L1 Head & Neck

Head and Neck Anatomy

• The head and neck are complex anatomical areas
• The head is made up of compartments formed by bone and soft tissue.
• Compartments include:
  • Cranial cavity: Largest compartment, houses the brain and meninges
  • Two ears: Located within the floor of the cranial cavity
  • Two orbits: Cone-shaped chambers, contain the eyes
  • Two nasal cavities: Upper part of respiratory tract
  • Oral cavity: Inferior to the nasal cavities
• The nasal cavities (nostrils) open anteriorly and have posterior openings (posterior nasal apertures).
• These are air-filled extensions (paranasal sinuses) and project into the surrounding bones, and the maxillary sinuses.
• The face is the anterior aspect, contains muscles that move the skin
• The scalp covers the superior, posterior, and lateral regions of the head.
• The neck extends from the head to the shoulders.
  • Its superior boundary is the mandible and bone features on the posterior skull
  • The posterior neck is higher than the anterior neck, connecting the cervical viscera, with openings to the nasal and oral cavities.
  • The inferior boundary of the neck runs from the sternum and clavicle, to the acromion.
  • The inferior limit of the neck is less defined posteriorly, but is approximated along the line between the acromion and spinous process vertebra CVII.

Neck Compartments

• The neck has four primary compartments enclosed by a musculofascial collar.
  • Vertebral compartment: Houses cervical vertebrae and associated postural muscles.
  • Visceral compartment: Holds glands such as the thyroid, parathyroid, and thymus, and portions of the respiratory and digestive tracts.
  • Two vascular compartments: Each side houses major blood vessels and the vagus nerve
• Larynx and Pharynx: Specialized structures related to the digestive and respiratory systems.
  • Larynx: Upper part of the lower airway, connected to the trachea and hyoid bone.
    • Multiple cartilages form the larynx's framework with a hollow channel whose size adjusts via surrounding soft tissue.
    • Two vocal folds project towards each other inside the laryngeal cavity
  • Pharynx: Funnel-shaped chamber, open to the nasal cavities, oral cavity, and larynx. Openings to the esophagus below.
    • Three parts: nasopharynx (behind nasal cavities), oropharynx (behind oral cavity), laryngopharynx (behind larynx).

Head and Neck Functions

• Protection: Protects upper parts of the respiratory and digestive tracts.
• Communication: Facilitates communication through vocalization.
• Positioning: Positions the head.
• Connects: Connects the upper and lower respiratory and digestive tracts.