Background: Congenital rib absence might be the absence of either single or several ribs or all ribs at one side. The sporadic cases were ever reported over years.

Methods: A full-term Chinese infant was noticed that both shoulders were asymmetric significantly with left sagged shoulder at the age of 6 months. Her left hand could not rise over her shoulder and her gripping power was a little bit poor. She presented a good mental and motor development without other deformity. Imaging examination was given to the infant  for diagnosis.

Results: The absence of left three ribs was found on her chest X-ray film. The results of three-dimensional CT reconstruction image confirmed the absence of left 1st-4th ribs, the overlapping of 5th-7th ribs on the left side and 2nd-3rd ribs on the right side.

Conclusions: Simple congenital absence of multiple ribs is confirmed based on her manifestation and imaging results.

Key words: infant; congenital rib absence; three-dimensional CT reconstruction