Introduction:
The skull is composed of 22 separate bones, most of them paired. It can be divided into a robust calvarium that surrounds and protects the brain, and a delicate facial skeleton composed mainly of thin walled bones, some of which contain air-filled cavities known collectively as the para-nasal sinuses. The cranial cavity contains the brain and the intracranial portions of the cranial and spinal nerves; the blood vessels that supply and drain the brain and the haemopoietic marrow of the overlying bones; the meninges (dura, arachnoid and pia mater) and the cerebrospinal fluid. The cavity is incompletely divided by dural partitions, notably the falx cerebri, lying between the cerebral hemispheres, and the tentorium cerebelli, lying between the cerebellum and occipital lobes. Almost all of the venous blood from the brain and cranial bones drains via sinuses lying between the endosteal and meningeal layers of the dura mater into the internal jugular vein. Internally, the cranial base is divided into anterior, middle and posterior cranial fossae, which contain the frontal and temporal lobes of the cerebral hemispheres and the cerebellum respectively.
Skull definition:
The skull is the bony skeleton of the head. It shields the brain, the organs of special sense and the cranial parts of the respiratory and digestive systems, and provides attachments for many of the muscles of the head and neck.
Movement of the lower jaw (mandible) occurs at the temporo-mandibular joint. The skull without the mandible is called the cranium.
Bones of the head:
The skull is the most complex osseous structure in the body. Most of the vault bones are fl at, and consist of two tables or plates of compact bone enclosing a narrow layer of relatively dense cancellous marrow (diploic bone). The marrow within the skull bones is a site of haemopoiesis, at least in the young individual. These bones form by intramembranous ossification of a highly vascular connective tissue membrane and have often been referred to as ‘dermal’ in deference to their alleged ancient phylogenetic origin. We are full discussion about skull bone given bellow.
Skull types:
The skull is subdivided into the neurocranium and viscerocranium. The neurocranium protects the brain, while the viscerocranium houses and protects the facial regions. Do you know how many cranial bones are there? There are 8 cranial bones and 14 facial bones. That’s given bellow.
Neurocranium: The cranial bones or neurocranium are given bellow.
- Ethmoid bone (cribriform plate)
- Frontal bone
- Occipital bone
- Parietal bone (2)
- Sphenoid bone
- Temporal bone (petrous and squamous parts).
Viscerocranium: Bones of the face or viscerocranium are given bellow.
- Inferior nasal concha (2)
- Lacrimal bone (2)
- Mandible
- Maxilla (2)
- Nasal bone (2)
- Palatine bone (2)
- Sphenoid bone (pterygoid process)
- Temporal bone (2)
- Vomer
Most of the ethmoid bone is in the viscerocranium, most of the sphenoid bone is in the neurocranium.
How many bones are in the skull?
The parts of the skull are generally Twenty two bones. The name of the skull bones are given bellow-
- Frontal Bone: The Frontal bone forming the forehead and top of the eye sockets and articulating especially with the parietal Read more