Surgical anatomy is an important and fundamental aspect for all surgical procedures. Anatomy provides a surgeon with the basic and in-depth knowledge that is required and mandatory when performing an operation. Although this subject might be tedious and routine, it is compulsory and should not be overlooked or neglected to avoid any possible postoperative complications. An aggressive and hasty operation without anatomic considerations might cause adverse effects that are irreversible even though a surgical anatomy of the nose is quite simple.
The nasal envelope, also known as skin and soft tissue envelope (SSTE), is the skin that covers the exterior of nose. The nasal envelope is made up of soft tissues and includes all intranasal soft tissue except the osteocartilaginous framework. Because the epidermis, dermis and subcutaneous tissues are among the tissues that make up the nasal envelope, it may at times lead to confusion for surgeons. No matter how thick or thin the skin may be, it is the SSTE which guides a surgeon for understanding the elasticity of the nasal envelope. Therefore, when performing rhinoplasty on a patient with thin skin, the skin and soft tissue might be considered as a single compound.
There are five layers that make up the nasal envelope. They include skin, superficial fatty layer, fibro-muscular layer, deep fatty layer, and perichondrium or periosteum (
A nasal skin is very specialized organ keeping its own shape and characteristics with differing from other parts of body. In short, it especially at thick nasal tip keeps its own shape and pattern if cadaveric nasal skin is harvested and observed. It is an evidence of difficulty for change at nasal tip with surgical manipulation [
The characteristics of the nasal envelope varies significantly in different portion of the nose. The nasal skin is thicker when the elasticity and stretch capacity are lower, and the proportions of the fibrous tissue and sebaceous glands are higher [
The superficial fatty layer consists of adipose tissue. In histology, the superficial fatty layer has interlacing vertical fibrous septae that is evenly distributed around the nose, typically at the glabella and the supratip area (
The fibromuscular layer is the core part of nose; consisting of nasal superficial musculo-aponeurotic system (SMAS) along with a superficial fatty layer. The main function of the fibromuscular layer is to allow movement of the nasal envelope, to offer blood supply and to maintain the thickness of the skin. They also integrate and transmit the contractile force of nasal muscles [
Although a nasal SMAS is considered as a continued structure from the facial SMAS, there is a slight compositional difference between the nasal dorsum and the tip. The proximal nasal SMAS is a collection of collagen supporting the dynamic property, whereas the distal nasal SMAS is a structure that is firmly attached between the skin and muscle (
The open approach is preferred to dissect the deep fatty layer while separating the nasal envelope. Lack of major vessels and fibrous septa along with the movement of muscular aponeurosis makes it less challenging. The advantage of dissection on this plane is possible to maintain the integrity of nasal envelope and to reduce the chance of damaging the neurovascular bundles.
The fifth layer consists of fused perichondrium or periosteum with fibrous tissue. It is located under the deep fatty layer. It can be divided as a periosteal component and a perichondral component. Histologically, a periosteum consists of superficial and deep layers [
A periosteum is a special tissue consisting of fibro-vascular membrane. In Asian rhinoplasty, a dorsal implant material is usually located under the periosteum. It might cause migration, descent or deviation of the implant if pocket dissection is located within superficial plane, too wide or out of place. The periosteum becomes thicker as it ascends above the nasofrontal suture line. The collagen fibers called Sharpey’s fiber, extending from the periosteum intervene with the suture line. Sharpey’s fiber may hinder more subperiosteal cephalic dissection in cases with acute nasofrontal angle and flat nasal dorsum (
The nasal base is the least understood and thus most complex area of the nose. Therefore, analysis is also complex, and surgical results and outcome is difficult to predict before the operation because every tip plasty affects the nasal base on the final result afterwards.
The topographic anatomy of the nasal base is illustrated as (
The pyriform ligament first named by Rohrich et al. [
There is a distinct fibrous structure, “tela subcutanea cutis” described by Daniel et al. [
Nasal muscles control facial animation and nasal respiration, during aerobic activity. Nasal muscles can be divided into four groups. All of them are innervated by temporal, zygomatic and buccal branch of facial nerve. The superficial nasal muscles are connected by their aponeurosis together, thus distributing their forces each other. There are numerous nomenclatures about nasal muscles, more detailed investigation is necessary since there are another intrinsic functional muscles beside listed nasal muscles [
They shorten nasal length and dilate nostril. Procerus muscle: originates from the periosteum of the nasal bones and the aponeurosis of the transverse nasalis before inserting into the glabellar skin. Levator labii superioris alaeque nasi muscle: originates from the periosteum of the frontal process of the maxilla medial to the orbicularis oris, and inserts at muscle and skin of nasolabial fold, nasal alae and upper lip [
They lengthen nasal length and dilate nostril. Dilator naris posterior muscle (alar portion of the nasalis muscle): the main portion of the dilator naris posterior originates from the periosteum of the maxilla above the canine tooth and inserts into the alar base. Depressor septi nasi muscle: originates from the periosteum of the maxilla above the canine tooth and inserts onto the footplates of the medial crura with attaching tightly to the anterior nasal spine and mucosa, perichondrium and membranous septum [
Transverse nasalis muscle (transverse portion of the nasalis muscle): originates from the periosteum of the maxilla above and lateral to the incisor fossa. It interdigitates on the nasal dorsum with its counterpart from the opposite side and the procerus muscle to form a sling [
Dilator naris anterior muscle: originates from the surface of the lateral crus and inserts into the nostril rim.
It is safe to dissect under nasal SMAS during the operation because nasal circulatory system runs within or above the nasal SMAS (
A dorsal nasal artery descends laterally from above medial canthal tendon through orbital septum and forms axial arterial network supplying abundant blood to nasal dorsal flap after meeting with supratrochlear and infra-orbital artery (
External nasal branch of ethmoidal artery and lateral branch of angular artery are responsible for blood supply mainly nasal tip (
It passes between alae and cheek, and runs into levator labii superioris alaeque nasi muscle. A lateral nasal artery is branched from the angular artery and mainly supplies the lateral aspect of nasal dorsum and tip [
It is a branch of superior labial artery ascending on the medial crura of alar cartilage within the columella. Anatomic variants such as absence of unilateral or bilateral branches are frequently observed [
When exiting the infraorbital foramen, an infraorbital artery has many branches running lateral aspect of nose.
An external nasal vein usually accompanies with the matched artery. It mainly drains into the cavernous sinus through ways of facial vein, pterygoid plexus and ophthalmic vein. In addition, it forms the anastomosis with lateral branches of angular artery.
The Kiesselbach’s plexus refers to gathering of terminal branches of vessels at anterior portion nasal septum. There are septal branches of anterior ethmoidal artery, sphenopalatine artery, greater palatine artery and the anterior portion of the septum. It is also known as the Little’s area and is the most common cause of bleeding at septal anterior portion, which accounts for 90% of total cause of nasal bleeding (
The external sensory nerves of the nose originate from the first branch (ophthalmic nerve) and the second branch (maxillary nerve) of trigeminal nerve (
The supra-trochlear nerve and infra-trochlear nerve which are branches of ophthalmic nerve are innervated by the sensory nasal root and some part of nasal lateral wall.
The external nasal branch of anterior ethmoidal nerve is the most important sensory nerve inne rvating the nasal tip. It runs from nasal dorsum to nasal tip after sprouting out between nasal bone and upper lateral cartilage. It is common to observe patients having transient sensory discomfort due to nerve injury or edema during early phase after rhinoplasty [
The infraorbital nerve, a branch of maxillary nerve, innervates the sensory of lateral wall of lower nose, columella, nasal vestibule and so on.
The nerves branched from pterygo-palatine ganglion located at posterior of middle turbinate are mainly innervating the nasal interior. The internal branch of anterior ethmoidal nerve innervates the anterior portion of nasal lateral wall and septum. The nasopalatine nerve branched from the pterygo-palatine ganglion is the main sensory innervation for the septum (
No potential conflict of interest relevant to this article was reported.
This study was performed in accordance with the principles of the Declaration of Helsinki. Written informed consent was obtained.
The patients provided written informed consent for the publication and the use of their images.
Skin and soft tissue envelope, composition of the external nasal coverage (5 layers). SMAS, superficial musculo-aponeurotic system. Reprinted from Jeong JY [
Histologic layers of the nose. SMAS, superficial musculoaponeurotic system. Reprinted from Jeong JY [
The subunits of the nose and the difference in skin thickness by subunits. Zone II is the thickest portion [
The superficial layer is tightly attached to the overlying skin with vertically oriented fibrous septae.
(A) Radix fat pad, supratip fat pad, sidewall fat pad and interdomal fat pad in front. (B) Radix fat pad, supratip fat pad, sidewall fat pad and interdomal fat pad in lateral. MCL, medial canthal ligament; LLSAN, levator labii superioris alaeque nasi muscle; TN, transverse nasalis muscle.
As a single layer, nasal superficial musculo-aponeurotic system (SMAS) contains the various muscular system. Reprinted from Jeong JY [
Nasal superficial musculo-aponeurotic system.
Two models of superficial musculo-aponeurotic system (SMAS) architecture [
The characteristics of superficial musculo-aponeurotic system are distinguished from each side of scroll area (H&E stain, ×10). Alar cartilage (red arrow), upper lateral cartilage (blue arrow), scroll area (white arrow).
Cadaveric model. (A) Nasal superficial musculo-aponeurotic system (SMAS) covering the transitional zone between alar cartilage and upper lateral cartilage. (B) Proximal nasal SMAS is partially connected to scroll area [
An injured nasal envelope due to chronic inflammation. (A) Contracture with silicone implant. (B) Extrusion of silicone implant. (C) Deformity with gore-tex implant.
Periosteal component and perichondral component are fused and form a hard-longitudinal fibrous sheath (red arrow) (Masson’s Trichrome stain, ×20).
(A, B) Periosteum of the nose.
Nasal base anatomy. (1) Columellar base, (2) central columellar pillar, (3) infralobular triangle, (4) soft triangle (facet), (5) lateral wall, (6) alar base, (7) nostril sill [
Pyriform ligament (red line area). Reprinted from Jeong JY [
Laterally, there is a distinct fibrous structure without any muscular or cartilaginous component that forms alar side wall and nostril sill in the lower nasal base. This specialized form is named by Goss and confirmed by Daniel [
(A) Illustration of nasal muscles. (B) Cadaver indicating nasal muscles. PR, procerus; TN, transverse nasalis; AN, anomalous nasi; LLSAN, levator labii superioris alaeque nasi; OO, orbicularis oculi; DNA, dilator naris anterior. Reprinted from Jeong JY [
A major circulatory system runs within or above nasal superficial musculo-aponeurotic system in the cross section of the nose (H&E stain, ×40). Lateral nasal artery (red arrow), sesamoid cartilage (blue arrow). Reprinted from Jeong JY. J Korean Soc Aesthetic Plast Surg 2010;16:125-38 [
Arteries of external nose [
The Kiesselbach’s plexus refers to gathering of terminal branches of vessels at anterior portion nasal septum. There are septal branches of anterior ethmoidal artery, sphenopalatine artery, greater palatine artery and the anterior portion of the septum. Reprinted from Jeong JY [
External sensory nerves [
Internal nervous system of lateral nasal wall. Reprinted from Jeong JY [
Internal nervous system of septal area. Reprinted from Jeong JY [
Zones of the nasal skin [
Zone | Definition | Characteristics |
---|---|---|
I | Covers the upper dorsum and sidewalls of the nose. | Its skin is smooth, thin and nonsebaceous and glides easily over the underlying bone and cartilage of the nasal hump. |
II | Begins about 1.5 cm above the supratip area and covers most of the nasal tip and alar lobules and to within 4 mm of the alar margin. | Skin is stiff, thick, and filled with sebaceous glands, It is underlaing by a layer of dense fat, which is 6–10 mm thick in the region of the supratip. |
III | Includes a 4 mm strip along the alar margin, the soft triangles, the lower half of the infratip lobule and the columella. | Skin is smooth, thin, and nonsebaceous. There is little subcutaneous fat. Unlike the smooth skin of zone I, the skin of zone III is fixed to the deep cartilage and fibrofatty structures and dose not move easily. The medial and middle crura and their intercrural groove are visible through the thin skin of zone III. |