Sella turcica – structure, function & diseases
Sella turcica
As part of the sphenoid, the sella turcica forms a bony structure at the base of the skull . The pituitary gland sits in the saddle-shaped depression and is connected to the thalamus via the pituitary stalk . From here, hormonal processes in the human body are controlled.
What is the sella turcica?
The term “Sella turcica” is made up of the Latin words for “seat” and “Turkish”. In German, the term “Turkish saddle” is also used synonymously.
The sella turcica is a bony prominence of the sphenoid bone ( sphenoid bone ) at the inner base of the skull. It divides the middle cranial fossa in the median plane into right and left halves.
The naming goes back to the Belgian anatomist and professor of anatomy and surgery Adriaan van den Spieghel (1578 – 1625). He compared the indentation of this bone structure to a high-backed saddle like the ones used by the Turks in the past. The sella turcica is the only structure in the human body that is named after an entire race.
Van den Spieghel first coined the term “Turkish saddle” in his work “De humani corporis fabrica libri decem”, which was published in 1627. A detailed discussion of the term “Sella turcica” can be found in the Austrian anatomist Joseph Hyrtl (1810 – 1894). He deals with this in his works “Onomatologia Anatomica” and “The Arabic and Hebrew in Anatomy”.
Anatomy & Structure
Anatomically, the sella turcica is assigned to the sphenoidal bone. This cranial bone is located in front of the temporal bone and the occipital bone at the base of the skull. It can be divided into a body (corpus ossis sphenoidalis) and two wings (alae majores and minores) as well as the pterygoid processes projecting backwards. This bone is the most complex in the human body and is also called the wasp leg because of its shape.
The sella turcica sits on top of the sphenoidal bone. The elevations characteristic of the Turkish saddle can be seen on two sides. In front, this is the tuberculum sellae (the saddle button) with two lateral protuberances, the processus clinoidei anteriores. The back boundary is formed by the Dorsum sellae (the seat back) with the Processus clinoidei posteriores. Between these two projections is a pit open to the brain, the hypophysial fossa. This is where the pituitary gland (pituitary gland) is located. The sella turcica is spanned by a part of the dura mater, the so-called diaphragma sellae. This separates the pituitary gland from the basal parts of the brain as well as the optic chiasm.
Function & Tasks
The sella turcica is a bony structure. This makes it part of the passive musculoskeletal system, which comprises around 200 bones. Part of the sphenoid, the Turkish saddle is an unpaired, irregular bone. Due to their complicated structure, these cannot be assigned to any other bone shape.
The human skull is the result of a long evolution that efficiently shaped the body. As an irregular bone, the sphenoid has a supportive and protective function. It is also involved in the shaping of the skull .
Unlike most other bones in the human body, the sphenoid does not form the origin or attachment of any muscle or muscles . Like every bone, the sphenoid bone contains myelinated bones and thus has a metabolic function. There are two types of bone marrow : red and white. The job of the red bone marrow is to form undifferentiated stem cells . It is called the blood-forming bone marrow. Erythrocytes , thrombocytes and leukocytes are produced there. The white bone marrow, also known as fat marrow, serves as an energy store.
When there is a large amount of blood loss, white bone marrow is converted to red. This process is called hematopoiesis . In infants, red bone marrow is found in all bones of the body, in adulthood only in the flat and short bones. The sella turcica houses the pituitary gland as part of the sphenoid bone. As the interface between the nervous system and hormone balance, metabolism , growth and the function of other endocrine organs are controlled here.
Diseases
The pituitary gland is protected by the bony structure of the sella turcica. Nevertheless, changes in the tissue or diseases can occur at this point.
Tumors in the area of the pituitary gland are often only recognized years later. Those affected suffer from nausea , a drop in performance, metabolic disorders or headaches , among other things . In addition, visual field defects can occur if the optic nerve is involved . In this case, an ophthalmological examination of the field of vision is necessary in addition to imaging diagnostics. Most pituitary tumors can be surgically removed through the nose.
If the pituitary gland is not visible on computed or magnetic resonance imaging, empty sella syndrome or empty sella syndrome is present. The reason for this is usually a bulging of the meninges into the sella turcica. This protrusion presses the pituitary gland against the edge of the sella, giving the impression of an empty sella in imaging procedures. Another cause can be damage to the pituitary tissue caused by infarction, surgery or radiation. If the affected person does not show a clinic, no further examinations are necessary.
The empty sella syndrome can manifest itself in headaches, a constant runny nose and blurred vision , among other things . Rarely, there is an overproduction of the messenger substance prolactin . This leads to milky discharge from the breasts, menstrual cycle disorders, erectile dysfunction and infertility . Symptoms can be treated with surgery or medication, depending on the cause.
Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.