Bone marrow

Bone marrow

Overview
Bone marrow is the flexible tissue
Biological tissue
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...

 found in the interior of bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

s. In human
Human
Humans are the only living species in the Homo genus...

s, bone marrow in large bones produces new blood cell
Blood cell
A blood cell, also called a hematocyte, is a cell normally found in blood. In mammals, these fall into three general categories:* red blood cells — Erythrocytes* white blood cells — Leukocytes* platelets — Thrombocytes...

s. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg (143 lbs), bone marrow accounts for approximately 2.6 kg (5.7 lbs). The hematopoietic compartment of bone marrow produces approximately 500 billion blood cells per day, which use the bone marrow vasculature as a conduit to the body's systemic circulation.

There are two types of bone marrow: medulla ossium rubra (red marrow), which consists mainly of hematopoietic tissue, and medulla ossium flava (yellow marrow), which is mainly made up of fat cells.
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Encyclopedia
Bone marrow is the flexible tissue
Biological tissue
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...

 found in the interior of bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

s. In human
Human
Humans are the only living species in the Homo genus...

s, bone marrow in large bones produces new blood cell
Blood cell
A blood cell, also called a hematocyte, is a cell normally found in blood. In mammals, these fall into three general categories:* red blood cells — Erythrocytes* white blood cells — Leukocytes* platelets — Thrombocytes...

s. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg (143 lbs), bone marrow accounts for approximately 2.6 kg (5.7 lbs). The hematopoietic compartment of bone marrow produces approximately 500 billion blood cells per day, which use the bone marrow vasculature as a conduit to the body's systemic circulation.

Marrow types


There are two types of bone marrow: medulla ossium rubra (red marrow), which consists mainly of hematopoietic tissue, and medulla ossium flava (yellow marrow), which is mainly made up of fat cells. Red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...

s, platelet
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes.  The average lifespan of a platelet is normally just 5 to 9 days...

s and most white blood cell
White blood cell
White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...

s arise in red marrow. Both types of bone marrow contain numerous blood vessels and capillaries. At birth, all bone marrow is red. With age, more and more of it is converted to the yellow type; only around half of adult bone marrow is red. Red marrow is found mainly in the flat bone
Flat bone
Flat bones are those bones which are found where the principal requirement is either extensive protection or the provision of broad surfaces for muscular attachment...

s, such as the hip bone
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...

, breast bone, cranium
Human skull
The human skull is a bony structure, skeleton, that is in the human head and which supports the structures of the face and forms a cavity for the brain.In humans, the adult skull is normally made up of 22 bones...

, rib
Rib
In vertebrate anatomy, ribs are the long curved bones which form the rib cage. In most vertebrates, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. They serve to protect the lungs, heart, and other internal organs of the thorax...

s, vertebrae and shoulder blades, and in the cancellous ("spongy") material at the epiphyseal
Epiphysis
The epiphysis is the rounded end of a long bone, at its joint with adjacent bone. Between the epiphysis and diaphysis lies the metaphysis, including the epiphyseal plate...

 ends of long bone
Long bone
The long bones are those that are longer than they are wide. They are one of five types of bones: long, short, flat, irregular and sesamoid. Long bones, especially the femur and tibia, are subjected to most of the load during daily activities and they are crucial for skeletal mobility. They grow...

s such as the femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...

 and humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....

. Yellow marrow is found in the medullary cavity
Medullary cavity
The medullary cavity is the central cavity of bone shafts where red bone marrow and/or yellow bone marrow is stored; hence, the medullary cavity is also known as the marrow cavity...

, the hollow interior of the middle portion of long bones. In cases of severe blood loss, the body can convert yellow marrow back to red marrow to increase blood cell production.

Stroma


The stroma
Stromal cell
In cell biology, stromal cells are connective tissue cells of any organ, for example in the uterine mucosa , prostate, bone marrow, and the ovary. They are cells that support the function of the parenchymal cells of that organ...

of the bone marrow is all tissue not directly involved in the primary function of hematopoiesis. Yellow bone marrow makes up the majority of bone marrow stroma, in addition to smaller concentrations of stromal cells located in the red bone marrow. Though not as active as parenchymal red marrow, stroma is indirectly involved in hematopoiesis, since it provides the hematopoietic microenvironment that facilitates hematopoiesis by the parenchymal cells. For instance, they generate colony stimulating factors, which have a significant effect on hematopoiesis. Cells that constitute the bone marrow stroma are:
  • fibroblasts (reticular connective tissue
    Reticular connective tissue
    Reticular connective tissue is a type of connective tissue. It has a network of reticular fibers, made of type III collagen. Reticular fibers are not unique to reticular connective tissue, but only in this type are they dominant....

    )
  • macrophages
  • adipocytes
  • osteoblasts
  • osteoclasts
  • endothelial cells, which form the sinusoids. These derive from endothelial stem cells, which are also present in the bone marrow.


Macrophages contribute especially to red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...

 production, as they deliver iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 for hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...

 production.

Bone marrow barrier


The blood vessels of the bone marrow constitute a barrier, inhibiting immature blood cells from leaving the marrow. Only mature blood cells contain the membrane protein
Membrane protein
A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle. More than half of all proteins interact with membranes.-Function:...

s required to attach to and pass the blood vessel endothelium
Endothelium
The endothelium is the thin layer of cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. These cells are called endothelial cells. Endothelial cells line the entire circulatory system, from the heart...

. Hematopoietic stem cells may also cross the bone marrow barrier, and may thus be harvested from blood.

Mesenchymal stem cells



The bone marrow stroma contain mesenchymal stem cells (MSCs), also called marrow stromal cells. These are multipotent stem cell
Stem cell
This article is about the cell type. For the medical therapy, see Stem Cell TreatmentsStem cells are biological cells found in all multicellular organisms, that can divide and differentiate into diverse specialized cell types and can self-renew to produce more stem cells...

s that can differentiate
Cellular differentiation
In developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...

 into a variety of cell types. MSCs have been shown to differentiate, in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...

 or in vivo
In vivo
In vivo is experimentation using a whole, living organism as opposed to a partial or dead organism, or an in vitro controlled environment. Animal testing and clinical trials are two forms of in vivo research...

, into osteoblast
Osteoblast
Osteoblasts are mononucleate cells that are responsible for bone formation; in essence, osteoblasts are specialized fibroblasts that in addition to fibroblastic products, express bone sialoprotein and osteocalcin.Osteoblasts produce a matrix of osteoid, which is composed mainly of Type I collagen...

s, chondrocyte
Chondrocyte
Chondrocytes are the only cells found in cartilage. They produce and maintain the cartilaginous matrix, which consists mainly of collagen and proteoglycans...

s, myocyte
Myocyte
A myocyte is the type of cell found in muscles. They arise from myoblasts.Each myocyte contains myofibrils, which are long, long chains of sarcomeres, the contractile units of the cell....

s, adipocyte
Adipocyte
However, in some reports and textbooks, the number of fat cell increased in childhood and adolescence. The total number is constant in both obese and lean adult...

s and beta-pancreatic islets cells
Beta cell
Beta cells are a type of cell in the pancreas located in the so-called islets of Langerhans. They make up 65-80% of the cells in the islets.-Function:...

. MSCs can also transdifferentiate into neuronal cells
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...

.

Types of cells


Cellular constitution of the red bone marrow parenchyma
Group Cell type Average
fraction
Reference
range
Reference range
In health-related fields, a reference range or reference interval usually describes the variations of a measurement or value in healthy individuals...

Cells of
myelopoiesis
Myelopoiesis
Myelopoiesis is the regulated formation of myeloid cells, including eosinophilic granulocytes, basophilic granulocytes, neutrophilic granulocytes, and monocytes...

 
Myeloblast
Myeloblast
The myeloblast is a unipotent stem cell, which will differentiate into one of the actors of the Granulocyte series.- Origin :These cells descend from the primitive reticulum cells, which are found in the stroma of the marrow. There is also an intermediate phase between the myeloblast and these...

s
0.9% 0.2-1.5
Promyelocyte
Promyelocyte
A promyelocyte is a granulocyte precursor, developing from the myeloblast and developing into the myelocyte.-External links: - "18. Bone Marrow and Hemopoiesis: bone marrow smear, promyelocyte and erythroblasts " "Bone marrow" "Bone marrow"* - "Bone marrow smear"...

s
3.3% 2.1-4.1
Neutrophilic myelocytes 12.7% 8.2-15.7
Eosinophilic myelocytes 0.8% 0.2-1.3
Neutrophilic metamyelocytes 15.9% 9.6-24.6
Eosinophilic metamyelocytes 1.2% 0.4-2.2
Neutrophilic band cells 12.4% 9.5-15.3
Eosinophilic band cells 0.9% 0.2-2.4
Segmented neutrophils 7.4% 6.0-12.0
Segmented eosinophils 0.5% 0.0-1.3
Segmented basophils + mast cell
Mast cell
A mast cell is a resident cell of several types of tissues and contains many granules rich in histamine and heparin...

s
0.1% 0.0-0.2
Cells of
erythropoiesis
Erythropoiesis
Erythropoiesis is the process by which red blood cells are produced. It is stimulated by decreased O2 in circulation, which is detected by the kidneys, which then secrete the hormone erythropoietin...

 
Pronormoblasts 0.6% 0.2-1.3
Basophilic normoblasts 1.4% 0.5-2.4
Polychromatic normoblasts 21.6% 17.9-29.2
Orthochromatic normoblast  2.0% 0.4-4.6
Other cell types Megakaryocyte
Megakaryocyte
The megakaryocyte is a bone marrow cell responsible for the production of blood thrombocytes , which are necessary for normal blood clotting...

s
< 0.1% 0.0-0.4
Plasma cell
Plasma cell
Plasma cells, also called plasma B cells, plasmocytes, and effector B cells, are white blood cells which produce large volumes of antibodies. They are transported by the blood plasma and the lymphatic system...

s
1.3% 0.4-3.9
Reticular cell
Reticular cell
A reticular cell is a type of fibroblast that synthesises type III collagen and uses it to produce reticular fibers. The cell surrounds the fibers with its cytoplasm, isolating it from other tissue components and cells....

s
0.3% 0.0-0.9
Lymphocyte
Lymphocyte
A lymphocyte is a type of white blood cell in the vertebrate immune system.Under the microscope, lymphocytes can be divided into large lymphocytes and small lymphocytes. Large granular lymphocytes include natural killer cells...

s
16.2% 11.1-23.2
Monocyte
Monocyte
Monocytes are a type of white blood cell and are part of the innate immune system of vertebrates including all mammals , birds, reptiles, and fish. Monocytes play multiple roles in immune function...

s
0.3% 0.0-0.8


In addition, the bone marrow contains hematopoietic stem cells, which give rise to the three classes of blood cells that are found in the circulation: white blood cell
White blood cell
White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...

s (leukocytes), red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...

s (erythrocytes), and platelets (thrombocytes).

Compartmentalization


There is biologic compartmentalization
Cellular compartment
Cellular compartments in cell biology comprise all closed parts within a cell, usually surrounded by a single or double lipid layer membrane. Most organelles are compartments like mitochondria, chloroplasts , peroxisomes, lysosomes, the endoplasmic reticulum, the cell nucleus or the Golgi apparatus...

 in the bone marrow, in that certain cell types tend to aggregate in specific areas. For instance, erythrocytes, macrophages, and their precursors tend to gather around blood vessels, while granulocytes gather at the borders of the bone marrow.

Lymphatic role


The red bone marrow is a key element of the lymphatic system
Lymphatic system
The lymphoid system is the part of the immune system comprising a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally toward the heart. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated...

, being one of the primary lymphoid organs that generate lymphocytes from immature hematopoietic progenitor cell
Progenitor cell
A progenitor cell is a biological cell that, like a stem cell, has a tendency to differentiate into a specific type of cell, but is already more specific than a stem cell and is pushed to differentiate into its "target" cell...

s. The bone marrow and thymus
Thymus
The thymus is a specialized organ of the immune system. The thymus produces and "educates" T-lymphocytes , which are critical cells of the adaptive immune system....

 constitute the primary lymphoid tissues involved in the production and early selection of lymphocytes. Furthermore, bone marrow performs a valve
Valve
A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...

-like function to prevent the backflow of lymphatic fluid in the lymphatic system.

Diseases involving the bone marrow


The normal bone marrow architecture can be displaced by malignancies
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

, aplastic anemia
Aplastic anemia
Aplastic anemia is a condition where bone marrow does not produce sufficient new cells to replenish blood cells. The condition, per its name, involves both aplasia and anemia...

, or infections such as tuberculosis
Tuberculosis
Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...

, leading to a decrease in the production of blood cells and blood platelets. In addition, cancers of the hematologic progenitor cells in the bone marrow can arise; these are the leukemia
Leukemia
Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...

s.

Exposure to radiation
Ionizing radiation
Ionizing radiation is radiation composed of particles that individually have sufficient energy to remove an electron from an atom or molecule. This ionization produces free radicals, which are atoms or molecules containing unpaired electrons...

 or chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....

 will kill many of the rapidly dividing cells of the bone marrow, and will therefore result in a depressed immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

. Many of the symptoms of radiation sickness
Radiation poisoning
Acute radiation syndrome also known as radiation poisoning, radiation sickness or radiation toxicity, is a constellation of health effects which occur within several months of exposure to high amounts of ionizing radiation...

 are due to damage to the bone marrow cells.

To diagnose diseases involving the bone marrow, a bone marrow aspiration is sometimes performed. This typically involves using a hollow needle to acquire a sample of red bone marrow from the crest of the ilium
Iliac crest
-External links: - "Superficial muscles of the gluteal region and posterior thigh." - "Anterior Abdominal Wall: Osteology and Surface Anatomy " - "The Back, Posterior View" * *...

 under general or local anesthesia
Local anesthesia
Local anesthesia is any technique to induce the absence of sensation in part of the body, generally for the aim of inducing local analgesia, that is, local insensitivity to pain, although other local senses may be affected as well. It allows patients to undergo surgical and dental procedures with...

.

Examination



Bone marrow examination is the pathologic
Pathology
Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....

 analysis of samples of bone marrow obtained by bone marrow biopsy and bone marrow aspiration. Bone marrow examination is used in the diagnosis of a number of conditions, including leukemia
Leukemia
Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...

, multiple myeloma
Multiple myeloma
Multiple myeloma , also known as plasma cell myeloma or Kahler's disease , is a cancer of plasma cells, a type of white blood cell normally responsible for the production of antibodies...

, anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...

, and pancytopenia
Pancytopenia
Pancytopenia is a medical condition in which there is a reduction in the number of red and white blood cells, as well as platelets.If only two parameters from the full blood count are low, the term bicytopenia can be used...

. The bone marrow produces the cellular elements of the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

, including platelet
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes.  The average lifespan of a platelet is normally just 5 to 9 days...

s, red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...

s and white blood cell
White blood cell
White blood cells, or leukocytes , are cells of the immune system involved in defending the body against both infectious disease and foreign materials. Five different and diverse types of leukocytes exist, but they are all produced and derived from a multipotent cell in the bone marrow known as a...

s. While much information can be gleaned by testing the blood itself (drawn from a vein by phlebotomy
Venipuncture
In medicine, venepuncture, venopuncture or venipuncture is the process of obtaining intravenous access for the purpose of intravenous therapy or for blood sampling of venous blood. This procedure is performed by medical laboratory scientists, medical practitioners, some EMTs, paramedics,...

), it is sometimes necessary to examine the source of the blood cells in the bone marrow to obtain more information on hematopoiesis; this is the role of bone marrow aspiration and biopsy.

Donation and transplantation of bone marrow



In a bone marrow transplant, hematopoietic stem cells are removed from a person and infused into another person (allogenic) or into the same person at a later time (autologous). If donor and recipient are compatible, these infused cells will then travel to the bone marrow and initiate blood cell production. Transplantation from one person to another is performed in severe cases of disease of the bone marrow. The patient's marrow is first killed off with drugs or radiation, and then the new stem cells are introduced. Before radiation therapy or chemotherapy in cases of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

, some of the patient's hematopoietic stem cells are sometimes harvested and later infused back when the therapy is finished to restore the immune system.

Harvesting


The stem cells are harvested directly from the red marrow in the crest of the ilium
Iliac crest
-External links: - "Superficial muscles of the gluteal region and posterior thigh." - "Anterior Abdominal Wall: Osteology and Surface Anatomy " - "The Back, Posterior View" * *...

, often under general anesthesia. The procedure is minimally invasive and does not require stitches afterwards. Depending on the donor health and reaction to the procedure, the actual harvesting can be an outpatient procedure
Outpatient surgery
Outpatient surgery, also known as ambulatory surgery, same-day surgery or day surgery, is surgery that does not require an overnight hospital stay. The term “outpatient” arises from the fact that surgery patients may go home and do not need an overnight hospital bed...

 or requiring 1–2 days of recovery in the hospital. Another option is to administer certain drugs that stimulate the release of stem cells from the bone marrow into circulating blood. An IV
Intravenous therapy
Intravenous therapy or IV therapy is the infusion of liquid substances directly into a vein. The word intravenous simply means "within a vein". Therapies administered intravenously are often called specialty pharmaceuticals...

 is inserted into the donor's arm, and the stem cells are filtered out of the blood. The procedure is similar to donating blood or platelets. It may also be taken from the sternum. The tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

 may seem a good source, since it is very superficial. However, except in children, this bone marrow does not contain any substantial amount of red bone marrow, only yellow bone marrow. In newborns, stem cells may be retrieved from the umbilical cord
Umbilical cord
In placental mammals, the umbilical cord is the connecting cord from the developing embryo or fetus to the placenta...

.

Bone marrow as a food



Many cultures have utilized bone marrow as a food throughout history. Some anthropologists believe that early humans
Homo (genus)
Homo is the genus that includes modern humans and species closely related to them. The genus is estimated to be about 2.3 to 2.4 million years old, evolving from australopithecine ancestors with the appearance of Homo habilis....

 were scavenger
Scavenger
Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...

s rather than hunters. Marrow would then have been a food source (largely for its fat content) for tool-using hominids, who were able to crack open the bones of carcasses left by apex predator
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...

s such as lions.

In Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...

, beef bone marrow is used as the soup base for the national staple dish, phở
PHO
PHO may refer to:* Primary Health Organisation* Potentially hazardous object, an asteroid or comet that could potentially collide with Earth...

, while in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...

, the soup bulalo is made primarily of beef stock and marrow bones, seasoned with vegetables and boiled meat; a similar soup in the Philippines is called kansi. In Indonesia, bone marrow is called sumsum and can be found especially in Minangkabau cuisine. Sumsum is often cooked as soup or as gulai
Gulai
Gulai is a type of food contained rich, spicy and succulent curry-like sauce. The main ingredients might be chicken, beef, mutton, various kinds of offals, fish and seafoods, and also vegetables such as cassava leafs and young jackfruit. The gulai sauce commonly have thick consistency with...

(a curry
Curry
Curry is a generic description used throughout Western culture to describe a variety of dishes from Indian, Pakistani, Bangladeshi, Sri Lankan, Thai or other Southeast Asian cuisines...

-like dish). In India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

 and Pakistan
Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...

, slow-cooked marrow is the core ingredient of the dish nalli nihari.

In Hungary
Hungary
Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...

, tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

 is a main ingredient of beef soup
Broth
Broth is a liquid food preparation, typically consisting of either water or an already flavored stock, in which bones, meat, fish, cereal grains, or vegetables have been simmered. Broth is used as a basis for other edible liquids such as soup, gravy, or sauce. It can be eaten alone or with garnish...

; the bone is chopped into short (10–15 cm) pieces and the ends are covered with salt to prevent the marrow from leaking from the bone while cooking. Upon serving the soup, the marrow is usually spread on toast.

Beef bone marrow is also the main ingredient in Italian
Italian cuisine
Italian cuisine has developed through centuries of social and political changes, with roots as far back as the 4th century BCE. Italian cuisine in itself takes heavy influences, including Etruscan, ancient Greek, ancient Roman, Byzantine, Jewish and Arab cuisines...

 dish ossobuco (braised veal shanks), and beef marrow bones are often included in the French
French cuisine
French cuisine is a style of food preparation originating from France that has developed from centuries of social change. In the Middle Ages, Guillaume Tirel , a court chef, authored Le Viandier, one of the earliest recipe collections of Medieval France...

 pot-au-feu
Pot-au-feu
The pot-au-feu is a French beef stew. According to chef Raymond Blanc, the pot-au feu is "the quintessence of French family cuisine, it is the most celebrated dish in France...

 broth, the cooked marrow being traditionally eaten on toasted bread with sprinkled coarse sea salt
Sea salt
Sea salt, salt obtained by the evaporation of seawater, is used in cooking and cosmetics. It is historically called bay salt or solar salt...

.

In Iranian cuisine
Iranian cuisine
Iranian cuisine is diverse, with each province featuring dishes, culinary traditions and styles distinct to its region.It includes a wide variety of foods ranging from chelo kabab , khoresht Iranian cuisine is diverse, with each province featuring dishes, culinary traditions and styles distinct to...

, lamb shanks are usually broken before cooking to allow diners to suck out and eat the marrow when the dish is served. Similar practices are also common in Pakistani cuisine. Some Native Alaskans eat the bone marrow of caribou and moose
Moose
The moose or Eurasian elk is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic configuration...

.

European diners in the 18th century often used a marrow scoop (or marrow spoon), often of silver and with a long thin bowl, as a table implement for removing marrow from a bone.

Though once used in various preparations, including pemmican
Pemmican
Pemmican is a concentrated mixture of fat and protein used as a nutritious food. The word comes from the Cree word pimîhkân, which itself is derived from the word pimî, "fat, grease". It was invented by the native peoples of North America...

, bone marrow's popularity is now relatively limited in the western world. Nonetheless, it remains in use in some gourmet restaurants and is popular among food enthusiasts.

See also

  • Aplastic anemia
    Aplastic anemia
    Aplastic anemia is a condition where bone marrow does not produce sufficient new cells to replenish blood cells. The condition, per its name, involves both aplasia and anemia...

  • Bone marrow examination
  • Gift of Life Bone Marrow Foundation
    Gift of Life Bone Marrow Foundation
    The Gift of Life Bone Marrow Foundation is one of the public bone marrow, blood stem cell and umbilical cord blood registries in the United States...

  • John Raymond Hobbs
    John Raymond Hobbs
    John Raymond Hobbs MRCS, FRCP, FRCPath, FRCPaed was a professor who was at the forefront of the techniques of Clinical Immunology, Protein Biochemistry and Bone Marrow Transplantation, specifically in Child Health.-Early life:...

  • Leukemia
    Leukemia
    Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...

  • Ossobuco

Further reading