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Concept: Temporal bone

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The site of Dmanisi, Georgia, has yielded an impressive sample of hominid cranial and postcranial remains, documenting the presence of Homo outside Africa around 1.8 million years ago. Here we report on a new cranium from Dmanisi (D4500) that, together with its mandible (D2600), represents the world’s first completely preserved adult hominid skull from the early Pleistocene. D4500/D2600 combines a small braincase (546 cubic centimeters) with a large prognathic face and exhibits close morphological affinities with the earliest known Homo fossils from Africa. The Dmanisi sample, which now comprises five crania, provides direct evidence for wide morphological variation within and among early Homo paleodemes. This implies the existence of a single evolving lineage of early Homo, with phylogeographic continuity across continents.

Concepts: Human, Evolution, Evolutionary biology, Skull, Temporal bone, Paleontology, Human evolution, Charles Darwin

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Preservation of fossil vertebrates in volcanic rocks is extremely rare. An articulated skull (cranium and mandible) of a rhinoceros was found in a 9.2±0.1 Ma-old ignimbrite of Cappadocia, Central Turkey. The unusual aspect of the preserved hard tissues of the skull (rough bone surface and brittle dentine) allows suspecting a peri-mortem exposure to a heating source.

Concepts: Bone, Skull, Temporal bone, Volcanic rock, Tetrapod, Synapsid, Pumice, Turkey

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A 20-year-old man was transferred to this hospital because of recurrent ear pain for 8 months despite antibiotics, with new fever and headache. Imaging showed opacification of the middle ears and mastoid air cells and erosion of the right temporal bone.

Concepts: Cartilage, Skull, Middle ear, Temporal bone, French Revolution, Bones of the head and neck, Mastoiditis, Jimmy Eat World

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Although robust algorithms for registration and segmentation are available, the majority of surgical approaches to the temporal bone are nowadays made without navigation assistance. Beside instrument navigation (IN), functions such as distance control (DC) and navigated control (NC) can be used. This study analyzes the application of these navigation functionalities in lateral skull base and middle ear surgery.

Concepts: Medicine, Physician, Skull, Al-Andalus, Middle ear, Temporal bone, Occipital bone, Squamosal

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A spontaneous meningoencephalocele of the temporal bone may present with effusion in the middle ear, a cerebrospinal fluid leak, hearing loss, or rarely otitic meningitis. Repair of spontaneous encephaloceles in the temporal bone has been performed using transmastoid and transcranial middle fossa approaches or a combination of the two with varied results. The authors present a technical paper on the transmastoid extradural intracranial approach for the management of temporal lobe encephaloceles.

Concepts: Intracranial pressure, Temporal lobe, Primary auditory cortex, Skull, Middle ear, Temporal bone, Cerebrospinal fluid, Lobe

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BACKGROUND: Reduction malarplasty via an intraoral approach for correction of a prominent malar complex is quite popular in the Orient. However, one point of fixation in the anterior zygoma body area, the most widely used method, sometimes is insufficient and likely to result in malunion and cheek drooping. We designed a new assisted fixation technique to strengthen the effect of fixation. METHODS: Two parallel oblique vertical ostectomies were performed on the zygomatic body with a groove left in the inner osteotomy line. The zygomatic arch root was cut obliquely through a small sideburn incision just in front of articular tubercle, medial to lateral and anterior to posterior. The freed malar complex was medially and superiorly repositioned with the zygomatic body wedged in the groove, followed by fixation with one miniplate or wire. Finally, the periosteum in the zygomatic area was pulled and sutured to the deep temporal fascia. RESULTS: Most patients were satisfied with their results. No inferiorly displaced malunion occurred in the zygomatic body. There were no serious complications such as nonunion or permanent facial nerve injury. Minor complications, including palpable step-off, mild asymmetry, hematoma, and mild cheek drooping, occurred in some cases. CONCLUSION: Our assisted fixation method, combined with subperiosteal lifting, can provide ideal effects and sufficient fixation in malar reduction to prevent many complications such as malunion and cheek drooping. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Concepts: Evidence-based medicine, Temporal bone, Buccal branch of the facial nerve, Bones of the head and neck, Zygomatic bone, Zygomatic arch, Zygoma, Zygomatic process

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Much of the fossil record for dogs consists of mandibles. However, can fossil canid mandibles be reliably identified as dogs or wolves? 3D geometric morphometric analysis correctly classifies 99.5% of the modern dog and wolf mandibles. However, only 4 of 26 Ust'-Polui fossil mandibles, a Russian Arctic site occupied from 250BCE to 150CE, were identified as dogs and none of the 20 Ivolgin mandibles, an Iron Age site in southern Russia, were identified as dogs. Three of the Ust'-Polui mandibles and 8 of the Ivolgin mandibles were identified as wolves. In contrast, all 12 Ivolgin skulls and 5 Ust'-Polui skulls were clearly identified as dogs. Only the classification of the UP6571 skull as a dog (Dog Posterior Probability = 1.0) was not supported by the typical probability. Other evidence indicates these canids were domesticated: they were located within human dwellings, remains at both sites have butchery marks indicating that they were consumed, and isotope analysis of canid and human remains from Ust'-Polui demonstrate that both were consuming freshwater protein; indicating that the humans were feeding the canids. Our results demonstrate that the mandible may not evolve as rapidly as the cranium and the mandible is not reliable for identifying early dog fossils.

Concepts: Temporal bone, Dog, Canidae, Carnivora, Fox, Gray Wolf, Coyote, Canis

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This study describes the microsurgical anatomy of the middle cranial fossa approach using temporal bone three-dimensional (3D) computed tomography (CT) reconstruction, which should contribute to determining the drilling point for the internal auditory meatus (IAM) when bony landmarks are absent. Thirty temporal bone CT scans were reviewed retrospectively. We measured the shortest and longest distances to IAM from the petrous ridge, and measured the angle between the facial nerve and various labyrinth structures. Three-dimensional reconstructed images were obtained using high-resolution axial temporal bone CT (0.7-mm-thick slices, FOV 90 × 90, KVp 120, 305 mA, width 2,800, and level 800). The mean shortest and longest distances to IAM from the petrous ridge were 5.22 and 10.1 mm, respectively. The mean distance to the IAM from the cochlea was 9.91 mm. The mean angle between the IAM and superior semicircular canal was 47.21°, which was more acute than previously reported. The mean angle between the IAM and geniculate ganglion (GG) and external auditory canal was 113.8°, and the mean distance from the GG to the IAM was 15.44 mm. Understanding the 3D relationships among the microsurgical structures will help to decide the drilling point for the IAM when bony landmarks are absent. A preoperative evaluation might be useful for preserving important neurovascular structures while approaching the middle fossa.

Concepts: Skull, Auditory system, Temporal bone, Length, Ear canal, Facial nerve, Geniculate ganglion, Internal auditory meatus

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“Notohippidae” is a probably paraphyletic family of medium sized notoungulates with complete dentition and early tendency to hypsodonty. They have been recorded from early Eocene to early Miocene, being particularly diverse by the late Oligocene. Although Rhynchippus equinus Ameghino is one of the most frequent notohippids in the fossil record, there are scarce data about cranial osteology other than the classical descriptions which date back to the early last century. In this context, we describe the exceptionally preserved specimen MPEF PV 695 (based on CT scanning technique and 3D reconstruction) with the aim of improving our knowledge of the species, especially regarding auditory region (petrosal, tympanic and surrounding elements), sphenoidal and occipital complexes. Besides a modular description of the whole skull, osteological correlates identified on the basicranium are used to infer some soft-tissue elements, especially those associated with vessels that supply the head, mainly intracranially. One of the most informative elements was the petrosal bone, whose general morphology matches that expected for a toxodont. The endocranial surface, together with the surrounding parietal, basisphenoid, occipital, and squamosal, enabled us to propose the location and communication of main venous sinuses of the lateral head wall (temporal, inferior and sigmoid sinuses), whereas the tympanic aspect and the identification of a posterior carotid artery canal provided strong evidence in support of an intratympanic course of the internal carotid artery, a controversial issue among notoungulates. Regarding the arrangement of tympanic and paratympanic spaces, the preservation of the specimen allowed us to appreciate the three connected spaces that constitute a heavily pneumatized middle ear; the epitympanic sinus, the tympanic cavity itself, and the ventral expansion of the tympanic cavity through the notably inflated bullae. We hope this study stimulates further inquires and provides potentially informative data for future research involving other representatives of the order.

Concepts: Bone, Skull, Internal carotid artery, Common carotid artery, Temporal bone, External carotid artery, Internal jugular vein, Eocene