The meninges, which are a composite tissue surrounding the brain, play an important role in the mechanopathology of traumatic brain injury. Studies have demonstrated that the meninges are pivotal in mitigating the damaging strains placed on the cortex from both physiological and pathophysiological head movement, which can occur during dynamic events such as traffic accidents. Conversely, structures such as the falx and tentorium have been shown to induce large deleterious strains within the brain. Understanding the mechanical behaviour of these tissues is important to predict computational model brain strains. This study provides the first biomechanical and structural evaluation of the structures anatomically tethered to the falx cerebri, the superior sagittal sinus. We utilise uniaxial tensile testing, digital image correlation analysis and scanning electron microscopy on porcine superior sagittal sinus tissue to show that these structures are mechanically stiffer (with elastic moduli ranging from 33 to 58 MPa) than the properties that are typically assigned to them in computational models of traumatic brain injury (elastic modulus of 31.5 MPa). This work has the potential to improve the biofidelity of traumatic brain injury finite element models, thus improving crash reconstruction and injury prediction efforts.