The crown is the top portion of the

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple animals ...

behind the

vertex Vertex, vertices or vertexes may refer to: Science and technology Mathematics and computer science *Vertex (geometry), a point where two or more curves, lines, or edges meet *Vertex (computer graphics), a data structure that describes the position ...

. The

anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having i ...

of the crown varies between different

organism In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells ( cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fu ...

s. The human crown is made of three layers of the scalp above the skull. The crown also covers a range of bone sutures, and contains

blood vessel The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide awa ...

s and branches of the

trigeminal nerve In neuroanatomy, the trigeminal nerve ( lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for sensation in the face and motor functions such as biting and che ...

. The structure of the human crown provides a protective cavity for the brain and optimizes the crown's ability to ensure the

neocortex The neocortex, also called the neopallium, isocortex, or the six-layered cortex, is a set of layers of the mammalian cerebral cortex involved in higher-order brain functions such as sensory perception, cognition, generation of motor commands, sp ...

is safe. Different parts of the neocortex, such as the

frontal lobe The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere (in front of the parietal lobe and the temporal lobe). It is parted from the parietal lobe by a groove be ...

and the parietal lobe, are protected by the

meninges In anatomy, the meninges (, ''singular:'' meninx ( or ), ) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in ...

and bone structures. Other organisms, such as

whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

s, have their blowholes on their crown, causing a flattened head shape. Some bird species have a crest located on their crown, used for

communication Communication (from la, communicare, meaning "to share" or "to be in relation with") is usually defined as the transmission of information. The term may also refer to the message communicated through such transmissions or the field of inqui ...

and

courtship Courtship is the period wherein some couples get to know each other prior to a possible marriage. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marriage. A courtship may be an informal and private m ...

. Macroevolution of the human crown has led to different structures between modern and archaic human species, such as significant changes to the

cranial vault The cranial vault is the space in the skull within the neurocranium, occupied by the brain. Development In humans, the cranial vault is imperfectly composed in newborns, to allow the large human head to pass through the birth canal. During bi ...

. The human crown is prone to different injuries and disorders with various causes,

medical sign Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...

s and

symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...

s, methods of

diagnosis Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine "cause and effect". In systems engin ...

, and treatments. For example, illnesses such as cerebrospinal fluid leak, which results in intense

headache Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches. Headaches can occur as a result ...

s that are localised underneath the crown. Other diseases include

meningioma Meningioma, also known as meningeal tumor, is typically a slow-growing tumor that forms from the meninges, the membranous layers surrounding the brain and spinal cord. Symptoms depend on the location and occur as a result of the tumor pressing ...

, a tumor surrounding essential blood vessels and nerves that may be near the crown, causing symptoms such as memory loss.

Structure

The crown is at the top of the

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...

, and contains the different layers of the scalp. The scalp has three distinct layers including the cutaneous layer, a subcutaneous connective tissue layer, and a muscular layer. The crown covers bone layers of the skull. It is between thick, and varies between different people. It tends to increase in thickness with age. Sobo 1909 46

Below the crown, the

frontal bone The frontal bone is a bone in the human skull. The bone consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, ...

and the

parietal bone The parietal bones () are two bones in the skull which, when joined at a fibrous joint, form the sides and roof of the cranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is n ...

s are separated by a range of

fibrous joint In anatomy, fibrous joints are joints connected by fibrous tissue, consisting mainly of collagen. These are fixed joints where bones are united by a layer of white fibrous tissue of varying thickness. In the skull the joints between the bones ...

s called sutures. The sutures are an essential part of growth and development, allowing the skull to expand as the brain increases in size. Different sutures between the frontal and parietal

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

s of the skull expand in specific directions, causing a symmetrically shaped human head. The frontal bone and the

s are joined at the frontal suture. The frontal bone has a number of parts, including the squamous part, the orbital part, and the nasal parts. The frontal bone connects to the parietal bone at the

coronal suture The coronal suture is a dense, fibrous connective tissue joint that separates the two parietal bones from the frontal bone of the skull. Structure The coronal suture lies between the paired parietal bones and the frontal bone of the skull ...

to shape the crown and sides of the skull. The two separate parietal bones are joined at the sagittal suture, ensuring the crown is stable. Other structures of the human crown include blood vessels and nerves, which are essential for the allocation of nutrients to the brain, and the transmission of information to the brain. The

superficial temporal artery In human anatomy, the superficial temporal artery is a major artery of the head. It arises from the external carotid artery when it splits into the superficial temporal artery and maxillary artery. Its pulse can be felt above the zygomatic a ...

branches from the common

external carotid artery The external carotid artery is a major artery of the head and neck. It arises from the common carotid artery when it splits into the external and internal carotid artery. External carotid artery supplies blood to the face and neck. Structure T ...

and delivers oxygenated

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...

to the crown. The crown also contains branches of the

Organisms such as whales and birds have different crown structures and species use them in different situations. Sperm whales have their blowholes situated asymmetrically on the crown of the head to breathe, causing a flattened head shape. In

bird anatomy Bird anatomy, or the physiological structure of birds' bodies, shows many unique adaptations, mostly aiding flight. Birds have a light skeletal system and light but powerful musculature which, along with circulatory and respiratory systems cap ...

, the crown is the top of the head, or more specifically the zone from the

frons Insect morphology is the study and description of the physical form of insects. The terminology used to describe insects is similar to that used for other arthropods due to their shared evolutionary history. Three physical features separate insec ...

, or forehead, extending posteriorly to the occiput and laterally on both sides to the temples. The upper part of the head, including frons, crown, and occiput, is called the pileum. A bird with a crest covering the pileum is described as "pileated" such as the pileated woodpecker. The range of

feather Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and a premie ...

s that make up the crest determines the bird's emotions and courtship behaviors. For instance, bird species such as the

northern cardinal The northern cardinal (''Cardinalis cardinalis'') is a bird in the genus ''Cardinalis''; it is also known colloquially as the redbird, common cardinal, red cardinal, or just cardinal (which was its name prior to 1985). It can be found in southea ...

move the crest intensely to signify dominance and communication.

Function

The main function of the crown is to protect the brain from specific physical injuries. The

neurocranium In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria or skul ...

has the frontal and parietal bones that make up the crown and protect parts of the brain including the frontal lobe as well as the parietal lobe. The three

membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. ...

s of the meninges ensures stability and prevents injuries directed to these lobes. For instance, the meninges which include flexible sheets between the brain,

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the sp ...

, and skull aim to protect the frontal lobe, located behind the

forehead In human anatomy, the forehead is an area of the head bounded by three features, two of the skull and one of the scalp. The top of the forehead is marked by the hairline, the edge of the area where hair on the scalp grows. The bottom of the fo ...

. The cerebrospinal fluid within the ventricles of the skull reduces the extent of the injury by acting as a cushion. Protecting the frontal lobe allows humans to perform motor movements and to execute functions. The parietal lobe of the neocortex which contains a strip targeting the sense of touch and allows for the representation of space for action is protected due to the thick layers of the crown.

Injuries and Diseases

The crown or human head is subjected to a range of injuries and diseases causing the brain to be vulnerable. The extent of the injuries and diseases directed to the human crown causes additional implications to the brain, impacting the individual's ability to function normally. The range of injuries and disorders have specific causes, medical signs and symptoms, diagnosis methods and treatments.

Cerebrospinal fluid leak (CSF leak)

A common disease associated with the crown includes the cerebrospinal fluid leak, which involves the excess removal of fluid within the meninges. The cerebrospinal fluid leak is mainly caused by a head, brain, or spinal injury which tears the meninges membrane. The excessive leakage of the cerebrospinal fluid leads to symptoms that include intense headaches often localised to the crown. An extreme sign of this disorder includes the leakage of fluid from the patient's ears and nose. The

of the cerebrospinal fluid leak is determined from examinations including a computerised tomography scan which involves an

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

image of parts of the skull including the crown.

Health professional A health professional, healthcare professional, or healthcare worker (sometimes abbreviated HCW) is a provider of health care treatment and advice based on formal training and experience. The field includes those who work as a nurse, physician (suc ...

s offer treatments to manage the symptoms associated with the disease. For example, consuming

fluid In physics, a fluid is a liquid, gas, or other material that continuously deforms (''flows'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear ...

s such as water aims to stop excess leakage and reduce headaches, and

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...

s are also provided if signs of

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable di ...

are clear such as

fever Fever, also referred to as pyrexia, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using val ...

and

chills Chills is a feeling of coldness occurring during a high fever, but sometimes is also a common symptom which occurs alone in specific people. It occurs during fever due to the release of cytokines and prostaglandins as part of the inflammatory ...

Meningioma

Meningioma is a cranial disorder and is characterised by tumor growth on the meninges, surrounding the blood vessels and nerves near the crown. The causes of the disorder include a rapid division of

cells Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

around the area. The patients that have meningioma develop signs and symptoms including

amnesia Amnesia is a deficit in memory caused by brain damage or disease,Gazzaniga, M., Ivry, R., & Mangun, G. (2009) Cognitive Neuroscience: The biology of the mind. New York: W.W. Norton & Company. but it can also be caused temporarily by the use ...

and

epileptic seizure An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with los ...

s. The direct impact to the frontal lobe of the brain causes symptoms such as weakness to the arms and

legs A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element c ...

. Diagnosis is made via imaging tests such as

magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio wave ...

(MRI) which involves high-frequency

radio wave Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz ( GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (sho ...

s and a strong

magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...

allowing for the measurement of

proton A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...

s in the water. The treatments involve

surgery Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pa ...

to remove the tumor from the patient's meninges and the extent of the surgery depends on the

size Size in general is the magnitude or dimensions of a thing. More specifically, ''geometrical size'' (or ''spatial size'') can refer to linear dimensions ( length, width, height, diameter, perimeter), area, or volume. Size can also be me ...

and aggression of the meningioma. Cleidocranial2

Fractures

Bone fracture A bone fracture (abbreviated FRX or Fx, Fx, or #) is a medical condition in which there is a partial or complete break in the continuity of any bone in the body. In more severe cases, the bone may be broken into several fragments, known as a '' ...

s to the crown of the head are linear or depressed and range in severity based on the impact to the skull. The linear fracture involves a break to the skull whereas the depressed fracture results in the scatter of skull fragments. The skull fractures are mainly caused by incidents involving a vehicle, assault, or a fall. In more severe cases, penetrating skull fractures are caused by an object such as a metal rod or bullet breaking through the skull completely. Based on the severity of the fracture, symptoms may include

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of th ...

, memory loss,

concussion A concussion, also known as a mild traumatic brain injury (mTBI), is a head injury that temporarily affects brain functioning. Symptoms may include loss of consciousness (LOC); memory loss; headaches; difficulty with thinking, concentration ...

bruise A bruise, also known as a contusion, is a type of hematoma of tissue, the most common cause being capillaries damaged by trauma, causing localized bleeding that extravasates into the surrounding interstitial tissues. Most bruises occur close ...

, and

lethargy Lethargy is a state of tiredness, sleepiness, weariness, fatigue, sluggishness or lack of energy. It can be accompanied by depression, decreased motivation, or apathy. Lethargy can be a normal response to inadequate sleep, overexertion, overwo ...

. Another symptom such as

bleeding Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...

results in the build-up of pressure in the skull since it is an enclosed cavity and thus pushes the brain to the

brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is ...

opening leading to a

coma A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. Coma patients exhi ...

. Diagnosis occurs due to a range of physical exams which identifies the extent of the injury and possible treatments. For example, the computerised tomography scan identifies the site of the fracture and any associated injuries to the brain, whereas magnetic resonance imaging highlights the damaged tissue. The treatments of severe skull fractures include surgery and

medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field and ...

to avoid infection, however, for linear fractures treatment involves rest for approximately 5 to 10 days, so that the crown can heal.

Gorham Disease

Gorham disease is a condition that targets the

human musculoskeletal system The human musculoskeletal system (also known as the human locomotor system, and previously the activity system) is an organ system that gives humans the ability to move using their muscular and skeletal systems. The musculoskeletal system prov ...

including the crown of the skull. The chronic disorder involves the progressive loss of bone, although, symptoms such as intense

pain Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...

are not evident during the initial stages. The cause of the Gorham disease has not been discovered, however, cells associated with the breakdown of fragile and old bones which include osteoclasts are considered to be the main link towards identifying the cause. The symptoms of the disease are clear after a fracture to the crown of the skull causing patients to experience abnormal deformities as well as issues to the nervous system. Diagnosis occurs through physical exams such as X-rays and magnetic resonance imaging which find the decrease in bone mass (

osteolysis Osteolysis is an active resorption of bone matrix by osteoclasts and can be interpreted as the reverse of ossification. Although osteoclasts are active during the natural formation of healthy bone the term "osteolysis" specifically refers to a pa ...

) and deformities. Treatment of the disease involves a range of techniques to prevent spread from the skull to the spine or chest of the patient.

Chemotherapy Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemother ...

and surgery, as well as lifestyle changes such as consuming a diet of high

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

, aim to minimise the severity of the disease.

Evolution

The macroevolution of the human species resulted in changes such as the increase in bone and muscle structures that support the crown of the head, compared to

primate Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians ( monkeys and apes, the latter includin ...

s. Modern human species have a cranial base which is more angled and a cranial vault that is rounded, compared to archaic human species. Modern human species have their

temporal lobe The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe is involved i ...

s positioned under the cranial base signifying the increase in the size of the human brain and skull. The sagittal vault's morphology, which is the area that joins the two parietal bones together to make up the structure of the crown, has remained the same for archaic and modern human species. The

cartilage Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck ...

embedded within the skull plays a major role in the changes of the crown. The cartilage evident within the cranium were an essential part in defending the central nervous system, however, over time the cartilage began to shape the crown by a process known as

endochondral ossification Endochondral ossification is one of the two essential processes during fetal development of the mammalian skeletal system by which bone tissue is produced. Unlike intramembranous ossification, the other process by which bone tissue is produced ...

. This process involves the replacement of grown cartilage with bone to develop the bone structure of the skull.

References

External links

Visible Interactive human
(

Ohio University Ohio University is a public research university in Athens, Ohio. The first university chartered by an Act of Congress and the first to be chartered in Ohio, the university was chartered in 1787 by the Congress of the Confederation and subse ...

Heritage College of Osteopathic Medicine)
Head Injury
(

Columbia university Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...

department of neurology) {{DEFAULTSORT:Crown (Anatomy) Bird anatomy Human head and neck