In an infant with no head tilt or rotation and normal sternocleidomastoid muscles but a right‑side body tilt when supine, is congenital muscular torticollis likely or is this simply a positional preference?

This is most likely a positional preference, not congenital muscular torticollis

With normal sternocleidomastoid muscles and no head tilt or rotation, congenital muscular torticollis (CMT) is effectively ruled out, and the right-side body tilt when supine represents a benign positional preference that requires only repositioning strategies and tummy time.

Why This Is Not CMT

CMT is defined by unilateral shortening or fibrosis of the sternocleidomastoid muscle, which produces characteristic findings that are absent in this infant 1, 2:

• Ipsilateral head tilt (toward the affected side)
• Contralateral rotation (face turned away from affected side)
• Palpable SCM tightness or mass in some cases
• Restricted cervical range of motion

The absence of head tilt, rotation abnormality, and normal SCM examination excludes all three classifications of CMT 3:

• Postural torticollis (44.9% of cases) - still shows head tilt
• Muscular torticollis with joint limitation (31.4%) - has restricted ROM
• Congenital torticollis with nodule (23.7%) - has palpable SCM mass

What This Actually Represents

A body tilt without head involvement is a positional preference - essentially a habitual asymmetric posture that infants develop from spending time in one position. This is fundamentally different from structural muscle pathology.

Management Approach

Implement supervised tummy time and positional variation immediately 4:

• Daily supervised tummy time while awake - start as early as possible to promote motor development and prevent positional deformities
• Vary head position during sleep - alternate which direction the infant faces when placed supine
• Increase upright holding time when the infant is not sleeping
• Avoid prolonged time in car seats or sitting devices outside of travel

The AAP guidelines emphasize that positional plagiocephaly (and by extension, positional body preferences) are most likely when infants spend little time in varied positions 4.

Reassurance Points

• This positional preference will resolve spontaneously with repositioning strategies
• No physical therapy referral is needed at this time
• Continue to place the infant supine for all sleep to reduce SIDS risk 5
• Once the infant can roll both ways (typically 4-6 months), allow them to assume their preferred sleep position 4

Red Flags That Would Change This Assessment

Refer for evaluation if you observe:

• Development of head tilt or rotational preference
• Palpable SCM tightness or mass
• Restricted cervical range of motion
• Facial asymmetry or plagiocephaly developing
• Failure to achieve motor milestones 6

The key distinction is that CMT is a structural muscle problem with specific head positioning abnormalities, while this infant has a postural habit affecting body position only, with completely normal head and neck examination.