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The brain case consists of eight bones. These include the paired parietal and temporal bones, plus the unpaired frontal, occipital, sphenoid, and ethmoid bones.

Parietal bone

The parietal bone    forms most of the upper lateral side of the skull (see [link] ). These are paired bones, with the right and left parietal bones joining together at the top of the skull. Each parietal bone is also bounded anteriorly by the frontal bone, inferiorly by the temporal bone, and posteriorly by the occipital bone.

Temporal bone

The temporal bone    forms the lower lateral side of the skull (see [link] ). Common wisdom has it that the temporal bone (temporal = “time”) is so named because this area of the head (the temple) is where hair typically first turns gray, indicating the passage of time.

The temporal bone is subdivided into several regions ( [link] ). The flattened, upper portion is the squamous portion of the temporal bone. Below this area and projecting anteriorly is the zygomatic process of the temporal bone, which forms the posterior portion of the zygomatic arch. Posteriorly is the mastoid portion of the temporal bone. Projecting inferiorly from this region is a large prominence, the mastoid process    , which serves as a muscle attachment site. The mastoid process can easily be felt on the side of the head just behind your earlobe. On the interior of the skull, the petrous portion of each temporal bone forms the prominent, diagonally oriented petrous ridge    in the floor of the cranial cavity. Located inside each petrous ridge are small cavities that house the structures of the middle and inner ears.

Temporal bone

This image shows the location of the temporal bone. A small image of the skull on the top left shows the temporal bone highlighted in pink and a magnified view of this region then highlights the important parts of the temporal bone.
A lateral view of the isolated temporal bone shows the squamous, mastoid, and zygomatic portions of the temporal bone.

Important landmarks of the temporal bone, as shown in [link] , include the following:

  • External acoustic meatus (ear canal)—This is the large opening on the lateral side of the skull that is associated with the ear.
  • Internal acoustic meatus —This opening is located inside the cranial cavity, on the medial side of the petrous ridge. It connects to the middle and inner ear cavities of the temporal bone.
  • Mandibular fossa —This is the deep, oval-shaped depression located on the external base of the skull, just in front of the external acoustic meatus. The mandible (lower jaw) joins with the skull at this site as part of the temporomandibular joint, which allows for movements of the mandible during opening and closing of the mouth.
  • Articular tubercle —The smooth ridge located immediately anterior to the mandibular fossa. Both the articular tubercle and mandibular fossa contribute to the temporomandibular joint, the joint that provides for movements between the temporal bone of the skull and the mandible.
  • Styloid process —Posterior to the mandibular fossa on the external base of the skull is an elongated, downward bony projection called the styloid process, so named because of its resemblance to a stylus (a pen or writing tool). This structure serves as an attachment site for several small muscles and for a ligament that supports the hyoid bone of the neck. (See also [link] .)
  • Stylomastoid foramen —This small opening is located between the styloid process and mastoid process. This is the point of exit for the cranial nerve that supplies the facial muscles.
  • Carotid canal —The carotid canal is a zig-zag shaped tunnel that provides passage through the base of the skull for one of the major arteries that supplies the brain. Its entrance is located on the outside base of the skull, anteromedial to the styloid process. The canal then runs anteromedially within the bony base of the skull, and then turns upward to its exit in the floor of the middle cranial cavity, above the foramen lacerum.

Questions & Answers

what is the difference between anatomy and physiology
MICHAEL Reply
Anatomy means structures and physiology means functions
Aliyu
brain behaviour relation
Sneha Reply
Act as mother of all gland
johnson
What is neurons?
Luqman Reply
a specialized cell transmitting nerve impulses; a nerve cell.
Shain
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Luqman
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Luqman
why are cells small
Hajiahamdy Reply
what is the change if take normal water in our body
Algur Reply
What are variations in physiology
John Reply
pls let's talk about d difference between mitosis and meiosis
olatemiju Reply
through remodeling and formation of new bones
Amoako Reply
please what is it
Monica
what is blood pressure
HALLELUYAH
what is blood pressure reading
HALLELUYAH
sketch and label blood vessels
HALLELUYAH
veins is........
KING
draw the male reproductive system
Jeremaih Reply
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Pednyin
how life
Jeremaih
join
Hajiahamdy
Explain how different foods can affect metabolism
Abraham Reply
what is Endocrine system?
Islam Reply
which secrete hormones and other products direct into the blood
Aadi
Cell is basic, structural and functional unit of life
Kabuja Reply
The cell is the structural and functional unit of all living organisms, and is sometimes called the "building block of life." Some organisms, such as bacteria, are unicellular, consisting of a single cell.
Br_
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Rachel
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hingi
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HALLELUYAH
can some one help
HALLELUYAH
what is the basic function of the lymphatic system
HALLELUYAH
The other main function is that of defense in the immune system. Lymph is very similar to blood plasma: it contains lymphocytes. It also contains waste products and cellular debris together with bacteria and proteins. Associated organs composed of lymphoid tissue are the sites of lymphocyte producti
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the function of lymphatic system are 1fluid balance 2 lipid absorption and 3 defence
Sidra
destroyed microognism
Usman
lymphatic systems main function is to transport lymph
Colleen
may i know the meaning of infestation of parasite?
Aminiely
Which of the following accurately describe external respirations
Robin Reply
different between anatomy and physiology
Samwel Reply
anatomy is the study of STRUCTURE of the body while physiology is the study of the function of the part of the body
Gborgbor
Anatomy deals with the structure and parts of the body while physiology is the function of the the body parts
Archie
Anatomy is the study which deals with anatomical position while physiology deals with the function
Luqman
not understanding what is a cell
Kesa Reply
its the fundamental unit of life or its the primary step in which two or more cell combine to form a tissue .
Sidra
Is the smallest structural and functional unit of life
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cell is the basic you unit of life
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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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