A newborn delivered by forceps exhibits an asymmetrical Moro reflex. This finding is indicative of injury to:

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Question

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AIIMS NORCET 7 Prelims Memory Based Paper 2024

Answer 1

Correct Answer: Brachial plexus

Rationale:

The Moro reflex, also known as the startle reflex, is an involuntary response that is present at birth and usually disappears by 4-6 months of age. It is elicited by a sudden loss of support or a loud noise, causing the baby to extend and then retract the arms and legs.
An asymmetrical Moro reflex can indicate an injury to the nerves that control the movement of the arms, such as those in the brachial plexus.
The brachial plexus is a network of nerves that originate from the spinal cord in the neck (cervical and upper thoracic regions) and control muscle movements and sensation in the shoulder, arm, and hand.
Injuries to the brachial plexus can occur during delivery, especially if forceps are used, leading to conditions such as Erb's palsy or Klumpke's palsy, which can result in weakness or paralysis of the affected arm.

Explanation of Other Options:

Femoral plexus

Rationale: The femoral plexus, also known as the lumbar plexus, is a network of nerves that provide motor and sensory function to the lower abdomen, thighs, and legs. Injuries to the femoral plexus are not typically associated with an asymmetrical Moro reflex, as they do not affect the upper limbs.

Sacral plexus

Rationale: The sacral plexus is a network of nerves that provide motor and sensory function to the pelvis, buttocks, genitals, thighs, calves, and feet. Similar to the femoral plexus, injuries to the sacral plexus do not affect the upper limbs and therefore do not cause an asymmetrical Moro reflex.

Cervical plexus

Rationale: The cervical plexus is a network of nerves located in the neck that provides motor and sensory function to the neck, shoulders, and diaphragm. While the cervical plexus can be involved in some upper limb movements, it does not control the specific muscles responsible for the Moro reflex, making it an unlikely cause of an asymmetrical response.

Conclusion:

In conclusion, an asymmetrical Moro reflex in a newborn delivered by forceps is most indicative of an injury to the brachial plexus. This network of nerves controls the movements and sensations in the shoulder, arm, and hand, and can be injured during a difficult delivery.