False about Duane’s retraction syndrome
**Core Concept**
Duane's retraction syndrome is a congenital eye movement disorder characterized by limited or absent abduction of the eye, often accompanied by retraction of the globe or narrowing of the palpebral fissure upon adduction. This condition is usually associated with anomalies in the superior oblique and lateral rectus muscles.
**Why the Correct Answer is Right**
The primary pathophysiology of Duane's retraction syndrome involves a deficiency or absence of the sixth cranial nerve (abducens nerve) or its associated muscle, the lateral rectus. In some cases, the superior oblique muscle may also be affected. The retraction of the globe during adduction is thought to be due to the unopposed action of the medial rectus muscle. The exact cause of Duane's retraction syndrome is often idiopathic, but it is believed to result from a genetic mutation affecting the development of the cranial nerves and their associated muscles.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Duane's retraction syndrome is typically characterized by limited or absent abduction, not adduction.
**Option B:** This option is incorrect because the primary muscle affected in Duane's retraction syndrome is usually the lateral rectus, not the medial rectus.
**Option C:** This option is incorrect because Duane's retraction syndrome is a congenital condition, not a result of trauma or injury.
**Clinical Pearl / High-Yield Fact**
Duane's retraction syndrome is often associated with other congenital anomalies, such as heart defects, cleft palate, and craniofacial abnormalities. A high index of suspicion is necessary to diagnose this condition, as the clinical presentation can be subtle.
**Correct Answer: C. This option is incorrect because Duane's retraction syndrome is a congenital condition, not a result of trauma or injury.**