Surgical Anatomy of the Nose for Rhinoplasty

👃 Surgical Anatomy of the Nose for Rhinoplasty

A sound knowledge of the surgical anatomy of the external nose is essential before learning rhinoplasty.

This post covers:

• Parts of the external nose
• Bony pyramid and articulations of the nasal bone
• Surface landmarks of the bony vault
• Upper cartilaginous vault, keystone area and related triangles
• Lower cartilaginous vault, lobule and columella
• Tripod concept and types of dome
• Soft tissue covering, muscles, blood supply and nerve supply
• Anatomy of the septum and nasal valves

📋 Parts of the External Nose

The external nose is anatomically divided into three parts:

1️⃣ Bony pyramid

2️⃣ Upper cartilaginous vault

3️⃣ Lower cartilaginous vault

🦴 Bony Pyramid

Structures Forming the Bony Pyramid

1- Paired nasal bones

2- Frontal process of the maxilla (on both sides)

3- Nasal part of the frontal bone

⭐ All osteotomies in rhinoplasty are performed on the nasal bone.

What are the articulations of the Nasal Bone?

📍 Surface Landmarks of the Bony Vault

What is Radix Nasi?

What is Dorsum Nasi?

What is the Nasal Bridge?

What is the Nasofrontal Angle? What is it's normal value?

⚠️ Applied Importance of the Bony Vault

Anatomical Variations of the Nasal Bones

• Symmetrical or asymmetrical
• Agenesis of one or both nasal bones
• Markedly large nasal bones

Lateral Osteotomy

❌ Lateral osteotomy should not extend up to the upper thickened end of the nasal bone at the level of the nasion.

⭐ At this level, the bone is thickest and cannot be compressed further.

🔺 Upper Cartilaginous Vault

Structures Forming the Upper Cartilaginous Vault

1- Upper lateral cartilages on both sides (major portion)

2- A part of the cartilaginous septum

⭐ Both have the same embryological origin, are enclosed in a common perichondrial sheath, and constitute a single cartilaginous unit.

What is the Keystone Area? What is its clinical importance?

Relations of the Upper Lateral Cartilage

1- Lateral

• The upper lateral cartilages fall just short of the piriform edge of the maxilla
• The intervening gap is filled with dense fibrous tissue

What is the Empty Triangle of the nose?

2- Superior

• The upper margins (cephalic borders) are united under the lower ends of the nasal bone and frontal process of the maxilla by connective tissue
• The upper lateral cartilage extends about 1 cm above the lower edge of the nasal bone
• There is fusion of the perichondrium and periosteum at this level

⭐ This firm connection allows transmission of the motion of the nasal bone to the upper lateral cartilage.

3- Inferior

• The caudal edge of the upper lateral cartilage is rolled outwards and upwards, forming a scroll
• The scroll contributes to widening of the dorsal area and the lateral wall

⚠️ Prominent scrolls may need to be excised, as they can produce a Polly beak deformity.

What is Pollybeak deformity?

What is Anterior Septal Angle?

What is Posterior Septal Angle?

What is Weak Triangle of Converse? What is it's clinical significance?

🔻 Lower Cartilaginous Vault

Structures Forming the Lower Cartilaginous Vault

1- Lower lateral cartilages (Alar cartilages) - one on each side

2- Sesamoid cartilages

Parts of the Lower Lateral Cartilage

The lower lateral cartilage is a single piece of cartilage on each side, with three parts:

1- Medial Crus

• Lies immediately under the skin of the columella
• The two medial crura join in the midline, attached to each other by fibrous tissue
• Attached to the lower end of the septum by the membranous septum

2- Dome

• The meeting point of the medial crus and lateral crus
• Contributes to the formation of the lobule and the tip of the nose

3- Lateral Crus

• About 1 mm in thickness
• Its upper edge also forms a scroll, overlapping the lower edge of the upper lateral cartilage

What is the Soft Triangle in the nose? What is it's clinical significance?

Lobule

Formed By

• Lateral crura of the lower lateral cartilage
• Dome of the lower lateral cartilage

Tip

• Formed by the two domes
• The most anterior part of the lobule

What are the boundaries of the Lobule?

⭐ Mobility of the Lobule

The lower cartilaginous part is a separate part of the nose, with no connection to other structures except an aponeurosis formed by the continuity of the fibrous envelope investing the upper and lower lateral cartilages.

👉 Therefore, the lobule is freely mobile upwards, downwards and from side to side.

Columella

🔍 What is it?

The structure extending between the lip and the tip of the nose.

Formed By

• The two medial crura with intervening areolar tissue
• Covered with a thin layer of skin

⭐ Its shape depends on the size and contour of the medial crura.

Parts of the Columella

1- Upper lobular part

2- Middle narrow part

3- Wider lower (basal) part

What is the effect of length of Medial Crura on the size and shape of nose?

What is the normal angle Between the Medial Crura?

🔺 Tripod Concept (Anderson, 1969)

Anderson compared the lower lateral cartilage to a tripod, consisting of:

• One relatively long leg - the lateral crura
• One short leg - the medial crura

Structures Supporting the Tripod

1- Part of the upper lateral cartilage

2- Part of the caudal border of the septal cartilage

3- Soft tissue at the base of the columella

4- Membranous septum

What is the Applied Importance of Tripod Concept given by Anderson?

What are the Types of Dome given by Bernstein?

Define Anatomical Dome.

Define Surgical Dome.

Define Clinical Dome.

🧴 Soft Tissue Covering

The nasal skin is not uniform throughout.

• Skin over the lower part of the nose is thicker and more firmly attached to the cartilages
• Skin over the nasal bone and upper lateral cartilage is mobile
• Skin of the alar region has abundant sebaceous glands

💪 Muscles of the Nose

1- Procerus

2- Compressor Naris (Transverse part of Nasalis)

3- Dilator Naris (Alar part of Nasalis)

4- Depressor Septi

Which muscle is sectioned when a transfixion incision is given in rhinoplasty?

🩸 Blood Supply of the External Nose

⭐ The arteries and veins of the external nose lie superficially in the soft tissue.

Arteries

Branches of the Facial Artery

• Angular artery → Lateral nasal artery
• Superior labial artery → Columellar branch and Septal branch

Branches of the Ophthalmic Artery

• Dorsal nasal artery
• Anterior ethmoidal artery → External nasal branch

Infraorbital Artery

Veins

• Angular veins
• Ophthalmic veins

⚠️ Applied Importance

While mobilizing the soft tissue after the opening incisions, the plane of dissection must be close to the bony and cartilaginous framework.

👉 This avoids injury to the muscles and superficial vessels, which can cause:

• Unnecessary bleeding
• Button-holing of the skin

🧠 Sensory Nerve Supply of the External Nose

Supplied primarily by the ophthalmic and maxillary divisions of the trigeminal nerve (5th cranial nerve).

⭐ The external nasal nerve exits between the nasal bone and the upper lateral cartilage.

⭐ Knowledge of the nerve supply is important for pre-operative infiltration.

🧱 Anatomy of the Nasal Septum

Parts of the Septum

1- Columellar septum

2- Membranous septum

3- Septum proper - osseous and cartilaginous parts

Cartilaginous Part

• Septal cartilage

Bony Part

Major Contribution

• Perpendicular plate of the ethmoid
• Vomer

Minor Contribution

• Crest of the nasal bone
• Nasal spine of the frontal bone
• Anterior nasal spine of the maxilla
• Crest of the maxilla
• Crest of the palatine bone
• Rostrum of the sphenoid

What is the detailed anatomy of the nasal septum?

What are the boundaries of the External Nasal Valve?

What are the boundaries of the Internal Nasal Valve?

What is the anatomy of the internal nose?

⭐ Exam Pearls

• Bony pyramid → Nasal bones, frontal process of maxilla, nasal part of frontal bone
• Nasal bone is thick above and thin below
• Lateral osteotomy should not extend up to the level of the nasion
• Weakening of the keystone area → Saddle nose deformity
• Prominent scroll → Polly beak deformity
• Tip of the nose is formed by the two domes
• Tripod concept → Anderson, 1969
• Types of dome → Bernstein, 1974
• Nasal skin is thickest at the nasion and thin at the rhinion
• Internal nasal valve → Least cross-sectional area of the nose

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