Meckel’s Cartilage: From 1 Different Sources
a cartilaginous bar in the fetus around which the *mandible develops. Part of Meckel’s cartilage develops into the malleus (an ear ossicle) in the adult. [J. F. Meckel, the Younger (1781–1833), German anatomist]
A hard but pliant substance forming parts of the skeleton – for example, the cartilages of the ribs, of the larynx and of the ears. Microscopically, cartilage is found to consist of cells arranged in twos or in rows, and embedded in a ground-glass-like material devoid of blood vessels and nerves. The end of every long bone has a smooth layer of hyaline cartilage on it where it forms a joint with other bones (articular cartilage), and in young persons up to about the age of 16 there is a plate of cartilage (epiphyseal cartilage) running right across the bone about 12 mm (half an inch) from each end. The latter, by constantly thickening and changing into bone, causes the increase in length of the bone. (See also BONE.) In some situations there is found a combination of cartilage and ?brous tissue, as in the discs between the vertebrae of the spine. This ?bro-cartilage, as it is known, combines the pliability of ?brous tissue with the elasticity of cartilage. (For cartilages of the knee, see KNEE.)... cartilage
The largest cartilage in the LARYNX and forms the prominence of the Adam’s apple in front of the neck.... thyroid cartilage
A common problem, present at birth, in which a small, hollow, wide-mouthed sac protrudes from the ileum. Symptoms only occur when the diverticulum becomes infected, obstructed, or ulcerated. The most common symptom is painless bleeding, which may be sudden and severe, making immediate blood transfusion necessary. Inflammation may cause symptoms very similar to those of acute appendicitis. Meckel’s diverticulum occasionally causes intussusception or volvulus of the small intestine. Diagnosis of Meckel’s diverticulum may be made by using technetium radionuclide scanning. If complications occur, they are treated by surgical removal of the diverticulum.... meckel’s diverticulum
A hollow pouch sometimes found attached to the small INTESTINE. It is placed on the small intestine about 90–120 cm (3–4 feet) from its junction with the large intestine, is several centimetres long, and ends blindly. It is lined with cells similar to those which line the stomach, and so may produce acid. This leads to occasional illness – Meckel’s diverticulitis with ulceration, which causes abdominal pain and fever (sometimes referred to as ‘left-sided appendicitis’). Perforation may result in PERITONITIS and, rarely, may be the lead point of an INTUSSUSCEPTION.... meckel’s diverticulum
Two crescentic layers of ?bro-cartilage on the outer and inner edges of the knee-joint, which form hollows on the upper surface of the tibia in which the condyles at the lower end of the femur rest. The inner cartilage is especially liable to be displaced by a sudden and violent movement at the KNEE.... semilunar cartilages
See XIPHOID PROCESS.... xiphoid cartilage
either of the two pyramid-shaped cartilages that lie at the back of the *larynx next to the upper edges of the cricoid cartilage.... arytenoid cartilage
a cartilage that connects a *rib to the breastbone (*sternum). The first seven ribs (true ribs) are directly connected to the sternum by individual costal cartilages. The next three ribs are indirectly connected to the sternum by three costal cartilages, each of which is connected to the one immediately above it.... costal cartilage
the cartilage, shaped like a signet ring, that forms part of the anterior and lateral walls and most of the posterior wall of the *larynx.... cricoid cartilage
a type of *cartilage in which elastic fibres are distributed in the matrix. It is yellowish in colour and is found in the external ear.... elastic cartilage
see xiphoid process.... ensiform cartilage
the most common type of *cartilage: a bluish-white elastic material with a matrix of chondroitin sulphate in which fine collagen fibrils are embedded.... hyaline cartilage
one of a pair of crescent-shaped cartilages in the knee joint situated between the femur and tibia.... semilunar cartilage
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