Anatomy of the optic canal and its clinical role

The optic canal is a short funnel-like structure extending from the optic foramen to the orbital apex, where the optic nerve (ON) and the ophthalmic artery (OA) pass through. The relationship between these two structures has been already well reported, in particular in the majority of cases the artery runs within the optic sheath below the ON, which is surrounded be arachnoidal membrane in this part. [1]. However, few anatomical variants have been reported, such as the origin of the OA from the intracavernous tract of the internal carotid artery [1]. In this case, it is possible for the OA not to pass thorough the optic canal, but in the superior orbital fissure [1]. For its course and for the normal location of the OA it could be difficult to analyze the anatomy of the content of the optic canal from the classic transcranial dissection [2,3]. Therefore, we performed the opening of the ventral surface of the optic canal in 6 cadavers (12 pairs of optic canals), adopting an endonasal route, performed with the auxilium of the endoscopic visualization technology. Our dissections clearly show the relationship between OA and ON in the optic canal. This knowledge is of particular importance for tumors invading the optic canal, such as tubercular sellae meningiomas, which can be safely approached through this endoscopic endonasal route, avoiding the risk of injury of OA within the optic canal [2.3

Quantification of Squalene and Lactic Acid in Hair Bulbs with Damaged Sheaths: Are They Metabolic Wastes in Alopecia?

Alopecia is a pathological and multifactorial condition characterised by an altered hair growth cycle and ascribed to different pathogenic causes. Cell energetic imbalances in hair follicles occurring in this disorder could lead to the production of some “metabolic wastes”, including squalene and lactic acid, which could be involved in the clinically observed sheath damage. The aim of this work was the extraction and analytical quantification of squalene and lactic acid from hair bulbs of subjects with clinical alopecia in comparison with controls, using HPLC-DAD and HPLC-MS techniques. The analytical quantification was performed after a preliminary observation through a polarised optical microscope to assess sheath damage and morphological alterations in the cases group. A significantly larger amount of squalene was quantified only in subjects affected by alopecia (n = 31) and with evident damage to hair sheaths. For lactic acid, no statistically significant differences were found between cases (n = 21) and controls (n = 21) under the experimental conditions used. Therefore, the obtained results suggest that squalene can represent a metabolic and a pathogenic marker for some alopecia conditions