Chicken breast deformity is generally considered as hereditary as funnel chest deformity. Most people think that it is caused by the overgrowth of ribs and costal cartilage, and sternal deformity is secondary to rib deformity. Chest wall deformities that affect respiratory circulation, such as funnel chest, chicken breast and pectoral muscle fissure, need surgical correction in addition to the mental burden and personality influence caused by the deformities. Chicken breast deformity is generally considered as hereditary as funnel chest deformity. Most people think that it is caused by the overgrowth of ribs and costal cartilage, and sternal deformity is secondary to rib deformity. Some people think it is related to the abnormal development of diaphragm attachment. The front of diaphragm is undeveloped, not attached to xiphoid process and rib arch, but attached to the back rib arch of rectus abdominis sheath, but attached to the back of rectus abdominis sheath. When inhaling deeply, the upper part of rectus abdominis is pulled inward, and the muscles of the overgrown lateral part of diaphragm contract, which makes Hausdorf deeper, while the lower part of sternum moves forward without diaphragm support, resulting in chicken breast deformity. Others believe that chicken breast deformity is related to repeated chronic respiratory infections. Long-term chronic respiratory infection reduces lung tissue compliance and respiratory function. In order to meet the needs of breathing, the diaphragmatic movement is strengthened, pulling Hausdorf to invaginate, and gradually forming chicken breast deformity. Most chicken breasts are not found immediately after birth like pectus excavatum, and are often gradually noticed after five or six years old. Generally, there are few symptoms of pressing the heart and lungs in chicken breasts. Severe chicken breast often has recurrent upper respiratory tract infection and bronchial wheezing, which leads to poor activity endurance and easy fatigue. More importantly, patients have a great mental burden because of deformity.
The chicken breast is opposite to the funnel chest, and the sternum protrudes forward. There are generally two kinds. The first is the common sternal protrusion, that is, the lower part of the sternum moves forward more obviously than the upper part. The attachment of xiphoid process is often the most prominent. The longitudinal surface of the pectoral muscle is arched, and the 4-8 costal cartilage on both sides is in the shape of a deep groove parallel to the sternum, which makes the protruding part more obvious, just like a giant hand grasping the sternum and crushing the costal cartilage on both sides. Another kind of chicken breast is rare. The costal cartilage of the sternum stalk, the upper part of the sternum body and the upper chest protrude forward, the middle part of the sternum body bends backward, and the lower part of the pectoral muscle protrudes forward. The sagittal plane of the sternum is Z-shaped, and the costal cartilage on both sides is also depressed inward, so some people call this deformity funnel chest.