Morphometric study of the posterior longitudinal ligament at the lumbar spine.

PURPOSE: There are only two descriptions of posterior longitudinal ligament (PLL) at the lumbar spine level but its morphologic characteristics are different to cervical and thoracic levels. METHOD: Spine explantation (from Th12 to L5) followed by resection of the neural arch and the dural sheath in 13 fresh cadavers was performed. The PLL was isolated from other epidural structures and its width was measured and compared to the vertebral body width at each vertebral levels. It was conducted at a microanatomic study concerning the PLL and the posterior outer annulus fibrosus. RESULTS: The PLL width was reduced craniocaudaly significantly, becoming thin from L4. The average width of PLL was 7.8 mm at L1 and 1.9 mm at L5. The width decreased gradually from L1 to L5 or abruptly from L4. The ratio of PLL width compared to the vertebral body width was 21% at L1 and 3% at L5. Microanatomic study confirmed that the PLL is less thick at its annulus fibrosus adhesion at L4-L5 and L5-S1. The relationship between the PLL and other epidural structures are discussed. CONCLUSIONS: The presence and function of the ilio-lumbar ligaments and the articular process orientation of L5-S1 may be explanations for PLL width decrease at L4-L5 and L5-S1. Furthermore, this aspect may be considered as one factor contributing to the occurrence of disc herniations at these levels, which levels are more frequently involved in this pathology.

Extrinsic and intrinsic blood supply to the optic chiasm.

Although there have been many studies of the arterial cerebral blood supply, only seven have described the optic chiasm (OC) blood supply and their results are contradictory. The aim of this study was to analyze the extrinsic and intrinsic OC blood supply on cadaveric specimens using dissections and microcomputer tomography (Micro-CT). Thirteen human specimens were dissected and the internal or common carotid arteries were injected with red latex, China Ink with gelatin or barium sulfate. Three Micro-CTs were obtained to reveal the intrinsic blood supply to the OC. The superior hypophyseal arteries (SupHypA) (13/13) and posterior communicating artery (PCoA) (12/13) supplied the pial network on the inferior side of the OC. The first segment of the anterior cerebral artery (ACA) (10/10), SupHypA (7/10), the anterior communicating artery (ACoA) (9/10), and PComA (1/10) supplied the pial network of its superior side. The intrinsic OC blood supply was divided into three networks (two lateral and one central). Capillaries entering the OC originated principally from the inferior pial network. The lateral network capillaries had the same orientation as the visual lateral pathways, but the central network was not correlated with the nasal fibers crossing into the OC. There was no anastomosis in the pial or intrinsic networks. Only SupHypA, PCoA, ACoA, and ACA were involved in the OC blood supply. Because there was no extrinsic or intrinsic anastomosis, all arteries should be preserved. Tumor compression of the inferior intrinsic arterial network could contribute to visual defects. Clin. Anat. 31:432-440, 2018. © 2017 Wiley Periodicals, Inc.

Ciliary ganglion afferents and efferents variations: a possible explanation of postganglionic mydriasis.

PURPOSE: Ciliary ganglion is a pre-visceral vegetative ganglion, relay of ocular bulb vegetative pathways, concerning three types of fibers: parasympathetic, sympathetic and somatosensory. The objective of this study was to describe the different patterns of distribution of those fibers around the ciliary ganglion to explain rare post-traumatic or postoperative ocular symptoms. METHODS: Dissection of 20 orbits, from cavernous sinus to ocular bulb, after intravascular injection of colored latex. RESULTS: Concerning afferents, or roots, three dispositions have to be described: all of them were identified (55 %); parasympathetic root was absent and ciliary ganglion was attached directly to the inferior branch of the oculomotor nerve (25 %); sympathetic root was absent (20 %). Somatosensory root, coming from nasociliary nerve, was constant. Efferents (short ciliary nerves), including these three types of fibers, were variable in number but always constituted two bundles. CONCLUSION: The absence of identifiable parasympathetic root, resulting in a close relationship between ciliary ganglion and the inferior branch of the oculomotor nerve, could be a possible explanation of postganglionic mydriasis following blow-out orbital floor fracture or surgical repair of this type of fracture. The absence of sympathetic root is due to a forward retro-orbital connection between internal carotid plexus and ophthalmic nerve within cavernous sinus, corresponding to gray rami communicans.

[Umbilical hernia]. / Hernies ombilicales.

Frequent and well known pathology, umbilical hernias are different if they occur in children or adults. Embryology and anatomy are necessary to understand all mechanisms which can explain a weakness or non complete closure of the umbilical ring. An umbilical hernia during infancy, is congenital. The diagnosis is easy, as well as its surgical treatment, usually without recurrence. In adulthood such an hernia has an acquired origin. Its treatment is often more complex, especially in obese middle-aged multiparous women, and cirrhotics. The most important is to choose the right time for surgery before complications occur: strangulation or umbilical ruptures in cirrhotics, above all with ascites. In these cases, the rate of morbidity and mortality is high, and recurrences as well.