FIBROUS DYSPLASIA OF BONE affecting several bones. When melanotic pigmentation (CAFE-AU-LAIT SPOTS) and multiple endocrine hyperfunction are additionally associated it is referred to as Albright syndrome.
A disease of bone marked by thinning of the cortex by fibrous tissue containing bony spicules, producing pain, disability, and gradually increasing deformity. Only one bone may be involved (FIBROUS DYSPLASIA, MONOSTOTIC) or several (FIBROUS DYSPLASIA, POLYOSTOTIC).
FIBROUS DYSPLASIA OF BONE involving only one bone.
A disease marked by repeated episodes of increased bone resorption followed by excessive attempts at repair, resulting in weakened, deformed bones of increased mass. The resultant architecture of the bone assumes a mosaic pattern in which the fibers take on a haphazard pattern instead of the normal parallel symmetry.
The facial skeleton, consisting of bones situated between the cranial base and the mandibular region. While some consider the facial bones to comprise the hyoid (HYOID BONE), palatine (HARD PALATE), and zygomatic (ZYGOMA) bones, MANDIBLE, and MAXILLA, others include also the lacrimal and nasal bones, inferior nasal concha, and vomer but exclude the hyoid bone. (Jablonski, Dictionary of Dentistry, 1992, p113)
A benign central bone tumor, usually of the jaws (especially the mandible), composed of fibrous connective tissue within which bone is formed.
A family of heterotrimeric GTP-binding protein alpha subunits that activate ADENYLYL CYCLASES.
Cancers or tumors of the MAXILLA or MANDIBLE unspecified. For neoplasms of the maxilla, MAXILLARY NEOPLASMS is available and of the mandible, MANDIBULAR NEOPLASMS is available.
An irregular unpaired bone situated at the SKULL BASE and wedged between the frontal, temporal, and occipital bones (FRONTAL BONE; TEMPORAL BONE; OCCIPITAL BONE). Sphenoid bone consists of a median body and three pairs of processes resembling a bat with spread wings. The body is hollowed out in its inferior to form two large cavities (SPHENOID SINUS).
Developmental bone diseases are a category of skeletal disorders that arise from disturbances in the normal growth and development of bones, including abnormalities in size, shape, structure, or composition, which can lead to various musculoskeletal impairments and deformities.
The SKELETON of the HEAD including the FACIAL BONES and the bones enclosing the BRAIN.
'Mandibular diseases' refer to various medical conditions that primarily affect the structure, function, or health of the mandible (lower jawbone), including but not limited to infections, tumors, developmental disorders, and degenerative diseases.
The bones of the free part of the lower extremity in humans and of any of the four extremities in animals. It includes the FEMUR; PATELLA; TIBIA; and FIBULA.
The bone that forms the frontal aspect of the skull. Its flat part forms the forehead, articulating inferiorly with the NASAL BONE and the CHEEK BONE on each side of the face.
Light brown pigmented macules associated with NEUROFIBROMATOSIS and Albright's syndrome (see FIBROUS DYSPLASIA, POLYOSTOTIC).
A group of hereditary disorders involving tissues and structures derived from the embryonic ectoderm. They are characterized by the presence of abnormalities at birth and involvement of both the epidermis and skin appendages. They are generally nonprogressive and diffuse. Various forms exist, including anhidrotic and hidrotic dysplasias, FOCAL DERMAL HYPOPLASIA, and aplasia cutis congenita.
Maxillary diseases refer to various medical conditions primarily affecting the maxilla (upper jaw) bone, including inflammatory processes, tumors, cysts, or traumatic injuries, which may cause symptoms such as pain, swelling, or functional impairment.
One of the paired air spaces located in the body of the SPHENOID BONE behind the ETHMOID BONE in the middle of the skull. Sphenoid sinus communicates with the posterosuperior part of NASAL CAVITY on the same side.
A set of twelve curved bones which connect to the vertebral column posteriorly, and terminate anteriorly as costal cartilage. Together, they form a protective cage around the internal thoracic organs.
Diseases of the bony orbit and contents except the eyeball.

A cluster of oppositely imprinted transcripts at the Gnas locus in the distal imprinting region of mouse chromosome 2. (1/108)

Imprinted genes tend to occur in clusters. We have identified a cluster in distal mouse chromosome (Chr) 2, known from early genetic studies to contain both maternally and paternally imprinted, but unspecified, genes. Subsequently, one was identified as Gnas, which encodes a G protein alpha subunit, and there is clinical and biochemical evidence that the human homologue GNAS1, mutated in patients with Albright hereditary osteodystrophy, is also imprinted. We have used representational difference analysis, based on parent-of-origin methylation differences, to isolate candidate imprinted genes in distal Chr 2 and found two oppositely imprinted genes, Gnasxl and Nesp. Gnasxl determines a variant G protein alpha subunit associated with the trans-Golgi network and Nesp encodes a secreted protein of neuroendocrine tissues. Gnasxl is maternally methylated in genomic DNA and encodes a paternal-specific transcript, whereas Nesp is paternally methylated with maternal-specific expression. Their reciprocal imprinting may offer insight into the distal Chr 2 imprinting phenotypes. Remarkably, Gnasxl, Nesp, and Gnas are all part of the same transcription unit; transcripts for Gnasxl and Nesp are alternatively spliced onto exon 2 of Gnas. This demonstrates an imprinting mechanism in which two oppositely imprinted genes share the same downstream exons.  (+info)

A mutation in the heterotrimeric stimulatory guanine nucleotide binding protein alpha-subunit with impaired receptor-mediated activation because of elevated GTPase activity. (2/108)

It has been reported that substitution of Arg258, a residue within the GTPase domain of the heterotrimeric guanine nucleotide binding protein (G protein) alpha-subunit (alphas), to alanine (alphas-R258A) results in decreased activation by receptor or aluminum fluoride (AlF4-) and increased basal GDP release. Arg258 interacts with Gln170 in the helical domain, and, presumably, loss of this interaction between the GTPase and helical domain leads to more rapid GDP release, resulting in decreased activation by AlF4- and increased thermolability. In this study, we mutate Gln170 to alanine (alphas-Q170A) and demonstrate that this mutant, like alphas-R258A, has decreased activation by AlF4-, increased thermolability (both reversed in the presence of excess guanine nucleotide), and an increased rate of GDP release. However, unlike alphas-R258A, alphas-Q170A does not have impaired receptor-mediated activation. Therefore, this interdomain interaction is critical to maintain normal guanine nucleotide binding (and hence normal activation by AlF4-) but is not important for receptor-mediated activation. In single turnover GTPase assays, the catalytic rate for GTP hydrolysis of alphas-R258A was 14-fold higher than normal whereas that of alphas-Q170A was unaffected. Examination of the alphas crystal structure suggests that Arg258, through interactions with Glu50, might constrain the position of Arg201, a residue critical for catalyzing the GTPase reaction. This is an example of a mutation in a heterotrimeric G protein that results in an increased intrinsic GTPase activity and provides another mechanism by which G protein mutations can impair signal transduction.  (+info)

Familial cryptic translocation between chromosomes 2qter and 8qter: further delineation of the Albright hereditary osteodystrophy-like phenotype. (3/108)

Recently five patients with an Albright hereditary osteodystrophy (AHO)-like phenotype were reported to have a subtelomeric deletion of the long arm of chromosome 2. These patients showed a striking resemblance to a number of patients from a large pedigree known to us for a long time. After molecular confirmation of a subtelomeric deletion in one patient, FISH analysis was used and a cryptic translocation between the long arms of chromosomes 2 and 8, t(2;8)(q37.3;q24.3), was detected. Remarkably, five proven and 10 probable cases with a 2qter deletion were found in the family, but none with an 8qter deletion. This was not explained by increased fetal loss. The major clinical characteristics of terminal 2q deletion are a short, stocky build, round face, sparse hair, deeply set eyes, bulbous nose, thin vermilion border, brachymetaphalangism, seizures, and developmental delay. A specific behavioural phenotype consisting of periods of hyperkinesia and aggression can develop with age. The overall phenotype is sufficiently characteristic to allow clinical recognition. The cytogenetic and molecular studies did not narrow down the common deleted region. Both testing of additional 2q markers and characterisation of other AHO-like patients with 2q37 microdeletions may help to define the candidate gene region.  (+info)

Use of aromatase inhibitors in precocious puberty. (4/108)

During puberty, estrogen causes breast maturation and growth of the uterine lining in girls, and accelerates linear growth and bone maturation in both boys and girls. Decreasing the biosynthesis of estrogen can attenuate these processes. In 12 girls with the McCune-Albright syndrome (MAS), in which precocious puberty is due to production of estrogen from ovarian cysts, testolactone (40 mg/kg per day) decreased the volume of ovarian cysts, the frequency of menses, and the rates of growth and bone maturation, for periods of 1-4 years. In a 6-month pilot study of 12 children (eight boys; four girls) with congenital adrenal hyperplasia, testolactone, in combination with an antiandrogen (flutamide), a mineralocorticoid (fludrocortisone acetate, Florinef), and a reduced glucocorticoid dose, improved the control of growth and bone maturation compared with conventional therapy. In a 6-year study of 10 boys with familial male precocious puberty, testolactone, in combination with an antiandrogen (spironolactone), decreased rates of growth and bone maturation, and increased predicted adult height. All patients who developed evidence for gonadotropin-dependent puberty were also treated with a GnRH analog. Testolactone had no important adverse effects in any group of patients, although the need for a four-times-daily dosing schedule made compliance difficult for many families. We conclude that suppressing of estrogen with testolactone was effective therapy, and that more potent and specific inhibitors of aromatase could further improve the treatment of these disorders.  (+info)

Variable imprinting of the heterotrimeric G protein G(s) alpha-subunit within different segments of the nephron. (5/108)

The heterotrimeric G protein G(s) is required for hormone-stimulated intracellular cAMP generation because it couples hormone receptors to the enzyme adenylyl cyclase. Hormones that activate G(s) in the kidney include parathyroid hormone, glucagon, calcitonin, and vasopressin. Recently, it has been demonstrated that the G(s)alpha gene is imprinted in a tissue-specific manner, leading to preferential expression of G(s)alpha from the maternal allele in some tissues. In the kidney, G(s)alpha is imprinted in the proximal tubule but not in more distal nephron segments, such as the thick ascending limb or collecting duct. This most likely explains why in both humans and mice heterozygous mutations in the maternal allele lead to parathyroid hormone resistance in the proximal tubule whereas mutations in the paternal allele do not. In contrast, heterozygous mutations have little effect on vasopressin action in the collecting ducts. In mice with heterozygous null G(s)alpha mutations (both those with mutations on the maternal or paternal allele), expression of the Na-K-2Cl cotransporter was decreased in the thick ascending limb, suggesting that its expression is regulated by cAMP. The G(s)alpha genes also generate alternative, oppositely imprinted transcripts encoding XLalphas, a G(s)alpha isoform with a long NH(2)-terminal extension, and NESP55, a chromogranin-like neurosecretory protein. The role, if any, of these proteins in renal physiology is unknown.  (+info)

Inverted duplications are recurrent rearrangements always associated with a distal deletion: description of a new case involving 2q. (6/108)

We studied the case of a subject with an inverted duplication of 40 cM of 2q33-q37 concurrent with a 10 cM deletion of the distal 2q, the latter not being detectable by cytogenetics. Microsatellite analysis demonstrated the absence of maternal alleles in the deleted region and a double dosage for one of the maternal alleles in the duplication region. We hypothesised that this type of rearrangement occurs at meiosis I, while the two homologues are synapsed for most of their length. The presence of inverted duplicons in the same chromosome arm would favour the partial refolding of one homologue into itself so leading to the intrachromatid synapsis and recombination of the inverted repeats. The arising recombinant chromosome is deleted for the region beyond the most distal repeat and with the chromatids joined together at the level of the region located between the two duplicons. At meiosis II, the two linked chromatids can join the opposite poles provided that a breakage between the two centromeres occurs leading to a duplicated/deleted chromosome and a simply deleted chromosome. This model can be extended to all the so-called inverted duplication cases and to part of the terminal deletions. In fact the finding that, in our invdup(2q), the entire 40 cM duplication region involves only one of the two maternal alleles, indeed indicates that the abnormal crossover occurs between sister chromatids. The phenotype associated with our 2q rearrangement led us to narrow the critical region for the Albright-like syndrome to 10 cM in the subterminal 2q region.  (+info)

A comparative study of fibrous dysplasia and osteofibrous dysplasia with regard to Gsalpha mutation at the Arg201 codon: polymerase chain reaction-restriction fragment length polymorphism analysis of paraffin-embedded tissues. (7/108)

Fibrous dysplasia and osteofibrous dysplasia are both benign fibro-osseous lesions of the bone and are generally seen during childhood or adolescence. Histologically, the features of these bone lesions sometimes look quite similar, but their precise nature remains controversial. Mutation of the alpha subunit of signal-transducing G proteins (Gsalpha), with an increase in cyclic adenosine monophosphate (cAMP) formation, has been implicated in the development of multiple endocrinopathies of the Albright-McCune syndrome and in the development of fibrous dysplasia. We studied Gsalpha mutation at the Arg201. codon in seven cases of fibrous dysplasia (six monostotic lesions and one polyostotic lesion) and seven cases of osteofibrous dysplasia using formalin-fixed, paraffin-embedded tissue, by means of polymerase chain reaction-restriction fragment length polymorphism and direct sequencing analysis. All of the seven cases of fibrous dysplasia showed missense point mutations in Gsalpha at the Arg201 codon that resulted in Arg-to-His substitution in three cases and Arg-to-Cys substitution in four cases. On the other hand, the seven cases of osteofibrous dysplasia and the normal bone used as a control showed no such mutation. These data suggest that fibrous dysplasia and osteofibrous dysplasia have different pathogeneses and that the detection of Gsalpha mutation at the Arg201 codon is quite useful for distinguishing between these lesions.  (+info)

Oral manifestations of Albright hereditary osteodystrophy: a case report. (8/108)

Albright hereditary osteodystrophy is a hereditary metabolic disorder of dominant autosomal etiology that is commonly characterized by short stature, round face, small metacarpus and metatarsus, mental retardation, osteoporosis, subcutaneous calcification, variable hypocalcemia, and hyperphosphatemia. In this study, we report a clinical case of a 17-year-old woman with Albright hereditary osteodystrophy, and we discuss her clinical, radiographic, and laboratory test characteristics together with the oral manifestations, and we correlate them with the characteristics found in the literature. We also discuss the odontological management of treatment of related periodontal disease and planning for corrections of related malocclusions.  (+info)

Fibrous Dysplasia, Polyostotic is a rare genetic disorder that affects the bone tissue. It is characterized by the replacement of normal bone tissue with fibrous (scar-like) tissue, leading to weak and fragile bones that are prone to fractures and deformities. The term "polyostotic" refers to the involvement of multiple bones in the body.

In this condition, there is an abnormal development of the bone during fetal growth or early childhood due to a mutation in the GNAS gene. This results in the formation of fibrous tissue instead of normal bone tissue, leading to the characteristic features of Fibrous Dysplasia, Polyostotic.

The symptoms of this condition can vary widely depending on the severity and location of the affected bones. Common symptoms include:

* Bone pain and tenderness
* Bone deformities (such as bowing of the legs)
* Increased risk of fractures
* Skin pigmentation changes (cafe-au-lait spots)
* Hearing loss or other hearing problems (if the skull is affected)

Fibrous Dysplasia, Polyostotic can also be associated with endocrine disorders such as precocious puberty and hyperthyroidism. Treatment typically involves a combination of medications to manage pain and prevent fractures, as well as surgical intervention to correct bone deformities or stabilize fractures.

Fibrous Dysplasia of Bone is a rare, benign bone disorder that is characterized by the replacement of normal bone tissue with fibrous (scar-like) and immature bone tissue. This results in weakened bones that are prone to fractures, deformities, and pain. The condition can affect any bone in the body but most commonly involves the long bones of the legs, arms, and skull. It can occur as an isolated finding or as part of a genetic disorder called McCune-Albright syndrome. The exact cause of fibrous dysplasia is not fully understood, but it is believed to result from a genetic mutation that occurs during early bone development. There is no cure for fibrous dysplasia, and treatment typically focuses on managing symptoms and preventing complications.

Fibrous dysplasia, monostotic is a benign bone disorder that affects a single bone (monostotic) and is characterized by the replacement of normal bone tissue with fibrous (scar-like) tissue. This results in the formation of abnormal bone that is weakened and more susceptible to fractures. The lesions can cause deformities, pain, and decreased mobility, depending on their size and location. Monostotic fibrous dysplasia is the most common form of fibrous dysplasia, accounting for approximately 70-80% of all cases. It typically manifests during childhood or adolescence and may stabilize or progress slowly over time. In some cases, it can be associated with endocrine disorders such as precocious puberty, hyperthyroidism, or growth hormone excess.

Osteitis deformans, also known as Paget's disease of bone, is a chronic disorder of the bone characterized by abnormal turnover and remodeling of the bone. In this condition, the bone becomes enlarged, thickened, and deformed due to excessive and disorganized bone formation and resorption.

The process begins when the bone-remodeling cycle is disrupted, leading to an imbalance between the activity of osteoclasts (cells that break down bone) and osteoblasts (cells that form new bone). In Paget's disease, osteoclasts become overactive and increase bone resorption, followed by an overzealous response from osteoblasts, which attempt to repair the damage but do so in a disorganized manner.

The affected bones can become weakened, prone to fractures, and may cause pain, deformities, or other complications such as arthritis, hearing loss, or neurological symptoms if the skull or spine is involved. The exact cause of Paget's disease remains unknown, but it is believed that genetic and environmental factors play a role in its development.

Early diagnosis and treatment can help manage the symptoms and prevent complications associated with osteitis deformans. Treatment options include medications to slow down bone turnover, pain management, and orthopedic interventions when necessary.

The facial bones, also known as the facial skeleton, are a series of bones that make up the framework of the face. They include:

1. Frontal bone: This bone forms the forehead and the upper part of the eye sockets.
2. Nasal bones: These two thin bones form the bridge of the nose.
3. Maxilla bones: These are the largest bones in the facial skeleton, forming the upper jaw, the bottom of the eye sockets, and the sides of the nose. They also contain the upper teeth.
4. Zygomatic bones (cheekbones): These bones form the cheekbones and the outer part of the eye sockets.
5. Palatine bones: These bones form the back part of the roof of the mouth, the side walls of the nasal cavity, and contribute to the formation of the eye socket.
6. Inferior nasal conchae: These are thin, curved bones that form the lateral walls of the nasal cavity and help to filter and humidify air as it passes through the nose.
7. Lacrimal bones: These are the smallest bones in the skull, located at the inner corner of the eye socket, and help to form the tear duct.
8. Mandible (lower jaw): This is the only bone in the facial skeleton that can move. It holds the lower teeth and forms the chin.

These bones work together to protect vital structures such as the eyes, brain, and nasal passages, while also providing attachment points for muscles that control chewing, expression, and other facial movements.

A fibroma, ossifying is a benign (non-cancerous) tumor that typically develops in the periodontal ligament, which is the tissue that connects the tooth to the jawbone. This type of fibroma is characterized by the formation of bone-like tissue within the tumor. It usually appears as a firm, slow-growing nodule or mass that can cause pain or discomfort, particularly when biting down on the affected tooth.

The exact cause of ossifying fibromas is not well understood, but they are thought to arise from an overgrowth of cells in the periodontal ligament. They are more common in women than men and typically occur in people between the ages of 20 and 40. Treatment usually involves surgical removal of the tumor, along with any affected tissue or teeth. In some cases, recurrence may occur, so regular follow-up appointments with a dental professional are recommended.

GTP-binding protein alpha subunits, Gs, are a type of heterotrimeric G proteins that play a crucial role in the transmission of signals within cells. These proteins are composed of three subunits: alpha, beta, and gamma. The alpha subunit of Gs proteins (Gs-alpha) is responsible for activating adenylyl cyclase, an enzyme that converts ATP to cyclic AMP (cAMP), a secondary messenger involved in various cellular processes.

When a G protein-coupled receptor (GPCR) is activated by an extracellular signal, it interacts with and activates the Gs protein. This activation causes the exchange of guanosine diphosphate (GDP) bound to the alpha subunit with guanosine triphosphate (GTP). The GTP-bound Gs-alpha then dissociates from the beta-gamma subunits and interacts with adenylyl cyclase, activating it and leading to an increase in cAMP levels. This signaling cascade ultimately results in various cellular responses, such as changes in gene expression, metabolism, or cell growth and differentiation.

It is important to note that mutations in the GNAS gene, which encodes the Gs-alpha subunit, can lead to several endocrine and non-endocrine disorders, such as McCune-Albright syndrome, fibrous dysplasia, and various hormone-related diseases.

Jaw neoplasms refer to abnormal growths or tumors in the jawbone (mandible) or maxilla (upper jaw). These growths can be benign (non-cancerous) or malignant (cancerous). Benign neoplasms are not considered life-threatening, but they can still cause problems by invading nearby tissues and causing damage. Malignant neoplasms, on the other hand, can spread to other parts of the body and can be life-threatening if not treated promptly and effectively.

Jaw neoplasms can present with various symptoms such as swelling, pain, loose teeth, numbness or tingling in the lips or tongue, difficulty chewing or swallowing, and jaw stiffness or limited movement. The diagnosis of jaw neoplasms typically involves a thorough clinical examination, imaging studies such as X-rays, CT scans, or MRI, and sometimes a biopsy to determine the type and extent of the tumor.

Treatment options for jaw neoplasms depend on several factors, including the type, size, location, and stage of the tumor, as well as the patient's overall health and medical history. Treatment may involve surgery, radiation therapy, chemotherapy, or a combination of these modalities. Regular follow-up care is essential to monitor for recurrence or metastasis (spread) of the neoplasm.

The sphenoid bone is a complex, irregularly shaped bone located in the middle cranial fossa and forms part of the base of the skull. It articulates with several other bones, including the frontal, parietal, temporal, ethmoid, palatine, and zygomatic bones. The sphenoid bone has two main parts: the body and the wings.

The body of the sphenoid bone is roughly cuboid in shape and contains several important structures, such as the sella turcica, which houses the pituitary gland, and the sphenoid sinuses, which are air-filled cavities within the bone. The greater wings of the sphenoid bone extend laterally from the body and form part of the skull's lateral walls. They contain the superior orbital fissure, through which important nerves and blood vessels pass between the cranial cavity and the orbit of the eye.

The lesser wings of the sphenoid bone are thin, blade-like structures that extend anteriorly from the body and form part of the floor of the anterior cranial fossa. They contain the optic canal, which transmits the optic nerve and ophthalmic artery between the brain and the orbit of the eye.

Overall, the sphenoid bone plays a crucial role in protecting several important structures within the skull, including the pituitary gland, optic nerves, and ophthalmic arteries.

Developmental bone diseases are a group of medical conditions that affect the growth and development of bones. These diseases are present at birth or develop during childhood and adolescence, when bones are growing rapidly. They can result from genetic mutations, hormonal imbalances, or environmental factors such as poor nutrition.

Some examples of developmental bone diseases include:

1. Osteogenesis imperfecta (OI): Also known as brittle bone disease, OI is a genetic disorder that affects the body's production of collagen, a protein necessary for healthy bones. People with OI have fragile bones that break easily and may also experience other symptoms such as blue sclerae (whites of the eyes), hearing loss, and joint laxity.
2. Achondroplasia: This is the most common form of dwarfism, caused by a genetic mutation that affects bone growth. People with achondroplasia have short limbs and a large head relative to their body size.
3. Rickets: A condition caused by vitamin D deficiency or an inability to absorb or use vitamin D properly. This leads to weak, soft bones that can bow or bend easily, particularly in children.
4. Fibrous dysplasia: A rare bone disorder where normal bone is replaced with fibrous tissue, leading to weakened bones and deformities.
5. Scoliosis: An abnormal curvature of the spine that can develop during childhood or adolescence. While not strictly a developmental bone disease, scoliosis can be caused by various underlying conditions such as cerebral palsy, muscular dystrophy, or spina bifida.

Treatment for developmental bone diseases varies depending on the specific condition and its severity. Treatment may include medication, physical therapy, bracing, or surgery to correct deformities and improve function. Regular follow-up with a healthcare provider is essential to monitor growth, manage symptoms, and prevent complications.

The skull is the bony structure that encloses and protects the brain, the eyes, and the ears. It is composed of two main parts: the cranium, which contains the brain, and the facial bones. The cranium is made up of several fused flat bones, while the facial bones include the upper jaw (maxilla), lower jaw (mandible), cheekbones, nose bones, and eye sockets (orbits).

The skull also provides attachment points for various muscles that control chewing, moving the head, and facial expressions. Additionally, it contains openings for blood vessels, nerves, and the spinal cord to pass through. The skull's primary function is to protect the delicate and vital structures within it from injury and trauma.

Mandibular diseases refer to conditions that affect the mandible, or lower jawbone. These diseases can be classified as congenital (present at birth) or acquired (developing after birth). They can also be categorized based on the tissues involved, such as bone, muscle, or cartilage. Some examples of mandibular diseases include:

1. Mandibular fractures: These are breaks in the lower jawbone that can result from trauma or injury.
2. Osteomyelitis: This is an infection of the bone and surrounding tissues, which can affect the mandible.
3. Temporomandibular joint (TMJ) disorders: These are conditions that affect the joint that connects the jawbone to the skull, causing pain and limited movement.
4. Mandibular tumors: These are abnormal growths that can be benign or malignant, and can develop in any of the tissues of the mandible.
5. Osteonecrosis: This is a condition where the bone tissue dies due to lack of blood supply, which can affect the mandible.
6. Cleft lip and palate: This is a congenital deformity that affects the development of the face and mouth, including the lower jawbone.
7. Mandibular hypoplasia: This is a condition where the lower jawbone does not develop properly, leading to a small or recessed chin.
8. Developmental disorders: These are conditions that affect the growth and development of the mandible, such as condylar hyperplasia or hemifacial microsomia.

'Leg bones' is a general term that refers to the bones in the leg portion of the lower extremity. In humans, this would specifically include:

1. Femur: This is the thigh bone, the longest and strongest bone in the human body. It connects the hip bone to the knee.

2. Patella: This is the kneecap, a small triangular bone located at the front of the knee joint.

3. Tibia and Fibula: These are the bones of the lower leg. The tibia, or shin bone, is the larger of the two and bears most of the body's weight. It connects the knee to the ankle. The fibula, a slender bone, runs parallel to the tibia on its outside.

Please note that in medical terminology, 'leg bones' doesn't include the bones of the foot (tarsal bones, metatarsal bones, and phalanges), which are often collectively referred to as the 'foot bones'.

The frontal bone is the bone that forms the forehead and the upper part of the eye sockets (orbits) in the skull. It is a single, flat bone that has a prominent ridge in the middle called the superior sagittal sinus, which contains venous blood. The frontal bone articulates with several other bones, including the parietal bones at the sides and back, the nasal bones in the center of the face, and the zygomatic (cheek) bones at the lower sides of the orbits.

Café-au-lait spots are light to dark brown, flat patches on the skin that are benign and usually harmless. The term "café-au-lait" means "coffee with milk," which describes the color of these spots. They can vary in size from a few millimeters to several centimeters in diameter and can appear anywhere on the body, although they are most commonly found on the trunk and buttocks.

While café-au-lait spots are common and can occur in up to 20% of the general population, having multiple (more than six) such spots, especially if they are large or present at birth, may be a sign of an underlying medical condition, such as neurofibromatosis type 1 (NF1), a genetic disorder that affects the growth and development of nerve tissue.

Therefore, it is essential to monitor café-au-lait spots and report any changes or concerns to a healthcare provider.

Ectodermal dysplasia (ED) is a group of genetic disorders that affect the development and formation of ectodermal tissues, which include the skin, hair, nails, teeth, and sweat glands. The condition is usually present at birth or appears in early infancy.

The symptoms of ED can vary widely depending on the specific type and severity of the disorder. Common features may include:

* Sparse or absent hair
* Thin, wrinkled, or rough skin
* Abnormal or missing teeth
* Nail abnormalities
* Absent or reduced sweat glands, leading to heat intolerance and problems regulating body temperature
* Ear abnormalities, which can result in hearing loss
* Eye abnormalities

ED is caused by mutations in genes that are involved in the development of ectodermal tissues. Most cases of ED are inherited in an autosomal dominant or autosomal recessive pattern, meaning that a child can inherit the disorder even if only one parent (dominant) or both parents (recessive) carry the mutated gene.

There is no cure for ED, but treatment is focused on managing the symptoms and improving quality of life. This may include measures to maintain body temperature, such as cooling vests or frequent cool baths; dental treatments to replace missing teeth; hearing aids for hearing loss; and skin care regimens to prevent dryness and irritation.

Maxillary diseases refer to conditions that affect the maxilla, which is the upper bone of the jaw. This bone plays an essential role in functions such as biting, chewing, and speaking, and also forms the upper part of the oral cavity, houses the upper teeth, and supports the nose and the eyes.

Maxillary diseases can be caused by various factors, including infections, trauma, tumors, congenital abnormalities, or systemic conditions. Some common maxillary diseases include:

1. Maxillary sinusitis: Inflammation of the maxillary sinuses, which are air-filled cavities located within the maxilla, can cause symptoms such as nasal congestion, facial pain, and headaches.
2. Periodontal disease: Infection and inflammation of the tissues surrounding the teeth, including the gums and the alveolar bone (which is part of the maxilla), can lead to tooth loss and other complications.
3. Maxillary fractures: Trauma to the face can result in fractures of the maxilla, which can cause pain, swelling, and difficulty breathing or speaking.
4. Maxillary cysts and tumors: Abnormal growths in the maxilla can be benign or malignant and may require surgical intervention.
5. Oral cancer: Cancerous lesions in the oral cavity, including the maxilla, can cause pain, swelling, and difficulty swallowing or speaking.

Treatment for maxillary diseases depends on the specific condition and its severity. Treatment options may include antibiotics, surgery, radiation therapy, or chemotherapy. Regular dental check-ups and good oral hygiene practices can help prevent many maxillary diseases.

The sphenoid sinuses are air-filled spaces located within the sphenoid bone, which is one of the bones that make up the skull base. These sinuses are located deep inside the skull, behind the eyes and nasal cavity. They are paired and separated by a thin bony septum, and each one opens into the corresponding nasal cavity through a small opening called the sphenoethmoidal recess. The sphenoid sinuses vary greatly in size and shape between individuals. They develop during childhood and continue to grow until early adulthood. The function of the sphenoid sinuses, like other paranasal sinuses, is not entirely clear, but they may contribute to reducing the weight of the skull, resonating voice during speech, and insulating the brain from trauma.

In medical terms, ribs are the long, curved bones that make up the ribcage in the human body. They articulate with the thoracic vertebrae posteriorly and connect to the sternum anteriorly via costal cartilages. There are 12 pairs of ribs in total, and they play a crucial role in protecting the lungs and heart, allowing room for expansion and contraction during breathing. Ribs also provide attachment points for various muscles involved in respiration and posture.

Orbital diseases refer to a group of medical conditions that affect the orbit, which is the bony cavity in the skull that contains the eye, muscles, nerves, fat, and blood vessels. These diseases can cause various symptoms such as eyelid swelling, protrusion or displacement of the eyeball, double vision, pain, and limited extraocular muscle movement.

Orbital diseases can be broadly classified into inflammatory, infectious, neoplastic (benign or malignant), vascular, traumatic, and congenital categories. Some examples of orbital diseases include:

* Orbital cellulitis: a bacterial or fungal infection that causes swelling and inflammation in the orbit
* Graves' disease: an autoimmune disorder that affects the thyroid gland and can cause protrusion of the eyeballs (exophthalmos)
* Orbital tumors: benign or malignant growths that develop in the orbit, such as optic nerve gliomas, lacrimal gland tumors, and lymphomas
* Carotid-cavernous fistulas: abnormal connections between the carotid artery and cavernous sinus, leading to pulsatile proptosis and other symptoms
* Orbital fractures: breaks in the bones surrounding the orbit, often caused by trauma
* Congenital anomalies: structural abnormalities present at birth, such as craniofacial syndromes or dermoid cysts.

Proper diagnosis and management of orbital diseases require a multidisciplinary approach involving ophthalmologists, neurologists, radiologists, and other specialists.

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