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Mastoid Fontanelle
The asterion is a meeting point between three sutures between bones of the skull. It is an important surgical landmark. Structure In human anatomy, the asterion is a visible (craniometric) point on the exposed skull. It is just posterior to the ear. It is the point where three cranial sutures meet: * the lambdoid suture. * parietomastoid suture. * occipitomastoid suture. It is also the point where three cranial bones meet: * the parietal bone. * the occipital bone. * the mastoid portion of the temporal bone. In the adult, it lies 4 cm behind and 12 mm above the center of the entrance to the ear canal. Its relation to other anatomical structures is fairly variable. Clinical significance Neurosurgeons may use the asterion to orient themselves, in order to plan safe entry into the skull for some operations, such as when using a retro-sigmoid approach. Etymology The asterion receives its name from the Greek ἀστέριον (''astērion''), meaning "star" or "starry". T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skeletal System
A skeleton is the structural frame that supports the body of an animal. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside the body, and the hydroskeleton, a flexible internal skeleton supported by fluid pressure. Vertebrates are animals with a vertebral column, and their skeletons are typically composed of bone and cartilage. Invertebrates are animals that lack a vertebral column. The skeletons of invertebrates vary, including hard exoskeleton shells, plated endoskeletons, or Sponge spicule, spicules. Cartilage is a rigid connective tissue that is found in the skeletal systems of vertebrates and invertebrates. Etymology The term ''skeleton'' comes . ''Sceleton'' is an archaic form of the word. Classification Skeletons can be defined by several attributes. Solid skeletons consist of hard substances, such as bone, cartilage, or cuticle. These can be further ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occipitomastoid Suture
The occipitomastoid suture or occipitotemporal suture is the cranial suture between the occipital bone and the mastoid portion of the temporal bone. It is continuous with the lambdoidal suture. See also * Jugular foramen Additional images File:Occipitomastoid suture - animation03.gif, Animation. Occipitomastoid suture shown in red. File:Occipitomastoid suture - animation06.gif, Temporal bones and occipital bone, seen from inside. File:Occipitomastoid suture - skull - inferior view.png, Base of skull The base of skull, also known as the cranial base or the cranial floor, is the most inferior area of the skull. It is composed of the endocranium and the lower parts of the calvaria. Structure Structures found at the base of the skull are for .... Inferior surface. File:Sobo 1909 42 - Occipitomastoid suture.png, Base of skull. Inferior surface. References External links * * * Bones of the head and neck Cranial sutures Human head and neck Joints Joints o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercedes-Benz
Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquartered in Stuttgart, Baden-Württemberg, Germany. Mercedes-Benz AG produces consumer luxury vehicles and commercial vehicles badged as Mercedes-Benz. From November 2019 onwards, Mercedes-Benz-badged heavy commercial vehicles (trucks and buses) are managed by Daimler Truck, a former part of the Mercedes-Benz Group turned into an independent company in late 2021. In 2018, Mercedes-Benz was the largest brand of premium vehicles in the world, having sold 2.31 million passenger cars. The brand's origins lie in Daimler-Motoren-Gesellschaft's 1901 Mercedes and Carl Benz's 1886 Benz Patent-Motorwagen, which is widely regarded as the first internal combustion engine in a self-propelled automobile. The slogan for the brand is "the best or nothing". Hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurosurgeons
Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty concerned with the surgical treatment of disorders which affect any portion of the nervous system including the brain, spinal cord and peripheral nervous system. Education and context In different countries, there are different requirements for an individual to legally practice neurosurgery, and there are varying methods through which they must be educated. In most countries, neurosurgeon training requires a minimum period of seven years after graduating from medical school. United States In the United States, a neurosurgeon must generally complete four years of undergraduate education, four years of medical school, and seven years of residency (PGY-1-7). Most, but not all, residency programs have some component of basic science or clinical research. Neurosurgeons may pursue additional training in the form of a fellowship after residency, or, in some cases, as a senior resid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ear Canal
The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the pinna to the eardrum and is about in length and in diameter. Structure The human ear canal is divided into two parts. The elastic cartilage part forms the outer third of the canal; its anterior and lower wall are cartilaginous, whereas its superior and back wall are fibrous. The cartilage is the continuation of the cartilage framework of pinna. The cartilaginous portion of the ear canal contains small hairs and specialized sweat glands, called apocrine glands, which produce cerumen ( ear wax). The bony part forms the inner two thirds. The bony part is much shorter in children and is only a ring (''annulus tympanicus'') in the newborn. The layer of epithelium encompassing the bony portion of the ear canal is much thinner and therefore, more sensitive in comparison to the cartilaginous portion. Size and sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Bone
The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears. The lower seven cranial nerves and the major vessels to and from the brain traverse the temporal bone. Structure The temporal bone consists of four parts— the squamous, mastoid, petrous and tympanic parts. The squamous part is the largest and most superiorly positioned relative to the rest of the bone. The zygomatic process is a long, arched process projecting from the lower region of the squamous part and it articulates with the zygomatic bone. Posteroinferior to the squamous is the mastoid part. Fused with the squamous and mastoid parts and between the sphenoid and occipital bones lies the petrous part, which is shaped like a pyramid. The tympanic part is relatively small and lies inferior to the squamous part, anterior to the mast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occipital Bone
The occipital bone () is a neurocranium, cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cerebrum. At the base of skull in the occipital bone, there is a large oval opening called the foramen magnum, which allows the passage of the spinal cord. Like the other cranial bones, it is classed as a flat bone. Due to its many attachments and features, the occipital bone is described in terms of separate parts. From its front to the back is the basilar part of occipital bone, basilar part, also called the basioccipital, at the sides of the foramen magnum are the lateral parts of occipital bone, lateral parts, also called the exoccipitals, and the back is named as the squamous part of occipital bone, squamous part. The basilar part is a thick, somewhat quadrilateral piece in front of the foramen magnum and directed towards the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parietal Bone
The parietal bones () are two bones in the Human skull, skull which, when joined at a fibrous joint, form the sides and roof of the Human skull, cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin ''paries'' (''-ietis''), wall. Surfaces External The external surface [Fig. 1] is convex, smooth, and marked near the center by an eminence, the parietal eminence (''tuber parietale''), which indicates the point where ossification commenced. Crossing the middle of the bone in an arched direction are two curved lines, the superior and inferior temporal lines; the former gives attachment to the temporal fascia, and the latter indicates the upper limit of the muscular origin of the temporal muscle. Above these lines the bone is covered by a tough layer of fibrous tissue – the epicranial aponeurosis; below them it forms part of the temporal fossa, and affords attachment to the temporal muscle. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squamosal Suture
The squamosal suture, or squamous suture, arches backward from the pterion and connects the temporal squama with the lower border of the parietal bone: this suture is continuous behind with the short, nearly horizontal parietomastoid suture, which unites the mastoid process of the temporal with the region of the mastoid angle of the parietal bone. The term parietotemporal suture may refer to both of these sutures or exclusively to the parietomastoid suture and its use is, therefore, best avoided. Gallery File:Squamosal suture - animation04.gif, Animation. Left parietal bone removed. Squamosal sutures shown in red. File:Squamosal suture - animation06.gif, Parietal bones (above) and temporal bone The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears. Th ...s (below). File:Gray188 - Squamosal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, these two parts are the neurocranium and the viscerocranium ( facial skeleton) that includes the mandible as its largest bone. The skull forms the anterior-most portion of the skeleton and is a product of cephalisation—housing the brain, and several sensory structures such as the eyes, ears, nose, and mouth. In humans these sensory structures are part of the facial skeleton. Functions of the skull include protection of the brain, fixing the distance between the eyes to allow stereoscopic vision, and fixing the position of the ears to enable sound localisation of the direction and distance of sounds. In some animals, such as horned ungulates (mammals with hooves), the skull also has a defensive function by providing the mount (on the front ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ScienceDirect
ScienceDirect is a website which provides access to a large bibliographic database of scientific and medical publications of the Dutch publisher Elsevier. It hosts over 18 million pieces of content from more than 4,000 academic journals and 30,000 e-books of this publisher. The access to the full-text requires subscription, while the bibliographic metadata is free to read. ScienceDirect is operated by Elsevier. It was launched in March 1997. Usage The journals are grouped into four main sections: ''Physical Sciences and Engineering'', ''Life Sciences'', ''Health Sciences'', and ''Social Sciences and Humanities''. Article abstracts are freely available, and access to their full texts (in PDF and, for newer publications, also HTML) generally requires a subscription or pay-per-view purchase unless the content is freely available in open access. Subscriptions to the overall offering hosted on ScienceDirect, rather than to specific titles it carries, are usually acquired through a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambdoid Suture
The lambdoid suture (or lambdoidal suture) is a dense, fibrous connective tissue joint on the posterior aspect of the skull that connects the parietal bones with the occipital bone. It is continuous with the occipitomastoid suture. Structure The lambdoid suture is between the paired parietal bones and the occipital bone of the skull. It runs from the asterion on each side. Nerve supply The lambdoid suture may be supplied by a branch of the supraorbital nerve, a branch of the frontal branch of the trigeminal nerve. Clinical significance At birth, the bones of the skull do not meet. If certain bones of the skull grow too fast, then craniosynostosis (premature closure of the sutures) may occur. This can result in skull deformities. If the lambdoid suture closes too soon on one side, the skull will appear twisted and asymmetrical, a condition called "plagiocephaly". Plagiocephaly refers to the shape and not the condition. The condition is craniosynostosis. The lambdoid sut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
