part of part of has part has part characteristic of inheres in has modifier Decreased number of sternal ossification centers HP:0006611 UMLS:C1856223 A less than normal number of sternal ossification centers. The sternum is initially formed from bilateral sternal plates that chondrify and begin to fuse with ribs at 10 weeks gestational age. Ossification starts in the manubrium and upper part of the sternal body at the 6th month, in the middle of the sternal body at the 7th month, in the lower part of the body during the 1st postnatal year and in the xiphoid process between years 5 and 18. The number of ossification centers vary up to six, and it is the ossification centers that are visualized by prenatal ultrasound. This term describes a reduction in the number of ossification centers compared with age-related norms. Decreased number of sternal ossification centres Abnormal sternal ossification abnormal decreased amount sternum ossification center