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Tentorium Cerebelli
The cerebellar tentorium or tentorium cerebelli (Latin for "tent of the cerebellum") is one of four dural folds that separate the cranial cavity into four (incomplete) compartments. The cerebellar tentorium separates the cerebellum from the cerebrum forming a supratentorial and an infratentorial region; the cerebrum is supratentorial and the cerebellum infratentorial. The free border of the tentorium gives passage to the midbrain (the upper-most part of the brainstem). Structure Free border The free border of the tentorium is U-shaped; it forms an aperture - the tentorial notch (tentorial incisure) - which gives passage to the midbrain. The free border of each side extends anteriorly beyond the medial end of the superior petrosal sinus (i.e. the apex of the petrous part of the temporal bone) to overlap the attached margin, thenceforth forming a ridge of dura matter upon the roof of the cavernous sinus, terminating anteriorly by attaching at the anterior clinoid process. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meninges
In anatomy, the meninges (; meninx ; ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in the subarachnoid space between the arachnoid mater and the pia mater. The primary function of the meninges is to protect the central nervous system. Structure Dura mater The dura mater (), is a thick, durable membrane, closest to the Human skull, skull and vertebrae. The dura mater, the outermost part, is a loosely arranged, fibroelastic layer of cells, characterized by multiple interdigitating cell processes, no extracellular collagen, and significant extracellular spaces. The middle region is a mostly fibrous portion. It consists of two layers: the endosteal layer, which lies closest to the skull, and the inner meningeal layer, which lies closer to the brain. It contains larger blood vessels that split into the capillaries in the pia mater. It is composed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temporal Bone
The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bones fuse. Each temple is covered by a temporal muscle. The temporal bones 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 li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcification
Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature Materials'' 12, 476-478 (2013). causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification. Calcification may also refer to the processes of normal mineral deposition in biological systems, such as the formation of stromatolites or mollusc shells (see Biomineralization). Signs and symptoms Calcification can manifest itself in many ways in the body depending on the location. In the pulpal structure of a tooth, calcification often presents asymptomatically, and is diagnosed as an incidental finding during radiographic interpretation. Individual teeth with calcified pulp will typically respond negatively to vitality testing; teeth with calcified pulp often lack ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uncal Herniation
Brain herniation is a potentially deadly side effect of very high pressure within the skull that occurs when a part of the brain is squeezed across structures within the skull. The brain can shift across such structures as the falx cerebri, the tentorium cerebelli, and even through the foramen magnum (the hole in the base of the skull through which the spinal cord connects with the brain). Herniation can be caused by a number of factors that cause a mass effect and increase intracranial pressure (ICP): these include traumatic brain injury, intracranial hemorrhage, or brain tumor. Herniation can also occur in the absence of high ICP when mass lesions such as hematomas occur at the borders of brain compartments. In such cases local pressure is increased at the place where the herniation occurs, but this pressure is not transmitted to the rest of the brain, and therefore does not register as an increase in ICP. Because herniation puts extreme pressure on parts of the brain and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oculomotor Nerve
The oculomotor nerve, also known as the third cranial nerve, cranial nerve III, or simply CN III, is a cranial nerve that enters the orbit through the superior orbital fissure and innervates extraocular muscles that enable most movements of the eye and that raise the eyelid. The nerve also contains fibers that innervate the intrinsic eye muscles that enable pupillary constriction and accommodation (ability to focus on near objects as in reading). The oculomotor nerve is derived from the basal plate of the embryonic midbrain. Cranial nerves IV and VI also participate in control of eye movement. Structure The oculomotor nerve originates from the third nerve nucleus at the level of the superior colliculus in the midbrain. The third nerve nucleus is located ventral to the cerebral aqueduct, on the pre-aqueductal grey matter. The fibers from the two third nerve nuclei located laterally on either side of the cerebral aqueduct then pass through the red nucleus. From the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mydriasis
Mydriasis is the Pupillary dilation, dilation of the pupil, usually having a non-physiological cause, or sometimes a physiological pupillary response. Non-physiological causes of mydriasis include disease, Physical trauma, trauma, or the use of certain types of drug, drugs. It may also be of unknown cause. Normally, as part of the pupillary light reflex, the pupil dilates in the dark and miosis, constricts in the light to respectively improve vividity at night and to protect the retina from sunlight damage during the day. A ''mydriatic'' pupil will remain excessively large even in a bright environment. The excitation of the radial fibres of the iris which increases the pupillary aperture is referred to as a mydriasis. More generally, mydriasis also refers to the natural dilation of pupils, for instance in low light conditions or under sympathetic stimulation. Mydriasis is frequently induced by drugs for certain Ophthalmology, ophthalmic examinations and procedures, particularly th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herniation
A hernia (: hernias or herniae, from Latin, meaning 'rupture') is the abnormal exit of tissue or an organ, such as the bowel, through the wall of the cavity in which it normally resides. The term is also used for the normal development of the intestinal tract, referring to the retraction of the intestine from the extra-embryonal navel coelom into the abdomen in the healthy embryo at about 7 weeks. Various types of hernias can occur, most commonly involving the abdomen, and specifically the groin. Groin hernias are most commonly inguinal hernias but may also be femoral hernias. Other types of hernias include hiatus, incisional, and umbilical hernias. Symptoms are present in about 66% of people with groin hernias. This may include pain or discomfort in the lower abdomen, especially with coughing, exercise, or urinating or defecating. Often, it gets worse throughout the day and improves when lying down. A bulge may appear at the site of hernia, that becomes larger when bending ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bleeding
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vagina, or anus, or through a puncture in the skin. Hypovolemia is a massive decrease in blood volume, and death by excessive loss of blood is referred to as exsanguination. Typically, a healthy person can endure a loss of 10–15% of the total blood volume without serious medical difficulties (by comparison, blood donation typically takes 8–10% of the donor's blood volume). The stopping or controlling of bleeding is called hemostasis and is an important part of both first aid and surgery. Types * Upper head ** Intracranial hemorrhage — bleeding in the skull. ** Cerebral hemorrhage — a type of intracranial hemorrhage, bleeding within the brain tissue itself. ** Intracerebral hemorrhage — bleeding in the brain caused by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain Tumor
A brain tumor (sometimes referred to as brain cancer) occurs when a group of cells within the Human brain, brain turn cancerous and grow out of control, creating a mass. There are two main types of tumors: malignant (cancerous) tumors and benign tumor, benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and metastasis, secondary tumors, which most commonly have spread from tumors located outside the brain, known as brain metastasis tumors. All types of brain tumors may produce symptoms that vary depending on the size of the tumor and the part of the brain that is involved. Where symptoms exist, they may include headaches, seizures, problems with visual perception, vision, vomiting and cognition, mental changes. Other symptoms may include difficulty walking, speaking, with sensations, or unconsciousness. The cause of most brain tumors is unknown, though up to 4% of brain cancers may be caused by CT scan radiation. Uncommo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Straight Sinus
The straight sinus, also known as tentorial sinus or the , is an area within the skull beneath the brain. It receives blood from the inferior sagittal sinus and the great cerebral vein, and drains into the confluence of sinuses. Structure The straight sinus is situated within the dura mater, where the falx cerebri meets the midline of tentorium cerebelli. It forms from the confluence of the inferior sagittal sinus and the great cerebral vein. It may also drain blood from the superior cerebellar veins and veins from the falx cerebri. In cross-section, it is triangular, contains a few transverse bands across its interior, and increases in size as it proceeds backward. It is usually around 5 cm long. Variation The straight sinus is usually an unpaired structure. However, there may be two straight sinuses, which may be one on top of the other or parallel. Function The straight sinus allows blood to drain from the inferior center of the head outwards posteriorly. It receive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Falx Cerebri
The falx cerebri (also known as the cerebral falx) is a large, crescent-shaped fold of dura mater that descends vertically into the longitudinal fissure to separate the cerebral hemispheres.Saladin K. "Anatomy & Physiology: The Unity of Form and Function. New York: McGraw Hill, 2014. Print. pp 512, 770-773 It supports the dural sinuses that provide venous and CSF drainage from the brain. It is attached to the crista galli anteriorly, and blends with the tentorium cerebelli posteriorly. The falx cerebri is often subject to age-related calcification, and a site of falcine meningiomas. The falx cerebri is named for its sickle-like shape. Anatomy The falx cerebri is a strong, crescent-shaped sheet of dura mater lying in the sagittal plane between the two cerebral hemispheres. It is one of four dural partitions of the brain along with the falx cerebelli, tentorium cerebelli, and diaphragma sellae; it is formed through invagination of the dura mater into the longitudina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Petrosal Sinuses
The superior petrosal sinus is one of the dural venous sinuses located beneath the brain. It receives blood from the cavernous sinus and passes backward and laterally to drain into the transverse sinus. The sinus receives superior petrosal veins, some cerebellar veins, some inferior cerebral veins, and veins from the tympanic cavity. They may be affected by arteriovenous malformation or arteriovenous fistula, usually treated with surgery. Structure The superior petrosal sinus is located beneath the brain. It originates from the cavernous sinus. It passes backward and laterally to drain into the transverse sinus. The sinus runs in the attached margin of the tentorium cerebelli, in a groove in the petrous part of the temporal bone formed by the sinus itself - the superior petrosal sulcus. Function The superior petrosal sinus drains many veins of the brain, including superior petrosal veins, some cerebellar veins, some inferior cerebral veins, and veins from the tympanic cavit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
