Ten Horn's sign

Ten Horn's sign is a clinical sign used in the diagnosis of certain neurological conditions, particularly those affecting the facial nerve. It is named after the physician who first described it. The sign is observed when a patient attempts to close their eyes tightly. In a healthy individual, both eyelids will close completely. However, in a patient with a lesion affecting the facial nerve, the eyelid on the affected side will not close completely, and the white of the eye, or sclera, will remain visible. This phenomenon is due to weakness or paralysis of the orbicularis oculi muscle, which is responsible for eyelid closure.

Etiology

Ten Horn's sign can be indicative of several conditions that involve the facial nerve, such as Bell's Palsy, Lyme disease, and various types of facial nerve palsy. It is particularly associated with peripheral lesions of the facial nerve. The sign helps in distinguishing between central and peripheral causes of facial nerve paralysis. In central lesions, such as those caused by a stroke, Ten Horn's sign is typically absent due to the bilateral representation of the upper facial muscles in the cerebral cortex.

Clinical Importance

The presence of Ten Horn's sign is a crucial observation in the neurological examination. It assists clinicians in localizing the lesion and determining its nature, whether it be peripheral or central. This, in turn, guides further diagnostic testing and management strategies. Early detection and appropriate management can significantly improve the prognosis for patients with facial nerve paralysis.

Diagnosis

In addition to observing Ten Horn's sign, a comprehensive evaluation of a patient suspected to have facial nerve involvement may include:

• History taking, to identify symptoms such as sudden onset of facial weakness, pain behind the ear, and changes in taste.
• Physical examination, focusing on the entire course of the facial nerve.
• Neurological examination, to assess the function of other cranial nerves and look for signs of central involvement.
• Imaging studies, such as MRI or CT scans, to identify the site and cause of the lesion.
• Electromyography (EMG), to evaluate the electrical activity of muscles and the integrity of the facial nerve.

Management

Management of conditions presenting with Ten Horn's sign depends on the underlying cause. Treatment may include:

• Corticosteroids, to reduce inflammation in cases such as Bell's Palsy.
• Antiviral or antibiotic therapy, if an infection is identified as the cause.
• Surgical intervention, in cases where there is a compressive lesion affecting the facial nerve.
• Physical therapy, to maintain muscle tone and prevent long-term complications.

Prognosis

The prognosis for patients presenting with Ten Horn's sign varies depending on the underlying cause and the timeliness of intervention. Many patients experience a full recovery, especially in cases where treatment is initiated promptly. However, some may have residual weakness or other complications.

See Also

• Facial nerve paralysis
• Bell's Palsy
• Lyme disease
• Neurological examination