Olivier Armstrong

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

PurposeCiliary 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.MethodsDissection of 20 orbits, from cavernous sinus to ocular bulb, after intravascular injection of colored latex.ResultsConcerning afferents, or roots,xa0three dispositions have to be described: all of them were identified (55xa0%); parasympathetic root was absent and ciliary ganglion was attached directly to the inferior branch of the oculomotor nerve (25xa0%); sympathetic root was absent (20xa0%). 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.ConclusionThe 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.

Morphometric study of the posterior longitudinal ligament at the lumbar spine

PurposeThere 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.MethodSpine 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.ResultsThe PLL width was reduced craniocaudaly significantly, becoming thin from L4. The average width of PLL was 7.8xa0mm at L1 and 1.9xa0mm 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.ConclusionsThe 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: 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.

Limites anatomiques de l’orifice musculo-pectinéal

But L’orifice musculo-pectineal est compose dans sa portion crâniale du canal inguinal, par lequel passe le cordon spermatique ou le ligament rond de l’uterus, et pour sa portion caudale, de l’orifice femoral, lieu de passage des vaisseaux femoraux. Les deux orifices sont separes par le ligament inguinal. Il s’agit d’une zone complexe dont la comprehension est primordiale d’un point de vue chirurgicale. En effet, l’orifice musculo-pectineal est une zone de faiblesse de la paroi abdominale, ce qui en fait un lieu de predilection de la pathologie herniaire. Materiel et methodes La region inguino-femorale de trois sujets (deux masculins et un feminin) a ete dissequee respectivement de maniere unilaterale, bilaterale, et par un abord chirurgical anterieur unilateral. Des coupes de la meme region, parasagittales et d’autres dans l’axe du ligament inguinal ont ete realisees apres congelation d’un dernier sujet masculin. Resultats Les limites de l’orifice musculo-pectineal sont de nature assez differente selon qu’on se trouve au-dessus ou en dessous du ligament inguinal. La portion craniale de l’orifice musculo-pectineal est limitee par le fascia transversalis, en haut par l’arche musculaire qu’est la faux inguinale, en dedans par le tendon conjoint, le ligament de Henle et le ligament reflechi, en avant par l’aponevrose de l’oblique externe et en bas par le ligament inguinal. C’est structures sont relativement lâches et peuvent se distendre aisement. La portion caudale de l’orifice musculo-pectine est limitee par des structures beaucoup plus solidesxa0: le ligament inguinal au-dessus, ligament lacunaire en dedans qui se moule sur le contour des vaisseaux femoraux, ligament pectine en bas, epais et insere sur la branche superieure du pubis, et bandelette ilio-pectineale en dehors.

Limites anatomiques de l’orifice fémoral

But Alors que l’orifice femoral est plus large que l’orifice profond du canal inguinal, les hernies femorales de representent qu’environ 5xa0% du total des hernies de la region de l’aine. Il nous est apparu interessant d’etudier les limites de l’orifice femoral, afin de mieux comprendre la physiopathologie et le traitement des hernies femorales. Materiel et methodes Quatre sujets (deux hommes et deux femmes) dont l’âge variait de 75xa0a 95 ans ont ete utilises pour ce travail. Pour deux sujets (une homme, une femme), une injection intra-arterielle par du latex 671xa0colore en rouge a ete realisee. Trois sujets ont ete disseques, en abordant l’orifice femoral par sa face externe puis par sa face endo-pelvienne. Le quatrieme sujet a permis la realisation de coupes transversales et parasagittales de la region inguinale. Resultats L’orifice femoral fait partie de la lacune vasculaire ou chemine la veine et l’artere iliaque externe ainsi que le nerf genito-femoral. Il est limite en avant par le ligament inguinal, medialement par le ligament lacunaire, lateralement par la veine iliaque externe et en arriere par le ligament pectineal et le pecten du pubis. Cet orifice est cloisonne par le fascia transversalis.