HESI General Chairside Assisting Practice Exam

Where does the blood and nerve supply of a tooth enter and exit?

1. Crown

2. Apical foramen

3. Dentin

4. Cementum

The correct answer is: Apical foramen

The apical foramen is the critical entry and exit point for the blood vessels and nerves that supply the tooth. This small opening is located at the tip of the tooth's root and allows for the passage of the dental pulp tissue, which is rich in nerves and blood vessels, into and out of the root canal. The blood supply nourishes the tooth and maintains the vitality of the pulp, while the nerve supply is responsible for sensation, including pain. The health of the tooth relies significantly on this supply, as it enables the tooth to respond to thermal and tactile stimuli. In contrast, the crown is the visible part of the tooth and does not serve as a point of entry or exit for dental nerves and blood vessels. Dentin is the hard tissue beneath the enamel that makes up the bulk of the tooth and does not have direct access to the nerve and blood supply. Cementum is the mineralized tissue that covers the roots of teeth and anchors them in the jawbone, but like the crown and dentin, it does not provide a pathway for the blood and nerve supply of the tooth. Therefore, the apical foramen is uniquely positioned to facilitate these vital connections.