Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)
Applied Basic Sciences
A solid grasp of basic sciences is essential for clinical OMFS. Focus on head and neck anatomy: the course and branches of the facial nerve, the trigeminal nerve divisions, the blood supply (external carotid branches), and the lymphatic drainage of the oral cavity. Understand the physiology of wound healing, bone metabolism, and the stress response. In pathology, know the difference between hyperplasia, hypertrophy, metaplasia, dysplasia, and neoplasia; recognize the cardinal signs of inflammation and the phases of healing. Microbiology covers the oral flora, common pathogens in odontogenic infections, and the principles of antibiotic therapy.
Traps in exams: Questions often test the facial nerve branches and their functions; remember "Ten Zebras Bit My Coccyx" for temporal, zygomatic, buccal, marginal mandibular, and cervical branches. Another trap is the lingual nerve vs inferior alveolar nerve in third molar surgery. In physiology, distinguish between primary and secondary healing. In pathology, dysplasia is not cancer but a pre-malignant change. In microbiology, know that Streptococcus viridans is the most common cause of odontogenic infections, but anaerobes predominate in deep space infections.
Rule of thumb: For nerve injuries, the marginal mandibular nerve is at risk in submandibular incisions; test by asking the patient to grimace. For antibiotic prophylaxis, follow current guidelines (e.g., AHA for infective endocarditis).
Worked example: A patient has numbness of the lower lip after third molar extraction. Which nerve is likely injured? The inferior alveolar nerve, as it runs in the mandibular canal. If the tongue is also numb, the lingual nerve may be involved.