Site of glomus jugulare?

Ans. is 'b' i.e., Hypotympanum Glomus tumor Glomus tumor is the most common benign tumor of middle ear. It arises from the glomus bodies, therefore named Glomus tumor. It is well recognised that glomus tumors arise from paraganglions, which are normally occuring structures usually found in close association with sympathetic ganglions along the aoa and its main branches. The chief cells (paraganglionic cells) of the paraganglions are of neural crest origin and are components of the diffuse neuroendocrine system (DNES). These paraganglionic cells are derived from embryonic neuroepithelium (neural crest). Glomus tumors are also referred to as chemodectomas or nonchromaffin paragangliomas. There are two types of glomus tumors :- Glomus jugulare These glomus tumors arise from the dome of the internal jugular vein in the hypotympanum and jugular foramen. In jugular foramen they can invade IX to XII cranial nerves. Glomus tympanicum They arise from the promontory of the middle ear along the course of the tympanic branch of the IXth cranial nerve. Although rare, glomus tumors are the most common tumor of the middle ear and are second to acoustic neuroma (vestibular schwannoma) as the most common tumor of the temporal bone. It is more common in females with female to male ratio of 3-6 : 1. Glomus jugulare tumors have also been noted to be more common on the left side, especially in females. o Most tumors occur in patient 40-60 years. Multicentric tumors are found in 3-10% of sporadic cases and in 25-50% of familial cases.