"DNA. Petrous part of the temporal bone The petrous part of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones. Directed medially, forward, and a little upward, it presents a base, an apex, three surfaces, and three angles, and houses in its interior, the components of the inner ear. The petrous portion is among the most basal elements of the skull and forms part of the endocranium. Petrous comes from the Latin word ""petrosus"", meaning ""stone-like, hard"". It is one of the densest bones in the body. The"
"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 (). The stapes articulates with the incus through the incudostapedial joint. The stapes is the smallest bone in the human body, and measures roughly 3 x 2.5mm, greater along the head-base span. The stapes develops from the second pharyngeal arch during the sixth to eighth week of embryological life. The central cavity of the stapes, the obturator foramen, is"
"by a persistent stapedial artery, fibrosis-related damage to the base of the bone, or obliterative otosclerosis, resulting in obliteration of the base. The stapes is commonly described as having been discovered by the professor Giovanni Filippo Ingrassia in 1546 at the University of Naples, although this remains the nature of some controversy, as Ingrassia's description was published posthumously in his 1603 anatomical commentary '. Spanish anatomist Pedro Jimeno is first to have been credited with a published description, in ' (1549). The bone is so-named because of its resemblance to a stirrup (), an example of a late Latin word,"
"nerve VII. Stapedius muscle 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 stapedius emerges from a pinpoint foramen in the apex of the pyramidal eminence (a hollow, cone-shaped prominence in the posterior wall of the tympanic cavity), and inserts into the neck of the stapes. The stapedius is supplied by the nerve to stapedius, a branch of the facial nerve. The stapedius dampens the vibrations of the stapes by pulling on the neck of that bone."
"Stapedius muscle 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 stapedius emerges from a pinpoint foramen in the apex of the pyramidal eminence (a hollow, cone-shaped prominence in the posterior wall of the tympanic cavity), and inserts into the neck of the stapes. The stapedius is supplied by the nerve to stapedius, a branch of the facial nerve. The stapedius dampens the vibrations of the stapes by pulling on the neck of that bone. It prevents"
"due to the presence embryologically of the stapedial artery, which usually regresses. The stapes is one of three ossicles in mammals. In non-mammalian four-legged animals, the bone homologous to the stapes is usually called the columella; however, in reptiles, either term may be used. In fish, the homologous bone is called the ""hyomandibular"", and is part of the gill arch supporting either the spiracle or the jaw, depending on the species. The equivalent term in amphibians is the """". The stapes appears to be relatively constant in size in different ethnic groups. In 0.01-0.02% of people, the stapedial artery does"
"the stapes (the smallest bone in the human body) in which to secure a prosthetic. The CO laser allows the surgeon to create very small, precisely placed holes without increasing the temperature of the inner ear fluid by more than one degree, making this an extremely safe surgical solution. The hole diameter can be predetermined according to the prosthesis diameter. Treatment can be completed in a single operation visit using anesthesia, normally followed by one or two nights' hospitalization with subsequent at-home recovery time a matter of days or weeks. Comparisons have shown stapedotomy to yield either as good or"
"stifle joint in different species. These sesamoids assist with the smooth movement of tendon/muscle over the joint. The most well-known sesamoid bone is the patella, more commonly known as the 'knee cap'. It is located cranially to the joint and sits in the trochlear groove of the femur. It guides the patellar ligament of the quadriceps over the knee joint to its point of insertion on the tibia. Caudal to the joint, in the dog for example, are the two fabellae, which lie in the two tendons of origin of gastrocnemius. Fourth, there is often a small sesamoid bone in"
"Sternum The sternum or breastbone is a long flat bone located in the center of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Shaped roughly like a necktie, it is one of the largest and longest flat bones of the body. Its three regions are the manubrium, the body, and the xiphoid process. The word ""sternum"" originates from the Greek στέρνον, meaning ""chest"". The sternum is a long, flat bone, forming the middle portion of the front of"
"""head."" Capitate bone The capitate bone is found in the center of the carpal bone region, colloquially known as the wrist, which is at the distal end of the radius and ulna bones. It articulates with the third metacarpal bone (the middle finger) and forms the third carpometacarpal joint. The capitate bone is the largest of the carpal bones in the human hand. It presents, above, a rounded portion or head, which is received into the concavity formed by the scaphoid and lunate bones; a constricted portion or neck; and below this, the body. The bone is also found in"
"Capitate bone The capitate bone is found in the center of the carpal bone region, colloquially known as the wrist, which is at the distal end of the radius and ulna bones. It articulates with the third metacarpal bone (the middle finger) and forms the third carpometacarpal joint. The capitate bone is the largest of the carpal bones in the human hand. It presents, above, a rounded portion or head, which is received into the concavity formed by the scaphoid and lunate bones; a constricted portion or neck; and below this, the body. The bone is also found in many"
"shallow dish. Patella The patella, also known as the kneecap, is a thick, circular-triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as mice, cats and birds, but not in whales, or most reptiles. In humans, the patella is the largest sesamoid bone in the body. Babies are born with a patella of soft cartilage which begins to ossify into bone at about three years of age. The patella is a sesamoid bone roughly triangular in shape, with the apex"
"Patella The patella, also known as the kneecap, is a thick, circular-triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as mice, cats and birds, but not in whales, or most reptiles. In humans, the patella is the largest sesamoid bone in the body. Babies are born with a patella of soft cartilage which begins to ossify into bone at about three years of age. The patella is a sesamoid bone roughly triangular in shape, with the apex of the"
"Pubis (bone) In vertebrates, the pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis. It is covered by a layer of fat, which is covered by the mons pubis. It is divisible into a body, a superior ramus and an inferior ramus. In the female, the pubic bone is anterior to the urethral sponge. The left and right hip bones join at the pubic symphysis. The pubis is the lower limit of the suprapubic region. The body forms one-fifth of the acetabulum, contributing by its external surface both to the lunate"
"the upper jaw (the articular and quadrate bones) lost their purpose in the jaw joint and were put to new use in the middle ear, connecting to the existing stapes bone and forming a chain of three bones, the ossicles, which transmit sounds more efficiently and allow more acute hearing. In mammals, these three bones are known as the malleus, incus, and stapes (hammer, anvil, and stirrup respectively). Mammals and birds also differ from other vertebrates by having evolved a cochlea. The evidence that the malleus and incus are homologous to the reptilian articular and quadrate was originally embryological, and"
"deep): the malleus, incus, and stapes, terms that in Latin are translated as ""the hammer, anvil, and stirrup"". Studies have shown that ear bones in mammal embryos are attached to the dentary, which is part of the jaw. These are ossified portions of cartilage—called Meckel's cartilage—that are attached to the jaw. As the embryo develops, the cartilage hardens to form bone. Later in development, the bone structure breaks loose from the jaw and migrates to the inner ear area. The structure is known as the middle ear, and is made up of the stapes, incus, malleus, and tympanic membrane. These"
"Both cardo and stipes are loosely joined to the head by membrane so they are capable of movement. Distally on the stipes are two lobes, an inner lacinea and an outer galea, one or both of which may be absent. More laterally on the stipes is a jointed, leglike palp made up of a number of segments; in Orthoptera there are five. Anterior and posterior rotator muscles are inserted on the cardo, and ventral adductor muscles arising on the tentorium are inserted on both cardo and stipes. Arising in the stipes are flexor muscles of lacinea and galea and another"
"is synonymous with the os triquetrum secundarium. The ""os carpi centrale"" (also briefly ""os centrale"") is, where present, located on the dorsal side of the wrist between the scaphoid, the trapezoid and capitate, radially to the deep fossa of the capitate. The bone is present in almost every human embryo of 17–49 mm length, but then usually fuses with the ulnar side of the scaphoid. Sometimes it fuses with the capitate or the trapezoid. The literature also refers to an ""os centrale"" at the palm of the carpus, but this existence is questioned. The ""os carpi centrale"" appears many other"
"pre-pubic bones can be found as os penises. Pubis (bone) In vertebrates, the pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis. It is covered by a layer of fat, which is covered by the mons pubis. It is divisible into a body, a superior ramus and an inferior ramus. In the female, the pubic bone is anterior to the urethral sponge. The left and right hip bones join at the pubic symphysis. The pubis is the lower limit of the suprapubic region. The body forms one-fifth of the acetabulum, contributing"
"Scaphoid bone The scaphoid bone is one of the carpal bones of the wrist. It is situated between the hand and forearm on the thumb side of the wrist (also called the lateral or radial side). It forms the radial border of the carpal tunnel. The scaphoid bone is the largest bone of the proximal row of wrist bones, its long axis being from above downward, lateralward, and forward. It is approximately the size and shape of a medium cashew. The scaphoid is situated between the proximal and distal rows of carpal bones. It is located on the radial side"
"Sacrum The sacrum ( or ; plural: ""sacra"" or ""sacrums""), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of sacral vertebrae S1S5 between 18 and 30years of age. The sacrum is situated at the upper, back part of the pelvic cavity, between the two wings of the pelvis. It forms joints with four other bones. The two projections at the sides of the sacrum are called the alae (wings), and articulate with the ilium at the L-shaped sacroiliac joints. The upper part of the sacrum connects with the last"
"Spine of scapula The spine of the scapula or scapular spine is a prominent plate of bone, which crosses obliquely the medial four-fifths of the scapula at its upper part, and separates the supra- from the infraspinatous fossa. It begins at the vertical [vertebral or medial border] border by a smooth, triangular area over which the tendon of insertion of the lower part of the Trapezius glides, and, gradually becoming more elevated, ends in the acromion, which overhangs the shoulder-joint. The spine is triangular, and flattened from above downward, its apex being directed toward the vertebral border. The ""root of"
"(this time from the latin word “navis” = boat), since there is also a bone in a similar position in the foot which is called the navicular. Scaphoid bone The scaphoid bone is one of the carpal bones of the wrist. It is situated between the hand and forearm on the thumb side of the wrist (also called the lateral or radial side). It forms the radial border of the carpal tunnel. The scaphoid bone is the largest bone of the proximal row of wrist bones, its long axis being from above downward, lateralward, and forward. It is approximately the"
"Scrotum The scrotum is an anatomical male reproductive structure that consists of a suspended dual-chambered sack of skin and smooth muscle that is present in most terrestrial male mammals and located under the penis. One testis is typically lower than the other to avoid compression in the event of impact. The perineal raphe is a small, vertical, slightly raised ridge of scrotal skin under which is found the scrotal septum. It appears as a thin longitudinal line that runs front to back over the entire scrotum. The scrotum contains the external spermatic fascia, testes, epididymis and ductus deferens. It is"
"caudal and thoracic vertebrae to form a single structure called the synsacrum. In the frog the ilium is elongated and forms a mobile joint with the sacrum that acts as an additional limb to give more power to its leaps. Sacrum The sacrum ( or ; plural: ""sacra"" or ""sacrums""), in human anatomy, is a large, triangular bone at the base of the spine that forms by the fusing of sacral vertebrae S1S5 between 18 and 30years of age. The sacrum is situated at the upper, back part of the pelvic cavity, between the two wings of the pelvis. It"
"Carpal bones The carpal bones are the eight small bones that make up the wrist (or carpus) that connects the hand to the forearm. The term ""carpus"" is derived from the Latin carpus and the Greek καρπός (karpós), meaning ""wrist"". In human anatomy, the main role of the wrist is to facilitate effective positioning of the hand and powerful use of the extensors and flexors of the forearm, and the mobility of individual carpal bones increase the freedom of movements at the wrist. In tetrapods, the carpus is the sole cluster of bones in the wrist between the radius and"
"Ilium (bone) The ilium () (plural ilia) is the uppermost and largest part of the hip bone, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an ilium. The ilium of the human is divisible into two parts, the body and the wing; the separation is indicated on the top surface by a curved line, the arcuate line, and on the external surface by the margin of the acetabulum. The name comes from the Latin (""ile"","
"via multiple structures, including the stapes. Thus, the discovery of a slender stapes in ""Cacops aspidephorus"" suggested that ""Cacops"" had an ability to hear airborne sound. The presence of a tympanum in contemporary amniotes is a difference between these terrestrial vertebrates that suggests these two groups had very different abilities to hear airborne sound. This type of hearing is important for both prey detection and intraspecific communication. Two series of osteoderms of the presacral vertebral column impact the biomechanics of the axial skeleton. ""Cacops"" have an internal series, which consist of an osteoderm fused to the distal tips of each"
"Tarsus (skeleton) The tarsus is a cluster of seven articulating bones in each foot situated between the lower end of tibia and fibula of the lower leg and the metatarsus. It is made up of the midfoot (cuboid, medial, intermediate, and lateral cuneiform, and navicular) and hindfoot (talus and calcaneus). The tarsus articulates with the bones of the metatarsus, which in turn articulate with the proximal phalanges of the toes. The joint between the tibia and fibula above and the tarsus below is referred to as the ankle joint. In humans the largest bone in the tarsus is the calcaneus,"
"Interparietal bone An interparietal bone (os interparietale or Inca bone or os Inca. Var.) is a dermal bone situated between the parietal and supraoccipital. In humans, it corresponds to the upper portion of the squama of the occipital bone that lies superior to the highest nuchal line and is completely fused to the supraoccipital. However, in some individuals this portion remains separate from the rest of the occipital bone throughout life. In such cases, this separate bone is particularly referred as Inca bone. Inca bones in humans were first found in the skulls of contemporary indigenous peoples of the southern"
"to the interior. Thus the stapes became an important element in an impedance matching system, coupling airborne sound waves to the receptor system of the inner ear. This system had evolved independently within several different amphibian lineages. The impedance matching ear had to meet certain conditions to work. The stapes had to be perpendicular to the tympanum, small and light enough to reduce its inertia, and suspended in an air-filled cavity. In modern species that are sensitive to over 1 kHz frequencies, the footplate of the stapes is 1/20th the area of the tympanum. However, in early amphibians the stapes"
"in humans. A similar change occurred in the fibula bone of the hind limbs. These changes were first seen in the genus ""Merychippus"", approximately 17 million years ago. The anatomy of the forelegs begin at the scapula. This is the shoulder in which provides the ease of movement as it is connected to various bones surrounding it such as the cervical vertebra (a section of the spine). The next bone is the humerus which leads onto the radius below. The radius is then connected to the bones of the knee. The carpus is located at front of the knee and"
"the neck of the imaginary Scottie dog; the Scottie dog's eye is the pedicle, its hindlegs the spinous process, its nose the transverse process, its ear the superior articular facet and its forelegs the inferior articular facet. Stress fractures of the ""pars interarticularis"" are known to be associated with playing sports such as volleyball, although the mechanism is somewhat unclear. Patients with spina bifida occulta have an increased risk for spondylolysis. Pars interarticularis The pars interarticularis, or pars for short, is the part of a vertebra located between the inferior and superior articular processes of the facet joint. In the"