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Disorders of the Orbit
Published in John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie, Basic Sciences Endocrine Surgery Rhinology, 2018
Nithin D. Adappa, James N. Palmer
The medial wall is most relevant to otorhinolaryngologists due to the proximity of the paranasal sinuses. From an anterior to posterior direction, the boney contribution of anterior lacrimal crest originates at the frontal process of the maxilla. The lacrimal bone makes up the second one half of the lacrimal sac fossa and the posterior lacrimal crest. The lamina papyracea (arising from ethmoid bone) makes up the majority of the medial orbital wall. The paper-thin bone overlies the ethmoid sinuses.2 The anterior and posterior ethmoid foramina are found in the superior aspect of the orbit along the fronto-ethmoidal suture line. The anterior ethmoid foramen is a useful landmark and is identified 20–25 mm posterior to the anterior lacrimal crest and the posterior ethmoid foramen is 30–35 mm posterior to the anterior lacrimal crest.3 The thick bone of the sphenoid body forms the most posterior portion of the medial orbital wall adjoining the optic canal.
Growth of the Cranial Base HHiH
Published in D. Dixon Andrew, A.N. Hoyte David, Ronning Olli, Fundamentals of Craniofacial Growth, 2017
Figure 11.14 illustrates in diagram form the dates of fusion of sutures in the human skull base (Hoyte, 1991), similar in most respects to timings given by Friede (1981). Some uncertainties remain. Thus Melsen (1974) found no activity of the frontoethmoidal suture after 1 year of age, though Ohtsuki et al. (1982) recorded some growth there up to 3 years. What growth does occur there most probably is from the ethmoid, since there is no deposition on the interior of the frontal bone at that time (Melsen, loc. cit. supra). Questions arise again about ethmoid growth, both in width and in length, of which Ford (1958) made detailed studies. Perhaps the problem arises from descriptive terminology. Ford measured the cribriform plate, but this is not the whole ethmoid. Lengthwise growth was discussed above (Section II.C). Of the width he wrote that the cribriform plate width increases by 1.6 mm from birth to 2 years, “but thereafter seems to diminish. In the adult it is actually 1 mm less than in the newborn child ... unless a synchondrosis persists between the lateral margin of the cribriform plate and the ethmoidal labyrinth, under cover of the orbital plate of the frontal bone where it cannot be seen (and this is not so, in two skulls in which the region was visible), it can be said that the nasal septum and ethmoidal labyrinths are united by bone well before the age of 2 years (possibly before 1 year of age). ... not surprising in view of the fact that the two halves of the frontal bone are firmly united by the end of the first year, thus preventing further separation of the orbital plates of the frontal bone. ... Subsequent apparent diminution in width (of the cribriform plate) is due to encroachment of the orbital plates of the frontal bone upon its intracranial surface.” Note, however, the very varied appearance of the cribriform plate described in Lang (1983), as many as 5 morphological types.
Sensitivity of Computed Tomography for the Assessment of Spontaneous Dermoid Cyst Localized Rupture with Granulomatous Reaction
Published in Seminars in Ophthalmology, 2018
Alicia Galindo-Ferreiro, Sahar M Elkhamary, Saif Aldossari, Patricia M. Akaishi, Hind Alkatan, Rajiv Khandekar, Denny Marcos Garcia, Yerena Muiños-Diaz, Silvana A Schellini, A. Augusto V. Cruz
The dermoid cyst (DC) is a benign congenital lesion derived from the ectoderm and mesoderm. Orbital DCs are usually diagnosed in childhood near sites of developmental fusion of bones, such as the fronto-zygomatic and fronto-ethmoidal suture.1 Since DCs tend to expand, provoking bone destruction, they are typically managed with surgical excision.2