Instruct: Given a question, retrieve relevant passages that answer the question.
Query: What is the smallest bone in the human body?
The stapes or stirrup is a bone in the middle ear of humans and other mammals which is involved in the conduction of sound vibrations to the inner ear. The stirrup-shaped small bone is on and transmits these to the oval window, medially. The stapes is the smallest and lightest named bone in the human body, and is so-called because of its resemblance to a stirrup (Latin: Stapes).
The first book constitutes about a quarter of the entire collection. It presents Vesalius' observations on human bones and cartilage, which he collected from cemeteries. It covers the physical appearance of human bones and the differentiation of human bones and cartilage by function. In each chapter Vesalius describes the bones in great detail, explaining their physical qualities in different ways. In the opening chapters, Vesalius "gives general aspects of bones and skeletal organisation, dealing with the differences in texture, strength, and resilience between bone and cartilage; explaining the complex differences between types of joints and reviewing some basic elements of descriptive techniques and terminology." A major theme of this book is whether Galen described the bones of the human skeleton accurately. When Vesalius lectured on the human skeleton, he also had to present the bones of animals to give credibility to Galen's observations.
Here Vesalius describes the structure of the muscles, the agents used in creating movement by the body, and the material used to hold the joints together. Through his observations of butchers cutting meat, he was able to incorporate the skills they used in the dissection of the human body. The order in which to dissect a human body to effectively observe each muscle in the body is laid out. Each illustration displays a deepening view of the human body which can be followed while dissecting a human body. Vesalius also mentions the instruments needed to perform a dissection. Here Vesalius begins to describe how Galen's anatomical descriptions do not match his own observations. In order to show respect to Galen, he suggests Galen's use of anatomical structure is in fact correct, but not for humans. He even continues to describe some of the structures in the way Galen would.
The alveolar bone is the bone of the jaw which forms the alveolus around teeth. Like any other bone in the human body, alveolar bone is modified throughout life. Osteoblasts create bone and osteoclasts destroy it, especially if force is placed on a tooth. As is the case when movement of teeth is attempted through orthodontics, an area of bone under compressive force from a tooth moving toward it has a high osteoclast level, resulting in bone resorption. An area of bone receiving tension from periodontal ligaments attached to a tooth moving away from it has a high number of osteoblasts, resulting in bone formation.
Early in the Cold War, in studies known as Project GABRIEL and Project SUNSHINE, researchers in the United States, the United Kingdom, and Australia tried to determine how much nuclear fallout would be required to make the Earth uninhabitable. They realized that atmospheric nuclear testing had provided them an opportunity to investigate this. Such tests had dispersed radioactive contamination worldwide, and examination of human bodies could reveal how readily it was taken up and hence how much damage it caused. Of particular interest was strontium-90 in the bones. Infants were the primary focus, as they would have had a full opportunity to absorb the new contaminants. As a result of this conclusion, researchers began a program to collect human bodies and bones from all over the world, with a particular focus on infants. The bones were cremated and the ashes analyzed for radioisotopes. This project was kept secret primarily because it would be a public relations disaster; as a result parents and family were not told what was being done with the body parts of their relatives.
The skeletal system serves many important functions; it provides the shape and form for the body, support and protection, allows bodily movement, produces blood for the body, and stores minerals. The number of bones in the human skeletal system is a controversial topic. Humans are born with over 300 bones; however, many bones fuse together between birth and maturity. As a result, an average adult skeleton consists of 206 bones. The number of bones varies according to the method used to derive the count. While some consider certain structures to be a single bone with multiple parts, others may see it as a single part with multiple bones. There are five general classifications of bones. These are long bones, short bones, flat bones, irregular bones, and sesamoid bones. The human skeleton is composed of both fused and individual bones supported by ligaments, tendons, muscles and cartilage. It is a complex structure with two distinct divisions; the axial skeleton, which includes the vertebral column, and the appendicular skeleton.
In the human body at birth, there are over 270 bones, but many of these fuse together during development, leaving a total of 206 separate bones in the adult, not counting numerous small sesamoid bones. The largest bone in the body is the femur or thigh-bone, and the smallest is the stapes in the middle ear.
The human skeleton consists of both fused and individual bones supported and supplemented by ligaments, tendons, muscles and cartilage. It serves as a scaffold which supports organs, anchors muscles, and protects organs such as the brain, lungs, heart and spinal cord. Although the teeth do not consist of tissue commonly found in bones, the teeth are usually considered as members of the skeletal system.
The biggest bone in the body is the femur in the upper leg, and the smallest is the stapes bone in the middle ear. In an adult, the skeleton comprises around 14% of the total body weight, and half of this weight is water.
The horse skeleton averages 205 bones.[59] A significant difference between the horse skeleton and that of a human is the lack of a collarbone—the horse's forelimbs are attached to the spinal column by a powerful set of muscles, tendons, and ligaments that attach the shoulder blade to the torso. The horse's legs and hooves are also unique structures. Their leg bones are proportioned differently from those of a human. For example, the body part that is called a horse's "knee" is actually made up of the carpal bones that correspond to the human wrist. Similarly, the hock contains bones equivalent to those in the human ankle and heel. The lower leg bones of a horse correspond to the bones of the human hand or foot, and the fetlock (incorrectly called the "ankle") is actually the proximal sesamoid bones between the cannon bones (a single equivalent to the human metacarpal or metatarsal bones) and the proximal phalanges, located where one finds the "knuckles" of a human. A horse also has no muscles in its legs below the knees and hocks, only skin, hair, bone, tendons, ligaments, cartilage, and the assorted specialized tissues that make up the hoof.[60]
The stapedius is the smallest skeletal muscle in the human body. At just over one millimeter in length, its purpose is to stabilize the smallest bone in the body, the stapes.
The stapes is the third bone of the three ossicles in the middle ear. The stapes is a stirrup-shaped bone, and the smallest in the human body. It rests on the oval window, to which it is connected by an annular ligament. The stapes is described as having a base, resting on the oval window, as well as a head that articulates with the incus. These are connected by anterior and posterior limbs (Latin: crura).[1]:862 The stapes articulates with the incus through the incudostapedial joint.[2] The stapes is the smallest bone in the human body, and measures roughly 3 x 2.5mm, greater along the head-base span.[3]
They are the smallest of the working terriers. They are active and compact, free moving, with good substance and bone. Good substance means good spring of rib and bone that matches the body such that the dog can be a very agile ratter or earth-dog.
The trapezoid bone (lesser multangular bone) is a carpal bone in tetrapods, including humans. It is the smallest bone in the distal row of carpal bones that give structure to the palm of the hand. It may be known by its wedge-shaped form, the broad end of the wedge constituting the dorsal, the narrow end the palmar surface; and by its having four articular facets touching each other, and separated by sharp edges. It is homologous with the "second distal carpal" of reptiles and amphibians.
In 1536, Andreas Vesalius challenged the known world of medicine and anatomy. As a 22-year-old medical student, he had a lot to lose when he began stealing bodies from the Paris cemetery, even if it was in the name of science. He would take the bodies back to his home and boil off the skin until there were only bones remaining. Vesalius wanted to identify every bone in the human body and reconstruct it like a jigsaw puzzle. At the time, there was only one set of text books about the body at Vesalius's disposal, written by Claudius Galen 1300 years earlier. Vesalius made over 200 corrections to Galen's book based on what he had learned from dissecting stolen bodies, and ignited a new age of modern medicine.
Human anatomy is the study of the shape and form of the human body. The human body has four limbs (two arms and two legs), a head and a neck which connect to the torso. The body's shape is determined by a strong skeleton made of bone and cartilage, surrounded by fat, muscle, connective tissue, organs, and other structures. The spine at the back of the skeleton contains the flexible vertebral column which surrounds the spinal cord, which is a collection of nerve fibres connecting the brain to the rest of the body. Nerves connect the spinal cord and brain to the rest of the body. All major bones, muscles, and nerves in the body are named, with the exception of anatomical variations such as sesamoid bones and accessory muscles.
The femur (, pl. "femurs" or "femora" ) or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with the tibia and kneecap forming the knee joint. By most measures the femur is the strongest bone in the body. The femur is also the longest bone in the human body.
Estimated at under in weight, "Albinykus" was one of the smallest alvarezsaurs and among the smallest nonavian dinosaurs. The body size of alvarezsaurs decreased throughout their evolutionary history, and "Albinykus" represents a particularly derived form. One distinguishing feature of "Albinykus" not seen in other alvarezsaurids is the complete fusion of the tarsals to other bones of the leg; the proximal tarsals are fused to the tibia bone of the lower leg and the distal tarsals are fused to the metatarsal bones of the foot.
There is evidence, both archaeological and genetic, that cannibalism has been practiced for hundreds of thousands of years by early Homo Sapiens and archaic hominins. Human bones that have been "de-fleshed" by other humans go back 600,000 years. The oldest "Homo sapiens" bones (from Ethiopia) show signs of this as well. Some anthropologists, such as Tim D. White, suggest that ritual cannibalism was common in human societies prior to the beginning of the Upper Paleolithic period. This theory is based on the large amount of "butchered human" bones found in Neanderthal and other Lower/Middle Paleolithic sites. Cannibalism in the Lower and Middle Paleolithic may have occurred because of food shortages. It has been also suggested that removing dead bodies through ritual cannibalism might have been a means of predator control, aiming to eliminate predators' and scavengers' access to hominid (and early human) bodies. Jim Corbett proposed that after major epidemics, when human corpses are easily accessible to predators, there are more cases of man-eating leopards, so removing dead bodies through ritual cannibalism (before the cultural traditions of burying and burning bodies appeared in human history) might have had practical reasons for hominids and early humans to control predation.
In Gough's Cave, England, remains of human bones and skulls, around 14,700 years old, suggest that cannibalism took place amongst the people living in or visiting the cave, and that they may have used human skulls as drinking vessels.
The success of the memoir "Death’s Acre" inspired Jon Jefferson to create a series of collaborative crime-fiction novels with Bass using the pen name Jefferson Bass. In 2006, the pair published a debut novel, "Carved in Bone", which reached # 25 on the New York Times Best Seller List. Every year thereafter, Jefferson Bass published another novel in the Body Farm series, including: "Flesh and Bone", "The Devil's Bones", "Bones of Betrayal", "The Bone Thief", "The Bone Yard", "The Inquisitor's Key" and "Cut to the Bone". Based on accurate forensic science, the Body Farm series has helped to increase popular interest in forensic criminal investigations involving the remains of the human body. Jefferson's second nonfiction collaboration with Bass, "Beyond the Body Farm," recounts additional cases Bass worked, including the deadly 1983 Benton fireworks disaster.
Body composition may be analyzed in terms of molecular type e.g., water, protein, connective tissue, fats (or lipids), hydroxylapatite (in bones), carbohydrates (such as glycogen and glucose) and DNA. In terms of tissue type, the body may be analyzed into water, fat, muscle, bone, etc. In terms of cell type, the body contains hundreds of different types of cells, but notably, the largest number of cells contained in a human body (though not the largest mass of cells) are not human cells, but bacteria residing in the normal human gastrointestinal tract.
The ossicles (also called auditory ossicles) are three bones in either middle ear that are among the smallest bones in the human body. They serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea). The absence of the auditory ossicles would constitute a moderate-to-severe hearing loss. The term "ossicle" literally means "tiny bone". Though the term may refer to any small bone throughout the body, it typically refers to the malleus, incus, and stapes (hammer, anvil, and stirrup) of the middle ear.
Bone marrow is a semi-solid tissue which may be found within the spongy or cancellous portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production or hematopoiesis. It is composed of hematopoietic cells, marrow adipose tissue, and supportive stromal cells. In adult humans, bone marrow is primarily located in the ribs, vertebrae, sternum, and bones of the pelvis. On average, bone marrow constitutes 4% of the total body mass of humans; in an adult having 65 kilograms of mass (143 lb), bone marrow typically accounts for approximately .
These relatively small snakes rarely exceed 30 cm in length; only "Trilepida macrolepis" and "Leptotyphlops occidentalis" grow larger. The cranium and upper jaws are immobile and no teeth are in the upper jaw. The lower jaw consists of a much elongated quadrate bone, a tiny compound bone, and a relatively larger dentary bone. The body is cylindrical with a blunt head and a short tail. The scales are highly polished. The pheremones they produce protect them from attack by termites. Among these snakes is what is believed to be the world's smallest: "L. carlae" .
In the human body, the cuboid bone is one of the seven tarsal bones of the foot.
The human skeleton is the internal framework of the body. It is composed of around 270 bones at birth – this total decreases to around 206 bones by adulthood after some bones get fused together. The bone mass in the skeleton reaches maximum density around age 21. The human skeleton can be divided into the axial skeleton and the appendicular skeleton. The axial skeleton is formed by the vertebral column, the rib cage, the skull and other associated bones. The appendicular skeleton, which is attached to the axial skeleton, is formed by the shoulder girdle, the pelvic girdle and the bones of the upper and lower limbs.
Andreas Vesalius (1514-1564), a Flemish anatomist, was at first a "Galenist" at the University of Paris. When he moved to Italy and entered the University of Padua, he began dissecting human bodies. He studied many details of human anatomy and found that Galen made some anatomical mistakes. For example, Galen wrote that the sternum has seven segments, but Vesalius found it has three segments. Galen wrote that the bone of the arm is the longest bone in the human body, but Vesalius found that the bone of the thigh is actually the longest bone in human body. At age 25 Vesalius realized that the anatomical knowledge of Galen was derived from animal anatomy and therefore Galen had never dissected a human body.