Ossification of parts of the intracranial dura mater is common and is generally accepted as an age-related finding. Additionally, duplication of the abducens nerve along its course to the lateral rectus muscle is a known, although uncommon anatomical variant. During routine cadaveric dissection, an ossified portion of dura mater traveling over the trigeminal nerve's entrance (porus trigeminus) into the middle cranial fossa was observed unilaterally. Ipsilaterally, a duplicated abducens nerve was also observed, with a unique foramen superolateral to the entrance of Dorello's canal. To our knowledge, there has been no existing report of a simultaneous ossified roof of the porus trigeminus with an ipsilateral duplicated abducens nerve. Herein, we discuss this case and the potential clinical and surgical applications. We believe this case report will be informative for the skull base surgeon in the diagnosis of neuralgic pain in the frontomaxillary, andibular, orbital, and external and middle ear regions.
Abducens Nerve ; Cadaver ; Cranial Fossa, Middle ; Diagnosis ; Dura Mater ; Ear, Middle ; Orbit ; Skull Base ; Trigeminal Neuralgia

Trabeculae or septations in the transverse sinus can have potentially life-threatening clinical significance. The current study demonstrates trabecula/septum patterning within the transverse sinus with measurements and distribution data supplemented by imaging, and describes the possible etiology of idiopathic intracranial hypertension and turbulent blood flow in the transverse sinus. Twenty-four sides from 12 cadaveric heads, all fresh-frozen, were used (five males, seven females; age at death 65–91 years, mean 79.1 years). The length and diameter of the transverse sinus were measured along with the number and locations of septations/trabeculae and their tensile strength. The mean length of the transverse sinus was 68.43 mm on the right side and 74.31 mm on the left. A total of 42 septations were found in the 24 transverse sinuses.The number of septations per side ranged from zero to four with a mean of 1.75. The septations were located in the proximal 1/3 in 54.8% (23/42), the middle 1/3 in 21.4% (9/42), and the distal 1/3 in 23.8% (10/42). The work presented here furthers our understanding of transverse sinus anatomy, including its detailed internal architecture. The measurements can provide a technical guide for neurosurgeons and influence instrument selection when a large thrombus forms or anchors in one of these trabeculae or septa and necessitates treatment.

Anatomical variations of the sternocleidomastoid muscle (SCM) have been observed to occupy multiple origins and insertion points and have supernumerary heads, sometimes varying in thickness. During routine dissection, a SCM was observed to have six distinct insertions that interface with the course of the superior nuchal line, ending at the midline, bilaterally. This variation was also seen to receive innervation from the accessory nerve as well as the great auricular nerve. To our knowledge, this variant of supernumerary insertions and nerve innervations has not yet been reported. These variants may pose as problematic during surgical approaches to the upper neck and occiput, and should thus be appreciated by the clinician. Herein we discuss the case report, possible embryological origins, and the clinical significance of the observed variant SCM.
Accessory Nerve ; Head ; Mastoid ; Neck

In this paper, the authors discuss the embryology and anatomy of the choroidal fissure, as well as the pathophysiology and treatment of cerebrospinal fluid cysts of this structure. Understanding its anatomical relations to nearby structures plays an essential role during brain surgeries. With the advancement and availability of imaging techniques, lesions of the choroidal fissure are often found incidentally. Patients are usually asymptomatic or exhibit symptoms that do not correlate with anatomical location or do not require surgical treatment. The choroidal fissure is a key landmark used during brain surgery. Therefore, a comprehensive understanding of it and nearby anatomical structures is essential. Choroidal fissure cysts can be found incidentally, and well-known key features will allow one to differentiate them from other lesions. Surgical treatment should be reserved for symptomatic patients while asymptomatic patients should be monitored.