Bone - wikipedia Bone This article is about the skeletal organ. For other uses, see Bone ( disambiguation ) and Bones ( disambiguation ). This article uses anatomical terminology ; for an overview, see Anatomical terminology. Bone A bone dating from the Pleistocene Ice Age of an extinct species of elephant. A scanning electronic micrograph of bone at 10,000 x magnification. Identifiers TA A02. 0.00. 000 TH H3. 01.00. 0.00001 FMA 30317 Anatomical terminology ( edit on Wikidata ) A bone is a rigid organ that constitutes part of the vertebrate skeleton. Bones support and protect the various organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility. Bones come in a variety of shapes and sizes and have a complex internal and external structure. They are lightweight yet strong and hard, and serve multiple functions. Bone tissue ( osseous tissue ) is a hard tissue, a type of dense connective tissue. It has a honeycomb - like matrix internally, which helps to give the bone rigidity. Bone tissue is made up of different types of bone cells. Osteoblasts and osteocytes are involved in the formation and mineralization of bone ; osteoclasts are involved in the resorption of bone tissue. Modified ( flattened ) osteoblasts become the lining cells that form a protective layer on the bone surface. The mineralised matrix of bone tissue has an organic component of mainly collagen called ossein and an inorganic component of bone mineral made up of various salts. Bone tissue is a mineralized tissue of two types, cortical bone and cancellous bone. Other types of tissue found in bones include bone marrow, endosteum, periosteum, nerves, blood vessels and cartilage. 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 Latin word for bone is os, hence the many terms that use it as a prefix -- such as osseous and osteopathy. Contents 1 Structure 1.1 Cortical bone 1.2 Cancellous bone 1.3 Bone marrow 1.4 Bone tissue 1.4. 1 Osteoblast 1.4. 2 Osteocyte 1.4. 3 Osteoclast 1.5 Extracellular matrix 1.5. 1 Deposition 1.6 Types 1.7 Terminology 2 Development 3 Function 3.1 Mechanical 3.2 Synthetic 3.3 Metabolic 3.4 Remodeling 3.5 Bone volume 4 Clinical significance 4.1 Fractures 4.2 Tumors 4.3 Cancer 4.4 Painful conditions 4.5 Osteoporosis 4.6 Osteopathy 5 Osteology 6 Other animals 7 Society and culture 8 Additional images 9 See also 10 References 11 Footnotes 12 External links Structure Cross-section of bone Bone is not uniformly solid, but includes a tough matrix. This matrix makes up about 30 % of the bone and the other 70 % is of salts that give strength to it. The matrix is made up of between 90 and 95 % collagen fibers, and the remainder is ground substance. The primary tissue of bone, bone tissue ( osseous tissue ), is relatively hard and lightweight. Its matrix is mostly made up of a composite material incorporating the inorganic mineral calcium phosphate in the chemical arrangement termed calcium hydroxylapatite ( this is the bone mineral that gives bones their rigidity ) and collagen, an elastic protein which improves fracture resistance. The collagen of bone is known as ossein. Bone is formed by the hardening of this matrix around entrapped cells. When these cells become entrapped from osteoblasts they become osteocytes. Cortical bone Cross-section details of a long bone The hard outer layer of bones is composed of cortical bone also called compact bone being much denser than cancellous bone. It forms the hard exterior ( cortex ) of bones. The cortical bone gives bone its smooth, white, and solid appearance, and accounts for 80 % of the total bone mass of an adult human skeleton. It facilitates bone 's main functions : to support the whole body, protect organs, provide levers for movement, and store and release chemical elements, mainly calcium. It consists of multiple microscopic columns, each called an osteon. Each column is multiple layers of osteoblasts and osteocytes around a central canal called the haversian canal. Volkmann 's canals at right angles connect the osteons together. The columns are metabolically active, and as bone is reabsorbed and created the nature and location of the cells within the osteon will change. Cortical bone is covered by a periosteum on its outer surface, and an endosteum on its inner surface. The endosteum is the boundary between the cortical bone and the cancellous bone. The primary anatomical and functional unit of cortical bone is the osteon. Cancellous bone Micrograph of cancellous bone Cancellous bone also known as trabecular or spongy bone tissue is the internal tissue of the skeletal bone and is an open cell porous network. Cancellous bone has a higher surface - area - to - volume ratio than cortical bone because it is less dense. This makes it softer and weaker, but more flexible. The greater surface area also makes it suitable for metabolic activities such as the exchange of calcium ions. Cancellous bone is typically found at the ends of long bones, near to joints and within the interior of vertebrae. Cancellous bone is highly vascular and frequently contains red bone marrow where haematopoiesis, the production of blood cells, occurs. The primary anatomical and functional unit of cancellous bone is the trabecula. The trabeculae are aligned towards the mechanical load distribution that a bone experiences within long bones such as the femur. As far as short bones are concerned, trabecular alignment has been studied in the vertebral pedicle. Thin formations of osteoblasts covered in endosteum create an irregular network of spaces, known as trabeculae. Within these spaces are bone marrow and hematopoietic stem cells that give rise to platelets, red blood cells and white blood cells. Trabecular marrow is composed of a network of rod - and plate - like elements that make the overall organ lighter and allow room for blood vessels and marrow. Trabecular bone accounts for the remaining 20 % of total bone mass but has nearly ten times the surface area of compact bone. The words cancellous and trabecular refer to the tiny lattice - shaped units ( trabeculae ) that form the tissue. It was first illustrated accurately in the engravings of Crisóstomo Martinez. Bone marrow Bone marrow, also known as myeloid tissue in red bone marrow, can be found in almost any bone that holds cancellous tissue. In newborns, all such bones are filled exclusively with red marrow or hematopoietic marrow, but as the child ages the hematopoietic fraction decreases in quantity and the fatty / yellow fraction called marrow adipose tissue ( MAT ) increases in quantity. In adults, red marrow is mostly found in the bone marrow of the femur, the ribs, the vertebrae and pelvic bones. Bone tissue Bone cells Bone is a metabolically active tissue composed of several types of cells. These cells include osteoblasts, which are involved in the creation and mineralization of bone tissue, osteocytes, and osteoclasts, which are involved in the reabsorption of bone tissue. Osteoblasts and osteocytes are derived from osteoprogenitor cells, but osteoclasts are derived from the same cells that differentiate to form macrophages and monocytes. Within the marrow of the bone there are also hematopoietic stem cells. These cells give rise to other cells, including white blood cells, red blood cells, and platelets. Osteoblast Light micrograph of cancellous decalcified bone displaying osteoblasts actively synthesizing osteoid, containing two osteocytes. Osteoblasts are mononucleate bone - forming cells. They are located on the surface of osteon seams and make a protein mixture known as osteoid, which mineralizes to become bone. The osteoid seam is a narrow region of newly formed organic matrix, not yet mineralized, located on the surface of a bone. Osteoid is primarily composed of Type I collagen. Osteoblasts also manufacture hormones, such as prostaglandins, to act on the bone itself. The osteoblast creates and repairs new bone by actually building around itself. First, the osteoblast puts up collagen fibers. These collagen fibers are used as a framework for the osteoblasts ' work. The osteoblast then deposits calcium phosphate which is hardened by hydroxide and bicarbonate ions. The brand new bone created by the osteoblast is called osteoid. Once the osteoblast is finished working it is actually trapped inside of the bone once it hardens. When the osteoblast becomes trapped, it becomes known as an osteocyte. Other osteoblasts remain on the top of the new bone and are used to protect the underlying bone, these become known as lining cells. Osteocyte Osteocyte Osteocytes are mostly inactive osteoblasts. Osteocytes originate from osteoblasts that have migrated into and become trapped and surrounded by bone matrix that they themselves produced. The spaces they occupy are known as lacunae. Osteocytes have many processes that reach out to meet osteoblasts and other osteocytes probably for the purposes of communication. Osteocytes remain in contact with other cells in the bone through gap junctions -- coupled cell processes -- which pass through small channels in the bone matrix called the canaliculi. Osteoclast Osteoclasts are very large multinucleate cells that are responsible for the breakdown of bones by the process of bone resorption. New bone is then formed by the osteoblasts. Bone is constantly remodelled by the resorption of osteoclasts and created by osteoblasts. Osteoclasts are large cells with multiple nuclei located on bone surfaces in what are called Howship 's lacunae ( or resorption pits ). These lacunae are the result of surrounding bone tissue that has been reabsorbed. Because the osteoclasts are derived from a monocyte stem - cell lineage, they are equipped with phagocytic - like mechanisms similar to circulating macrophages. Osteoclasts mature and / or migrate to discrete bone surfaces. Upon arrival, active enzymes, such as tartrate resistant acid phosphatase, are secreted against the mineral substrate. The reabsorption of bone by osteoclasts also plays a role in calcium homeostasis. Extracellular matrix Bones consist of living cells embedded in a mineralized organic matrix. This matrix consists of organic components, mainly Type I collagen -- `` organic '' referring to materials produced as a result of the human body -- and inorganic components, primarily hydroxyapatite and other salts of calcium and phosphate. Above 30 % of the acellular part of bone consists of the organic components, and 70 % of salts. The collagen fibers give bone its tensile strength, and the interspersed crystals of hydroxyapatite give bone its compressive strength. These effects are synergistic. The inorganic composition of bone ( bone mineral ) is primarily formed from salts of calcium and phosphate, the major salt being hydroxyapatite ( Ca ( PO ) ( OH ) ). The exact composition of the matrix may change over time and with nutrition, with the ratio of calcium to phosphate varying between 1.3 and 2.0 ( per weight ), and trace minerals such as magnesium, sodium, potassium and carbonate also being found. Type I collagen composes 90 -- 95 % of the organic matrix, with remainder of the matrix being a homogenous liquid called ground substance consisting of proteoglycans such as hyaluronic acid and chondroitin sulfate, as well as non-collagenous proteins such as osteocalcin, osteopontin or bone sialoprotein. Collagen consists of strands of repeating units, which give bone tensile strength, and are arranged in an overlapping fashion that prevents shear stress. The function of ground substance is not fully known. Two types of bone can be identified microscopically according to the arrangement of collagen : woven and lamellar. Woven bone, ( also known as fibrous bone ) which is characterized by a haphazard organization of collagen fibers and is mechanically weak Lamellar bone, which has a regular parallel alignment of collagen into sheets ( `` lamellae '' ) and is mechanically strong Transmission electron micrograph of decalcified woven bone matrix displaying characteristic irregular orientation of collagen fibers. Woven bone is produced when osteoblasts produce osteoid rapidly, which occurs initially in all fetal bones, but is later replaced by more resilient lamellar bone. In adults woven bone is created after fractures or in Paget 's disease. Woven bone is weaker, with a smaller number of randomly oriented collagen fibers, but forms quickly ; it is for this appearance of the fibrous matrix that the bone is termed woven. It is soon replaced by lamellar bone, which is highly organized in concentric sheets with a much lower proportion of osteocytes to surrounding tissue. Lamellar bone, which makes its first appearance in humans in the fetus during the third trimester, is stronger and filled with many collagen fibers parallel to other fibers in the same layer ( these parallel columns are called osteons ). In cross-section, the fibers run in opposite directions in alternating layers, much like in plywood, assisting in the bone 's ability to resist torsion forces. After a fracture, woven bone forms initially and is gradually replaced by lamellar bone during a process known as `` bony substitution. '' Compared to woven bone, lamellar bone formation takes place more slowly. The orderly deposition of collagen fibers restricts the formation of osteoid to about 1 to 2 μm per day. Lamellar bone also requires a relatively flat surface to lay the collagen fibers in parallel or concentric layers. Deposition The extracellular matrix of bone is laid down by osteoblasts, which secrete both collagen and ground substance. These synthesise collagen within the cell, and then secrete collagen fibrils. The collagen fibres rapidly polymerise to form collagen strands. At this stage they are not yet mineralised, and are called `` osteoid ''. Around the strands calcium and phosphate precipitate on the surface of these strands, within a days to weeks becoming crystals of hydroxyapatite. In order to mineralise the bone, the osteoblasts secrete vesicles containing alkaline phosphatase. This cleaves the phosphate groups and acts as the foci for calcium and phosphate deposition. The vesicles then rupture and act as a centre for crystals to grow on. More particularly, bone mineral is formed from globular and plate structures. Types Structure of a long bone There are five types of bones in the human body : long, short, flat, irregular, and sesamoid. Long bones are characterized by a shaft, the diaphysis, that is much longer than its width ; and by an epiphysis, a rounded head at each end of the shaft. They are made up mostly of compact bone, with lesser amounts of marrow, located within the medullary cavity, and areas of spongy, cancellous bone at the ends of the bones. Most bones of the limbs, including those of the fingers and toes, are long bones. The exceptions are the eight carpal bones of the wrist, the seven articulating tarsal bones of the ankle and the sesamoid bone of the kneecap. Long bones such as the clavicle, that have a differently shaped shaft or ends are also called modified long bones. Short bones are roughly cube - shaped, and have only a thin layer of compact bone surrounding a spongy interior. The bones of the wrist and ankle are short bones. Flat bones are thin and generally curved, with two parallel layers of compact bones sandwiching a layer of spongy bone. Most of the bones of the skull are flat bones, as is the sternum. Sesamoid bones are bones embedded in tendons. Since they act to hold the tendon further away from the joint, the angle of the tendon is increased and thus the leverage of the muscle is increased. Examples of sesamoid bones are the patella and the pisiform. Irregular bones do not fit into the above categories. They consist of thin layers of compact bone surrounding a spongy interior. As implied by the name, their shapes are irregular and complicated. Often this irregular shape is due to their many centers of ossification or because they contain bony sinuses. The bones of the spine, pelvis, and some bones of the skull are irregular bones. Examples include the ethmoid and sphenoid bones. Terminology Main article : Anatomical terms of bone In the study of anatomy, anatomists use a number of anatomical terms to describe the appearance, shape and function of bones. Other anatomical terms are also used to describe the location of bones. Like other anatomical terms, many of these derive from Latin and Greek. Some anatomists still use Latin to refer to bones. The term `` osseous '', and the prefix `` osteo - '', referring to things related to bone, are still used commonly today. Some examples of terms used to describe bones include the term `` foramen '' to describe a hole through which something passes, and a `` canal '' or `` meatus '' to describe a tunnel - like structure. A protrusion from a bone can be called a number of terms, including a `` condyle '', `` crest '', `` spine '', `` eminence '', `` tubercle '' or `` tuberosity '', depending on the protrusion 's shape and location. In general, long bones are said to have a `` head '', `` neck '', and `` body ''. When two bones join together, they are said to `` articulate ''. If the two bones have a fibrous connection and are relatively immobile, then the joint is called a `` suture ''. Development Endochondral ossification Section through a juvenile knee joint ( rat ) showing the cartilagineous growth plates The formation of bone is called ossification. During the fetal stage of development this occurs by two processes : intramembranous ossification and endochondral ossification. Intramembranous ossification involves the formation of bone from connective tissue whereas endochondral ossification involves the formation of bone from cartilage. Intramembranous ossification mainly occurs during formation of the flat bones of the skull but also the mandible, maxilla, and clavicles ; the bone is formed from connective tissue such as mesenchyme tissue rather than from cartilage. The process includes : the development of the ossification center, calcification, trabeculae formation and the development of the periosteum. Endochondral ossification occurs in long bones and most other bones in the body ; it involves the development of bone from cartilage. This process includes the development of a cartilage model, its growth and development, development of the primary and secondary ossification centers, and the formation of articular cartilage and the epiphyseal plates. Endochondral ossification begins with points in the cartilage called `` primary ossification centers. '' They mostly appear during fetal development, though a few short bones begin their primary ossification after birth. They are responsible for the formation of the diaphyses of long bones, short bones and certain parts of irregular bones. Secondary ossification occurs after birth, and forms the epiphyses of long bones and the extremities of irregular and flat bones. The diaphysis and both epiphyses of a long bone are separated by a growing zone of cartilage ( the epiphyseal plate ). At skeletal maturity ( 18 to 25 years of age ), all of the cartilage is replaced by bone, fusing the diaphysis and both epiphyses together ( epiphyseal closure ). In the upper limbs, only the diaphyses of the long bones and scapula are ossified. The epiphyses, carpal bones, coracoid process, medial border of the scapula, and acromion are still cartilaginous. The following steps are followed in the conversion of cartilage to bone : Zone of reserve cartilage. This region, farthest from the marrow cavity, consists of typical hyaline cartilage that as yet shows no sign of transforming into bone. Zone of cell proliferation. A little closer to the marrow cavity, chondrocytes multiply and arrange themselves into longitudinal columns of flattened lacunae. Zone of cell hypertrophy. Next, the chondrocytes cease to divide and begin to hypertrophy ( enlarge ), much like they do in the primary ossification center of the fetus. The walls of the matrix between lacunae become very thin. Zone of calcification. Minerals are deposited in the matrix between the columns of lacunae and calcify the cartilage. These are not the permanent mineral deposits of bone, but only a temporary support for the cartilage that would otherwise soon be weakened by the breakdown of the enlarged lacunae. Zone of bone deposition. Within each column, the walls between the lacunae break down and the chondrocytes die. This converts each column into a longitudinal channel, which is immediately invaded by blood vessels and marrow from the marrow cavity. Osteoblasts line up along the walls of these channels and begin depositing concentric lamellae of matrix, while osteoclasts dissolve the temporarily calcified cartilage. Function Functions of Bone Mechanical Protection Gives structure Facilitates movement Facilitates hearing Synthetic Contains bone marrow Metabolic Stores calcium Helps regulate the acid - base balance Bones have a variety of functions : Mechanical See also : Skeleton, Human skeleton, and List of bones of the human skeleton Bones serve a variety of mechanical functions. Together the bones in the body form the skeleton. They provide a frame to keep the body supported, and an attachment point for skeletal muscles, tendons, ligaments and joints, which function together to generate and transfer forces so that individual body parts or the whole body can be manipulated in three - dimensional space ( the interaction between bone and muscle is studied in biomechanics ). Bones protect internal organs, such as the skull protecting the brain or the ribs protecting the heart and lungs. Because of the way that bone is formed, bone has a high compressive strength of about 170 MPa ( 1800 kgf / cm2 ), poor tensile strength of 104 -- 121 MPa, and a very low shear stress strength ( 51.6 MPa ). This means that bone resists pushing ( compressional ) stress well, resist pulling ( tensional ) stress less well, but only poorly resists shear stress ( such as due to torsional loads ). While bone is essentially brittle, bone does have a significant degree of elasticity, contributed chiefly by collagen. The macroscopic yield strength of cancellous bone has been investigated using high resolution computer models. Mechanically, bones also have a special role in hearing. The ossicles are three small bones in the middle ear which are involved in sound transduction. Synthetic The cancellous part of bones contain bone marrow. Bone marrow produces blood cells in a process called hematopoiesis. Blood cells that are created in bone marrow include red blood cells, platelets and white blood cells. Progenitor cells such as the hematopoietic stem cell divide in a process called mitosis to produce precursor cells. These include precursors which eventually give rise to white blood cells, and erythroblasts which give rise to red blood cells. Unlike red and white blood cells, created by mitosis, platelets are shed from very large cells called megakaryocytes. This process of progressive differentiation occurs within the bone marrow. After the cells are matured, they enter the circulation. Every day, over 2.5 billion red blood cells and platelets, and 50 -- 100 billion granulocytes are produced in this way. As well as creating cells, bone marrow is also one of the major sites where defective or aged red blood cells are destroyed. Metabolic Mineral storage -- bones act as reserves of minerals important for the body, most notably calcium and phosphorus. ° Determined by the species, age, and the type of bone, bone cells make up to 15 percent of the bone. Growth factor storage -- mineralized bone matrix stores important growth factors such as insulin - like growth factors, transforming growth factor, bone morphogenetic proteins and others. Fat storage -- marrow adipose tissue ( MAT ) acts as a storage reserve of fatty acids. Acid - base balance -- bone buffers the blood against excessive pH changes by absorbing or releasing alkaline salts. Detoxification -- bone tissues can also store heavy metals and other foreign elements, removing them from the blood and reducing their effects on other tissues. These can later be gradually released for excretion. Endocrine organ -- bone controls phosphate metabolism by releasing fibroblast growth factor -- 23 ( FGF - 23 ), which acts on kidneys to reduce phosphate reabsorption. Bone cells also release a hormone called osteocalcin, which contributes to the regulation of blood sugar ( glucose ) and fat deposition. Osteocalcin increases both the insulin secretion and sensitivity, in addition to boosting the number of insulin - producing cells and reducing stores of fat. Calcium balance -- The process of bone resorption by the osteoclasts releases stored calcium into the systemic circulation and is an important process in regulating calcium balance. As bone formation actively fixes circulating calcium in its mineral form, removing it from the bloodstream, resorption actively unfixes it thereby increasing circulating calcium levels. These processes occur in tandem at site - specific locations. Remodeling Main article : Bone remodeling Bone is constantly being created and replaced in a process known as remodeling. This ongoing turnover of bone is a process of resorption followed by replacement of bone with little change in shape. This is accomplished through osteoblasts and osteoclasts. Cells are stimulated by a variety of signals, and together referred to as a remodeling unit. Approximately 10 % of the skeletal mass of an adult is remodelled each year. The purpose of remodeling is to regulate calcium homeostasis, repair microdamaged bones from everyday stress, and to shape the skeleton during growth.. Repeated stress, such as weight - bearing exercise or bone healing, results in the bone thickening at the points of maximum stress ( Wolff 's law ). It has been hypothesized that this is a result of bone 's piezoelectric properties, which cause bone to generate small electrical potentials under stress. The action of osteoblasts and osteoclasts are controlled by a number of chemical enzymes that either promote or inhibit the activity of the bone remodeling cells, controlling the rate at which bone is made, destroyed, or changed in shape. The cells also use paracrine signalling to control the activity of each other. For example, the rate at which osteoclasts resorb bone is inhibited by calcitonin and osteoprotegerin. Calcitonin is produced by parafollicular cells in the thyroid gland, and can bind to receptors on osteoclasts to directly inhibit osteoclast activity. Osteoprotegerin is secreted by osteoblasts and is able to bind RANK - L, inhibiting osteoclast stimulation. Osteoblasts can also be stimulated to increase bone mass through increased secretion of osteoid and by inhibiting the ability of osteoclasts to break down osseous tissue. Increased secretion of osteoid is stimulated by the secretion of growth hormone by the pituitary, thyroid hormone and the sex hormones ( estrogens and androgens ). These hormones also promote increased secretion of osteoprotegerin. Osteoblasts can also be induced to secrete a number of cytokines that promote reabsorbtion of bone by stimulating osteoclast activity and differentiation from progenitor cells. Vitamin D, parathyroid hormone and stimulation from osteocytes induce osteoblasts to increase secretion of RANK - ligand and interleukin 6, which cytokines then stimulate increased reabsorption of bone by osteoclasts. These same compounds also increase secretion of macrophage colony - stimulating factor by osteoblasts, which promotes the differentiation of progenitor cells into osteoclasts, and decrease secretion of osteoprotegerin. Bone volume Bone volume is determined by the rates of bone formation and bone resorption. Recent research has suggested that certain growth factors may work to locally alter bone formation by increasing osteoblast activity. Numerous bone - derived growth factors have been isolated and classified via bone cultures. These factors include insulin - like growth factors I and II, transforming growth factor - beta, fibroblast growth factor, platelet - derived growth factor, and bone morphogenetic proteins. Evidence suggests that bone cells produce growth factors for extracellular storage in the bone matrix. The release of these growth factors from the bone matrix could cause the proliferation of osteoblast precursors. Essentially, bone growth factors may act as potential determinants of local bone formation. Research has suggested that cancellous bone volume in postemenopausal osteoporosis may be determined by the relationship between the total bone forming surface and the percent of surface resorption. Clinical significance See also : Bone disease A number of diseases can affect bone, including arthritis, fractures, infections, osteoporosis and tumours. Conditions relating to bone can be managed by a variety of doctors, including rheumatologists for joints, and orthopedic surgeons, who may conduct surgery to fix broken bones. Other doctors, such as rehabilitation specialists may be involved in recovery, radiologists in interpreting the findings on imaging, and pathologists in investigating the cause of the disease, and family doctors may play a role in preventing complications of bone disease such as osteoporosis. When a doctor sees a patient, a history and exam will be taken. Bones are then often imaged, called radiography. This might include ultrasound X-ray, CT scan, MRI scan and other imaging such as a Bone scan, which may be used to investigate cancer. Other tests such as a blood test for autoimmune markers may be taken, or a synovial fluid aspirate may be taken. Fractures Radiography used to identify possible bone fractures after a knee injury. Main article : Bone fracture In normal bone, fractures occur when there is significant force applied, or repetitive trauma over a long time. Fractures can also occur when a bone is weakened, such as with osteoporosis, or when there is a structural problem, such as when the bone remodels excessively ( such as Paget 's disease ) or is the site of the growth of cancer. Common fractures include wrist fractures and hip fractures, associated with osteoporosis, vertebral fractures associated with high - energy trauma and cancer, and fractures of long - bones. Not all fractures are painful. When serious, depending on the fractures type and location, complications may include flail chest, compartment syndromes or fat embolism. Compound fractures involve the bone 's penetration through the skin. Some complex fractures can be treated by the use of bone grafting procedures that replace missing bone portions. Fractures and their underlying causes can be investigated by X-rays, CT scans and MRIs. Fractures are described by their location and shape, and several classification systems exist, depending on the location of the fracture. A common long bone fracture in children is a Salter -- Harris fracture. When fractures are managed, pain relief is often given, and the fractured area is often immobilised. This is to promote bone healing. In addition, surgical measures such as internal fixation may be used. Because of the immobilisation, people with fractures are often advised to undergo rehabilitation. Tumors Main article : Bone tumour There are several types of tumour that can affect bone ; examples of benign bone tumours include osteoma, osteoid osteoma, osteochondroma, osteoblastoma, enchondroma, giant cell tumor of bone, and aneurysmal bone cyst. Cancer Main article : Bone metastases Cancer can arise in bone tissue, and bones are also a common site for other cancers to spread ( metastasise ) to. Cancers that arise in bone are called `` primary '' cancers, although such cancers are rare. Metastases within bone are `` secondary '' cancers, with the most common being breast cancer, lung cancer, prostate cancer, thyroid cancer, and kidney cancer. Secondary cancers that affect bone can either destroy bone ( called a `` lytic '' cancer ) or create bone ( a `` sclerotic '' cancer ). Cancers of the bone marrow inside the bone can also affect bone tissue, examples including leukemia and multiple myeloma. Bone may also be affected by cancers in other parts of the body. Cancers in other parts of the body may release parathyroid hormone or parathyroid hormone - related peptide. This increases bone reabsorption, and can lead to bone fractures. Bone tissue that is destroyed or altered as a result of cancers is distorted, weakened, and more prone to fracture. This may lead to compression of the spinal cord, destruction of the marrow resulting in bruising, bleeding and immunosuppression, and is one cause of bone pain. If the cancer is metastatic, then there might be other symptoms depending on the site of the original cancer. Some bone cancers can also be felt. Cancers of the bone are managed according to their type, their stage, prognosis, and what symptoms they cause. Many primary cancers of bone are treated with radiotherapy. Cancers of bone marrow may be treated with chemotherapy, and other forms of targeted therapy such as immunotherapy may be used. Palliative care, which focuses on maximising a person 's quality of life, may play a role in management, particularly if the likelihood of survival within five years is poor. Painful conditions Osteomyelitis is inflammation of the bone or bone marrow due to bacterial infection. Osteogenesis imperfecta Osteochondritis dissecans Arthritis Ankylosing spondylitis Skeletal fluorosis is a bone disease caused by an excessive accumulation of fluoride in the bones. In advanced cases, skeletal fluorosis damages bones and joints and is painful. Osteoporosis Main article : Osteoporosis Osteoporosis is a disease of bone where there is reduced bone mineral density, increasing the likelihood of fractures. Osteoporosis is defined in women by the World Health Organization as a bone mineral density of 2.5 standard deviations below peak bone mass, relative to the age and sex - matched average. This density is measured using dual energy X-ray absorptiometry ( DEXA ), 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 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 a healthy diet. Calcium supplements may also be advised, as may Vitamin D. When medication is used, it may include bisphosphonates, Strontium ranelate, and hormone replacement therapy. Osteopathy Main article : Osteopathy Osteopathic medicine is a school of medical thought originally developed based on the idea of the link between the musculoskeletal system and overall health, but now very similar to mainstream medicine. As of 2012, over 77,000 physicians in the United States are trained in Osteopathic medicine colleges. Osteology Human femurs and humerus from Roman period, with evidence of healed fractures The study of bones and teeth is referred to as osteology. It is frequently used in anthropology, archeology and forensic science for a variety of tasks. This can include determining the nutritional, health, age or injury status of the individual the bones were taken from. Preparing fleshed bones for these types of studies can involve the process of maceration. Typically anthropologists and archeologists study bone tools made by Homo sapiens and Homo neanderthalensis. Bones can serve a number of uses such as projectile points or artistic pigments, and can also be made from external bones such as antlers. Other animals Main articles : Bird anatomy and Exoskeleton Skeletal fluorosis in a cow 's leg, due to industrial contamination Leg and pelvic girdle bones of bird Bird skeletons are very lightweight. Their bones are smaller and thinner, to aid flight. Among mammals, bats come closest to birds in terms of bone density, suggesting that small dense bones are a flight adaptation. Many bird bones have little marrow due to their being hollow. A bird 's beak is primarily made of bone as projections of the mandibles which are covered in keratin. A deer 's antlers are composed of bone which is an unusual example of bone being outside the skin of the animal once the velvet is shed. The extinct predatory fish Dunkleosteus had sharp edges of hard exposed bone along its jaws. Many animals possess an exoskeleton that is not made of bone. These include insects and crustaceans. The proportion of cortical bone that is 80 % in the human skeleton may be much lower in other animals, especially in marine mammals and marine turtles, or in various Mesozoic marine reptiles, such as ichthyosaurs, among others. Many animals particularly herbivores practice osteophagy -- the eating of bones. This is presumably carried out in order to replenish lacking phosphate. Many bone diseases that affect humans also affect other vertebrates -- an example of one disorder is skeletal flurosis. Society and culture Bones from slaughtered animals have a number of uses. In prehistoric times, they have been used for making bone tools. They have further been used in bone carving, already important in prehistoric art, and also in modern time as crafting materials for buttons, beads, handles, bobbins, calculation aids, head nuts, dice, poker chips, pick - up sticks, ornaments, etc. A special genre is scrimshaw. Bone glue can be made by prolonged boiling of ground or cracked bones, followed by filtering and evaporation to thicken the resulting fluid. Historically once important, bone glue and other animal glues today have only a few specialized uses, such as in antiques restoration. Essentially the same process, with further refinement, thickening and drying, is used to make gelatin. Broth is made by simmering several ingredients for a long time, traditionally including bones. Ground bones are used as an organic phosphorus - nitrogen fertilizer and as additive in animal feed. Bones, in particular after calcination to bone ash, are used as source of calcium phosphate for the production of bone china and previously also phosphorus chemicals. Bone char, a porous, black, granular material primarily used for filtration and also as a black pigment, is produced by charring mammal bones. Oracle bone script was a writing system used in Ancient china based on inscriptions in bones. To point the bone at someone is considered bad luck in some cultures, such as Australian aborigines, such as by the Kurdaitcha. The wishbones of fowl have been used for divination, and are still customarily used in a tradition to determine which one of two people pulling on either prong of the bone may make a wish. Various cultures throughout history have adopted the custom of shaping an infant 's head by the practice of artificial cranial deformation. A widely practised custom in China was that of foot binding to limit the normal growth of the foot. Additional images Cells in bone marrow Scanning electron microscope of bone at 100x magnification See also Artificial bone Bone health Distraction osteogenesis National Bone Health Campaign Skeletal system References Jump up ^ Steele, D. Gentry ; Claud A. Bramblett ( 1988 ). The Anatomy and Biology of the Human Skeleton. Texas A&M University Press. p. 4. ISBN 0 - 89096 - 300 - 2. Jump up ^ Mammal anatomy : an illustrated guide. New York : Marshall Cavendish. 2010. p. 129. ISBN 9780761478829. Jump up ^ Hall, John ( 2011 ). Textbook of Medical Physiology ( 12th ed. ). Philadelphia : Elsevier. pp. 957 -- 960. ISBN 978 - 08089 - 2400 - 5. ^ Jump up to : Schmidt - Nielsen, Knut ( 1984 ). `` Scaling : Why Is Animal Size So Important ? ''. Cambridge : Cambridge University Press : 6. ISBN 0 - 521 - 31987 - 0. Jump up ^ `` ossein ''. The Free Dictionary. ^ Jump up to : Deakin 2006, p. 192. Jump up ^ Gdyczynski, C.M. ; Manbachi, A. ; et al. ( 2014 ). `` On estimating the directionality distribution in pedicle trabecular bone from micro-CT images ''. Journal of Physiological Measurements. 35 ( 12 ) : 2415 -- 2428. doi : 10.1088 / 0967 - 3334 / 35 / 12 / 2415. ^ Jump up to : Deakin 2006, p. 195. Jump up ^ Hall, Susan J. ( 2007 ). Basic Biomechanics with OLC ( 5th ed., Revised. ed. ). Burr Ridge : McGraw - Hill Higher Education. p. 88. ISBN 0 - 07 - 126041 - 2. 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ISBN 9781400849505 Jump up ^ Salentijn, L. Biology of Mineralized Tissues : Cartilage and Bone, Columbia University College of Dental Medicine post-graduate dental lecture series, 2007 Jump up ^ Bertazzo, S. ; Bertran, C.A. ( 2006 ). `` Morphological and dimensional characteristics of bone mineral crystals ''. Bioceramics. 309 -- 311 ( Pt. 1, 2 ) : 3 -- 10. doi : 10.4028 / scientific.net/KEM.309-311.3. Jump up ^ Bertazzo, S. ; Bertran, C.A. ; Camilli, J.A. ( 2006 ). `` Morphological Characterization of Femur and Parietal Bone Mineral of Rats at Different Ages ''. Key Engineering Materials. 309 -- 311 : 11 -- 14. doi : 10.4028 / scientific.net/KEM.309-311.11. Jump up ^ `` Types of bone ''. mananatomy.com. Retrieved 6 February 2016. Jump up ^ `` DoITPoMS - TLP Library Structure of bone and implant materials - Structure and composition of bone ''. www.doitpoms.ac.uk. Jump up ^ Bart Clarke ( 2008 ), `` Normal Bone Anatomy and Physiology '', Clinical Journal of the American Society of Nephrology, 3, doi : 10.2215 / CJN. 04151206 Jump up ^ Adriana Jerez, Susana Mangione, and Virginia Abdala ( 2010 ), `` Occurrence and distribution of sesamoid bones in squamates : a comparative approach '', Acta Zoologica, 91 ( 3 ) : 295 -- 305, doi : 10.1111 / j. 1463 - 6395.2009. 00408. x CS1 maint : Multiple names : authors list ( link ) Jump up ^ Pratt, Rebecca. `` Bone as an Organ ''. AnatomyOne. Amirsys, Inc. Retrieved 2012 - 09 - 28. Jump up ^ Agur, Anne ( 2009 ). Grant 's Atlas of Anatomy. Philadelphia : Lippincott, Williams, and Wilkins. p. 598. ISBN 978 - 0 - 7817 - 7055 - 2. ^ Jump up to : Saladin, Kenneth ( 2012 ). Anatomy and Physiology : The Unity of Form and Function. New York : McGraw - Hill. p. 217. ISBN 978 - 0 - 07 - 337825 - 1. Jump up ^ Vincent, Kevin. `` Topic 3 : Structure and Mechanical Properties of Bone ''. BENG 112A Biomechanics, Winter Quarter, 2013. Department of Bioengineering, University of California. Jump up ^ Turner, C.H. ; Wang, T. ; Burr, D.B. ( 2001 ). `` Shear Strength and Fatigue Properties of Human Cortical Bone Determined from Pure Shear Tests ''. Calcified Tissue International. 69 ( 6 ) : 373 -- 378. doi : 10.1007 / s00223 - 001 - 1006 - 1. PMID 11800235. Jump up ^ Levrero, F. ; Margetts, L. ; et al. ( 2016 ). `` Evaluating the macroscopic yield behaviour of trabecular bone using a nonlinear homogenisation approach ''. Journal of the Mechanical Behavior of Biomedical Materials. 61 : 384 -- 396. doi : 10.1016 / j. jmbbm. 2016.04. 008. Jump up ^ Fernández, KS ; de Alarcón, PA ( December 2013 ). `` Development of the hematopoietic system and disorders of hematopoiesis that present during infancy and early childhood ''. Pediatric clinics of North America. 60 ( 6 ) : 1273 -- 89. doi : 10.1016 / j. pcl. 2013.08. 002. PMID 24237971. Jump up ^ Deakin 2006, p. 60 - 61. Jump up ^ Deakin 2006, p. 60. Jump up ^ Deakin 2006, p. 57. Jump up ^ Deakin 2006, p. 46. Jump up ^ Doyle, Máire E. ; Jan de Beur, Suzanne M. ( 2008 ). `` The Skeleton : Endocrine Regulator of Phosphate Homeostasis ''. Current Osteoporosis Reports. 6 : 134 -- 141. doi : 10.1007 / s11914 - 008 - 0024 - 6 -- via Google Scholar. Jump up ^ Walker, Kristin. `` Bone ''. Encyclopedia Britannica. Retrieved 5 October 2017. Jump up ^ Styner, Maya ; Pagnotti, Gabriel M ; McGrath, Cody ; Wu, Xin ; Sen, Buer ; Uzer, Gunes ; Xie, Zhihui ; Zong, Xiaopeng ; Styner, Martin A ( 2017 - 05 - 01 ). `` Exercise Decreases Marrow Adipose Tissue Through ß - Oxidation in Obese Running Mice ''. Journal of Bone and Mineral Research : n / a -- n / a. doi : 10.1002 / jbmr. 3159. ISSN 1523 - 4681. Jump up ^ Lee, Na Kyung ; et al. ( 10 August 2007 ). `` Endocrine Regulation of Energy Metabolism by the Skeleton '' ( PDF ). Cell. 130 ( 3 ) : 456 -- 469. doi : 10.1016 / j. cell. 2007.05. 047. PMC 2013746. PMID 17693256. Archived from the original ( PDF ) on 6 January 2009. Retrieved 15 March 2008. Jump up ^ Manolagas, SC ( April 2000 ). `` Birth and death of bone cells : basic regulatory mechanisms and implications for the pathogenesis and treatment of osteoporosis ''. Endocrine Reviews. 21 ( 2 ) : 115 -- 37. doi : 10.1210 / edrv. 21.2. 0395. PMID 10782361. Jump up ^ ed, Russell T. Woodburne..., consulting ( 1999 ). Anatomy, physiology, and metabolic disorders ( 5. print. ed. ). Summit, N.J. : Novartis Pharmaceutical Corp. pp. 187 -- 189. ISBN 0 - 914168 - 88 - 6. ^ Jump up to : Boulpaep, Emile L. ; Boron, Walter F. ( 2005 ). Medical physiology : a cellular and molecular approach. Philadelphia : Saunders. pp. 1089 -- 1091. ISBN 1 - 4160 - 2328 - 3. ^ Jump up to : Mohan, S. ; Baylink, D.J. ( 1991 ). `` Bone growth factors ''. Clinical Orthopaedics and Related Research ( 263 ) : 30 -- 48. doi : 10.1097 / 00003086 - 199102000 - 00004. PMID 1993386. Jump up ^ Nordin, BE ; Aaron, J ; Speed, R ; Crilly, RG ( 8 August 1981 ). `` Bone formation and resorption as the determinants of trabecular bone volume in postmenopausal osteoporosis ''. Lancet. 2 ( 8241 ) : 277 -- 9. doi : 10.1016 / S0140 - 6736 ( 81 ) 90526 - 2. PMID 6114324. ^ Jump up to : Britton 2010, pp. 1059 -- 1062. ^ Jump up to : Britton 2010, pp. 1068. Jump up ^ Salter RB, Harris WR ( 1963 ). `` Injuries Involving the Epiphyseal Plate ''. J Bone Joint Surg Am. 45 ( 3 ) : 587 -- 622. doi : 10.2106 / 00004623 - 196345030 - 00019. Jump up ^ `` Benign Bone Tumors ''. Cleveland Clinic. 2017. Retrieved March 29, 2017. ^ Jump up to : Britton 2010, pp. 1125. Jump up ^ Britton 2010, pp. 1032. ^ Jump up to : Britton 2010, pp. 1116 -- 1121. Jump up ^ WHO ( 1994 ). `` Assessment of fracture risk and its application to screening for postmenopausal osteoporosis. Report of a WHO Study Group ''. World Health Organization technical report series. 843 : 1 -- 129. PMID 7941614. Jump up ^ Britton, the editors Nicki R. Colledge, Brian R. Walker, Stuart H. Ralston ; illustrated by Robert ( 2010 ). Davidson 's principles and practice of medicine ( 21st ed. ). Edinburgh : Churchill Livingstone / Elsevier. pp. 1116 -- 1121. ISBN 978 - 0 - 7020 - 3085 - 7. Jump up ^ `` 2012 OSTEOPATHIC MEDICAL PROFESSION REPORT '' ( PDF ). Osteopathic.org. American Osteopathic Organisation. Retrieved 26 November 2014. Jump up ^ Dumont, E.R. ( 17 March 2010 ). `` Bone density and the lightweight skeletons of birds ''. Proceedings of the Royal Society B : Biological Sciences. 277 ( 1691 ) : 2193 -- 2198. doi : 10.1098 / rspb. 2010.0117. PMC 2880151. PMID 20236981. Jump up ^ Hans J. Rolf ; Alfred Enderle ( 1999 ). `` Hard fallow deer antler : a living bone till antler casting ? ''. The Anatomical Record. 255 ( 1 ) : 69 -- 77. doi : 10.1002 / ( SICI ) 1097 - 0185 ( 19990501 ) 255 : 1 < 69 : : AID - AR8 > 3.0.CO ; 2 - R. PMID 10321994. Jump up ^ `` Dunkleosteus ''. American Museum of Natural History. Jump up ^ de Buffrénil V. ; Mazin J. - M. ( 1990 ). `` Bone histology of the ichthyosaurs : comparative data and functional interpretation ''. Paleobiology. 16 : 435 -- 447. JSTOR 2400968. Jump up ^ Laurin, M. ; Canoville, A. ; Germain, D. ( 2011 ). `` Bone microanatomy and lifestyle : a descriptive approach ''. Comptes Rendus Palevol. 10 ( 5 -- 6 ) : 381 -- 402. doi : 10.1016 / j. crpv. 2011.02. 003. Footnotes Katja Hoehn ; Marieb, Elaine Nicpon ( 2007 ). Human Anatomy & Physiology ( 7th Edition ). San Francisco : Benjamin Cummings. ISBN 0 - 8053 - 5909 - 5. Bryan H. Derrickson ; Tortora, Gerard J. ( 2005 ). Principles of anatomy and physiology. New York : Wiley. ISBN 0 - 471 - 68934 - 3. Britton, the editors Nicki R. Colledge, Brian R. Walker, Stuart H. Ralston ; illustrated by Robert ( 2010 ). Davidson 's principles and practice of medicine ( 21st ed. ). Edinburgh : Churchill Livingstone / Elsevier. ISBN 978 - 0 - 7020 - 3085 - 7. Deakin, Barbara Young ; et al. ( 2006 ). Wheater 's functional histology : a text and colour atlas ( 5th ed. ). ( Edinburgh ? ) : Churchill Livingstone / Elsevier. ISBN 978 - 0 - 443 - 068 - 508. -- drawings by Philip J. Hall, Arthur C. ; Guyton, John E. ( 2005 ). Textbook of medical physiology ( 11th ed. ). Philadelphia : W.B. Saunders. ISBN 978 - 0 - 7216 - 0240 - 0. Anthony, S. Fauci ; Harrison, T.R. ; et al. ( 2008 ). Harrison 's principles of internal medicine ( 17th ed. ). New York ( etc. ) : McGraw - Hill Medical. ISBN 978 - 0 - 07 - 147692 - 8. -- Anthony edits the current version ; Harrison edited previous versions. External links Wikimedia Commons has media related to Bones. Wikiquote has quotations related to : Bone Educational resource materials ( including animations ) by the American Society for Bone and Mineral Research Review ( including references ) of piezoelectricity and bone remodelling A good basic overview of bone biology from the Science Creative Quarterly Usha Kini ; B.N. Nandeesh. `` Ch 2 : Physiology of Bone Formation, Remodeling, and Metabolism ''. In Ignac Fogelman ; Gopinath Gnanasegaran ; Hans van der Wall. Radionuclide and hybrid bone imaging ( PDF ). Berlin : Springer. pp. 29 -- 57. ISBN 978 - 3 - 642 - 02399 - 6. Bone histology photomicrographs Bone and cartilage Cartilage perichondrium fibrocartilage callus metaphysis Cells chondroblast chondrocyte Types hyaline elastic fibrous Bone Ossification Primary bone intramembranous endochondral Cells osteoblast osteoid osteocyte osteoclast Types cancellous cortical Regions subchondral bone epiphysis epiphyseal plate / metaphysis diaphysis Condyle Epicondyle Structure Osteon Haversian canals Volkmann 's canals connective tissue endosteum periosteum Sharpey 's fibres enthesis lacunae canaliculi trabeculae medullary cavity bone marrow Shapes long short flat irregular sesamoid Bones of the human skeleton Bones in the human skeleton Axial skeleton Skull Neurocranium occipital parietal frontal temporal sphenoid ethmoid Face nasal maxilla lacrimal zygomatic palatine inferior nasal conchae vomer mandible hyoid Ear ossicles malleus incus stapes Thorax sternum rib cage rib Vertebral column vertebrae cervical thoracic lumbar sacrum coccyx Appendicular Shoulder clavicle scapula Arm humerus ulna radius Hand carpals ( scaphoid, lunate bone, triquetral, pisiform, trapezium, trapezoid, capitate, hamate ) metacarpals phalanges ( prox, int, dist ) Pelvis ilium ischium pubis Leg femur patella fibula tibia Foot tarsals heelbone anklebone navicular cuneiform cuboid metatarsals phalanges proximal intermediate distal accessory accessory navicular The facial skeleton of the skull Maxilla Surfaces Anterior : fossae ( Incisive fossa, Canine fossa ) Infraorbital foramen Anterior nasal spine Infratemporal : Alveolar canals Maxillary tuberosity Orbital : Infraorbital groove Infraorbital canal Nasal : Greater palatine canal Processes Zygomatic process Frontal process ( Agger nasi, Anterior lacrimal crest ) Alveolar process Palatine process ( Incisive foramen, Incisive canals, Foramina of Scarpa, Incisive bone, Anterior nasal spine ) Other Body of maxilla Maxillary sinus Zygomatic Orbital process ( Zygomatico - orbital ) Temporal process ( Zygomaticotemporal ) Lateral process ( Zygomaticofacial ) Palatine Fossae Pterygopalatine fossa Pterygoid fossa Plates Horizontal plate ( Posterior nasal spine ) Perpendicular plate ( Greater palatine canal, Sphenopalatine foramen ) Processes Pyramidal Orbital Sphenoidal Mandible Body external surface ( Mandibular symphysis, Lingual foramen, Mental protuberance, Mental foramen, Mandibular incisive canal ) internal surface ( Mental spine, Mylohyoid line, Sublingual fovea, Submandibular fovea ) Alveolar part Ramus Mylohyoid groove Mandibular canal Lingula Mandibular foramen Angle Coronoid process Mandibular notch Condyloid process Pterygoid fovea Nose Nasal bone Internasal suture Nasal foramina Inferior nasal concha Ethmoidal process Maxillary process Vomer Wing Other Lacrimal Posterior lacrimal crest Lacrimal groove Lacrimal hamulus The neurocranium of the skull Occipital Squamous part external Inion / External occipital protuberance External occipital crest Nuchal lines planes Occipital Nuchal internal Cruciform eminence Internal occipital protuberance Internal occipital crest Groove for transverse sinus Lateral parts Condyle Condyloid fossa Condylar canal Hypoglossal canal jugular Jugular process Jugular tubercle Basilar part Pharyngeal tubercle Clivus Other Foramen magnum Basion Opisthion Parietal Parietal eminence Temporal line Parietal foramen Sagittal sulcus Frontal Squamous part Frontal suture Frontal eminence external Superciliary arches Glabella foramina Supraorbital Cecum Zygomatic process internal Sagittal sulcus Frontal crest Orbital part Ethmoidal notch Fossa for lacrimal gland Trochlear fovea Frontal sinus Frontonasal duct Temporal Squamous part Articular tubercle Suprameatal triangle Mandibular fossa Petrotympanic fissure Zygomatic process Mastoid part Mastoid foramen Mastoid process ( Mastoid cells ) Mastoid notch Occipital groove Sigmoid sulcus Mastoid antrum ( Aditus ) Petrous part Carotid canal Facial canal Hiatus Internal auditory meatus Cochlear aqueduct Stylomastoid foramen fossae Subarcuate fossa Jugular fossa canaliculi Inferior tympanic Mastoid Styloid process Petrosquamous suture ( note : ossicles in petrous part, but not part of temporal bone ) Tympanic part Suprameatal spine Sphenoid Surfaces Superior surface : Sella turcica Dorsum sellae Tuberculum sellae Hypophysial fossa Posterior clinoid processes Ethmoidal spine Chiasmatic groove Middle clinoid process Petrosal process Clivus Lateral surface : Carotid groove Sphenoidal lingula Anterior surface : Sphenoidal sinuses Great wings foramina Rotundum Ovale Vesalii Spinosum Spine Infratemporal crest Sulcus of auditory tube Small wings Superior orbital fissure Anterior clinoid process Optic canal Pterygoid processes fossae Pterygoid Scaphoid pterygoid plates Lateral Medial Pterygoid canal Hamulus Other Body Sphenoidal conchae Ethmoid Plates Cribriform plate Crista galli Olfactory foramina Perpendicular plate Surfaces Lateral surface Orbital lamina Uncinate process Medial surface Supreme nasal concha Superior nasal concha Superior meatus Middle nasal concha Middle meatus Labyrinth Ethmoid sinus ethmoidal foramina Posterior Anterior Compound structures of skull Neurocranium Calvaria Diploë Asterion Pterion Stephanion Inion Bregma Lambda Fossae anterior middle posterior cranial cavity Base of skull Fontanelle anterior posterior sphenoidal mastoid Facial skeleton Nasion Gonion Both dacryon zygomatic arch temporal fossa infratemporal fossa pterygomaxillary fissure pterygopalatine fossa Bones of the arm Shoulder girdle, clavicle conoid tubercle trapezoid line costal tuberosity subclavian groove Scapula fossae ( subscapular, supraspinatous, infraspinatous ) notches ( suprascapular, great scapular ) glenoid cavity tubercles ( infraglenoid, supraglenoid ) spine of scapula acromion coracoid process angles ( superior, inferior, lateral ) Humerus upper extremity : necks ( anatomical, surgical ) tubercles ( greater, lesser ) bicipital groove body : radial sulcus deltoid tuberosity lower extremity : capitulum trochlea epicondyles ( lateral, medial ) supracondylar ridges ( lateral, medial ) fossae ( radial, coronoid, olecranon ) Forearm Radius near elbow ( head, tuberosity ) near wrist ( ulnar notch, styloid process, Lister 's tubercle ) Ulna near elbow ( tuberosity, olecranon, coronoid process, radial notch, trochlear notch ) near wrist ( styloid process ) Hand Carpal bones scaphoid lunate triquetral pisiform trapezium trapezoid capitate hamate hamulus Metacarpal bones 1st 2nd 3rd 4th 5th Phalanges proximal intermediate distal Bones of torso Vertebrae General structure Body Arch pedicle lamina notch Vertebral foramen Intervertebral foramen Processes transverse articular spinous Spinal canal Cervical vertebrae Uncinate process of vertebra Transverse foramen Anterior tubercle Carotid tubercle Posterior tubercle Atlas lateral mass anterior arch posterior arch Axis dens Vertebra prominens Thoracic vertebrae Costal facets superior inferior transverse Uncinate process of vertebra Lumbar vertebrae Processes accessory mammillary Sacrum Base sacral promontory Ala of sacrum Lateral surface sacral tuberosity Pelvic surface anterior sacral foramina Dorsal surface posterior sacral foramina Median sacral crest Medial sacral crest Lateral sacral crest Sacral canal sacral hiatus Coccyx none Thorax Rib cage Ribs true ribs false ribs floating ribs Parts angle tubercle costal groove neck head Sternum Suprasternal notch Manubrium Sternal angle Body of sternum Xiphisternal joint Xiphoid process Thoracic cage Thoracic inlet Thoracic outlet Intercostal space Costal margin Infrasternal angle Bones of the human leg Femur upper extremity head fovea neck greater trochanter fossa lesser trochanter intertrochanteric line intertrochanteric crest quadrate tubercle shaft linea aspera upper medial : merges with intertrochanteric line upper intermediate : pectineal line upper lateral : gluteal tuberosity / third trochanter lower extremity adductor tubercle patellar surface epicondyles lateral medial condyles lateral medial intercondylar fossa Tibia upper extremity Gerdy 's tubercle condyles lateral medial intercondylar area posterior anterior intercondylar eminence lateral tubercle medial tubercle shaft tuberosity soleal line lower extremity medial malleolus Anterior colliculus Posterior colliculus fibular notch Fibula lateral malleolus Other patella apex Foot Tarsus calcaneus sustentaculum tali calcaneal tubercle talus navicular cuboid cuneiform medial intermediate lateral Metatarsals 1st 2nd 3rd 4th 5th Other Phalanges Bones of the pelvis General sacrum coccyx hip bone Ilium body arcuate line wing gluteal lines posterior anterior inferior iliac spines anterior superior anterior inferior posterior superior posterior inferior other : crest tuberosity tubercle fossa Ischium body ischial spine lesser sciatic notch superior ramus tuberosity of the ischium inferior ramus no substructures Pubis body pubic crest superior ramus pubic tubercle obturator crest inferior ramus pectineal line Compound acetabulum acetabular notch iliopubic eminence / iliopectineal line linea terminalis ischiopubic ramus / pubic arch Foramina obturator foramen greater sciatic foramen / greater sciatic notch lesser sciatic foramen Landmarks pelvic inlet pelvic brim pelvic outlet Fractures and cartilage injuries ( Sx2, 800 -- 829 ) General Avulsion fracture Chalkstick fracture Greenstick fracture Open fracture Pathologic fracture Spiral fracture Head Basilar skull fracture Blowout fracture Mandibular fracture Nasal fracture Le Fort fracture of skull Zygomaticomaxillary complex fracture Zygoma fracture Spinal fracture Cervical fracture Jefferson fracture Hangman 's fracture Flexion teardrop fracture Clay - shoveler fracture Burst fracture Compression fracture Chance fracture Holdsworth fracture Ribs Rib fracture Sternal fracture Shoulder fracture Clavicle Scapular Arm fracture Humerus fracture : Supracondylar Holstein -- Lewis fracture Forearm fracture : Ulnar fracture Monteggia fracture Hume fracture Radius fracture / Distal radius Galeazzi Colles ' Smith 's Barton 's Essex - Lopresti fracture Hand fracture Scaphoid Rolando Bennett 's Boxer 's Pelvic fracture Duverney fracture Pipkin fracture Leg Tibia fracture : Bumper fracture Segond fracture Gosselin fracture Toddler 's fracture Pilon fracture Plafond fracture Tillaux fracture Fibular fracture : Maisonneuve fracture Le Fort fracture of ankle Bosworth fracture Combined tibia and fibula fracture : Trimalleolar fracture Bimalleolar fracture Pott 's fracture Crus fracture : Patella fracture Femoral fracture : Hip fracture Foot fracture Lisfranc Jones March Calcaneal GND : 4128031 - 3 NDL : 00563399 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Bone&oldid=832836112 '' Categories : Bones Skeletal system Connective tissue Hidden categories : Pages with unresolved properties CS1 maint : Multiple names : authors list Wikipedia indefinitely move - protected pages 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Question: bones are composed of a type of connective tissue called
Answer: hard tissue