Anatomy of the human nose[edit]Main article:Anatomy of the human noseEmbryologic development[edit]

Nasal anatomy: The embryonic human head, c. 30 days of gestation.At four (4) weeks of gestational development, theneural crestcells (the precursors of the nose) begin their caudad migration (from the posterior) towards the midface. Two symmetricalnasal placodes(the future olfactory epithelium) develop inferiorly, which the nasal pits then divide into the medial and the lateralnasal processes(the future upper lip and nose). The medial processes then form theseptum, thephiltrum, and the premaxilla of the nose; the lateral processes form the sides of the nose; and the mouth forms from thestomodeum(the anterior ectodermal portion of the alimentary tract), which is inferior to the nasal complex.A nasobuccal membrane separates the mouth from the nose; respectively, the inferior oral cavity (the mouth) and the superior nasal cavity (the nose). As the olfactory pits deepen, said development forms the choanae, the two openings that connect the nasal cavity and the nasopharynx (upper part of the pharynx that is continuous with the nasal passages). Initially, primitive-form choanae develop, which then further develop into the secondary, permanent choanae.At ten (10) weeks of gestation, the cells differentiate intomuscle,cartilage, andbone. If this important, early facial embryogenesis fails, it might result in anomalies such as choanal atresia (absent or closed passage), medial nasal clefts (fissures), or lateral nasal clefts, nasal aplasia (faulty or incomplete development), and polyrrhinia (double nose).[21]This normal, human embryologic development is exceptionally important because the newborn infant breathes through his or her nose during the first 6 weeks of life thus, when a child is afflicted with bilateral choanal atresia, the blockage of the posterior nasal passage, either by abnormal bony tissue or by abnormal soft tissue, emergency remedial action is required to ensure that the child can breathe.[22]The structures of the nose[edit]

Nasal anatomy: Squamous epithelium is one of several types of epithelia.

Nasal anatomy: The procerus muscle (musculus procerus, pyramidalis nasi, depressor glabellae).For plastic surgical correction, the structural anatomy of the nose comprehends:A.the nasal soft tissues;B.the aesthetic subunits and segments;C.the blood supply arteries and veins;D.the nasal lymphatic system;E.the facial and nasal nerves;F.the nasal bones; andG.the nasal cartilages.A. The nasal soft tissues Nasal skin Like the underlyingbone-and-cartilage(osseo-cartilaginous) support framework of the nose, the external skin is divided into vertical thirds (anatomic sections); from the glabella (the space between the eyebrows), to the bridge, to the tip, for corrective plastic surgery, the nasal skin is anatomically considered, as the:1. Upper third section the skin of the upper nose is thick, and relatively distensible (flexible and mobile), but then tapers, adhering tightly to the osseo-cartilaginous framework, and becomes the thinner skin of the dorsal section, the bridge of the nose.2. Middle third section the skin overlying the bridge of the nose (mid-dorsal section) is the thinnest, least distensible, nasal skin, because it most adheres to the support framework.3. Lower third section the skin of the lower nose is as thick as the skin of the upper nose, because it has more sebaceous glands, especially at the nasal tip. Nasal lining At the vestibule, the human nose is lined with amucous membraneofsquamous epithelium, which tissue then transitions to become columnarrespiratory epithelium, a pseudo-stratified,ciliated(lash-like) tissue with abundant seromucinous glands, which maintains the nasal moisture and protects the respiratory tract from bacteriologic infection and foreign objects. Nasal muscles The movements of the human nose are controlled by groups of facial and neck muscles that are set deep to the skin; they are in four (4) functional groups that are interconnected by the nasal superficial aponeurosis thesuperficial musculoaponeurotic system(SMAS) which is a sheet of dense, fibrous,collagenousconnective tissuethat covers, invests, and forms the terminations of the muscles.The movements of the nose are affected by1. the elevator muscle group which includes theprocerus muscleand thelevator labii superioris alaeque nasi muscle.2. the depressor muscle group which includes thealar nasalis muscleand thedepressor septi nasi muscle.3. the compressor muscle group which includes the transversenasalis muscle.4. the dilator muscle group which includes thedilator naris musclethat expands the nostrils; it is in two parts: (i) the dilator nasi anterior muscle, and (ii) the dilator nasi posterior muscle.

Rhinoplasty: the surgical nose as aesthetic nasal segments.B. Aesthetics of the nose nasal subunits and nasal segmentsTo plan, map, and execute the surgical correction of a nasal defect or deformity, the structure of the external nose is divided into nine (9)aesthetic nasal subunits, and six (6)aesthetic nasal segments, which provide the plastic surgeon with the measures for determining the size, extent, andtopographiclocale of the nasal defect or deformity.The surgical nose as nine (9)aesthetic nasal subunits1. tip subunit2. columellar subunit3. right alar base subunit4. right alar wall subunit5. left alar wall subunit6. left alar base subunit7. dorsal subunit8. right dorsal wall subunit9. left dorsal wall subunitIn turn, the nine (9) aesthetic nasal subunits are configured as six (6) aesthetic nasal segments; each segment comprehends a nasal area greater than that comprehended by a nasal subunit.The surgical nose as six (6)aesthetic nasal segments1. the dorsal nasal segment2. the lateral nasal-wall segments3. the hemi-lobule segment4. the soft-tissue triangle segments5. the alar segments6. the columellar segment

Rhinoplasty: The Common carotid artery.Using the co-ordinates of the subunits and segments to determine thetopographiclocation of the defect on the nose, the plastic surgeon plans, maps, and executes a rhinoplasty procedure. The unitary division of the nasal topography permits minimal, but precise, cutting, and maximal corrective-tissue coverage, to produce a functional nose of proportionate size, contour, and appearance for the patient. Hence, if more than 50 per cent of anaesthetic subunitis lost (damaged, defective, destroyed) the surgeon replaces the entireaesthetic segment, usually with a regionaltissue graft, harvested from either the face or the head, or with a tissue graft harvested from elsewhere on the patients body.[23]C. Nasal blood supply arteries and veinsLike the face, the human nose is well vascularized with arteries and veins, and thus supplied with abundantblood. The principal arterial blood-vessel supply to the nose is two-fold:(i)branches from theinternal carotid artery, the branch of the anterior ethmoid artery, the branch of the posterior ethmoid artery, which derive from theophthalmic artery;(ii)branches from theexternal carotid artery, the sphenopalatine artery, the greater palatine artery, the superior labial artery, and the angular artery.Theexternal noseis supplied with blood by thefacial artery, which becomes theangular arterythat 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 internalcommon carotid arterysystem.Internally, thelateral nasal wallis supplied with blood by thesphenopalatine artery(from behind and below) and by the anterior ethmoid artery and the posterior ethmoid artery (from above and behind). Thenasal septumalso is supplied with blood by the sphenopalatine artery, and by the anterior and posterior ethmoid arteries, with the additional circulatory contributions of thesuperior labial arteryand of the greater palatine artery. These three (3) vascular supplies to the internal nose converge in theKiesselbach plexus(the Little area), which is a region in the anteroinferior-third of the nasal septum, (in front and below). Furthermore, the nasal vein vascularisation of the nose generally follows the arterial pattern of nasal vascularisation. The nasal veins are biologically significant, because they have no vessel-valves, and because of their direct, circulatory communication to the sinus caverns, which makes possible the potential intracranial spreading of a bacterial infection of the nose. Hence, because of such an abundant nasal blood supply,tobaccosmokingdoes therapeutically compromise post-operative healing.D. Lymphatic system of the noseThe pertinent nasallymphatic systemarises from the superficial mucosa, and drains posteriorly to the retropharyngeal nodes (in back), and anteriorly (in front), either to the upper deep cervical nodes (in the neck), or to the submandibular glands (in the lower jaw), or into both the nodes and the glands of the neck and the jaw.

Nasal innervation: Cranial nerve V, the trigeminal nerve (nervus trigeminis) gives sensation to the nose, the face, and the upper jaw (maxilla).E. Nerves of the noseThe sensations registered by the human nose derive from the first two (2) branches ofcranial nerve V, thetrigeminal nerve(nervus trigeminis). Thenervelistings indicate the respective innervation (sensory distribution) of the trigeminal nerve branches within the nose, the face, and the upper jaw (maxilla).

Nasal innervation: Cranial nerve VII (nervus facialis) is the facial nerve that gives sensation to the nose and the upper jaw (maxilla).The indicatednerveserves the named anatomic facial and nasal regionsOphthalmic division innervation Lacrimal nerve conveys sensation to the skin areas of the lateralorbital(eye socket) region, except for the lacrimal gland. Frontal nerve conveys sensation to the skin areas of the forehead and the scalp. Supraorbital nerve conveys sensation to the skin areas of the eyelids, the forehead, and the scalp. Supratrochlear nerve conveys sensation to the medial region of the eyelid skin area, and the medial region of the forehead skin. Nasociliary nerve conveys sensation to the skin area of the nose, and the mucous membrane of the anterior (front)nasal cavity. Anterior ethmoid nerve conveys sensation in the anterior (front) half of the nasal cavity: (a) the internal areas of the ethmoid sinus and the frontal sinus; and (b) the external areas, from the nasal tip to the rhinion: the anterior tip of the terminal end of the nasal-bone suture. Posterior ethmoid nerve serves the superior (upper) half of the nasal cavity, the sphenoids, and the ethmoids. Intratrochlear nerve conveys sensation to the medial region of the eyelids, the palpebral conjunctiva, the nasion (nasolabial junction), and the bony dorsum.The maxillary division innervation Maxillary nerve conveys sensation to the upper jaw and the face. Infraorbital nerve conveys sensation to the area from below theeye socketto the external nares (nostrils). Zygomatic nerve through the zygomatic bone and the zygomatic arch, conveys sensation to the cheekbone areas. Superior posterior dental nerve sensation in the teeth and the gums. Superior anterior dental nerve mediates the sneeze reflex. Sphenopalatine nerve divides into the lateral branch and the septal branch, and conveys sensation from the rear and the central regions of thenasal cavity.

Nasal anatomy: The shell-form turbinates (conchae nasales).

Nasal anatomy: Theseptum nasibones and cartilages.The supply ofparasympatheticnerves to the face and the upper jaw (maxilla) derives from thegreater superficial petrosal(GSP) branch ofcranial nerve VII, thefacial nerve. The GSP nerve joins thedeep petrosal nerve(of the sympathetic nervous system), derived from the carotid plexus, to form thevidian nerve(in the vidian canal) that traverses thepterygopalatine ganglion(an autonomic ganglion of the maxillary nerve), wherein only the parasympathetic nerves form synapses, which serve thelacrimal glandand the glands of the nose and of the palate, via the (upper jaw) maxillary division ofcranial nerve V, thetrigeminal nerve.F. Bony anatomy of the noseIn the upper portion of the nose, the pairednasal bonesattach to the frontal bone. Above and to the side (superolaterally), the paired nasal bones connect to the lacrimal bones, and below and to the side (inferolaterally), they attach to the ascending processes of the maxilla (upper jaw). Above and to the back (posterosuperiorly), the bony nasal septum is composed of the perpendicular plate of the ethmoid bone. Thevomerbone lies below and to the back (posteroinferiorly), and partially forms the choanal opening into the nasopharynx, (the upper portion of thepharynxthat is continuous with the nasal passages). The floor of the nose comprises the premaxilla bone and the palatine bone, the roof of the mouth.The nasal septum is composed of the quadrangular cartilage, the vomer bone (the perpendicular plate of theethmoid bone), aspects of the premaxilla, and the palatine bones. Each lateral nasal wall contains three pairs ofturbinates(nasal conchae), which are small, thin, shell-form bones: (i) the superior concha, (ii) the middle concha, and (iii) the inferior concha, which are the bony framework of the turbinates. Lateral to the turbinates is the medial wall of the maxillary sinus. Inferior to the nasal conchae (turbinates) is the meatus space, with names that correspond to the turbinates, e.g. superior turbinate, superior meatus, et alii. The internal roof of the nose is composed by the horizontal, perforated cribriform plate (of the ethmoid bone) through which pass sensory filaments of theolfactory nerve(Cranial nerve I); finally, below and behind (posteroinferior) the cribriform plate, sloping down at an angle, is the bony face of thesphenoid sinus.G. The cartilaginous pyramid of the noseThe cartilaginousseptum(septum nasi) extends from the nasal bones in the midline (above) to the bony septum in the midline (posteriorly), then down along the bony floor. The septum is quadrangular; the upper half is flanked by two (2) triangular-to-trapezoidal cartilages: the upper lateral-cartilages, which are fused to the dorsal septum in the midline, and laterally attached, with loose ligaments, to the bony margin of the pyriform (pear-shaped) aperture, while the inferior ends of the upper lateral-cartilages are free (unattached). The internal area (angle), formed by the septum and upper lateral-cartilage, constitutes the internal valve of the nose; the sesamoid cartilages are adjacent to the upper lateral-cartilages in the fibroareolar connective tissue.Beneath the upper lateral-cartilages lay the lower lateral-cartilages; the paired lower lateral-cartilages swing outwards, from medial attachments, to the caudal septum in the midline (the medial crura) to an intermediate crus (shank) area. Finally, the lower lateral-cartilages flare outwards, above and to the side (superolaterally), as the lateral crura; these cartilages are mobile, unlike the upper lateral cartilages. Furthermore, some persons present anatomical evidence of nasal scrolling i.e. an outward curving of the lower borders of the upper lateral-cartilages, and an inward curving of the cephalic borders of the alar cartilages.