Facial Bones and Sinuses

Facial Bones

The facial bones form the structure of the face and support the organs of sight, smell, and taste. They also provide attachment points for muscles involved in facial expression and mastication.

• Nasal: Forms the bridge of the nose.

• Lacrimal: Small bones forming part of the medial wall of each orbit.

• Frontal: Forehead bone, also forms part of the eye socket.

• Ethmoid: Located between the eyes, contributes to the medial wall of the orbit and the nasal cavity.

• Sphenoid: Forms part of the base of the skull and the sides of the orbits.

• Maxillary: Upper jaw bone, forms part of the orbit, nose, and palate.

• Vomer: Forms the inferior part of the nasal septum.

• Palatine: Forms part of the hard palate and the nasal cavity.

Sinuses

Sinuses are air-filled spaces within the bones of the skull that help lighten its weight and contribute to voice resonance.

• Frontal Sinus: Located in the frontal bone above the eyes.

• Ethmoid Sinus: Located between the nose and the eyes.

• Sphenoid Sinus: Located behind the ethmoid sinuses, near the center of the skull.

• Maxillary Sinus: Largest sinuses, located in the cheekbones.

Nasal Cavity and Associated Structures

Olfactory Epithelium

The olfactory epithelium is a specialized tissue inside the nasal cavity responsible for detecting odors.

Apex and Ala of Nose

• Apex of nose: The tip of the nose.

• Ala of nose: The lateral flared portion of the nostrils.

Nasal Septum

The nasal septum divides the nasal cavity into left and right sides. It consists of bone and cartilage.

• Septal cartilage: The anterior part of the nasal septum.

Nasal Vestibule

The nasal vestibule is the front part of the nasal cavity, just inside the nostrils.

Nasal Conchae

The nasal conchae are curved bony structures that increase the surface area of the nasal cavity, aiding in warming and humidifying air.

• Superior

• Middle

• Inferior

Oral Cavity and Palate

• Uvula: A small fleshy extension at the back of the soft palate.

• Soft palate: The muscular part at the back of the roof of the mouth.

• Hard palate: The bony front part of the roof of the mouth.

Pharynx and Tonsils

• Nasopharynx: The upper part of the pharynx, connecting with the nasal cavity.

• Pharyngeal Tonsils (Adenoids): Lymphatic tissue in the nasopharynx.

• Pharyngotympanic Tubes (Eustachian Tubes): Connect the middle ear to the nasopharynx.

• Oropharynx: The middle part of the pharynx, behind the oral cavity.

• Lingual Tonsils: Located at the base of the tongue.

• Palatine Tonsils: Located on either side of the oropharynx.

• Laryngopharynx: The lower part of the pharynx, leading to the larynx and esophagus.

Hyoid Bone

The hyoid bone is a U-shaped bone in the neck that supports the tongue and is associated with swallowing.

Larynx and Associated Cartilages

Vocal Cords

• True Vocal Cords: Folds of tissue that vibrate to produce sound.

Laryngeal Cartilages

The larynx is composed of several cartilages that provide structure and support for voice production and airway protection.

• Cuneiform Cartilage

• Corniculate Cartilage

• Arytenoid Cartilage

• Thyroid Cartilage: Largest cartilage, forms the Adam's apple.

• Laryngeal Prominence: The visible projection of the thyroid cartilage.

• Cricoid Cartilage: Ring-shaped cartilage below the thyroid cartilage.

• Cricothyroid Ligament: Connects the cricoid and thyroid cartilages.

• Cricotracheal Ligament: Connects the cricoid cartilage to the trachea.

Trachea

• Tracheal Cartilages (Cartilage Rings): C-shaped rings that keep the trachea open.

Bronchial Tree and Lungs

Bronchi and Bronchioles

• Carina: The ridge at the base of the trachea where it divides into the primary bronchi.

• Primary Bronchi: Right and left main bronchi leading to each lung.

• Secondary Bronchi: Lobar bronchi, each serving a lobe of the lung.

• Tertiary Bronchi: Segmental bronchi, serving bronchopulmonary segments.

Alveoli

Alveoli are tiny air sacs in the lungs where gas exchange occurs.

Pulmonary Vessels

• Pulmonary Arteries: Carry deoxygenated blood from the heart to the lungs.

• Pulmonary Veins: Carry oxygenated blood from the lungs to the heart.

Pleura and Pleural Cavity

• Pleural Cavity: The space between the two layers of pleura surrounding each lung.

• Visceral Pleura: The inner layer covering the lungs.

Lung Lobes and Features

• Superior Lobe

• Middle Lobe (right lung only)

• Inferior Lobe

• Cardiac Notch: Indentation in the left lung for the heart.

Mediastinum

The mediastinum is the central compartment of the thoracic cavity, containing the heart, trachea, esophagus, and major vessels.

Thoracic Muscles and Ribs

Ribs

The ribs protect the thoracic organs and assist in breathing.

Intercostal Muscles

• External Intercostal Muscles: Elevate the ribs during inspiration.

• Internal Intercostal Muscles: Depress the ribs during forced expiration.

Diaphragm

The diaphragm is the primary muscle of respiration, separating the thoracic and abdominal cavities.

Respiratory Volumes and Capacities

Respiratory Volumes

Respiratory volumes are measurements of the amount of air moved in and out of the lungs during breathing.

• Tidal Volume (TV): The amount of air inhaled or exhaled during normal breathing.

• Inspiratory Reserve Volume (IRV): The additional air that can be inhaled after a normal inhalation.

• Expiratory Reserve Volume (ERV): The additional air that can be exhaled after a normal exhalation.

• Residual Volume (RV): The air remaining in the lungs after maximal exhalation.

Respiratory Capacities

Respiratory capacities are combinations of two or more respiratory volumes.

• Inspiratory Capacity (IC):

• Functional Residual Capacity (FRC):

• Vital Capacity (VC):

• Total Lung Capacity (TLC):

Anatomical Dead Space

Anatomical dead space refers to the volume of air in the respiratory tract that does not participate in gas exchange (e.g., trachea, bronchi).

Summary Table: Respiratory Volumes and Capacities