Valve of Thebesius is present at the opening of

Options

A. postcaval into right atrium
B. coronary sinus into right atrium
C. precaval into right atrium
D. pulmonary veins into left atrium

Answer

To solve the question regarding the location of the Valve of Thebesius, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks where the Valve of Thebesius is located. It provides four options related to the heart's anatomy.

2. **Identifying the Valve of Thebesius**: The Valve of Thebesius is known as a remnant of the embryonic sinoatrial valve. It is typically a fold of tissue.

3. **Locating the Valve**: The Valve of Thebesius is specifically found at the opening of the coronary sinus, which drains blood from the heart muscle itself into the right atrium.

4. **Evaluating the Options**:
- **Option 1**: Postcaval into right atrium - Incorrect, as this is related to the inferior vena cava.
- **Option 2**: Coronary sinus into right atrium - Correct, as this is where the Valve of Thebesius is located.
- **Option 3**: Pre-caval into right atrium - Incorrect, as this refers to the superior vena cava.
- **Option 4**: Pulmonary veins into the left atrium - Incorrect, as this is related to the left side of the heart.

5. **Conclusion**: Based on the anatomical knowledge, the Valve of Thebesius is present at the opening of the coronary sinus into the right atrium.

### Final Answer:
The Valve of Thebesius is present at the opening of the **coronary sinus into the right atrium** (Option 2).

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