Which are the causes of Erb's Palsy?

Erb's Palsy is primarily caused by a traction injury to the brachial plexus—a network of nerves near the shoulder—typically occurring during a difficult childbirth. While most cases result from physical stress on the nerves during delivery, the underlying etiology involves mechanical stretching or tearing of these nerve roots rather than genetic or metabolic disorders.

What are the primary causes of Erb's Palsy?

The fundamental cause of Erb's Palsy is trauma to the upper trunk of the brachial plexus (specifically the C5 and C6 nerve roots). Think of these nerves as a bundle of electrical wires connecting the spinal cord to the arm; when the shoulder is forced downward while the head is pushed to the side during delivery, these "wires" are stretched beyond their elastic limit, resulting in neuropraxia (temporary shock), axonotmesis (damage to the nerve fibers), or neurotmesis (a complete rupture).

Is Erb's Palsy a hereditary or genetic condition?

Erb's Palsy is not considered a genetic or hereditary condition. There are no known gene mutations or chromosomal abnormalities that cause this injury. Because the etiology is mechanical, it does not follow the inheritance patterns seen in genetic syndromes, though anatomical variations in the maternal pelvis or fetal size can influence the risk of birth complications.

What are the known risk factors for Erb's Palsy?

It is important to distinguish between the cause (the physical nerve injury) and the risk factors (conditions that increase the likelihood of that injury). Clinical literature identifies several key risk factors:

• Shoulder Dystocia: Where the infant's shoulder becomes lodged behind the mother’s pubic bone.


• Macrosomia: A birth weight exceeding 4,000–4,500 grams.


• Prolonged second stage of labor: Extended duration of the pushing phase.


• Instrument-assisted delivery: The use of vacuum extraction or forceps.


• Maternal diabetes: Often associated with larger fetal size.

What does current research say about the etiology of Erb's Palsy?

While the mechanical nature of Erb's Palsy is well-understood, current research focuses on early intervention and nerve regeneration. Scientists are investigating how to better predict Erb's Palsy through advanced prenatal imaging and how to optimize the timing of surgical nerve grafts to improve functional outcomes for children affected by Erb's Palsy.

Next steps

• Consult a pediatric neurologist or an orthopedic surgeon specializing in brachial plexus injuries.


• Inquire about physical and occupational therapy, which are the cornerstones of recovery for Erb's Palsy.


• Connect with the Erb's Palsy community at DiseaseMaps.org to share experiences and find support.

Medical disclaimer: This content is for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Brachial Plexus Birth Injury


• Orphanet: Brachial plexus birth palsy


• MedlinePlus: Brachial plexus injury


• The American Academy of Orthopaedic Surgeons (AAOS): Brachial Plexus Birth Palsy