The difference between the posture inside a hammock or an infant carrier is the curvature of the spinal column. In the infant carrier your baby is in a sitting position - meaning the weight of the head compresses spinal column, dorsal vertebras and lumbar vertebras. In a hammock your baby is lying on its back. The spinal column is rounded evenly over the full length. There is no pressure point as each part of the spinal column is stressed evenly.