Sclera pass. The thickness of the sclera varies from 1mm at the posterior pole to 0.3 mm just behind the rectus muscle insertions. The sclera's blood vessels are mainly on the surface. Along with the vessels of the conjunctiva (which is a thin layer covering the sclera), those in the episclera render the inflamed eye bright red. In many vertebrates, the sclera is reinforced with plates of cartilage or bone, together forming a circular structure called the sclerotic ring. In primitive fish, this ring consists of four plates, but the number is lower in many living ray-finned fishes, and much higher
History of beliefs about the human body much on discourse about bodies, rather than on material bodies themselves. Drawing on Mikhail Bakhtin's 1965 "Rabelais and His World", they promoted a more materially orientated direction in the history of the body. The Ebers Papyrus is an Egyptian medical text and is the oldest known record of the human body, dating back to 3000 BC. The Ebers Papyrus describes the body by physical examination and what can be felt. Clinical investigations such as the Pulse, percussion of the body, the recognition of diseased or disordered states. “If thou examinst a swelling of the covering of his belly’s horns above