Maxillofacial Trauma and Lower Lip Paresthesia Analysis

The question describes a patient experiencing maxillofacial trauma with specific neurological symptoms: paresthesia of the lower lip. Paresthesia refers to abnormal sensations like numbness or tingling. The key is to identify which injury directly affects the nerve supply to the lower lip.

Nerve Supply to the Lower Lip

• The sensation of the lower lip is primarily supplied by the mental nerve.
• The mental nerve is a branch of the inferior alveolar nerve.
• The inferior alveolar nerve runs within the mandible and exits via the mental foramen, located on the body of the mandible.

Evaluating Injury Options

• Option 1: Fracture involving infraorbital foramen: This foramen transmits the infraorbital nerve, which supplies the *upper* lip, lower eyelid, and side of the nose. Injury here causes upper lip, not lower lip, paresthesia.
• Option 2: Fracture involving floor of orbit: While potentially associated with facial trauma, orbital floor fractures are less directly linked to isolated lower lip sensory loss compared to mandibular injuries.
• Option 3: Fracture of the mandibular body: A fracture in the mandibular body, especially near the mental foramen, can directly damage or compress the mental nerve. This is the most direct cause of paresthesia of the lower lip.
• Option 4: Fracture of temporal bone: Temporal bone fractures affect cranial nerves related to hearing, balance, and facial movement (e.g., CN VII), not the sensory nerves of the lower lip.

Conclusion

Given the specific symptom of paresthesia of the lower lip following maxillofacial trauma, a fracture of the mandibular body is the most probable diagnosis as it directly involves the path of the mental nerve responsible for lower lip sensation.