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66-445: A typical human thoracic cage consists of 12 pairs of ribs and the adjoining costal cartilages , the sternum (along with the manubrium and xiphoid process ), and the 12 thoracic vertebrae articulating with the ribs. The thoracic cage also provides attachments for extrinsic skeletal muscles of the neck , upper limbs , upper abdomen and back , and together with the overlying skin and associated fascia and muscles , makes up

132-459: A flail chest which is a life-threatening condition. A dislocated rib can be painful and can be caused simply by coughing, or for example by trauma or lifting heavy weights. One or more costal cartilages can become inflamed – a condition known as costochondritis ; the resulting pain is similar to that of a heart attack. Abnormalities of the rib cage include pectus excavatum ("sunken chest") and pectus carinatum ("pigeon chest"). A bifid rib

198-413: A bone mineral density 2.5 standard deviations below peak bone mass, relative to the age and sex-matched average, as measured by dual energy X-ray absorptiometry , with the term "established osteoporosis" including the presence of a fragility fracture . Osteoporosis is most common in women after menopause , when it is called "postmenopausal osteoporosis", but may develop in men and premenopausal women in

264-400: A complete costal facet on its body. The eleventh and twelfth ribs , the floating ribs , have a single articular facet on the head, which is of rather large size. They have no necks or tubercles, and are pointed at their anterior ends. The eleventh has a slight angle and a shallow costal groove, whereas the twelfth does not. The twelfth rib is much shorter than the eleventh rib, and only has

330-427: A given population. It is not known whether or to what extent those differences are genetic or environmental. A variety of gross morphological traits of the human skull demonstrate sexual dimorphism, such as the median nuchal line , mastoid processes , supraorbital margin , supraorbital ridge , and the chin . Human inter-sex dental dimorphism centers on the canine teeth , but it is not nearly as pronounced as in

396-452: A healthy diet. Calcium supplements may also be advised, as may vitamin D . When medication is used, it may include bisphosphonates , strontium ranelate , and osteoporosis may be one factor considered when commencing hormone replacement therapy . The Sushruta Samhita , composed between the 6th century  BCE and 5th century CE speaks of 360 bones. Books on Salya-Shastra (surgical science) know of only 300. The text then lists

462-518: A mixture of chondroitin sulfate and hydroxyapatite , the latter making up 70% of a bone. Hydroxyapatite is in turn composed of 39.8% of calcium, 41.4% of oxygen, 18.5% of phosphorus, and 0.2% of hydrogen by mass. Chondroitin sulfate is a sugar made up primarily of oxygen and carbon. Bone cells release a hormone called osteocalcin , which contributes to the regulation of blood sugar ( glucose ) and fat deposition . Osteocalcin increases both insulin secretion and sensitivity, in addition to boosting

528-409: A one articular facet. The sternum is a long, flat bone that forms the front of the rib cage. The cartilages of the top seven ribs (the true ribs ) join with the sternum at the sternocostal joints. The costal cartilage of the second rib articulates with the sternum at the sternal angle making it easy to locate. The manubrium is the wider, superior portion of the sternum. The top of the manubrium has

594-433: A rib. The ability of the human rib to regenerate itself has been appreciated for some time. However, the repair has only been described in a few case reports. The phenomenon has been appreciated particularly by craniofacial surgeons, who use both cartilage and bone material from the rib for ear, jaw, face, and skull reconstruction. The perichondrium and periosteum are fibrous sheaths of vascular connective tissue surrounding

660-428: A shallow, U-shaped border called the jugular (suprasternal) notch. The clavicular notch is the shallow depression located on either side at the superior-lateral margins of the manubrium. This is the site of the sternoclavicular joint , between the sternum and clavicle. The first ribs also attach to the manubrium. The transversus thoracis muscle is innervated by one of the intercostal nerves and superiorly attaches at

726-402: A skeleton. Superior costal facet The superior costal facet (or superior costal fovea ) is a site where a rib forms a joint with the top of a vertebra . Ribs connect to the thoracic vertebrae at two main points, the inferior and superior costal facets. These connection points are located on two different vertebrae that are located on top of one another. The superior costal facet

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792-419: A small facet for articulation with the transverse costal facet on the transverse process of T1. There is no angle , but at the tubercle, the rib is slightly bent, with the convexity upward, so that the head of the bone is directed downward. The upper surface of the body is marked by two shallow grooves, separated from each other by a slight ridge prolonged internally into a tubercle, the scalene tubercle , for

858-424: A tendon of the iliocostalis muscle . At this point, the rib is bent in two directions, and at the same time twisted on its long axis. The distance between the angle and the tubercle is progressively greater from the second to the tenth ribs. The area between the angle and the tubercle is rounded, rough, and irregular, and serves for the attachment of the longissimus dorsi muscle . The first rib (the topmost one)

924-403: Is a bifurcated rib, split towards the sternal end, and usually just affecting one of the ribs of a pair. It is a congenital defect affecting about 1.2% of the population. It is often without symptoms though respiratory difficulties and other problems can arise. Rib removal is the surgical removal of one or more ribs for therapeutic or cosmetic reasons. Rib resection is the removal of part of

990-427: Is credited to be the pioneer of the field. His works are lost but are often cited by notable persons in the field such as Galen and Rufus of Ephesus . Galen himself did little dissection though and relied on the work of others like Marinus of Alexandria, as well as his own observations of gladiator cadavers and animals. According to Katherine Park , in medieval Europe dissection continued to be practiced, contrary to

1056-428: Is curved inwards to allow the child to have a " funnel " to assist in the child's pathway from the uterus to the birth canal . There are many classified skeletal disorders. One of the most common is osteoporosis . Also common is scoliosis , a side-to-side curve in the back or spine, often creating a pronounced "C" or "S" shape when viewed on an x-ray of the spine. This condition is most apparent during adolescence, and

1122-430: Is divided by a horizontal crest into two articulating regions. The upper region articulates with the inferior costal facet on the vertebra above, and the larger region articulates with the superior costal facet on the vertebra with the same number. The transverse process of a thoracic vertebra also articulates at the transverse costal facet with the tubercle of the rib of the same number. The crest gives attachment to

1188-401: Is formed by the vertebral column (32–34 bones; the number of the vertebrae differs from human to human as the lower 2 parts, sacral and coccygeal bone may vary in length), a part of the rib cage (12 pairs of ribs and the sternum ), and the skull (22 bones and 7 associated bones). The upright posture of humans is maintained by the axial skeleton, which transmits the weight from the head,

1254-457: Is known as the bucket handle movement , facilitated by gliding at the costovertebral joints . In this way, the transverse diameter is expanded and the lungs can fill. The circumference of the normal adult human rib cage expands by 3 to 5 cm during inhalation. Rib fractures are the most common injury to the rib cage. These most frequently affect the middle ribs. When several adjacent ribs incur two or more fractures each, this can result in

1320-507: Is located on the inferior thoracic vertebrae. The inferior costal facet is located on the superior vertebrae. While these terms may be confusing, it helps to know that the costal facets are named for their position on the vertebral body itself, not for the part of the rib that they articulate with. Costal facets only apply to ribs 2–9. Ribs 1, 10, 11, and 12 articulate completely onto the thoracic vertebrae rather than in between two of them. [REDACTED] This article incorporates text in

1386-408: Is most common with females. Arthritis is a disorder of the joints. It involves inflammation of one or more joints. When affected by arthritis, the joint or joints affected may be painful to move, may move in unusual directions or may be immobile completely. The symptoms of arthritis will vary differently between types of arthritis. The most common form of arthritis, osteoarthritis , can affect both

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1452-513: Is not as sexually dimorphic as that of many other primate species, but subtle differences between sexes in the morphology of the skull, dentition , long bones , and pelvis exist. In general, female skeletal elements tend to be smaller and less robust than corresponding male elements within a given population. The human female pelvis is also different from that of males in order to facilitate childbirth . Unlike most primates, human males do not have penile bones . The axial skeleton (80 bones)

1518-434: Is supplied to the abdominal viscera by the diaphragm contracting. A greater extension can be achieved by the diaphragm itself moving down, rather than simply the domes flattening. The second plane is the anteroposterior and this is expanded by a movement known as the ' pump handle '. The downward sloping nature of the upper ribs are as such because they enable this to occur. When the external intercostal muscles contract and lift

1584-417: Is the most curved and usually the shortest of all the ribs; it is broad and flat, its surfaces looking upward and downward, and its borders inward and outward. The head is small and rounded, and possesses only a single articular facet, for articulation with the body of the first thoracic vertebra . The neck is narrow and rounded. The tubercle , thick and prominent, is placed on the outer border. It bears

1650-422: The bone marrow . In children, haematopoiesis occurs primarily in the marrow of the long bones such as the femur and tibia. In adults, it occurs mainly in the pelvis, cranium, vertebrae, and sternum. The bone matrix can store calcium and is involved in calcium metabolism , and bone marrow can store iron in ferritin and is involved in iron metabolism . However, bones are not entirely made of calcium, but

1716-428: The intercostal veins , intercostal arteries , and intercostal nerves . The ninth rib has a frontal part at the same level as the first lumbar vertebra . This level is called the transpyloric plane , since the pylorus is also at this level. The tenth rib attaches directly to the body of vertebra T10 instead of between vertebrae like the second through ninth ribs. Due to this direct attachment, vertebra T10 has

1782-403: The intra-articular ligament . The neck of the rib is the flattened part that extends laterally from the head. The neck is about 3 cm long. Its anterior surface is flat and smooth, whilst its posterior is perforated by numerous foramina and its surface rough, to give attachment to the ligament of the neck. Its upper border presents a rough crest ( crista colli costae ) for the attachment of

1848-421: The lungs would collapse. The joints between bones allow movement, some allowing a wider range of movement than others, e.g. the ball and socket joint allows a greater range of movement than the pivot joint at the neck. Movement is powered by skeletal muscles , which are attached to the skeleton at various sites on bones. Muscles, bones, and joints provide the principal mechanics for movement, all coordinated by

1914-427: The meridians , although given that Hua Tuo regularly performed surgery, there may be some distance between medical theory and actual understanding. Leonardo da Vinci made studies of the skeleton, albeit unpublished in his time. Many artists, Antonio del Pollaiuolo being the first, performed dissections for better understanding of the body, although they concentrated mostly on the muscles. Vesalius , regarded as

1980-415: The neck , back , pectoral and abdominal muscles . Each rib consists of a head, neck, and a shaft. All ribs are attached posteriorly to the thoracic vertebrae . They are numbered to match the vertebrae they attach to – one to twelve, from top (T1) to bottom. The head of the rib is the end part closest to the vertebra with which it articulates . It is marked by a kidney-shaped articular surface which

2046-458: The public domain from the 20th edition of Gray's Anatomy (1918) Human skeleton The human skeleton is the internal framework of the human 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 makes up about 14% of the total body weight (ca. 10–11 kg for an average person) and reaches maximum mass between

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2112-487: The sternum respectively. The first seven rib pairs known as the fixed or vertebrosternal ribs are the true ribs ( Latin : costae verae ) as they connect directly to the sternum via their own individual costal cartilages . The next five pairs (eighth to twelfth) are the false ribs ( Latin : costae spuriae ) or vertebrochondral ribs, which do not connect directly to the sternum. The first three pairs of vertebrochondral ribs (eighth to tenth) connect indirectly to

2178-460: The thoracic wall . In tetrapods , the rib cage intrinsically holds the muscles of respiration ( diaphragm , intercostal muscles , etc.) that are crucial for active inhalation and forced exhalation , and therefore has a major ventilatory function in the respiratory system . There are thirty-three vertebrae in the human vertebral column. The rib cage is associated with TH1−TH12. Ribs are described based on their location and connection with

2244-576: The ages of 25 and 30. 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. The human skeleton performs six major functions: support, movement, protection, production of blood cells , storage of minerals, and endocrine regulation. The human skeleton

2310-400: The anterior costotransverse ligament ; its lower border is rounded. On the posterior surface at the neck, is an eminence—the tubercle that consists of an articular and a non-articular portion. The articular portion is the lower and more medial of the two and presents a small, oval surface for articulation with the transverse costal facet on the end of the transverse process of the lower of

2376-426: The attachment of the anterior scalene ; the anterior groove transmits the subclavian vein , the posterior the subclavian artery and the lowest trunk of the brachial plexus . Behind the posterior groove is a rough area for the attachment of the medial scalene . The under surface is smooth and without a costal groove. The outer border is convex, thick, and rounded, and at its posterior part gives attachment to

2442-476: The count of bones in the two schools is partly because Charaka Samhita includes 32 tooth sockets in its count, and their difference of opinions on how and when to count a cartilage as bone (which both sometimes do, unlike modern anatomy). The study of bones in ancient Greece started under Ptolemaic kings due to their link to Egypt. Herophilos , through his work by studying dissected human corpses in Alexandria,

2508-423: The first digitation of the serratus anterior . The inner border is concave, thin, and sharp, and marked about its center by the scalene tubercle. The anterior extremity is larger and thicker than that of any of the other ribs. The second rib is the second uppermost rib in humans or second most frontal in animals that walk on four limbs. In humans, the second rib is defined as a true rib since it connects with

2574-399: The floor of the thoracic cavity, contracts and flattens, while the contraction of intercostal muscles lift the rib cage up and out. Expansion of the thoracic cavity is driven in three planes; the vertical, the anteroposterior and the transverse. The vertical plane is extended by the help of the diaphragm contracting and the abdominal muscles relaxing to accommodate the downward pressure that

2640-406: The formation of a functional rib cage. Variations in the number of ribs occur. About 1 in 200–500 people have an additional cervical rib , and there is a female predominance. Intrathoracic supernumerary ribs are extremely rare. The rib remnant of the 7th cervical vertebra on one or both sides is occasionally replaced by a free extra rib called a cervical rib , which can mechanically interfere with

2706-473: The founder of modern anatomy, authored the book De humani corporis fabrica , which contained many illustrations of the skeleton and other body parts, correcting some theories dating from Galen, such as the lower jaw being a single bone instead of two. Various other figures like Alessandro Achillini also contributed to the further understanding of the skeleton. As early as 1797, the death goddess or folk saint known as Santa Muerte has been represented as

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2772-489: The integument of salamanders . The grooves run between the axilla to the groin . Each groove overlies the myotomal septa to mark the position of the internal rib. Birds and reptiles have bony uncinate processes on their ribs that project caudally from the vertical section of each rib. These serve to attach sacral muscles and also aid in allowing greater inspiration. Crocodiles have cartilaginous uncinate processes. [REDACTED] This article incorporates text in

2838-500: The larger and smaller joints of the human skeleton. The cartilage in the affected joints will degrade, soften and wear away. This decreases the mobility of the joints and decreases the space between bones where cartilage should be. Osteoporosis is a disease of bone where there is reduced bone mineral density , increasing the likelihood of fractures . Osteoporosis is defined by the World Health Organization in women as

2904-452: The major organs of digestion, excretion and reproduction. The skeleton serves six major functions: support, movement, protection, production of blood cells, storage of minerals and endocrine regulation. The skeleton provides the framework which supports the body and maintains its shape. The pelvis, associated ligaments and muscles provide a floor for the pelvic structures. Without the rib cages, costal cartilages , and intercostal muscles ,

2970-460: The nerves ( brachial plexus ) going to the arm. In several ethnic groups, most significantly the Japanese, the tenth rib is sometimes a floating rib , as it lacks a cartilaginous connection to the seventh rib. The human rib cage is a component of the human respiratory system . It encloses the thoracic cavity, which contains the lungs. An inhalation is accomplished when the muscular diaphragm , at

3036-431: The nervous system. It is believed that the reduction of human bone density in prehistoric times reduced the agility and dexterity of human movement. Shifting from hunting to agriculture has caused human bone density to reduce significantly. The skeleton helps to protect many vital internal organs from being damaged. The skeleton is the site of haematopoiesis , the development of blood cells that takes place in

3102-564: The number of insulin-producing cells and reducing stores of fat. Anatomical differences between human males and females are highly pronounced in some soft tissue areas, but tend to be limited in the skeleton. The human skeleton is not as sexually dimorphic as that of many other primate species, but subtle differences between sexes in the morphology of the skull, dentition , long bones , and pelvis are exhibited across human populations. In general, female skeletal elements tend to be smaller and less robust than corresponding male elements within

3168-426: The origin of the lower part of the first and the whole of the second digitation of the serratus anterior; behind and above this is attached the posterior scalene . The internal surface, smooth, and concave, is directed downward and a little inward: on its posterior part there is a short costal groove between the ridge of the internal surface of the rib and the inferior border. It protects the intercostal space containing

3234-475: The other great apes . Long bones are generally larger in males than in females within a given population. Muscle attachment sites on long bones are often more robust in males than in females, reflecting a difference in overall muscle mass and development between sexes. Sexual dimorphism in the long bones is commonly characterized by morphometric or gross morphological analyses. The human pelvis exhibits greater sexual dimorphism than other bones, specifically in

3300-400: The popular understanding that such practices were taboo and thus completely banned. The practice of holy autopsy , such as in the case of Clare of Montefalco further supports the claim. Alexandria continued as a center of anatomy under Islamic rule, with Ibn Zuhr a notable figure. Chinese understandings are divergent, as the closest corresponding concept in the medicinal system seems to be

3366-411: The posterior surface of the lower sternum. Its inferior attachment is the internal surface of costal cartilages two through six and works to depress the ribs. Expansion of the rib cage in males is caused by the effects of testosterone during puberty. Thus, males generally have broad shoulders and expanded chests, allowing them to inhale more air to supply their muscles with oxygen. The development of

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3432-479: The presence of particular hormonal disorders and other chronic diseases or as a result of smoking and medications , specifically glucocorticoids . Osteoporosis usually has no symptoms until a fracture occurs. For this reason, DEXA scans are often done in people with one or more risk factors, who have developed osteoporosis and be at risk of fracture. Osteoporosis treatment includes advice to stop smoking, decrease alcohol consumption, exercise regularly, and have

3498-525: The rib cage is influenced by a combination of genetic and environmental factors, as well as specific stages of embryonic growth. Genetic factors play a critical role, with specific genes regulating the formation of bones and cartilage to ensure the proper development and alignment of the ribs and sternum. During the embryonic stage , the rib cage begins to form from the mesoderm, one of the three primary germ layers. Ribs develop from structures called somites, which later segment into vertebrae and ribs. Initially,

3564-464: The rib cartilage and bone respectively. These tissues containing a source of progenitor stem cells that drive regeneration. The position of ribs can be permanently altered by a form of body modification called tightlacing , which uses a corset to compress and move the ribs. The ribs, particularly their sternal ends, are used as a way of estimating age in forensic pathology due to their progressive ossification. The number of ribs as 24 (12 pairs)

3630-712: The ribs are composed of cartilage , which gradually ossifies into bone through a process known as endochondral ossification. As the embryo grows, the ribs elongate and differentiate into three types: true ribs , which attach directly to the sternum; false ribs , which connect to the sternum via cartilage; and floating ribs , which do not attach to the sternum. Additionally, environmental factors such as maternal health, nutrition, and exposure to certain substances can impact rib cage development. For instance, deficiencies in essential nutrients like calcium and vitamin D may hinder proper bone growth and development. Together, these genetic, developmental, and environmental influences ensure

3696-476: The ribs, the upper ribs are able also to push the sternum up and out. This movement increases the anteroposterior diameter of the thoracic cavity, and hence aids breathing further. The third, transverse, plane is primarily expanded by the lower ribs (some say it is the 7th to 10th ribs in particular), with the diaphragm's central tendon acting as a fixed point. When the diaphragm contracts, the ribs are able to evert (meaning turn outwards or inside out) and produce what

3762-406: The size and shape of the pelvic cavity , ilia , greater sciatic notches, and the sub-pubic angle. The Phenice method is commonly used to determine the sex of an unidentified human skeleton by anthropologists with 96% to 100% accuracy in some populations. Women's pelvises are wider in the pelvic inlet and are wider throughout the pelvis to allow for child birth. The sacrum in the women's pelvis

3828-449: The sternum or any of the costal cartilages. These ribs are relatively small and delicate, and include a cartilaginous tip. The spaces between the ribs are known as intercostal spaces ; they contain the instrinsic intercostal muscles and the neurovascular bundles containing intercostal nerves , arteries and veins . The superficial surface of the rib cage is covered by the thoracolumbar fascia , which provides external attachments for

3894-399: The sternum through the intervention of the costal cartilage anteriorly (at the front). Posteriorly, the second rib is connected with the vertebral column by the second thoracic vertebra . The second rib is much longer than the first rib , but has a very similar curvature. The non-articular portion of the tubercle is occasionally only feebly marked. The angle is slight and situated close to

3960-418: The sternum via the costal cartilages of the ribs above them, and the overall elasticity of their articulations allows the bucket handle movements of the rib cage essential for respiratory activity. The phrase floating rib ( Latin : costae fluctuantes ) or vertebral rib refers to the two lowermost (the eleventh and twelfth) rib pairs; so-called because they are attached only to the vertebrae and not to

4026-474: The sternum. All ribs are attached posteriorly to the thoracic vertebrae and are numbered accordingly one to twelve. Ribs that articulate directly with the sternum are called true ribs , whereas those that do not articulate directly are termed false ribs . The false ribs include the floating ribs (eleven and twelve) that are not attached to the sternum at all. The terms true ribs and false ribs describe rib pairs that are directly or indirectly attached to

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4092-533: The total of 300 as follows: 120 in the extremities (e.g. hands, legs), 117 in the pelvic area, sides, back, abdomen and breast, and 63 in the neck and upwards. The text then explains how these subtotals were empirically verified. The discussion shows that the Indian tradition nurtured diversity of thought, with Sushruta school reaching its own conclusions and differing from the Atreya-Caraka tradition. The differences in

4158-425: The trunk, and the upper extremities down to the lower extremities at the hip joints . The bones of the spine are supported by many ligaments. The erector spinae muscles are also supporting and are useful for balance. The appendicular skeleton (126 bones) is formed by the pectoral girdles, the upper limbs, the pelvic girdle or pelvis, and the lower limbs. Their functions are to make locomotion possible and to protect

4224-399: The tubercle. The body is not twisted so that both ends touch any plane surface upon which it may be laid; but there is a bend, with its convexity upward, similar to, though smaller than that found in the first rib. The body is not flattened horizontally like that of the first rib. Its external surface is convex, and looks upward and a little outward; near the middle of it is a rough eminence for

4290-453: The two vertebrae to which the head is connected. The non-articular portion is a rough elevation and affords attachment to the ligament of the tubercle. The tubercle is much more prominent in the upper ribs than in the lower ribs. The angle of a rib (costal angle) may both refer to the bending part of it, and a prominent line in this area, a little in front of the tubercle. This line is directed downward and laterally; this gives attachment to

4356-555: Was noted by the Flemish anatomist Vesalius in his key work of anatomy De humani corporis fabrica in 1543, setting off a wave of controversy, as it was traditionally assumed from the Biblical story of Adam and Eve that men's ribs would number one fewer than women's. However, thirteenth or "cervical ribs" occur in 1% of humans and this is more common in females than in males. In herpetology , costal grooves refer to lateral indents along

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