Citation, DOI & article data
The hippocampal commissure, also called the commissure of the fornix, is a transversely-oriented white matter tract connecting the two hippocampi via the fornices 1. The specific function of the hippocampal commissure is currently unknown, although damage to the fornices has been shown to lead to memory loss 2.
Arching superiorly and medially over posterior surface of the thalamus, the fornix contains white matter fibers traveling from the hippocampus to the ipsilateral mammillary body 3,4. In the region of the fornix immediately below the splenium and body of the corpus callosum, a portion of the fibers within the fornix decussate and travel transversely to join the contralateral fornix 3. This collection of decussating fibers comprise the hippocampal commissure and form the psalterium, a thin triangular lamina spanning between the body of the left and right fornices 1.
Given the proximity of the hippocampal commissure to the interventricular foramen of Monro, the hippocampal commissure and the related fornices may be damaged during the endoscopic removal of a colloid cyst 4,5.
- 1 Gray, Henry, and S. Standring. "Gray’s anatomy: the anatomical basis of clinical practice, 40th edn. Churchill-Livingstone." (2008).
- 2. McMackin, D., et al., Correlation of fornix damage with memory impairment in six cases of colloid cyst removal. Acta Neurochir (Wien), 1995. 135(1-2): p. 12-8.
- 3. Thomas, A.G., P. Koumellis, and R.A. Dineen, The fornix in health and disease: an imaging review. Radiographics, 2011. 31(4): p. 1107-21.
- 4. Azab, W.A., et al., Colloid cysts posterior and anterior to the foramen of Monro: Anatomical features and implications for endoscopic excision. Surg Neurol Int, 2014. 5: p. 124.
- 5. Shapiro, S., et al., Interhemispheric transcallosal subchoroidal fornix-sparing craniotomy for total resection of colloid cysts of the third ventricle. J Neurosurg, 2009. 110(1): p. 112-5.