Dubravko Jalšovec

Mandibular neuralgia due to anatomical variations

Abstract In our large collection of macerated human adult skulls and disarticulated skulls of young individuals we found cases with an extremely large lateral lamina of the pterygoid process. The medial wall of the infratemporal fossa was defined as its formation by the lateral lamina of the pterygoid process and the medial pterygoid muscle. The muscular part formed two-thirds and the lateral lamina one-third of this wall. In cases of a very large lateral lamina in our specimens nearly the whole medial wall was osseous. The third portion of the trigeminal nerve gives off the lingual nerve and alveolar mandibular nerve in the region of the infratemporal fossa. These two nerves generally passed between the lateral and medial pterygoid muscles to their terminal sites. In cases of extremely large lateral laminae the nerves had to make a curve in their course, following the shape of the enlarged lamina. During contraction of the pterygoid muscles both nerves can be compressed. Since the lingual nerve runs between muscular elements, tension and compression is probably avoided. In contrast, the mandibular nerve fixed between the oval and mandibular foramina cannot avoid tension and compression. The result is possible pain, especially during chewing, and may finally create a trigeminal neuralgia. Similar symptoms could be provoked by a foramen pterygospinale or ovalis canal replacing the foramen ovale.

Variations of the ethmoid labyrinth and sphenoid sinus and CT imaging

SummaryThree hundred macerated and partly isolated postmortem mid-facial bones were studied for the development, variations and dimensions of the structures of the nasal cavity. On 184 axial CT scans of bones (102 male, 82 female) from patients ranging in age from 1 to 90 years old, the dimensions of the ethmoid labyrinth and sphenoid sinus were studied in detail in order to determine which anatomic situation might be unsafe during clinical endoscopic interventions. Six anatomic variations were identified. Most unsafe for surgery seemed to be the following types: type 111, in which the anterior diameter of the ethmoid labyrinth was large and the posterior ethmoid and sphenoid diameters were relatively narrow; type V, in which both ethmoid dimensions were large and the sphenoid diameter was narrow: type VI, in which the ethmoid labyrinth had an “hour-glass” shape. Present findings indicate that CT orientation before any endoscopic intervention might help to avoid serious complications.

Postnatal changes in osseous and mucosal morphology of the hard palate.

We investigated the postnatal changes in the dimensions, configuration, and surface pattern of the hard palate in 68 skulls, ranging in age from birth to 90 years of age. The number of palatine rugae of the palatine mucosa was assessed in 168 living subjects aged 11–98 years. Before the first dentition appeared, the osseous palate was concave, smooth, and lacked alveolar processes. In maxillar specimens from the end of the first year to the end of the fourth year of life, balloon‐like osseous formations, containing the elements of permanent teeth, appeared bilaterally behind the deciduous incisors. With age, the concavity of the palate diminished and became flat with the loss of the teeth. The presence of teeth was associated with the height of the alveolar ridge, which decreased from 7.3 ± 4.4 mm in specimens with intact teeth to 4.7 ± 4.1 mm in specimens without teeth (P = 0.020). Palatine rugae were a common finding in living subjects, but were more often absent in older age (2.2% in 11–50 age group vs. 12.8% in 51–98 age group, P = 0.0183). Our results suggest that the morphology of the hard palate rapidly changes during deciduous and permanent teeth eruption and is related to the presence of alveolar ridges and teeth in adults. Palate osseous morphology may be morphologically and functionally independent from its mucosal morphology. Changes in the morphology of the osseous palate are clinically relevant for dental prosthetics and tooth implantation. Clin. Anat. 21:158–164, 2008.

Relation of the ethmoidal cells to the floor of the anterior cranial fossa.

The shape of the anterior part of the anterior cranial fossa undergoes important changes in the postnatal life depending on the degree of pneumatisation of the ethmoid labyrinth and/or the frontal sinus. There exist three possibilities in these relations: 1) From the newborn period up to 9 years of age, in the majority of the cases the cribrous plate is situated at the level of the roof of the ethmoid labyrinth with the width of the ethmoid incisure corresponding to the width of the cribrous plate. 2) In the period from 9-35 years of age, in the majority of cases, the ethmoidal cells are partly or completely incorporated into the floor of the anterior cranial fossa with the width of the ethmoid incisure corresponding to the number of cells forming the floor of the anterior cranial fossa. 3) In the period from 35-80 years of age, the cribrous lamina is in the majority of cases lowered due to the intensive development of the frontal sinus. The medial wall of the ethmoid labyrinth consists of a thin bony strip, the width of which depends upon the degree of lowering of the cribrous plate. Adequate CT imaging may clarify the situation.

The frontal sinus and the ethmoidal labyrinth

In the “standard” anatomic description, the frontal bone and cribriform plate of the ethmoid bone form the base of the anterior cranial fossa. We studied the development of the ethmoidal bone as well as its relations to the frontal bone in macerated disarticulated skull bones and macerated skull bases of 35 individuals between 9 and 35 years of age. In 19 cases the ethmoidal cells were completely or partly uncovered by the frontal bone. In 6 of 19 cases the frontal bone did not cover any of the ethmoidal cells; in 10 further cases the frontal bone covered only the anterior and in 3 cases the anterior and middle ethmoidal cells. In a 60-year-old subject the ethmoidal cells were incorporated in the base of the anterior cranial fossa, a rare finding. Thus, a depressed lamina cribrosa is not the only danger in ethmoidectomy. Based on the present data ethmoidal cells uncovered by the frontal bone may involve a serious risk during ethmoidectomy even if the surgeon remains lateral to the insertion of the middle concha. The discrepancy between common descriptions of this region and our own findings may be related to imprecise data concerning the life stage of the cases described in the literature.

Development of the cribriform plate and of the lamina mediana

The development of the cribriform plate and lamina mediana was studied in macerated isolated ethmoid bones in specimens from late fetal life to the stage of its final shape (60 specimens). From fetal life to the first year of age, the ethmoid bone consisted of two separate symmetrical halves which had joined together by the end of the first year. Each half of the future ethmoid bone incorporated the superior, middle and occasionally also the supreme nasal concha. The ossification of the cribriform plate started in the new-born where it initially displayed a vertical position but became horizontal in the course of the first year. At the end of the first year both halves of the ethmoid bone had been united by the formation of the crista galli, lamina mediana and complete ossification of the cribriform plate. The lamina mediana reached its final shape by ten years of age. Each half of the ethmoid bone displayed furrows for the fila olfactoria in the region of the superior and occasionally also of the anterior part of the middle nasal concha. The furrows run in a postero-anterior direction. In the course of our investigations we found three cases where all three nasal conchae formed a unique block thus proving the common origin of these structures from the cartilaginous nasal capsule.

An anomalous relationship of the descending portion of the facial canal to the jugular notch in the human temporal bone

which the descending portion of the facial canal communicated with the jugular notch. As such a relationship is of interest in pathology of the facial nerve and/or jugular bulb as well as in surgical interventions, we have described our findings. Our findings concern the skull of 61-year-old man. To demonstrate our findings we performed 2-mm-high resolution axial, frontal and oblique computed tomographic projections of the right and left facial canals (CT scanner III gen). A wire was introduced into both facial canals to mark their positions. The deep right jugular fossa was found to be in direct contact with the vertical portion of the facial canal for approximately 5 mm, starting 2 mm above the stylomastoid foramen (Figs. 1–3). The left jugular fossa was not as deep as the right one and the facial canal was separated from the fossa by a bony wall (Fig. 1). A number of publications exists concerning the anatomic relationships of the facial canal to the jugular foramen and notch. The location of the sigmoid sinus depends on the degree of pneumatization of the temporal bone [1] and variations and positions of the upper genu of the sinus in anteroposterior, mediolateral and vertical directions [7]. The relationship of the bulb of the internal jugular vein to the structures of the middle and internal ear has also been examined [5], as well as the surgical associations of the jugular foramen to cranial nerves VII, IX, X, XI, XII and the internal carotid artery [2]. While variations of the facial nerve important in surgery have been reported [3, 4, 6, 8], we have not found any of a case in which the facial

Praktische Bedeutung der postnatalen Entwicklung des Canalis opticus und der Fissura orbitalis superior

An mazerierten zerlegten SchAdeln vom Neugeborenen bis zum Erwachsenen wurden sowohl die Dimensionen der intrakranialen und orbitalen Offnung des Canalis opticus als auch die grOsste LA