation induced by nasal allergen exposure augments this ‘naso-nasal’ reflex. Possible mechanisms for sensory nerve hyperresponsiveness include the increased release of nerve growth factor during allergic inflammation. Chemical mediators including histamine, cysLTs, and PAF induce plasma exudation directly from the blood vessels in the nasal mucosa, which constitutes a part of rhinorrhoea.
Other onset of AR symptoms Nasal congestion The underlying causes of nasal congestion in the early phase of allergic rhinitis are the relaxation of the smooth muscle layer of capacitance vessels in the nasal mucosa and the interstitial oedema induced by plasma exudation.Swelling of the nasal turbinate is induced by the parasympathetic reflex and the axon reflex through the nerve centre and the direct effects of the chemical mediators on the vascular system.
Nasal congestion When sensitized subjects inhale antigens, the antigens pass through the epithelial tight junctions in the nasal mucosa to bind IgE on the surface of mast cells in the epithelial layer of the nasal mucosa, inducing the release of chemical mediators including histamine, prostaglandins and cysLTs by aggregation of FceRI. Histamine regulates tight junctions via the coupling of H1 receptors and increases paracellular permeability. Other onset of AR symptoms
Nasal congestion This increased permeability allows DC to penetrate epithelial tight junctions easily and enhance antigen presentation to T cells. The early-phase response, which consists of sneezing, rhinorrhoea and nasal congestion, is caused by interactions between chemical mediators and the sensory nerve terminals and blood vessels in the nasal mucosa. Other onset of AR symptoms
Nasal congestion Dilation of the capacitance vessels and plasma exudation after excitation of the parasympathetic centre are caused by the nitric oxide (NO) released from parasympathetic terminals and vascular endothelial cells. However, the participation of the nerve reflex in nasal turbinate swelling after allergen challenge is minor compared with the direct effects of chemical mediators, such as histamine, cysLTs,PAF and prostaglandinD2 (PGD2) and kinin,on the vascular system in the nasal mucosa. Other onset of AR symptoms
Nasal congestion Nasal congestion in the late phase is induced by the allergic inflammation.The secondary reaction with inflammatory cells and their mediators, especially the cysLTs produced by eosinophils , causes oedema of the nasal mucosa. This inflammation, which develops 6–10 h after the allergen challenge, is referred to as the late-phase response. Other onset of AR symptoms
Intermittent allergic rhinitis (IAR): Less than 4 days a week. Or for less than 4 weeks. Persistent allergic rhinitis (PAR): More than 4 days a weeks. And for more than 4 weeks. New classification of AR
Mild No sleep disturbance. No impairment of daily activities 、 leisure 、 and/or sport. No impairment of school or work. No troublesome symptoms. New classification of AR
Moderate/severe O ne or more the following items are present: Sleep disturbance. Impairment of daily activities 、 leisure 、 and/or sport. Impairment of school or work. Troublesome symptoms. New classification of AR