<< Chapter < Page Chapter >> Page >

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 a nutrition ?
Jitu Reply
Nutrition is the process of providing or obtaining the food necessary for health and growth.
Gloria
Nutrition is the process of taking food and using it for growth , repair and metabolism ...
Om
how many parts of bone
Amir Reply
know the meaning of both messages
Amir
what is the name of suture that is present between frontal. parietal. occipetal ...
Amir
what is the name of suture that is present between frontal. parietal. occipetal ...
Amir
Coronal suture present between frontal and parietal bone and lambdoid suture present between parietal and occipital bone ...
Om
epinephrine is the true meaning of epi
Michele Reply
what does the word 'epi' means
Melex Reply
good evening, my question is what are function of metal in human body like aluminum?
Yosef Reply
please want you to help me in understanding digestive system
Hamidu Reply
this is muscular system?
Patel Reply
bruh moment
Viana
It is an organ system consisting of skeletal ,smooth and cardiac muscles
mishra
im too retarded to be here
Viana
naww Viana, I know it's hard to absorb info, I'm having the same issue, but keep practising, chin up.
Katarina
what is the question
Amir
to have a better understanding as to how our human bodies function. the knowledge we gain can improve our quality of life. Without our study of anatomy how could a doctor know what prescription to give us when our bodies is being attacked by a bacteria? We wouldn't!
Robin Reply
discuss nervers system in human being life.
Allen Reply
neuralgia what is other name of it
Muniba
how are neurons adapted to their function
Namiyaba Reply
machenic support production of blood cells locomotion protection of delicate organs
Ackson Reply
what are hormones?
Ackson
Hormones are chemical substances that affect the activity of another part of the Body. in essence, hormones serve as messenger , controlling and coordinating activities throughout the body .
Ifeoluwa
what is anatomy
Juma Reply
what are the functions of bones
Michael
To support and control the movements of the body
Mu
the study of human body is called anatomy
mishra
the study of human body is nt only anatomy but also physiology and histology
Evans
ooops lol I thought Michael was the one with the questions so sorry people. yes anatomy is the study of the body(structure)and it's physiology (functions).
Mu
what are the muscles of respiration?
Dorisha
Hi everyone, Why actyl choline decreases blood pressure although it affects adrenal gland leading it to secret adrenaline and noradrenaline which increase blood pressure?
cholinergic receptors are mostly under Parasympathetic response while adrenergic (norepinephrine) receptors are mostly sympathetic although they are cholinergic adrenergic receptors as well
Ayodeji
why do I have pain in my right side of the stomach I had ulcer
Mohammed
go to gastro physician may be but some time it is a gas
Amir
vocal cords
MT Reply
There are open during inhalation and come together to close during swallowing and phonation.
Ifeoluwa
musah was admitted to your ward yesterday with traumatic amputation of the right thump . he complained this morning that he has not passed enough urine. Questions. 1) will you consider his complain to be pathological or physiological?. 2) in less than three sentences, justify your opinion. 3) Apply your understanding of the renin- angiotensin-aldosterone system to explain the factors and mechanisms accounting for his complains.
Ellen Reply
please i want you guys to help understand digestive system
Hamidu
digestive system is the system that ingestion breakdown by mechanical and chemicals via mouth to stomach throughout alimentary canal
Girma
please alimentary canal what it is and it functions
Hamidu
Ellen de condition is physiological, traumatic amputation causes the body to go to shock in which less blood is sent to the organ (kidney) causing decreased in blood pressure in the renal tubules and low glomerular filtrate will be produced as ultrafiltration can't occur.
Nana
thanks
Hamidu
Alimentary canal is a long tube that runs from the mouth to the anus and helps in peristalsis and digestion of food to smaller soluble particles to be absorbed into the blood and assimilated into the cells for to obtain energy for cellular function
Nana
much thanks
Hamidu
accessory organs it functions
Hamidu
which accessory organs
Nana
that's the tongue,salivary gland and the teeth
Hamidu
accessory organ the organ which not part of digestive tract e.g tongue salivary gland liver pancreas gallbladder etc which heps in digestion
Salahudin
salivary glands (parotid, sublingual and submandibular) for secreting saliva for lubrucation and salivary amylase in carbohydrates breakdown in the mouth.teeth helps in chewing, tongue rolls de food into bolus.gallbladder stores biles produced by the liver and helps emulsify fats.liver detoxify food
Nana
my question is what is the location of pituitary gland in anatomy
Amir
what is average value of hair at scalp give me answer .if no one know about answer .so than I given answer
Amir
The value of hair at scalp is 100.000
Amir
please explain
Agbosu
100000 to 150000 scalp
Salahudin
OK good
Amir
where is cartilage present in large amount a)Thoracic cage b) head c) lower limb d)upper limb
Amir
the human scalp has almost 100000 to 150000 hair follicles from hair grow and come out the life of single hair grows have three different stages of hair growth it is considered normal if have lose 50 hairs approx
Salahudin
thinks
Salahudin
thoracic cage have 12
Salahudin
what is AV node?
Salahudin
amir khan
Salahudin
pituitary gland is small oval shape which present in brain
Salahudin
AV stands for atrioventricular node, it consist of cardiac muscle tissue and its lies in the right atrium along the lower part of the interartrial septum..
Om
what is the function of AV and SA nodes
Salahudin
SA node is the pacemaker of the human heart and it generates an electrical signal that cause upper chambers (atria) to contract .. the signal that passes through the AV node to the lower heart chambers (ventricles) causing them to contract or pump ...
Om
Anatomy ?
Rahil
it is the study of structure and parts of human body
Salahudin
when can someone have a shower after the operation of eyes ?
Rahil

Get the best Anatomy & Physiology course in your pocket!





Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Anatomy & Physiology' conversation and receive update notifications?

Ask