Understanding Sinuses and Their Causes A sinus is a blind tract lined by granulation tissue extending from an epithelial surface into surrounding tissues. It can be congenital, like pre-auricular sinuses, or acquired due to conditions such as tuberculosis (most common in India), actinomycosis with sulfur granules discharge, pilonidal sinuses in the natal cleft area, chronic osteomyelitis discharging bone fragments, or tuberculous neck sinuses. These examples highlight various presentations of sinus-related issues.
Fistulas: Types and Underlying Conditions A fistula represents abnormal communication between two epithelial surfaces—either internal viscera or external body areas—and may be congenital (e.g., brachial fistula) or acquired through trauma (post-surgery/accidents), inflammation (tuberculosis/Crohn's disease), malignancies eroding adjacent organs' walls. Examples include tracheoesophageal fistulas causing neonatal distress corrected surgically; arteriovenous connections altering vein characteristics for dialysis use; enterocutaneous types leaking fecal matter externally post-complications.