A case of hanging has come to forensic department for autopsy. The autopsy Dr. notices a ligature mark covering about 1/3rd of neck, protruded tongue, salivary stains, opened right eye, closed left eye, both pupils dilated. What is the probable reason for opened right eye?

1. A

   Compression of IJVs

2. B

   Compression of ICA

3. C

   Compression of Cervical sympathetic chain

4. D

   Compression of Vagus

Appeared in: NORCET 10 Mains

Explanation

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• The cervical sympathetic chain runs along the neck and provides sympathetic innervation to the head and face.
• In hanging, an asymmetrically placed ligature can compress this chain on one side.
• Compression of the sympathetic chain causes Horner's syndrome on the ipsilateral (same) side.
• Horner's syndrome includes ptosis (drooping/closing of the eyelid) due to paralysis of the superior tarsal muscle.
• In this scenario, the left eye is closed (ptosis) due to compression of the left sympathetic chain. The right eye remains open because its nerve supply is intact.
• Therefore, the entire phenomenon of one eye being open and the other closed is explained by the unilateral compression of the cervical sympathetic chain.

Why Other Options Were Wrong

• Option A: Compression of the Internal Jugular Veins (IJVs) primarily obstructs venous outflow from the head, leading to signs of congestion like facial cyanosis and petechiae, not specific neurological signs like unilateral ptosis.
• Option B: Compression of the Internal Carotid Arteries (ICAs) obstructs arterial blood flow to the brain, causing rapid cerebral ischemia and loss of consciousness. It does not selectively affect the sympathetic nerves controlling the eyelid.
• Option D: Compression of the Vagus nerve (vagovagal inhibition) can cause a sudden, drastic drop in heart rate and blood pressure, leading to cardiac arrest. It does not control the muscles of the eyelid.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Forensic findings in hanging and their pathophysiological basis as background academic context rather than a clinical decision trigger.
• In forensic pathology, specific external findings provide crucial clues about the mechanism of death. Recognizing Horner's syndrome can help determine the position of the ligature and the forces applied to the neck.
• This knowledge helps differentiate between typical and atypical hanging and can be vital in reconstructing the circumstances of death.
• What if? If both eyes were equally open or closed, it would suggest symmetrical pressure on the neck structures or a different primary mechanism of death, such as pure airway obstruction or cardiac arrest, rather than a specific unilateral nerve injury.

How to Approach the Question

• First, identify the core clinical puzzle in the question stem. Here, it is the asymmetric eye finding: 'opened right eye, closed left eye'.
• Consider the anatomy of the neck and the structures that can be compressed by a ligature: blood vessels (arteries and veins), nerves (sympathetic chain, vagus), and the airway.
• Think about the function of each compressed structure and the signs that would result from its compression.
• Relate the specific sign (unilateral ptosis, or a 'closed eye') to the potential anatomical structure responsible. The control of eyelid elevation is partly managed by sympathetic nerves.
• Evaluate the options. Compression of the cervical sympathetic chain is the only option that directly explains a unilateral ptosis (Horner's syndrome).
• Conclude that the 'opened' eye is the normal baseline, and the pathology lies with the 'closed' eye, with the root cause being the compression of the sympathetic chain.

Concept Tested & Keywords

• Concept Tested: Forensic findings in hanging and their pathophysiological basis.
• Stem keywords: hanging, autopsy, ligature mark, opened right eye, closed left eye
• Lead-in keywords: probable reason
• Clinical cues: The key finding is the asymmetry of the eye-opening (one open, one closed), which points to a unilateral neurological deficit.

Question ID

Qy9T6iiMGM0j1H9rf7BqtU

Copy ID

Reference Book

E6 Anatomy Grays 43e Vol 2 Part 1 p. 41-43

E6 Medicine Harrison 22e Part 2 p. 1461-1463