Overview of the Face and Related Structures

The Face

• The face is the anterior aspect of the head located anterior to the ears, extending from the forehead to the chin. The shape of the face is influenced by the underlying bones, muscles, and the amount of fat present. Notably, there is no deep fascia in the face.

Skin and Soft Tissue

• The skin of the face contains numerous sweat and sebaceous glands. It is connected to the underlying bones by loose connective tissue that includes embedded structures such as muscles and fat.

• The face contains:

  • Muscles: Primarily muscles of facial expression and two muscles involved in mastication (chewing).

  • Nerves:

    • Motor: Facial nerve (CRANIAL NERVE VII)

    • Sensory: Trigeminal nerve (CRANIAL NERVE V)

  • Blood Vessels: Including arteries and veins.

Primary Muscles of Facial Expression

• Muscles responsible for facial expressions are situated within the superficial fascia of the face and may influence the orifices of the eyes, nose, and mouth.

• Key characteristics of these muscles include:

  1. Absence of deep fascia in the face.

  2. Attached at one end to bony structures and at the other to the skin.

  3. Lacking true tendons, they usually terminate into the skin.

  4. Innervated by the facial nerve (VII).

Main Muscles of Facial Expression

• Significant muscles include:

  • Occipitofrontalis: Responsible for raising the eyebrows and creating horizontal wrinkles on the forehead.

  • Orbicularis Oculi: Circular muscle surrounding the eye, functioning as a sphincter to close the eyelids.

  • Orbicularis Oris: Circular fibers around the mouth that close the lips.

  • Zygomaticus Major and Minor: Muscles that elevate the upper lip and contribute to smiling.

  • Buccinator: Muscle of the cheek that helps compress the cheek against the teeth.

  • Levators and Depressors of the Lips: Muscles that modulate facial expressions by raising or lowering the lips.

  • Platysma: A muscle extending from the chest and shoulder to the jaw, involved in facial expression.

Muscles Functionality

• The muscles serve dual purposes:

  • Acting as sphincters or dilators at the orifices (eyes, nostrils, mouth).

  • Modifying facial expressions, thus enhancing communication through non-verbal cues.

• Tend to function either as dilators (elevating or depressing) or as sphincters (circular fibers).

Facial Nerve and Its Branches

• The facial nerve emerges from the brainstem, traverses the internal auditory meatus, and expands into several branches as it reaches the face:

  • Temporal Branches: Innervate muscles around the forehead.

  • Zygomatic Branches: Innervate muscles responsible for eye region movement.

  • Buccal Branches: Serve muscles controlling the lips and cheek.

  • Mandibular Branches: Control muscles moving the lower parts of the face.

  • Cervical Branches: Typically innervate the platysma muscle in the neck.

Sensory Innervation of the Face

• The facial sensory supply is primarily managed by the trigeminal nerve (V), responsible for sensation to the face, teeth, and certain parts of the oral cavity.

  • Divisions of the Trigeminal Nerve:

    • Ophthalmic (V1): Sensory function, includes branches reaching the forehead and upper eyelid.

    • Maxillary (V2): Supplies the mid-face, providing sensory innervation to areas like the cheeks, upper lip, and nasal cavity.

    • Mandibular (V3): Mixed function, supplying sensation to the lower face and motor functions to muscles of mastication.

Vascular Supply of the Face

• The facial arterial supply consists of branches from the external carotid artery, notably:

  • Facial Artery: Major contributor supplying various facial structures, such as the superficial and deep facial areas.

  • Temporal Artery: Provides blood supply to the scalp and upper facial structures.

Summary of Functions

• The face’s musculature and nerve supply play critical roles not only in facial expressions and sensory functions but also in mastication and various aesthetic aspects crucial in human interaction. The integration of these anatomical features underlines the complexity of facial anatomy in both functional and clinical contexts.