Key Functions and Disorders Associated with the Sella Turcica
The Sella Turcica, a bony pocket that supports the pituitary gland, is a cranial base developmental boundary that separates notochord-dependent posterior development from neural crest cell migration-driven anterior development.
The pituitary gland is housed in the Sella Turcica ("Turkish saddle"), a concave, midline depression in the basisphenoid (also called the hypophysis). The anterior clinoid processes of the lesser sphenoid wing and the tuberculin Sellae constitute Sella's anterior boundaries, while the dorsum Sellae forms the posterior boundary. Understanding Sella Turcica anatomy is vital to get a complete understanding of its function. The pituitary gland and the distal section of the pituitary stalk are housed in the Sella Turcica, a midline depression in the sphenoid bone. A dural reflection protects the Sella. The supraclinoid internal carotid arteries, pituitary stalk, optic nerves, chiasm, and tracts are all in the suprasellar cistern. The cavernous sinuses, which contain the carotid arteries, are located to the side of the Sella Turcica.
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One of the most widely utilized landmarks in cephalometrics is the Sella point, located in the middle of the Sella Turcica. In a radiographic examination of neurocranial and craniofacial complex nature, the Sella Turcica is an essential structure. The locations of the maxilla and mandible in respect to the cranium and themselves are measured using such markers found inside the craniofacial area.
Sella Turcica Anatomy
The sphenoid bone's Sella Turcica is a bony depression. The cavernous sinuses border the Sella laterally, the diaphragma Sellae (dural fold) superiorly, the sphenoid sinus anteroinferiorly, and the pontine cistern posteriorly. Usually, the pituitary gland is found within the Sella. An anterior lobe, middle (vestigial) lobe, and posterior lobe make up the gland.
The Sella Turcica function is to form the bony seat for the human body's pituitary gland. The adenohypophysis, which makes up about 75–80% of the overall gland, is a hub for hormone production, including thyroid-stimulating hormone, adrenocorticotropic hormone (ACTH), along with prolactin. The pituitary stalk connects the posterior lobe, hypothalamus, neurohypophysis, and the pituitary stalk receives hormones from the hypothalamus.
What is the Sphenoid Bone Sella Turcica?
Sphenoid bone Sella Turcica plays a vital role in the human body. The sphenoid bone is a part of eight bones forming the cranium, which encloses and helps in protecting the brain. The sphenoid bone is supposed to be developed like a butterfly. It is made up of a body, two pterygoid processes, and paired larger and lesser wings.
The sphenoid bone is divided into three sections: a core body with the Sella Turcica, two bigger wings, and two lesser wings laterally. The front regions of both middle fossae are made up of bigger wings, whereas the posterior portion of the anterior cranial fossae is made up of smaller wings.
The medial and lateral pterygoid muscles connect to the medial and lateral pterygoid processes on the sphenoid bone, facilitating jaw movement. The pterygoid or Vidian's canal can be seen inferomedial to the foramen rotundum when looking at the sphenoid bone from the front.
Empty Sella Syndrome
In many cases, Sella Turcica ends up facing issues; one such is the Empty Sella syndrome. The disorder known as empty Sella syndrome or the Sella Turcica pituitary gland occurs when the pituitary gland shrinks. The pituitary gland is a tiny gland that sits right under the brain. The pituitary stalk connects it to the bottom of the brain. The pituitary is housed in the Sella Turcica, a saddle-like compartment in the skull. On an MRI scan, the pituitary gland shrinks or flattens, and it is not visible. This gives the pituitary gland's location the appearance of an "empty Sella."
However, the Sella isn't empty. It's frequently stuffed with cerebrospinal fluid (CSF). The fluid that surrounds the brain and spinal cord is known as CSF. CSF has spilled into the Sella Turcica, placing pressure on the pituitary in empty Sella syndrome. The gland shrinks or flattens as a result of this. One can view this flattening through the Sella Turcica radiography system and analyze the syndrome.
The Sella Turcica radiology also showcases the size of the Turcica. The size of the Sella Turcica may be determined using radiographs in several ways, including linear measures and different area and volume measurements. The vertical size varies typically from 4 to 12 mm, whereas the anteroposterior dimension typically ranges from 5 to 16 mm.
Sella Turcica is an important portion of the human body and should be learned carefully to understand its uses.
FAQs on Sella Turcica: Structure, Role, and Medical Relevance
1. What is the sella turcica and where is it located?
The sella turcica is a saddle-shaped depression located in the superior surface of the sphenoid bone, which is situated at the base of the skull. Its central and most important feature is the hypophyseal fossa, the specific cavity that houses the pituitary gland.
2. What is the primary function of the sella turcica?
The primary function of the sella turcica is to form a protective bony enclosure for the pituitary gland (also known as the hypophysis). This structure shields the master endocrine gland from physical damage and pressure, ensuring its proper function in regulating various bodily hormones.
3. What are the main anatomical parts of the sella turcica?
The sella turcica is composed of three main parts that form its characteristic saddle shape:
- Tuberculum sellae: The anterior wall of the saddle.
- Hypophyseal fossa: The deep central depression or 'seat' of the saddle where the pituitary gland rests.
- Dorsum sellae: The posterior wall of the saddle, which slopes backwards.
4. How is the pituitary gland connected to the brain within the sella turcica?
The pituitary gland sits within the sella turcica but remains connected to the hypothalamus at the base of the brain via a structure called the pituitary stalk or infundibulum. A dural fold called the diaphragma sellae forms a roof over the sella turcica, with a small opening that allows this stalk to pass through.
5. What is Empty Sella Syndrome and its importance?
Empty Sella Syndrome (ESS) is a medical condition where the sella turcica appears 'empty' on imaging scans. This occurs when cerebrospinal fluid (CSF) leaks into the fossa, compressing the pituitary gland. In primary ESS, this happens due to a small anatomical defect, while secondary ESS can result from injury, surgery, or radiation. While often asymptomatic, it can sometimes lead to hormonal imbalances or headaches.
6. Why is the sella turcica named the 'Turkish saddle'?
The name sella turcica is Latin for 'Turkish saddle'. It was named this due to its distinct shape, which anatomists thought closely resembled the saddles used by Turkish cavalry. This anatomical analogy helps in visualizing its structure with the pituitary gland sitting in the 'seat' of the saddle.
7. How does the sella turcica's structure have clinical and diagnostic importance?
The size and shape of the sella turcica are of great clinical importance. Doctors use imaging techniques like MRI and X-rays to examine it. An enlarged or eroded sella turcica can be a key indicator of a pituitary adenoma (a tumour of the pituitary gland), as the growing tumour exerts pressure on the surrounding bone. Its regular appearance is a baseline for normal cranial anatomy.
8. What is the significance of the sella turcica during embryonic development?
During embryological development, the region of the sella turcica is crucial for the migration of neural crest cells. These cells are fundamental to the proper formation of craniofacial structures, including parts of the face and teeth. Therefore, the normal development of the sella turcica is linked to the overall development of the head's skeletal structure.
9. Can conditions other than pituitary tumours affect the sella turcica?
Yes, while pituitary tumours are a primary concern, other conditions can also affect the sella turcica. These can include craniopharyngiomas (a type of benign brain tumour), aneurysms of the internal carotid artery which runs alongside the sella, and inflammatory or infectious diseases that can cause bone erosion. These conditions are typically identified through radiological imaging.
