< 1/1000 live births
Maternal Risk Factors: low socioeconomic class, young, unmarried, smoking, drug abuse (methadone, cocaine), minority group
Child Risk Factors: prematurity, male, age 3 weeks and 6 mos (peak 2-4 mos), low birth weight, multiple birth, SIDS in prior sibling, brain and skeletal growth retardation.
Environmental Risk Factors: low temperature, between midnight and breakfast, overcrowded home
1992 The American Academy of Pediatrics Task Force on Infant Positioning and SIDS: placed on side or back; 1996: back only.
Time for a car in the sun to heat up: trunk of white car cooler than blue, passenger compartment at 89 - 97 degrees can heat up to 117-136 degrees F. On a 95 degree day in 20 min 120 degrees. In 40 minutes 150 degrees.

Radiological evidence in 1/3.
Location, nature & multifocality.
Specific for child abuse in newborn period:
- Epiphyseal-metaphyseal fractures of the long bones of arms and legs ("corner fractures" and "bucket-handle" fractures).
- Rib fractures (outside of neonatal period). [Rib fx from CPR rare, are anterior at sterno-chondral junction and MCL].
Suggestive but not specific:
- Multiple repetitive fractures of other areas.
- Spiral fractures in the non-walking child.
- Fractures of the distal end of clavicle (sudden traction).
- Subperiosteal hemorrhage (twisting).

Osteogenesis Imperfecta:
Mutations in a1 and a2 chain of Type 1 collagen.
AD transmission.
Multiple fractures, blue sclerae, joint laxity, sensorineural hearing loss, dental imperfections and skeletal fragility.
4 Types with Type 2 fatal in utero and Type 1 more often an acquired mutation with a normal life span but increased fractures in childhood.
Micro: osteoporosis, cortical thinning and trabeculae thinning. Some variants have foci of hypercellular woven bone.