Human nose

Human nose

Roman Nose (PSF)

A human nose from the front.

The human nose is a central and prominent feature of the face, playing a vital role in respiration, olfaction, and immune defense. Comprising bones, cartilage, and specialized tissues, the nose serves as the primary entryway for air into the body, assisting in filtering, humidifying, and warming inhaled air. Beyond its physiological roles, the nose also holds aesthetic and cultural significance across human societies.

Anatomy

External Structure

The visible portion of the nose, often referred to as the external nose, is characterized by its protrusion from the face and the presence of nostrils (nares). Its shape and size are determined by underlying skeletal structures such as the ethmoid bone and the nasal septum. The septum, predominantly cartilaginous, divides the nostrils. Typically, males possess larger noses than females, a distinction believed to be evolutionary and related to differences in oxygen intake and body mass.

Internal Structure

Internally, the nose is equipped with an area of specialized olfactory cells, essential for the sense of smell. This region is a part of the larger olfactory system which communicates directly with the brain. Additionally, the nasal passages contain fine hairs that act as a defense mechanism, trapping larger airborne particles and preventing them from reaching the lungs.

Functions

Olfaction: The nose detects a vast array of odors through its olfactory cells. Respiration: Serving as the primary passageway for air, the nose conditions inhaled air, adjusting its temperature and humidity levels to be more compatible with the body. Protection: By initiating sneezing, the nose expels irritants from the nasal passages. Sneezing can be triggered by various factors, including foreign particles, intense light (photic sneeze reflex), or physical stimulation of the ear canal.

Clinical Significance

Common Ailments

• Nosebleeds (Epistaxis): Often originating in Kiesselbach's area, or Little's area.
• Nasal Congestion: Typically a symptom of rhinitis, which may be allergic or due to other causes, like nasal spray overuse.
• Anosmia: The loss or decrease in the sense of smell, which can be temporary or permanent, resulting from various conditions such as infections, trauma, or neurodegenerative diseases like Parkinson's.
• Foreign Bodies: The nose can sometimes be a site for foreign objects, especially in children.

Diseases and Conditions

Various systemic diseases and conditions can affect the nose. This includes rhinophyma, skin cancer types like basal cell carcinoma, Wegener's granulomatosis, lupus, rheumatoid arthritis, and infections like syphilis, leprosy, or exposure to certain toxins. Certain conditions, such as acromegaly, can cause abnormal growth of the nose. Samter's triad is a condition characterized by the combination of asthma, nasal polyps, and sensitivity to aspirin.

Surgical Interventions

Rhinoplasty is a common surgical procedure performed to alter the shape or function of the nose for aesthetic or medical reasons.

Safety Considerations

The unique vascular supply to the nose and its vicinity means infections can spread retrogradely to the brain. The region from the corners of the mouth to the bridge of the nose is thus termed the "danger triangle of the face" by medical professionals due to this risk.

See Also

• Respiratory System
• Olfactory System
• Facial Anatomy
• From the Nose to the Eustachian Tube: Information, videos, tips for diving
• Your Nose: The Guardian Of Your Lungs

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