Rhinology includes nasal dysfunction and sinus diseases. The nostrils also had an intranarial septum, which separated the nasal passage from the sinus. A pilonidal cyst is a pilonidal sinus that is obstructed. The urinary bladder forms from the urogenital sinus. Lateral to the turbinates is the medial wall of the maxillary sinus. Fainting may result from subclavian steal syndrome or carotid sinus hypersensitivity. Occasionally a preauricular sinus or cyst can become infected. Expansion of the cyst causes erosion of the floor of the maxillary sinus. Material from the cyst drains through the pilonidal sinus. An OAC is an abnormal physical communication between the maxillary sinus and the mouth. Carotid sinus syncope is due to pressure on the carotid sinus in the neck. This part of the artery is known as the carotid sinus or the carotid bulb. Ivabradine is contraindicated in sick sinus syndrome. These include the origin of the artery from the right aortic sinus. The evidence or elective treatment of pilonidal sinus disease is poor.