What is the normal size of a lymph node?

The normal size of a lymph node is typically considered to be less than 1 cm. Lymph nodes serve as a crucial component of the immune system, filtering lymph fluid and contributing to the body's response to infection. In clinical practice, lymph nodes that measure more than 1 cm in the longest dimension are often considered abnormal and may be indicative of an underlying pathological process, such as infection, inflammation, or malignancy.

In contrast, options that suggest sizes greater than 1 cm do not conform to standard definitions of normal lymph node size. A lymph node larger than 1 cm is generally evaluated further to understand its clinical significance, making the threshold of 1 cm the critical cutoff for what is regarded as a typical size for healthy lymph nodes. Thus, the assertion that lymph nodes under 1 cm are normal aligns with established medical guidelines and aids in diagnostic practices.