abnormal male spongy urethra morphology abnormal navicular fossa morphology 2012-11-30T03:32:00Z MP:0011838 MPheno.ontology abnormal fossa navicularis urethrae morphology abnormal navicular fossa of male urethra any structural anomaly of the dilated terminal portion of the male spongy urethra located in the glans penis right before the external urethral orifice, also referred to as the most distal pendulous urethra; it is lined by stratified squamous, non-keratinizing epithelium; during development, the glans of the penis is initially solid but cannulates to give rise to the navicular fossa csmith