As the stapes first develops embryologically from the 6th to 8th week of life, it surrounds the stapedial artery, which supplies the majority of the vasculature of the embryonic head. After that period, the external carotid artery is generated and takes over for the stapedial artery, which subsequently involutes, leaving the stapes with a windowframe-like structure.
Vallejo-Valdezate LA, Martín-Gil J, José-Yacamán M, Martín-Gil FJ, Gil-Carcedo LM. (2000 Sep). "Scanning electron microscopy images and energy-dispersive X-ray microanalysis of the stapes in otosclerosis and van der Hoeve syndrome". Laryngoscope110 (9). pp. 1505–10.Check date values in: |date= (help)