Internal

Internal means to the inside or closer to the center of the an organ or cavity.

For instance, heart, lungs are examples of internal body organs situated within the thoracic cavity. Liver and stomach are examples of internal organs situated within the abdominal cavity.

Similarly, if we take the example of the muscles of anterior abdominal wall, we will find three main muscles situated from outside to inside. The outermost muscle is called external oblique as it is externally situated compared to the internal oblique muscle, which is more internally situated.