A hard lump in the middle of the ribs may be related to the following causes: 1. There may be an occupying lesion, such as a local tumor, and a protruding mass may be felt in the subcutaneous area between the two ribs, with heavy adhesions to the surrounding tissues and a surface that is not smooth to the touch and has a hard texture. 2. There may be excessive osteophytes, and if there was an old rib fracture in the past, it may produce a large amount of bony scab growth during its recovery. The patient is often seen doing extensive activities involving the trunk, or running vigorously resulting in accelerated breathing. At this time, the intercostal muscles spasm, followed by a hard mass felt in the middle of the two ribs.