Nose Anatomy and Function

Nose Anatomy and Function

• The nose functions as the body's primary organ for smell, and is part of the respiratory system
• Air enters the body through the nose and passes over specialized olfactory cells where the brain recognizes smells
• Hairs in the nose filter foreign particles from the air
• Air is warmed and humidified as it passes through the nasal passages before reaching the lungs
• The nose has an external portion covered in skin, and an internal nasal cavity
• The nose consists of bone, cartilage, and a mucous membrane lining

External and Internal Nasal Structures

• The external nose includes a bridge (upper portion), tip, and two oval openings called nares
• The nasal cavity is positioned between the mouth's roof and the cranium, extending from the anterior nares (nostrils) to the posterior nares which open into the nasopharynx
• The nasal septum divides the nasal cavity into two halves
• Kiesselbach's area, located in the front of the nasal septum, is rich with blood vessels and is a common site for nosebleeds
• The inner part of the nose is situated above the mouth's roof

Paranasal Sinuses

• Four pairs of paranasal sinuses (frontal, maxillary, ethmoidal, and sphenoidal) are located in the skull
• These sinuses are air-filled chambers that function during speech
• Paranasal sinuses are lined with ciliated mucous membranes that trap and expel debris
• Sinuses are prone to infection when blocked
• Frontal sinuses (above the eyes) and maxillary sinuses (in the upper jaw) can be examined by a nurse
• Ethmoidal and sphenoidal sinuses are smaller and located deeper within the skull, making them inaccessible to examination
• Sinus cavities reduce the skull's weight and contribute to resonance

Detailed Nasal Structures

• External nostrils consist of two chambers divided by the septum
• The septum is composed of bone and cartilage, covered by a mucous membrane
• Cartilage provides shape and support to the nose's outer part
• Nasal passages are lined with mucous membranes and tiny hairs (cilia)
• Sinuses comprise four pairs of air-filled cavities
• Ethmoid sinus is located inside the face around the nose's bridge area, present at birth and grows continuously
• Maxillary sinus is located inside the face around the cheek area, present at birth and grows continuously
• Frontal sinus is located within the forehead area, and does not develop until around 7 years of age
• The sphenoid sinus is located deep in the face, behind the nose, and does not typically develop until the teen years

Throat (Pharynx)

• The throat (pharynx) is located behind the mouth and nose
• It functions as a muscular passage for both food and air
• The upper part of the throat is called the nasopharynx
• The lower part of the throat is called the oropharynx
• Below the oropharynx is the laryngopharynx

Palatine and Lingual Structures

• The soft palate, anterior and posterior pillars, and the uvula connect to form arches behind the tongue
• Masses of lymphoid tissue are referred to as the palatine tonsils
• Palatine tonsils are located on both sides of the oropharynx at the end of the soft palate, between the anterior and posterior pillars
• Lingual tonsils lie at the base of the tongue
• Pharyngeal tonsils (adenoids) are located high in the nasopharynx
• Tonsils are masses of lymphoid tissue that help protect against infection

Nose and Sinuses Assessment

• Inspect and palpate the external nose
• Check the nostril airflow by occluding one nostril at a time, and asking the client to sniff
• Inspect the internal nose with an otoscope with a short, wide tip or a nasal speculum and penlight
• Palpate the maxillary and frontal sinuses for tenderness by pressing up on the brow on each side of the nose

Mouth and Oropharynx

• The mouth and oropharynx consist of structures including the lips, oral mucosa, tongue, mouth floor, teeth, gums, hard and soft palate, uvula, salivary glands, tonsillar pillars and tonsils

Salivary Glands

• Three pairs of salivary glands (parotid, submandibular, and sublingual) empty into the oral cavity
• Parotid glands are the largest, emptying through Stensen's duct opposite the second molar
• Submandibular glands empty through Wharton's duct on either side of the frenulum on the mouth floor
• The sublingual salivary gland lies on the mouth floor and has numerous openings

Dental Health Problems

• Dental caries (cavities) and periodontal disease (pyorrhea) frequently affect teeth, and are often associated with plaque and tartar deposits
• Plaque is an invisible soft film that adheres to the enamel surface and consists of bacteria, saliva molecules, and remnants of epithelial cells and leukocytes
• Tartar is a visible, hard deposit of plaque and dead bacteria that forms in the gum lines, and can disrupt bone tissue

Periodontal Diseases

• Gingivitis involves red, swollen gingiva (gums), bleeding, receding gum lines, and formation of pockets between teeth and gums
• Glossitis is inflammation of the tongue
• Stomatitis is inflammation of the oral mucosa
• Parotitis is inflammation of the parotid salivary gland
• Sordes is the accumulation of foul matter, such as foods, microorganisms, and epithelial elements on the teeth and gums

Lips and Buccal Mucosa Assessment

• Inspect the outer lip for symmetry of contour, color, and texture
• Inspect and palpate the inner lips and buccal mucosa for color, moisture, texture, and presence of lesions

Teeth and Gums Assessment

• Inspect the teeth and gums while examining the inner lips and buccal mucosa, viewing the buccal mucosa surface from top to bottom, and back to front, repeating on the other side
• Examine the back teeth, and use index fingers to retract the cheek for proper vision of molars
• Inspect the gums around the molars and observe for bleeding, color, edema, and lesions

Tongue, Mouth Floor, Palates, and Uvula Assessment

• Inspect the tongue surface for position, color, and texture
• Inspect tongue movement
• Inspect the base of the tongue, the mouth floor, and the frenulum
• Inspect the hard and soft palate for color, shape, texture, and presence of bony prominences
• Inspect the uvula for position and mobility while assessing the palates

Oropharynx and Tonsils Assessment

• Inspect the oropharynx for color and texture, one side at a time to avoid eliciting a gag response
• Inspect tonsils (behind the fauces) for color, discharge, and size