Congenital muscular torticollis (CMT) is the most common type of torticollis. CMT is present at birth and is the third highest incidence of congenital musculoskeletal abnormalities in infants. There are several risk factors that could predispose a child to develop CMT, however it could also occur due to random positioning of the baby in utero.
Possible risk factors for developing CMT:
- Constraint position or extreme head posturing in the womb
- Difficult or prolonged labor and delivery
- Large birth weight and/or long birth length
- Multiple births
- Low amniotic fluid
CMT is typically the result of in utero space constraint, or how the baby is positioned in the womb, particularly during the last 8 weeks of pregnancy. When the baby is lying the womb such that the head is turned or tilted towards a certain position for a period of time, the neck muscles adaptively shorten and thus become relatively tighter on one side compared to the other. Furthermore, if the head is resting against a bony prominence such as the rib cage or the pelvic bone, cranial mishapening can also begin in utero. Once the baby is born, the neck muscle is already predisposed to be biased and more comfortable turning or tilting towards one side, compared to the other. The primary neck muscle involved in this process is called the sternocleidomastoid, however other muscle groups can also subsequently become tight or “shortened” as a compensatory response.
Parents who observe the signs and symptoms in their child should seek an evaluation from a pediatric physical therapist to determine whether the child has muscular torticollis, as this is by far the most common cause for asymmetric head posturing. The child’s pediatrician will be able to rule out any other medical causes that may contribute to the torticollis such as anatomical/spinal, neurological, optical, or gastrointestinal disorders- although these causes are much more rare.