<prompt> Horners syndrome is caused by:Nasopharyngeal carcinoma metastasisFacial bone injuryMaxillary sinusitisEthmoid polyp  <response>: a Nasopharyngeal carcinoma metastasisRef. Scott Brown, 8th ed., Vol 3; 98Nasopharyngeal carcinoma metastasis or direct extension laterally to the parapharyngeal space post styloid compartment leads to the involvement of cervical sympathetic chain which is known as Horners syndrome. Signs of Horners syndrome:Mnemonic: AMPLE1. Anhidrosis decreased sweating on the affected side of the face2. Miosis small pupils3. Ptosis drooping of the upper eyelid from loss of sympathetic innervation to the superior tarsal muscle, also known as Mullers muscle4. Loss of ciliospinal reflex i.e. no dilation of the ipsilateral pupil in response to pain stimuli applied to the neck.5. Enophthalmos the impression that the eye is sunk in 