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75-520: Turano-Mongolian cattle are morphologically distinct from the European taurine cattle especially in the shape of their skull and their horns . The skull is wedge-shaped and has a narrow crown and a depression on the frontal bone . The horns grow upwards instead of forwards. Genetically the difference can be seen in the mtDNA haplogroups . Of the five mtDNA haplogroups (T, T1, T2, T3, T4) found in existing taurine cattle breeds, T2, T3 and T4 appear in

150-434: A maxillary process and a mandibular process , giving rise to structures including the bones of the lower two-thirds of the face and the jaw. The maxillary process becomes the maxilla (or upper jaw , although there are large differences among animals ), and palate while the mandibular process becomes the mandible or lower jaw . This arch also gives rise to the muscles of mastication . Meckel's cartilage forms in

225-994: A cranial capacity about 10 percent less than that of the male. However, later studies show that women's skulls are slightly thicker and thus men may be more susceptible to head injury than women. However, other studies shows that men's skulls are slightly thicker in certain areas. Some studies show that females are more susceptible to concussion than males. Men's skulls have also been shown to maintain density with age, which may aid in preventing head injury, while women's skull density slightly decreases with age. Male skulls can all have more prominent supraorbital ridges , glabella , and temporal lines . Female skulls generally have rounder orbits and narrower jaws. Male skulls on average have larger, broader palates , squarer orbits, larger mastoid processes , larger sinuses , and larger occipital condyles than those of females. Male mandibles typically have squarer chins and thicker, rougher muscle attachments than female mandibles. The cephalic index

300-569: A great hardiness and tolerance towards freezing temperatures as a result of adaption to harsh Asian climates . Especially the breeds of the Asian steppe and the Tibetan plateau are able to withstand temperature fluctuations from –50  °C to 35 °C (–60  °F to 95 °F). A singular adaption is shown by the Yakutian cattle of northern Siberia , whose center of breeding lies close to

375-509: A large amount of tension on the "obstetrical hinge", which is where the squamous and lateral parts of the occipital bone meet. A possible complication of this tension is rupture of the great cerebral vein . As growth and ossification progress, the connective tissue of the fontanelles is invaded and replaced by bone creating sutures . The five sutures are the two squamous sutures , one coronal , one lambdoid , and one sagittal suture . The posterior fontanelle usually closes by eight weeks, but

450-406: A remnant, the ligamentum arteriosum . During growth, these arteries descend into their ultimate positions in the chest, creating the elongated recurrent paths. Left 4th aortic arch: aortic arch Left 5th aortic arch: pulmonary artery and ductus arteriosus It has been proposed that the arches be re-named simply as 1–5. The argument is the existence of the fifth arch (and pouch), held to be

525-458: A second set of jaws in their throat, known as pharyngeal jaws , which develop using the same genetic pathways involved in oral jaw formation. During embryonic development , a series of pharyngeal arch pairs form. These project forward from the back of the embryo toward the front of the face and neck. Each arch develops its own artery, nerve that controls a distinct muscle group, and skeletal tissue. The arches are numbered from 1 to 6, with 1 being

600-403: A series of only loosely connected bones. Lampreys and sharks only possess a cartilaginous endocranium, with both the upper jaw and the lower jaws being separate elements. Bony fishes have additional dermal bone , forming a more or less coherent skull roof in lungfish and holost fish. The lower jaw defines the chin. The simpler structure is found in jawless fish , in which the cranium

675-444: Is a phenomenon wherein intense intracranial pressure disfigures the internal surface of the skull. The name comes from the fact that the inner skull has the appearance of having been beaten with a ball-peen hammer , such as is often used by coppersmiths . The condition is most common in children. Injuries to the brain can be life-threatening. Normally the skull protects the brain from damage through its high resistance to deformation;

750-405: Is no space for the brain to expand; this can result in significant brain damage or death unless an urgent operation is performed to relieve the pressure. This is why patients with concussion must be watched extremely carefully. Repeated concussions can activate the structure of skull bones as the brain's protective covering. Dating back to Neolithic times, a skull operation called trepanning

825-414: Is normally represented by a trough-like basket of cartilaginous elements only partially enclosing the brain, and associated with the capsules for the inner ears and the single nostril. Distinctively, these fish have no jaws. Cartilaginous fish , such as sharks and rays, have also simple, and presumably primitive, skull structures. The cranium is a single structure forming a case around the brain, enclosing

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900-423: Is one seventh of the size of the calvaria . (In the adult it is half the size). The base of the skull is short and narrow, though the inner ear is almost adult size. Craniosynostosis is a condition in which one or more of the fibrous sutures in an infant skull prematurely fuses, and changes the growth pattern of the skull. Because the skull cannot expand perpendicular to the fused suture, it grows more in

975-440: Is seen to be a transient structure and becomes the sixth arch, (the fifth being absent). More is known about the fate of the first arch than the remaining four. The first three contribute to structures above the larynx, whereas the last two contribute to the larynx and trachea . The recurrent laryngeal nerves are produced from the nerve of arch 5, and the laryngeal cartilages from arches 4 and 5. The superior laryngeal branch of

1050-452: Is the bone structure that forms the head in the human skeleton . It supports the structures of the face and forms a cavity for the brain . Like the skulls of other vertebrates, it protects the brain from injury. The skull consists of three parts, of different embryological origin—the neurocranium , the sutures , and the facial skeleton . The neurocranium (or braincase ) forms the protective cranial cavity that surrounds and houses

1125-450: Is the pre-trematic nerve. This double innervation is reflected in the nerve supply of anterior two-thirds of tongue which is derived from the first arch. The artery of the first arch is the first aortic arch , which partially persists as the maxillary artery . The second pharyngeal arch or hyoid arch , is the second of fifth pharyngeal arches that develops in fetal life during the fourth week of development and assists in forming

1200-431: Is the ratio of the width of the head, multiplied by 100 and divided by its length (front to back). The index is also used to categorize animals, especially dogs and cats. The width is usually measured just below the parietal eminence , and the length from the glabella to the occipital point. Humans may be: The vertical cephalic index refers to the ratio between the height of the head multiplied by 100 and divided by

1275-457: The Bos taurus turano-mongolicus group. They have previously also been classified as a distinct subspecies and even as a distinct species . The invalid scientific names resulting from these classifications are: (not necessarily comprehensive) Skull The skull , or cranium , is typically a bony enclosure around the brain of a vertebrate . In some fish , and amphibians ,

1350-430: The chicken . Although there are six pharyngeal arches, in humans the fifth arch exists only transiently during embryogenesis . The first pharyngeal arch , also mandibular arch (corresponding to the first branchial arch of fish), is the first of six pharyngeal arches that develops during the fourth week of development . It is located between the stomodeum and the first pharyngeal groove . This arch divides into

1425-432: The eyes , ears , nose , tongue and in fish specialized tactile organs such as barbels near the mouth. The skull is composed of three types of bone : cranial bones, facial bones and ossicles , which is made up of a number of fused flat and irregular bones . The cranial bones are joined at firm fibrous junctions called sutures and contains many foramina , fossae , processes , and sinuses . In zoology ,

1500-403: The facial skeleton (14) are the vomer , two inferior nasal conchae , two nasal bones , two maxilla , the mandible, two palatine bones , two zygomatic bones , and two lacrimal bones . Some sources count a paired bone as one, or the maxilla as having two bones (as its parts); some sources include the hyoid bone or the three ossicles of the middle ear , the malleus, incus, and stapes, but

1575-738: The facial skeleton and splanchnocranium with the mandible being its largest bone. The mandible articulates with the temporal bones of the neurocranium at the paired temporomandibular joints . The skull itself articulates with the spinal column at the atlanto-occipital joint . Functions of the skull include physical protection for the brain, providing attachments for neck muscles , facial muscles and muscles of mastication , providing fixed eye sockets and outer ears ( ear canals and auricles ) to enable stereoscopic vision and sound localisation , forming nasal and oral cavities that allow better olfaction , taste and digestion , and contributing to phonation by acoustic resonance within

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1650-405: The frontal bone ). The bones of the roof of the skull are initially separated by regions of dense connective tissue called fontanelles . There are six fontanelles: one anterior (or frontal), one posterior (or occipital), two sphenoid (or anterolateral), and two mastoid (or posterolateral). At birth, these regions are fibrous and moveable, necessary for birth and later growth. This growth can put

1725-536: The human embryo , the arches are first seen during the fourth week of development . They appear as a series of outpouchings of mesoderm on both sides of the developing pharynx . The vasculature of the pharyngeal arches are the aortic arches that arise from the aortic sac . In humans and other vertebrates , the pharyngeal arches are derived from all three germ layers (the primary layers of cells that form during embryonic development ). Neural crest cells enter these arches where they contribute to features of

1800-449: The mesoderm of the mandibular process and eventually regresses to form the incus and malleus of the middle ear , the anterior ligament of the malleus and the sphenomandibular ligament . The mandible or lower jaw forms by perichondral ossification using Meckel's cartilage as a 'template', but the maxillary does not arise from direct ossification of Meckel's cartilage. The skeletal elements and muscles are derived from mesoderm of

1875-440: The public domain from page 128 of the 20th edition of Gray's Anatomy (1918) First pharyngeal arch The pharyngeal arches , also known as visceral arches , are transient structures seen in the embryonic development of humans and other vertebrates , that are recognisable precursors for many structures. In fish , the arches support the gills and are known as the branchial arches , or gill arches. In

1950-425: The skull and facial skeleton such as bone and cartilage. However, the existence of pharyngeal structures before neural crest cells evolved is indicated by the existence of neural crest-independent mechanisms of pharyngeal arch development. The first, most anterior pharyngeal arch gives rise to the mandible . The second arch becomes the hyoid and jaw support. In fish, the other posterior arches contribute to

2025-421: The skull base and its fossae , the anterior , middle and posterior cranial fossae changes rapidly. The anterior cranial fossa changes especially during the first trimester of pregnancy and skull defects can often develop during this time. At birth, the human skull is made up of 44 separate bony elements. During development, many of these bony elements gradually fuse together into solid bone (for example,

2100-472: The stapes of the middle ear before being incorporated into the middle ear cavity, while the ventral portion ossifies to form the lesser cornu and upper part of the body of the hyoid bone . Caudal to what will eventually become the stapes , Reichert's cartilage also forms the styloid process of the temporal bone . The cartilage between the hyoid bone and styloid process will not remain as development continues, but its perichondrium will eventually form

2175-401: The stylohyoid muscle, the auricular muscle and the stapedius muscle of the middle ear. There is only one muscle of the third pharyngeal arch, the stylopharyngeus . The stylopharyngeus and other structures from the third pharyngeal arch are all innervated by the glossopharyngeal nerve . All the pharyngeal muscles of the fourth and sixth arches are innervated by the superior laryngeal and

2250-485: The stylohyoid ligament . Skeletal From the cartilage of the second arch arises Muscles Facial nerve (CN VII) The artery of the second arch is the second aortic arch , which gives origin to the stapedial artery in some mammals but atrophies in most humans. Pharyngeal muscles or Branchial muscles are striated muscles of the head and neck. Unlike skeletal muscles that developmentally come from somites , pharyngeal muscles are developmentally formed from

2325-404: The zygomatic processes . The fenestrae (from Latin, meaning windows ) are openings in the skull. The jugal is a skull bone that found in most of the reptiles, amphibians and birds. In mammals, the jugal is often called the zygomatic bone or malar bone. The prefrontal bone is a bone that separates the lacrimal and frontal bones in many tetrapod skulls. The skull of fish is formed from

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2400-552: The Central plain and Southern varieties of Chinese Yellow cattle , while showing pure taurine phenotypes , have in prehistorical and historical times been influenced by an admixture of zebu cattle . Only a very few breeds of Turano-Mongolian cattle, as for example the Yakutian cattle, can still be called purebred. Turano-Mongolian cattle are a subgroup of domestic cattle, Bos primigenius forma taurus , and as such often called

2475-695: The Turano-Mongolian group. T4 is unique to the breeds of this group. T is found in both Near Eastern and European breeds, while T1 appears only in African and (at lower frequencies) in Near Eastern breeds. T2 is found in all three Eurasian regions, though only at low frequencies in European and Turano-Mongolian breeds. Finally T3 is common to all Eurasian regions, but found only in very low numbers in Africa. Many breeds of Turano-Mongolian cattle show

2550-630: The U.S., researchers replaced a large percentage of a patient's skull with a precision, 3D-printed polymer implant . About 9 months later, the first complete cranium replacement with a 3D-printed plastic insert was performed on a Dutch woman. She had been suffering from hyperostosis , which increased the thickness of her skull and compressed her brain. A study conducted in 2018 by the researchers of Harvard Medical School in Boston, funded by National Institutes of Health (NIH), suggested that instead of travelling via blood , there are "tiny channels" in

2625-428: The anterior fontanel can remain open up to eighteen months. The anterior fontanelle is located at the junction of the frontal and parietal bones; it is a "soft spot" on a baby's forehead. Careful observation will show that you can count a baby's heart rate by observing the pulse pulsing softly through the anterior fontanelle. The skull in the neonate is large in proportion to other parts of the body. The facial skeleton

2700-433: The arch closest to the head of the embryo, and arch 5 existing only transiently. These grow and join in the ventral midline. The first arch, as the first to form, separates the mouth pit or stomodeum from the pericardium . By differential growth the neck elongates and new arches form, so the pharynx has six arches ultimately. Each pharyngeal arch has a cartilaginous stick, a muscle component that differentiates from

2775-444: The arch itself runs along the cranial side of the arch and is called post-trematic nerve of the arch. Each arch also receives a branch from the nerve of the succeeding arch called the pre-trematic nerve which runs along the caudal border of the arch. In human embryo, a double innervation is seen only in the first pharyngeal arch. The mandibular nerve is the post-trematic nerve of the first arch and chorda tympani (branch of facial nerve)

2850-466: The bones either absent or wholly or partly replaced by cartilage. In mammals and birds, in particular, modifications of the skull occurred to allow for the expansion of the brain. The fusion between the various bones is especially notable in birds, in which the individual structures may be difficult to identify. The skull is a complex structure; its bones are formed both by intramembranous and endochondral ossification . The skull roof bones, comprising

2925-416: The bones of the facial skeleton and the sides and roof of the neurocranium, are dermal bones formed by intramembranous ossification, though the temporal bones are formed by endochondral ossification. The endocranium , the bones supporting the brain (the occipital, sphenoid , and ethmoid ) are largely formed by endochondral ossification. Thus frontal and parietal bones are purely membranous. The geometry of

3000-462: The brain and brainstem . The upper areas of the cranial bones form the calvaria (skullcap). The facial skeleton (membranous viscerocranium) is formed by the bones supporting the face, and includes the mandible . The bones of the skull are joined by fibrous joints known as sutures— synarthrodial (immovable) joints formed by bony ossification , with Sharpey's fibres permitting some flexibility. Sometimes there can be extra bone pieces within

3075-438: The branchial skeleton, which support the gills; in tetrapods the anterior arches develop into components of the ear, tonsils, and thymus. The genetic and developmental basis of pharyngeal arch development is well characterized. It has been shown that Hox genes and other developmental genes such as DLX are important for patterning the anterior/posterior and dorsal/ventral axes of the branchial arches . Some fish species have

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3150-421: The cartilaginous tissue, an artery, and a cranial nerve . Each of these is surrounded by mesenchyme . Arches do not develop simultaneously but instead possess a "staggered" development. Pharyngeal pouches form on the endodermal side between the arches, and pharyngeal grooves (or clefts) form from the lateral ectodermal surface of the neck region to separate the arches. In fish, the pouches line up with

3225-566: The cavities and sinuses. In some animals such as ungulates and elephants , the skull also has a function in anti-predator defense and sexual selection by providing the foundation for horns , antlers and tusks . The English word skull is probably derived from Old Norse skulle , while the Latin word cranium comes from the Greek root κρανίον ( kranion ). The human skull fully develops two years after birth. The human skull

3300-443: The clefts, and these thin segments become gills . In mammals the endoderm and ectoderm not only remain intact but also continue to be separated by a mesoderm layer. The development of the pharyngeal arches provides a useful landmark with which to establish the precise stage of embryonic development. Their formation and development corresponds to Carnegie stages 10 to 16 in mammals , and Hamburger–Hamilton stages 14 to 28 in

3375-438: The desired sex. These procedures can be an important part of the treatment of transgender people for gender dysphoria . Artificial cranial deformation is a largely historical practice of some cultures. Cords and wooden boards would be used to apply pressure to an infant's skull and alter its shape, sometimes quite significantly. This procedure would begin just after birth and would be carried on for several years. Like

3450-531: The face, the skull and teeth can also indicate a person's life history and origin. Forensic scientists and archaeologists use quantitative and qualitative traits to estimate what the bearer of the skull looked like. When a significant amount of bones are found, such as at Spitalfields in the UK and Jōmon shell mounds in Japan, osteologists can use traits, such as the proportions of length, height and width, to know

3525-418: The foramen magnum lies immediately above a single condyle , articulating with the first vertebra . There are, in addition, at various points throughout the cranium, smaller foramina for the cranial nerves. The jaws consist of separate hoops of cartilage, almost always distinct from the cranium proper. In ray-finned fish , there has also been considerable modification from the primitive pattern. The roof of

3600-438: The frontal (top of head), parietal (back of head), premaxillary and nasal (top beak), and the mandible (bottom beak). The skull of a normal bird usually weighs about 1% of the bird's total bodyweight. The eye occupies a considerable amount of the skull and is surrounded by a sclerotic eye-ring, a ring of tiny bones. This characteristic is also seen in reptiles. Living amphibians typically have greatly reduced skulls, with many of

3675-484: The length of the head. Humans may be: Trepanning , a practice in which a hole is created in the skull, has been described as the oldest surgical procedure for which there is archaeological evidence, found in the forms of cave paintings and human remains. At one burial site in France dated to 6500 BCE, 40 out of 120 prehistoric skulls found had trepanation holes. [REDACTED] This article incorporates text in

3750-418: The lessening of the weight of the skull, the aiding of resonance to the voice and the warming and moistening of the air drawn into the nasal cavity . The foramina are openings in the skull. The largest of these is the foramen magnum , of the occipital bone, that allows the passage of the spinal cord as well as nerves and blood vessels . The many processes of the skull include the mastoid process and

3825-453: The lower jaw is composed of multiple bones, only the most anterior of which (the dentary) is homologous with the mammalian mandible. In living tetrapods, a great many of the original bones have either disappeared or fused into one another in various arrangements. Birds have a diapsid skull, as in reptiles, with a prelacrimal fossa (present in some reptiles). The skull has a single occipital condyle. The skull consists of five major bones:

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3900-406: The lower surface and the sides, but always at least partially open at the top as a large fontanelle . The most anterior part of the cranium includes a forward plate of cartilage, the rostrum , and capsules to enclose the olfactory organs. Behind these are the orbits, and then an additional pair of capsules enclosing the structure of the inner ear . Finally, the skull tapers towards the rear, where

3975-410: The mandibular divisions of the trigeminal nerve . These muscles include all the muscles of mastication , the anterior belly of the digastric , the mylohyoid , tensor tympani , and tensor veli palatini . All of the pharyngeal muscles of the second pharyngeal arch are innervated by the facial nerve . These muscles include the muscles of facial expression , the posterior belly of the digastric ,

4050-441: The mid-nineteenth century, anthropologists found it crucial to distinguish between male and female skulls. An anthropologist of the time, James McGrigor Allan , argued that the female brain was similar to that of an animal. This allowed anthropologists to declare that women were in fact more emotional and less rational than men. McGrigor then concluded that women's brains were more analogous to infants, thus deeming them inferior at

4125-505: The northern pole of cold (see climate data ). A number of traits, such as a thick winter coat , a small, fur-covered udder resp. scrotum , efficient thermoregulation , and low metabolic rates at low temperatures, lead to their extreme tolerance towards freezing temperatures. A compelling example of this is the case of several cows which survived on their own in the taiga forest for three months in late 2011 in deep snows and temperatures reaching as low as –40 °C (–40 °F). In

4200-401: The openings in the skull are called fenestrae , the most prominent of which is the foramen magnum , where the brainstem goes through to join the spinal cord . In human anatomy , the neurocranium (or braincase), is further divided into the calvarium and the endocranium , together forming a cranial cavity that houses the brain. The interior periosteum forms part of the dura mater ,

4275-442: The overall general consensus of the number of bones in the human skull is the stated twenty-two. Some of these bones—the occipital, parietal, frontal, in the neurocranium, and the nasal, lacrimal, and vomer, in the facial skeleton are flat bones . The skull also contains sinuses , air-filled cavities known as paranasal sinuses , and numerous foramina . The sinuses are lined with respiratory epithelium . Their known functions are

4350-493: The parallel direction. Sometimes the resulting growth pattern provides the necessary space for the growing brain, but results in an abnormal head shape and abnormal facial features. In cases in which the compensation does not effectively provide enough space for the growing brain, craniosynostosis results in increased intracranial pressure leading possibly to visual impairment, sleeping impairment, eating difficulties, or an impairment of mental development. A copper beaten skull

4425-428: The pharyngeal arches. Skeletal Muscles Other Mucous membrane and glands of the anterior two thirds of the tongue are derived from ectoderm and endoderm of the arch. The mandibular and maxillary branches of the trigeminal nerve ( CN V ) innervate the structures derived from the corresponding processes of the first arch. In some lower animals, each arch is supplied by two cranial nerves. The nerve of

4500-400: The pharyngeal arches. Most of the skeletal musculature supplied by the cranial nerves ( special visceral efferent ) is pharyngeal. Exceptions include, but are not limited to, the extraocular muscles and some of the muscles of the tongue. These exceptions receive general somatic efferent innervation. All of the pharyngeal muscles that come from the first pharyngeal arch are innervated by

4575-461: The recurrent laryngeal branches of the vagus nerve . These muscles include all the muscles of the palate (exception of the tensor veli palatini which is innervated by the trigeminal nerve ), all the muscles of the pharynx (except stylopharyngeus which is innervated by the glossopharyngeal nerve ), and all the muscles of the larynx. It has been proposed that the five arches in amniotes numbered 1–4 and 6, be re-named as simply 1–5. The fifth arch

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4650-399: The relationships of the population of the study with other living or extinct populations. The German physician Franz Joseph Gall in around 1800 formulated the theory of phrenology , which attempted to show that specific features of the skull are associated with certain personality traits or intellectual capabilities of its owner. His theory is now considered to be pseudoscientific . In

4725-526: The side and front of the neck . Cartilage in the second pharyngeal arch is referred to as Reichert's cartilage and contributes to many structures in the fully developed adult. In contrast to the Meckel's cartilage of the first pharyngeal arch it does not constitute a continuous element, and instead is composed of two distinct cartilaginous segments joined by a faint layer of mesenchyme . Dorsal ends of Reichert's cartilage ossify during development to form

4800-474: The skull is formed from cartilage , and its overall structure is reduced. The skulls of the earliest tetrapods closely resembled those of their ancestors amongst the lobe-finned fishes . The skull roof is formed of a series of plate-like bones, including the maxilla, frontals , parietals , and lacrimals , among others. It is overlaying the endocranium , corresponding to the cartilaginous skull in sharks and rays . The various separate bones that compose

4875-455: The skull is generally well formed, and although the exact relationship of its bones to those of tetrapods is unclear, they are usually given similar names for convenience. Other elements of the skull, however, may be reduced; there is little cheek region behind the enlarged orbits, and little, if any bone in between them. The upper jaw is often formed largely from the premaxilla , with the maxilla itself located further back, and an additional bone,

4950-423: The skull is of cartilage . The skull is at the head end of the vertebrate. In the human the skull comprises two prominent parts: the neurocranium , and the facial skeleton . which evolved from the first pharyngeal arch . The skull forms the frontmost portion of the axial skeleton and is a product of cephalization and vesicular enlargement of the brain, with several special senses structures such as

5025-409: The skull is one of the least deformable structures found in nature, needing the force of about 1 ton to reduce its diameter by 1 cm. In some cases of head injury , however, there can be raised intracranial pressure through mechanisms such as a subdural haematoma . In these cases, the raised intracranial pressure can cause herniation of the brain out of the foramen magnum ("coning") because there

5100-459: The skull through which the immune cells combined with the bone marrow reach the areas of inflammation after an injury to the brain tissues. Surgical alteration of sexually dimorphic skull features may be carried out as a part of facial feminization surgery or facial masculinization surgery , these reconstructive surgical procedures that can alter sexually dimorphic facial features to bring them closer in shape and size to facial features of

5175-404: The suture known as Wormian bones or sutural bones . Most commonly these are found in the course of the lambdoid suture . The human skull is generally considered to consist of 22 bones—eight cranial bones and fourteen facial skeleton bones. In the neurocranium these are the occipital bone , two temporal bones , two parietal bones , the sphenoid , ethmoid and frontal bones . The bones of

5250-457: The symplectic, linking the jaw to the rest of the cranium. Although the skulls of fossil lobe-finned fish resemble those of the early tetrapods, the same cannot be said of those of the living lungfishes . The skull roof is not fully formed, and consists of multiple, somewhat irregularly shaped bones with no direct relationship to those of tetrapods. The upper jaw is formed from the pterygoids and vomers alone, all of which bear teeth. Much of

5325-413: The temporal bone of humans are also part of the skull roof series. A further plate composed of four pairs of bones forms the roof of the mouth; these include the vomer and palatine bones . The base of the cranium is formed from a ring of bones surrounding the foramen magnum and a median bone lying further forward; these are homologous with the occipital bone and parts of the sphenoid in mammals. Finally,

5400-554: The time. To further these claims of female inferiority and silence the feminists of the time, other anthropologists joined in on the studies of the female skull. These cranial measurements are the basis of what is known as craniology . These cranial measurements were also used to draw a connection between women and black people. Research has shown that while in early life there is little difference between male and female skulls, in adulthood male skulls tend to be larger and more robust than female skulls, which are lighter and smaller, with

5475-404: The vagus nerve arises from arch 4. Its arteries, which project between the nerves of the fourth and fifth arches, become the left-side arch of the aorta and the right subclavian artery . On the right side, the artery of arch 5 is obliterated while, on the left side, the artery persists as the ductus arteriosus ; circulatory changes immediately following birth cause the vessel to close down, leaving

5550-701: The wake of modernization and specialization in animal husbandry, many Turano-Mongolian breeds have been replaced either outright or through extensive crossbreeding by modern international breeds and become extinct. Thus, for example, of the Siberian breeds only the Yakutian cattle remain, and at that only in very small numbers. Others, like Japanese Black and the Kazakh Whiteheaded , have been diluted by crossbreeding with international breeds to varying degrees and often are threatened by further crossbreeding. Many southern Turano-Mongolian breeds, especially

5625-400: Was sometimes performed. This involved drilling a burr hole in the cranium. Examination of skulls from this period reveals that the patients sometimes survived for many years afterward. It seems likely that trepanning was also performed purely for ritualistic or religious reasons. Nowadays this procedure is still used but is normally called a craniectomy . In March 2013, for the first time in

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