Cranial Apertures Research Articles

Evaluation of the Cranial Aperture of the Optic Canal on Cone-Beam Computed Tomography Images and its Clinical Implications for the Transcranial Approaches.

This study aimed to investigate morphometric properties of the cranial aperture (CA) of the optic canal. Cone-beam computed tomography images of 400 individuals (200 males and 200 females) aged 37.32 ± 15.87 years were retrospectively examined to assess the morphometry and morphology of the CA. The height and width of CA were found as 4.22 ± 0.74 mm and 7.27 ± 1.15 mm, respectively. The distances between the CA and the midsagittal line, the anterior and lateral boundaries of the anterior skull base were measured as 5.77 ± 1.32 mm, 64.97 ± 6.36 mm, and 41.00 ± 4.05, respectively. The angle of the optic canal in the sagittal plane was measured as 7.57° ± 3.95°, whereas in the horizontal plane as 38.96° ± 4.36°. The aperture shape was defined as the tear-drop (413 foramina, 51.62%), triangular (180 foramina, 22.50%), oval (158 foramina, 19.75%), round (30 foramina, 3.75%), and polygonal (19 foramina, 2.38%). The authors observed that the diameters, and angulations of the CA may change relative to gender and the shape. The anatomic features of CA are important for the positioning of the patient's head, the choice of the appropriate surgical approach or equipment, and the detection of anatomical landmarks during interventions. In this context, our dataset may be beneficial for surgeons helpful as a reference for radiological evaluations.

Anatomic features of the cranial aperture of the optic canal in children: a radiologic study.

This study aimed to peruse anatomic features of the cranial aperture of the optic canal (CAOC) for obtaining an extended morphometric dataset in children. Computed tomography images of 200 children were included in this retrospective work to analyze the shape, location and diameters of the CAOC. The CAOC area, width and height were observed as 17.53 ± 2.80mm2, 6.12 ± 0.84mm, and 4.35 ± 0.64mm, respectively. The angle of the optic canal in axial plane was found as 39.28 ± 5.13°, while in sagittal plane as 16.01 ± 6.76°. The distance between the CAOC and the midsagittal line was 7.17 ± 1.48mm. The CAOC was measured as 54.04 ± 5.23mm and 42.55 ± 3.28mm away from the anterior and lateral boundary of the anterior skull base, respectively. The CAOC shape was described as the tear-drop (186 foramina, 46.5%), triangular (156 foramina, 39%), oval (47 foramina, 11.8%), and round (11 foramina, 2.8%). The depth, angle and diameter measurements belonging to the CAOC were changing according to its shape or demographic data (e.g., sex and age). Therefore, preoperative radiologic evaluation containing the shape, location and size of the CAOC should be considered by multidisciplinary operating teams in terms of surgical interventions such as implant positioning.

Association between Foramen Size and Febrile Seizure Status in the Pediatric Population: A Two-Center Retrospective Analysis.

Objective Febrile seizures have been shown to occur in 2 to 5% of children between the ages of 6 months and 5 years, making them the most common seizures of childhood. Multiple risk factors for febrile seizures have been identified; however, no investigation has been conducted to explore foramen size and associated venous drainage as a potential risk factor for experiencing febrile seizures. Of particular interest are the parietal foramen and the condylar canal, which conduct the parietal emissary vein and the occipital emissary vein, respectively. Emissary veins lack valves, allowing them to play a crucial role in selective brain cooling via a bidirectional flow of blood from the head’s evaporating surface. Narrowed cranial apertures conducting these veins may lead to reduced cerebral venous outflow and delayed brain cooling, creating favorable conditions for a febrile event. This study seeks to explore the association between cranial aperture area and febrile seizure status. Methods A retrospective cross-sectional medical record review study from January 2011 to December 2017 was conducted at a 500-bed academic hospital and a 977-bed private hospital in Lubbock, Texas, United States. A total of 101 complex febrile seizure patients were compared with a similarly aged group of 75 trauma patients representing the normal population. Parietal foramen area and condylar canal area were electronically measured and defined as having “normal” or “below normal” area. Statistical Analysis Independent t -tests were used to compare foramen and canal areas by febrile seizure status. Logistic regression analyses were conducted to determine the association of small cranial aperture area with febrile seizure status. Results Below normal parietal foramen area had a strong association with febrile seizures in our patient population. Male sex, white race, and complete vaccination status were also found to have significant associations with febrile seizure status. Conclusion Our findings indicated that narrowed parietal foramen may be considered as a risk factor for febrile seizure development.

Why should we report posterior fossa emissary veins?

Posterior fossa emissary veins are valveless veins that pass through cranial apertures. They participate in extracranial venous drainage of the posterior fossa dural sinuses. The mastoid emissary vein, condylar veins, occipital emissary vein, and petrosquamosal sinus are the major posterior fossa emissary veins. We believe that posterior fossa emissary veins can be detected by radiologists before surgery with a thorough understanding of their anatomy. Describing them using temporal bone computed tomography (CT), CT angiography, and cerebral magnetic resonance (MR) venography examinations results in more detailed and accurate preoperative radiological interpretation and has clinical importance. This pictorial essay reviews the anatomy of the major and clinically relevant posterior fossa emissary veins using high-resolution CT, CT angiography, and MR venography images and discusses the clinical importance of reporting these vascular variants.

Persistence of multiple emissary veins of posterior fossa with unusual origin of left petrosquamosal sinus from mastoid emissary

Emissary veins are valveless veins which pass through the cranial apertures and connect the dural venous sinuses and the extracranial veins. The clinical importance of emissary veins is increasingly being appreciated. Some emissary veins like the petrosquamosal sinus and mastoid emissary vein may cause significant bleeding during middle ear and skull base surgeries. A dilated mastoid emissary vein or condylar emissary vein can sometimes be a rare cause of tinnitus. Radiological identification of these venous channels has been described in recent years and assumes significance in light of their clinical importance. We describe the CT and MRI findings of a rare case that had persistence of multiple emissary veins and presented clinically with tinnitus. The radiological findings included a dilated left mastoid emissary vein, bilateral petrosquamosal sinuses, posterior condylar veins, occipital emissary veins and an intrapetrous venule. The left petrosquamosal sinus had an unusual origin from the dilated mastoid emissary vein. The patient also had major anomalies of posterior fossa venous sinuses which are discussed. A relevant review of literature is included.

Craniospinal Involvement in a Patient with Isolated Bone Marrow Mastocytosis

Central nervous system involvement in systemic mastocytosis (SM) is very rare. This case report describes the computed tomography and magnetic resonance (MR) imaging findings of central nervous system involvement in a patient with isolated bone marrow mastocystosis. Bone marrow infiltration in SM caused cranial nerve dysfunction and meningeal irritation secondary to narrowing of cranial apertures and meningeal involvement, respectively. MR imaging is the modality of choice in both detection and follow-up of SM and also useful for differential diagnosis and detection of complications.

Structure of the optic canal in human ontogenesis

The aim of this work is to reveal the optic canal (OC) development regularities. It is of importance to identify the anatomical preconditions of tunnel syndrome and other pathologies of the OC. One hundred and five human embryos (195 OC, out of them 98 - left-hand, 97 - right-hand) from 4 up to 70 mm parietococcygeal length (PCL) have been studied. The diameters of the optic nerve (ON) and OC in its orbital, cranial apertures and middle part have been defined. In the same way the distances between the OC walls and the ON and ophthalmic artery have been measured. We have come to the conclusion that the morphogenesis of the OC walls is an asynchronous process. The development of the OC upper wall is retarded. Some asymmetry of the morphometric characteristics of the right and left OC has been revealed. The development of the OC depends on the organization of all its elements. The periods of the OC development have been identified. The OC constitutional features of its aperture form, the size of the OC walls and its apertures, ON size, the correlation between ON and OC diameters of the OC cranial and orbital apertures and "waist", and the arrangement of the OC compartments were revealed. The individual and typical features of the OC structure, revealed as a result of computer tomography (CT) analysis, account for CT effectiveness in the diagnosis of OC changes and the structures located in it.

Optimal Distal Screw Alignment in the Gamma Nail

AbstractThe effect of stress distribution due to the changes of the distal screw alignment in relation to the Gamma nail and the femoral shaft is thoroughly studied in this paper. Failure of the Gamma nail composite occurs through the cranial aperture of the distal screws and the insertion hole for the lag screw due to nonunion, delayed-union and continued weight-bearing. A three-dimensional finite element model was used to study the fractured femur, the Gamma nail, the lag screw and the distal locking screws. The first and the second distal screws were inserted into the Gamma nail in four different configurations. We found that the stress of the Gamma nail composite was substantially reduced with the two screws configured in the anterior to posterior direction. This alignment can bear greater loading in the more demanding fracture types. In the subtrochanteric fracture or the comminuted fractures at the proximal femur, the optimal alignment of the two distal screws was in the anterior to posterior direction.

Neuro-arterial relations in the region of the optic canal.

In this paper, we present the results of our investigations on the neuro-arterial relations in the region of the optic canal. A thorough knowledge of the microanatomic features of the ophthalmic artery, optic canal and optic nerve is very important for surgeons approaching lesions of this area. We aimed to extend our present knowledge of the origin of the ophthalmic artery and microsurgical anatomy of the optic canal with exposure of the optic nerve. The optic canal walls and width and height of the orbital and cranial apertures, and thickness of the bony roof of the optic canal were measured on the right and left sides of 57 sphenoid bones, 102 skull bases and 58 fixed adult cadaver heads. The ophthalmic artery originated from the rostromedial circumference of the internal carotid artery in 51.8%, from the medial circumference in 26.2% and the laterobasal circumference in 22% of the specimens. The outer diameter of the ophthalmic artery at its origin was 1.81 +/- 0.36 mm on the right and 1.75 +/- 0.37 mm on the left side.

Arachnoid villi obstruction in the cochlear aqueduct.

Temporal bone findings suggest mechanical obstruction of arachnoid villi by focal hemorrhage within the cochlear aqueduct midportion. Increased perilymphatic fluid pressure was evidenced by fluid backing through soft tissue about the cochlear aqueduct, and reaching the internal auditory canal. Backing up of perilymphatic fluid, rather than its mixing with fresh blood in a widely patent cochlear aqueduct, provides evidence that arachnoid villi have a resorptive function within the cochlear aqueduct, and that the cochlear aqueduct is not a free, open passageway between cerebrospinal fluid and perilymph. A previously reported case showed a similar tract between cochlear aqueduct and internal auditory canal. The aqueduct and tract contained fibrotic arachnoid, possibly representing true obstruction, rather than dural scarring that filled the cranial aperture of the aqueduct. The scarring of both dura and arachnoid suggest previous infection.

SYMMETRICAL OCCIPITAL APERTURES: A CASE REPORT.

The presence of cranial apertures which accommodate emissary vessels has long been recognized (3, 4). The authors believe that the following case report presents a previously undescribed type of symmetrical openings in the occipital bone. Case Report T. F., a 9-year-old white boy, was sent to the Cincinnati Children's Hospital for investigation of possible convulsive disorder. Radiographs of the skull, obtained as a part of his evaluation, demonstrated a pair of almost symmetrical radiolucent defects in the lower half of the squama of the occipital bone, slightly off the midline (Fig. 1). Because the defects appeared developmental in nature, other members of the family were brought in for x-ray examination of the skull. Two younger siblings, the patient's mother, and his paternal grandfather did not demonstrate any abnormal cranial apertures; but his father had identical openings (Fig. 2). Palpation of the heads of the patient and the father failed to identify defects corresponding to those found roentgenographically. Because of the satisfactory clinical course of the patient, in spite of mildly abnormal electroencephalographic findings, we did not feel justified in attempting any angiographic studies to elucidate the nature of the defects. Discussion Matson and Ingraham (5) reported 10 cases of congenital dermal sinus. A bony defect was noted at operation in every instance, but was not always apparent on conventional roentgenographic views. When radiographic findings were present, they usually consisted of single circular smooth midline defects visible particularly in the occipital (Towne) projection. O'Rahilly (6) stated that 73 per cent of 93 cranial meningoceles reported in the literature were occipital and occurred in or near the median plane at varying levels. He concluded that these defects were rarely above the occipital protuberance, sometimes at its level but most commonly between it and the foramen magnum. Boyd (1) reported his findings in 1,478 human skulls and their emissary foramina and concluded that in only 3.5 per cent of specimens were there no emissary foramina. No defects similar to the bilateral occipital ones described above are found in his collection. Boyd reported than in 1.6 per cent of the skulls an emissary foramen was noted in the region of the inion. These were always single with the exception of one specimen in which a single external opening communicated with two smaller ones internally. Kruyff and Munn (2) reported a radiographic incidence of 7.9 per cent of occipital emissary veins in normal children, with the opening in the vicinity of the torcular Herophili. Symmetrical lacunae of the occipital bone were reported by Pommé et al. (8) in a 23-year-old man. In this patient it was possible to palpate two defects “equal in size to a 2 franc piece,”2 the defects being separated by a bony bridge approximately 2 cm in length.