spinal dura mater
Anatomical term for the tough outermost membrane covering the spinal cord.
The spinal dura mater is one of the membranes that protect the spinal cord.
硬膜 refers to the dura mater in general (both cranial and spinal), while 脊髄硬膜 specifically denotes the spinal dura mater.
脊髄 means 'spinal cord', the structure that 脊髄硬膜 surrounds.
Compound of 脊髄 (せきずい, 'spinal cord') and 硬膜 (こうまく, 'dura mater'). The term is a direct anatomical designation.