How many bones is the human skull formed of?

Answer 1

In humans, the adult skull is normally made up of 29 bones.
***Eight bones form the neurocranium (braincase), a protective vault of bone surrounding the brain and medulla oblongata.
***Fourteen bones form the splanchnocranium, the bones supporting the face.
***six ear ossicles of the middle ear encased within the temporal bones.
***The hyoid bone, supporting the larynx,houghit is usually not considered as part of the skull.

Answer 2

In humans, the adult skull is normally made up of 29 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, semi-rigid articulations formed by bony ossification, the presence of Sharpey's fibres permitting a little flexibility.

Eight bones form the neurocranium (braincase), a protective vault of bone surrounding the brain and brain stem medulla oblongata. Fourteen bones form the splanchnocranium (facial bones), the bones supporting the face. Encased within the temporal bones are the six ear or auditory ossicles of the middle ear. The hyoid bone, supporting the larynx, is usually not considered as part of the skull, as it is the only bone that does not articulate with any other bones.

The skull also contains the sinus cavities, which are air-filled cavities lined with respiratory epithelium, which also lines the large airways. The exact functions of the sinuses are debatable; they contribute to lessening the weight of the skull with a minimal reduction in strength, they contribute to resonance of the voice, and assist in the warming and moistening of air drawn in through the nasal cavities. In some animals, such as the elephant, the sinuses are extensive. The elephant skull needs to be very large, to form an attachment for muscles of the neck and trunk, but is also unexpectedly light; the comparatively small brain-case is surrounded by large sinuses which reduce the weight.

The meninges are three layers of connective tissue, or membranes, which surround the structures of the central nervous system. They are known as the dura mater (outermost), the arachnoid mater (middle) and the pia mater (innermost). Each layer adds important protection functions.

In humans, the anatomical position for the skull is the Frankfurt plane, where the lower margins of the orbits and the upper borders of the ear canals are all in a horizontal plane, or anatomical position. This is the position where the subject is standing and looking directly forward. For comparison, the skulls of other species, notably primates and hominids, may sometimes be studied in the Frankfurt plane. However, this does not always equate to a natural posture in life.

Answer 3

In humans, the adult skull is normally made up of 29 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, semi-rigid articulations formed by bony ossification, the presence of Sharpey's fibres permitting a little flexibility.
Eight bones form the neurocranium (braincase), a protective vault of bone surrounding the brain and brain stem medulla oblongata. Fourteen bones form the splanchnocranium (facial bones), the bones supporting the face. Encased within the temporal bones are the six ear or auditory ossicles of the middle ear. The hyoid bone, supporting the larynx, is usually not considered as part of the skull, as it is the only bone that does not articulate with any other bones

Answer 4

In humans, the adult skull is normally made up of 29 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, semi-rigid articulations formed by bony ossification, the presence of Sharpey's fibres permitting a little flexibility.

Answer 5

22

Answer 6

the skull is formed of 24 bones

Answer 7

29

Answer 8

skull consists of 22 bones. brain case composed of -2 paired and 4 unpaired bones i.e.8 and facial skeleton is composed of 14 bones.

Answer 9

Human skull (front)
Human skull (side)In humans, the adult skull is normally made up of 29 bones. Except for the mandible, all of the bones of the skull are joined together by sutures, semi-rigid articulations formed by bony ossification, the presence of Sharpey's fibres permitting a little flexibility.

Eight bones form the neurocranium (braincase), a protective vault of bone surrounding the brain and brain stem medulla oblongata. Fourteen bones form the splanchnocranium (facial bones), the bones supporting the face. Encased within the temporal bones are the six ear or auditory ossicles of the middle ear. The hyoid bone, supporting the larynx, is usually not considered as part of the skull, as it is the only bone that does not articulate with any other bones.

The skull also contains the sinus cavities, which are air-filled cavities lined with respiratory epithelium, which also lines the large airways. The exact functions of the sinuses are debatable; they contribute to lessening the weight of the skull with a minimal reduction in strength, they contribute to resonance of the voice, and assist in the warming and moistening of air drawn in through the nasal cavities. In some animals, such as the elephant, the sinuses are extensive. The elephant skull needs to be very large, to form an attachment for muscles of the neck and trunk, but is also unexpectedly light; the comparatively small brain-case is surrounded by large sinuses which reduce the weight.

The meninges are three layers of connective tissue, or membranes, which surround the structures of the central nervous system. They are known as the dura mater (outermost), the arachnoid mater (middle) and the pia mater (innermost). Each layer adds important protection functions.

In humans, the anatomical position for the skull is the Frankfurt plane, where the lower margins of the orbits and the upper borders of the ear canals are all in a horizontal plane, or anatomical position. This is the position where the subject is standing and looking directly forward. For comparison, the skulls of other species, notably primates and hominids, may sometimes be studied in the Frankfurt plane. However, this does not always equate to a natural posture in life.

Contents [hide]
1 Development of the skull
2 Pathology
3 Craniometry and morphology of human skulls
3.1 Sexual dimorphism
3.2 Ancestry
4 See also
5 External links



[edit]
Development of the skull
The skull is a complex structure; its bones are formed both by intramembranous and endochondral ossification. The bones of the splanchnocranium (face) and the sides and roof of the neurocranium are formed by intramembranous (or dermal) ossification, while the bones supporting the brain (the occipital, sphenoid, temporal, and ethmoid) are largely formed by endochondral ossification.

At birth, the human skull is made up of 45 separate bony elements. As growth occurs, many of these bony elements gradually fuse together into solid bone (for example, the frontal bone). The bones of the roof of the skull are initially separated by regions of dense connective tissue called "cranial sutures". There are five sutures: the frontal suture, sagittal suture, lambdoid suture, coronal suture, and squamosal suture. At birth these regions are fibrous and moveable, necessary for birth and later growth. This growth can put 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 of Galen. Larger regions of connective tissue where multiple sutures meet are called fontanelles. The six fontanelles are: the anterior fontanelle, the posterior fontanelle, the two sphenoid fontanelles, and the two mastoid fontanelles. As growth and ossification progress, the connective tissue of the fontanelles is invaded and replaced by bone. The posterior fontanelle usually closes by eight weeks, but the anterior fontanelle 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 his or her pulse pulsing softly through the anterior fontanelle.

[edit]
Pathology
If the brain is bruised or injured it can be life-threatening. Normally the skull protects the brain from damage through its hard unyieldingness, but in some cases of head injury, 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 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.

Dating back to Neolithic times, a skull operation called trepanation was sometimes performed. This involved drilling holes in the cranium. Examination of skulls from this period reveals that the "patients" sometimes survived for many years afterward. It seems likely that trepanation was performed for ritualistic or religious reasons and not only as an attempted life-saving technique.


An image of a skull by Leonardo da Vinci[edit]
Craniometry and morphology of human skulls
Like the face of a living individual, a human skull and teeth can also tell, to a certain degree, the life history and origin of its owner. Forensic scientists and archaeologists use metric and nonmetric traits to estimate what the bearer of the skull looked like. When a significant amount of bones is found, such as at Spitalfields in the UK and Jomon shell mounds in Japan, osteologists can use traits, such as proportions of length, height, width, to know the relationships of population of the study, with 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. This theory is now considered to be obsolete.

The practice of craniometry has occasionally purported to reliably demonstrate racial or ethnic differences between skulls of different people. Occasionally this has been used as justification for ideas of racial supremacy. However, this theory is again obsolete.

Answer 10

1. E and 2. B