IS THE patient's carotid blood flow normal? The question is raised constantly in clinical diagnosis. Ophthalmoscopic inspection and ophthalmodynamometry both yield information—based on intraorbital circulation—about the status of carotid blood flow.1
Known to anatomists, but less appreciated in their diagnostic importance, are other more distal branches of the ophthalmic artery. These supraorbital and frontal arteries exist from each orbit and supply the skin over each inferior medial quadrant of the forehead (Fig 1 and 2). For practical purposes of temperature measurement, the external carotid artery normally has no primary contribution to the supply of this unique and discrete skin area.
There are important clinical implications of this regional supraorbital circulation. These implications were clearly realized and enunciated by Wood et al.2-4 These investigators assessed skin temperature (and thus blood flow) indirectly by measuring the infrared heat radiated from the skin. They used an ingenious, intricate system which
AUSTIN JH, SAJID MH. Direct Thermometry in Ophthalmic-Internal Carotid Blood Flow. Arch Neurol. 1966;15(4):376–392. doi:10.1001/archneur.1966.00470160042006
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