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CABARET LUNAIRE
Human skullsIn humans, the adult skull is normally made up of 29 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, rigid articulations permitting very little movement.Eight bones form the neurocranium (braincase), a protective vault of bone surrounding the brain and medulla oblongata. Fourteen bones form the splanchnocranium, the bones supporting the face. Encased within the temporal bones are the six ear ossicles of the middle ear. The hyoid bone, supporting the larynx, is usually not considered as part of the skull, as it does not articulate with any other bones.The skull also contains the sinus cavities, which are air-filled cavities lined with respiratory epithelium, which also lines the large airways. The exact functions of the sinuses are unclear; they may contribute to lessening the weight of the skull with a minimal reduction in strength, or they may be important in improving the resonance of the voice. In some animals, such as the elephant, the sinuses are extensive. The elephant skull needs to be very large, to form an attachment for muscles of the neck and trunk, but is also unexpectedly light; the comparatively small brain-case is surrounded by large sinuses which reduce the weight.The meninges are the three layers, or membranes, which surround the structures of the central nervous system. They are known as the dura mater, the arachnoid mater and the pia mater. Other than being classified together, they have little in common with each other.In humans, the anatomical position for the skull is the Frankfurt plane, where the lower margins of the orbits and the upper borders of the ear canals are all in a horizontal plane. This is the position where the subject is standing and looking directly forward. For comparison, the skulls of other species, notably primates and hominids, may sometimes be studied in the Frankfurt plane. However, this does not always equate to a natural posture in life.
In anatomy, an arm is one of the upper limbs of a two-legged animal. The term arm can also be used for analogous structures, such as one of the paired upper limbs of a four-legged animal, or the arms of an octopus.Anatomically, the term arm refers specifically to the segment between the shoulder and the elbow. The segment between the elbow and wrist is the forearm. However, in colloquial speech the term arm often refers to the entire upper limb from shoulder to wrist.In primates the arms are richly adapted for both climbing and for more skilled, manipulative tasks. The ball and socket shoulder joint allows for movement of the arms in a wide circular plane, while the presence of two forearm bones which can rotate around each other allows for additional range of motion at this level.
BONE MARROW
There are two types of bone marrow: red marrow (also known as myeloid tissue) and yellow marrow. Red blood cells, platelets and most white blood cells arise in red marrow; some white blood cells develop in yellow marrow. The color of yellow marrow is due to the much higher number of fat cells. Both types of bone marrow contain numerous blood vessels and capillaries.At birth, all bone marrow is red. With age, more and more of it is converted to the yellow type. Adults have on average about 2.6 kg of bone marrow, with about half of it being red. Red marrow is found mainly in the flat bones such as hip bone, breast bone, skull, ribs, vertebrae and shoulder blades, and in the cancellous ("spongy") material at the proximal ends of the long bones femur and humerus. Yellow marrow is found in the hollow interior of the middle portion of long bones.In cases of severe blood loss, the body can convert yellow marrow back to red marrow in order to increase blood cell production.