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External and internal views of base of skull

This image shows the superior and inferior view of the skull base. In the top panel, the inferior view is shown. A small image of the skull shows the viewing direction on the left. In the inferior view, the maxilla and the associated bones are shown. In the bottom panel, the superior view shows the ethmoid and sphenoid bones and their subparts.
(a) The hard palate is formed anteriorly by the palatine processes of the maxilla bones and posteriorly by the horizontal plate of the palatine bones. (b) The complex floor of the cranial cavity is formed by the frontal, ethmoid, sphenoid, temporal, and occipital bones. The lesser wing of the sphenoid bone separates the anterior and middle cranial fossae. The petrous ridge (petrous portion of temporal bone) separates the middle and posterior cranial fossae.

Frontal bone

The frontal bone    is the single bone that forms the forehead. At its anterior midline, between the eyebrows, there is a slight depression called the glabella    (see [link] ). The frontal bone also forms the supraorbital margin of the orbit. Near the middle of this margin, is the supraorbital foramen, the opening that provides passage for a sensory nerve to the forehead. The frontal bone is thickened just above each supraorbital margin, forming rounded brow ridges. These are located just behind your eyebrows and vary in size among individuals, although they are generally larger in males. Inside the cranial cavity, the frontal bone extends posteriorly. This flattened region forms both the roof of the orbit below and the floor of the anterior cranial cavity above (see [link] b ).

Occipital bone

The occipital bone    is the single bone that forms the posterior skull and posterior base of the cranial cavity ( [link] ; see also [link] ). On its outside surface, at the posterior midline, is a small protrusion called the external occipital protuberance    , which serves as an attachment site for a ligament of the posterior neck. Lateral to either side of this bump is a superior nuchal line    (nuchal = “nape” or “posterior neck”). The nuchal lines represent the most superior point at which muscles of the neck attach to the skull, with only the scalp covering the skull above these lines. On the base of the skull, the occipital bone contains the large opening of the foramen magnum    , which allows for passage of the spinal cord as it exits the skull. On either side of the foramen magnum is an oval-shaped occipital condyle    . These condyles form joints with the first cervical vertebra and thus support the skull on top of the vertebral column.

Posterior view of skull

This figure shows the posterior view of the skull and the major parts are labeled.
This view of the posterior skull shows attachment sites for muscles and joints that support the skull.

Sphenoid bone

The sphenoid bone    is a single, complex bone of the central skull ( [link] ). It serves as a “keystone” bone, because it joins with almost every other bone of the skull. The sphenoid forms much of the base of the central skull (see [link] ) and also extends laterally to contribute to the sides of the skull (see [link] ). Inside the cranial cavity, the right and left lesser wings of the sphenoid bone    , which resemble the wings of a flying bird, form the lip of a prominent ridge that marks the boundary between the anterior and middle cranial fossae. The sella turcica    (“Turkish saddle”) is located at the midline of the middle cranial fossa. This bony region of the sphenoid bone is named for its resemblance to the horse saddles used by the Ottoman Turks, with a high back and a tall front. The rounded depression in the floor of the sella turcica is the hypophyseal (pituitary) fossa    , which houses the pea-sized pituitary (hypophyseal) gland. The greater wings of the sphenoid bone extend laterally to either side away from the sella turcica, where they form the anterior floor of the middle cranial fossa. The greater wing is best seen on the outside of the lateral skull, where it forms a rectangular area immediately anterior to the squamous portion of the temporal bone.

Questions & Answers

list types epithelial tissue
Sangu Reply
Squeamus epithelial tissu Cubidal Columna Cilliated columna
explain how hormonal control aids in homeostasis regarding fluids and electrolytes, internal organs, clinical application, edema electrolyte imbalance?
Hensheal Reply
someone to help me explain those
parathyroid hormone : Calcium uptake, H+ and PO-4 wasting thyroid hormone, cortisol for temperature regulation by acting on B.V
also renin
why retro abdominal region called flank?
it is just Anatomical terminology
meaning side of body b/w rib cage and hip bone
list down all the hormones secreted by adrenal gland
Odong Reply
adrenaline hormones
The amount of blood pumped by the left ventricle of the heart in one contraction.
Javid Reply
how we can calculate the cardiac output
and how do we calculate the strock valume
stroke volume is not all the blood contained in the left ventricle; normally, only about two-thirds of the blood in the ventricle is expelled with each beat.
Cardiac output 5.5 l S. V 68.75 ml H. R 80bpm
If we consider SV 70, end systolic vol is about 15% of total(approx always) out of a total of 80-85 ml only 70ml is pumped per systole
what is macrophages?and its function
Sajjad Reply
macrophages they are white blood cells that engulf dead cells in the body
what is power stroke?
no idea
what is the stroke volume of heart?
If an autoimmune disorder targets the alpha cells, production of which hormone would be directly affected?
Samantha Reply
what is a muscle?
Gideon Reply
A band or bundle of fibrous tissue in a human or animal body that has the ability to contract, producing movement in or maintaining the position of parts of the body
what's endolphthamities and panophthalmities?
fluid around the brain
louise Reply
what ?
cerebro spinal fluid
The brain and spinal cord are surrounded by a clear fluid called cerebrospinal fluid (CSF). This fluid is produced and stored in cavities in the brain called ventricles. It circulatesaround the brain, moving from ventricle to ventricle. ... Hydrocephalus is a condition in which there is too much CSF
what is hydrocphalus
aminul Reply
Google krlena na madarchod yha maa chudwa rha ha sabko notification bhjke
when cerebrospinal fluid produce în the brain, i.e. brain ventricles, is to abundent in the brain and is not trăind out of the brain. as a consequence this lichid pute mechanical pressure oñ the brain and it pushes the cerebrum tissue. as a consequence this pressure on the neuronscan cause neurologi
cal disfunctions, for example clinical headache
. It is posible to drainout the fluid through a device dalles shunt,as i remember.
but where are also home medicinsfor decreasing the production of cerebrospin.fluid etc
there are some medicines that can decrease the production of csf
a neurologist advice is needed
i wrote some medicines NOT home medicines. it is a serious condition and specialized medical advice is needed. of course also general medical knowledge may be helpful, but not enough, a specialist is neede
if anyone help me in physiology
Radika Reply
i am BSN student of first year which book is best for physiology
i am BSN student of first year which book is best for physiology
ross and wilson anotomy and physiology
it's 1 book for anotomy and physiology it's best for bs nursing
yes Ross and wilson physiology is better for study
I'm also the student of bs nursing
I study guiton and hall &ganong
I'm also midwif help me be the best book for midwif
what ia the function of indocrine system
salam all friend
help me with this question; explain at least five emergency acute pain found in fundamental emergency medicine
Fascial compartment of forearm
what's a tissue?
Mwape Reply
a group of cells with the same function
tissue is a group of cells that perform the same functions.
explain a bit about a tissue
A tissue is made up of cells that are similar in shape and perform the same function, for instance brain cells form up a brain tissue. Whereas a group of tissues that perform the same function form an organ... so in this case the brain which is the organ is formed as a result of brain tissues.
what is gross anatomy
the branch of anatomy that deals with the structure of organs and tissues that are visible to the naked eye.
1.To know how the structures functions. 2.To easily identify the micro structures and the macro structures. 3.To be able to explain that anatomy is the study of the structures and physiology is the study of how the structures functions
Abban Reply
Describe the two classes of hormones (3 with subclasses) and how they affect their target cells.
Shalaeha Reply
what is control centre
Gohil Reply
Angie The larger air passage of the lung is
Angie Reply

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