Neonatal asymmetric crying facies: a new look at an old problem
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Updated: Aug 19, 2026
Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale
Published on: August 25, 2014
Samuel O Sapin1, Alvin A Miller, Harold N Bass
1David Geffen School of Medicine at UCLA, Los Angeles, California 91403, USA.
Insights
Neonatal asymmetric crying facies, a condition affecting 1 in 160 newborns, results from facial nerve issues. Differentiating causes like nerve compression versus developmental problems is key for appropriate infant care.
Area of Science:
- Pediatrics
- Neurology
- Genetics
Background:
- Neonatal asymmetric crying facies (NACF) presents as unilateral partial peripheral facial nerve paralysis.
- Affecting approximately 1 in 160 live births, NACF has two primary etiologies: facial nerve compression or developmental abnormalities.
- Developmental cases may involve major malformations in about 10% of instances.
Purpose of the Study:
- To differentiate the causes of neonatal asymmetric crying facies.
- To highlight overlooked clinical signs and diagnostic tools for NACF management.
Main Methods:
- Review of clinical presentation and known etiologies of NACF.
- Discussion of diagnostic utility of ultrasound imaging and electrodiagnostic testing.
- Identification of associated malformations and specific physical clues.
Main Results:
- Facial nerve compression typically resolves spontaneously, unlike developmental causes.
- Mandibular asymmetry and maxillary-mandibular asynclitism are significant indicators of nerve compression.
- Ultrasound and electrodiagnostic tests aid in differential diagnosis.
Conclusions:
- Accurate diagnosis of NACF etiology is crucial for predicting prognosis and guiding management.
- Recognizing subtle physical signs can improve early identification of nerve compression.
- Advanced imaging and testing offer valuable support for clinical assessment.
Abstract:
Neonatal asymmetric crying facies, described 75 years ago, is a clinical phenotype resembling unilateral partial peripheral facial nerve paralysis, with an incidence of approximately 1 per 160 live births. The cause is either facial nerve compression or faulty facial muscle and/or nerve development. Spontaneous resolution is expected with the former, but not necessarily with the latter etiology. Approximately 10% of the developmental cases have associated major malformations. Mandibular asymmetry and maxillary-mandibular asynclitism (non-parallelism of the gums) are frequently overlooked visual clues to nerve compression. Ultrasound imaging of facial muscles and electrodiagnostic testing may be useful for differential diagnosis and management.
