Rhinoplasty
Bony-cartilaginous framework
Bony part
Upper third
Cartilaginous part
formed of 2 nasal bones connected in the midline by internasal suture
Attached to
superior: frontal bone
lateral: frontal process of maxilla
Inferior: cartilaginous nose "pyriform operature"
Upper lateral cartilage (pair)
Lower lateral (alar) cartilage (pair)
Triangular in shape
Occupies middle third of external nose
Attached to
They fuse at the midline with the dorsal part of the septum Except in teh lower third forming "internal nasal valve"
Superior: nasal bone & frontal process
Inferior: lower lateral cartilage
Occupies lower third of external nose
Each is composed of : medial & lateral crus joined at "Dome"
Horse-shoe in shape
N.B
columella
lateral crus
Medial crus
Dome
lies medial to nostril
both medial crura form together "the columella"
soft tissue portion between nostrils
forms the ala
its weakness causes external valve collapse
lateral to nostrils
lateral end connects pyriform operrature by a dense CT aponeurosis containing a chain minor accessory cartilages
largest component of lower lateral cartilage
Scroll: attachement of upper lateral to lower lateral cartilage
Upper lateral: directed lateral + upwards
lowerr lateral: directed nedial + downwards
Both domes together form cartilaginous framework of the nasal tip
Change of interdomal distance affects tip's width
point of union of medial and lateral crura
Soft tissue of external nose
Upper half: thin, mobile skin
lower half: thick, more adherent skin
skin, subcutaneous & muscles
muscles
procerus
nasalis
supplied by facial nerve
levator labii superioris alaeque nasi
Depressor septi nosi
Insertion: upper lip + ala
Action: elevate upper lip + dilate the nostrils
Origin: frontal process of maxilla
facial paralysis and loss of its function causing nasal obstruction
Insertion: runs upwards between medial crura nad insetred into membranous nasal septum , may continue upwards to tip
Action: pull the tip downwards with speaking or smiling
Origin: premaxilla & ant. nasal spine
Applied anatomy
Dorsal > posterior
Ventral > anterior
caudas > towards the feet
Divisions (3 equal thirds)
cephalic > towards the head
Cartilaginous vault
Nasal lobule
Bony vault
Upper third
Nasal bone + frontal process
Middle third
Upper lateral cartilages + Dorsal cartilaginous septum
Mobile Lower third
Tip + Ala + columella + membranous septum
Support mechanisms of the tip
Fibrous attachment of the medial crural feet to the posterior caudal septum
Interdomal ligament
The scroll
Accessory cartilages
Medial & lateral crura "size, shape, strength"
weaken by aging
The nasal septum
Bony septum
Membranous septum
Cartilaginous septum
Dorsal: attached to upper lateral cartilage
Postero-superior: attached to perpendicular plate of ethmoid
Anterior part
Postero-inferior: attached to vomerr + maxillary crest + anterior nasal spine
posterior & inferior parts
Perpendicular plate of ethmoid + vomer + maxillary crest + ANS
join columella to the caudal border of septal catilage
provide the free mobility of columella
N.B (parts have the direct impact on the shape of external nose:)
Caudal part of cartilaginous septum
Dorsal + Caudal parts = L-shaped strut ( have to be preserved in any septal surgery to avoid deforming the external nose)
Dorsal part of cartilaginous septum
Deviation > external nose deviation
Loss > saddling (due to the loss of dorsal support)
Deviation > columellar deflection & nostril asymmetry
Loss > tip ptosis (due to loss of tip support)