NEET MDS Synopsis
Most Common Site of Primary Bone Tumors
Orthopaedics
Most Common Site of Primary Bone Tumors
Epiphyseal
- Chondroblastoma (before physeal closure)
- Osteoclastom/Giant cell tumor (after physeal closure in adults)
- Articular osteochondroma
Metaphyseal
- Chondrosarcoma
- Enchondroma
- Osteochondroma
- Osteoblastoma
- Bone cyst
- Osteosarcorna
- Osteoclastoma (in children)
- Osteomyelitis mostly starts in metaphysis
?Diaphyseal
- Round cell lesions: Ewing’s sarcoma/Multiple myeloma /Reticulum cell sarcoma
- Admantinoma
- Osteoid osteoma
Hyperthyroidism
General Pathology
Hyperthyroidism
Hyperthyroidism (Thyrotoxicosis) is a hypermetabolic state caused by elevated circulating levels of free T3 and T4 . This may primary (Graves disease) or rarely, secondary (due to pituitary or hypothalamic diseases).
- The diagnosis is based on clinical features and laboratory data.
Lab Test
- The measurement of serum TSH concentration provides the most useful single screening test for hyperthyroidism, because TSH levels are decreased in primary cases, even when the disease is still be subclinical.
- In secondary cases TSH levels are either normal or raised.
- A low TSH value is usually associated with increased levels of free T4 .
- Occasionally, hyperthyroidism results from increased levels of T3 .
Nerve Supply of the Muscles of the Orbit
AnatomyNerve Supply of the Muscles of the Orbit (pp. 715-6)
Three cranial nerves supply the muscles of the eyeball; the oculomotor (CN III), trochlear (CN IV) and abducent (CN IV) nerves.
All three enter the orbit via the superior orbital fissure.
The trochlear nerve supplies the superior oblique muscle.
The abducent nerve supplies the lateral rectus muscle.
The oculomotor nerve supplies everything else.
A mnemonic that is used is this formula for this strange sulfate: SO4(LR6)3
Parasympathetic Ganglia Of Head And Neck
Anatomy
Important parasympathetic ganglia in head and neck are :
(i) otic ganglion,
(ii) submandibular ganglion,
(iii) pterygopalatine ganglion
(iv) ciliary ganglion.
Otic Ganglion
Topographically, it is connected to mandibular nerve, while functionally it is related to glossopharyngeal (IX) nerve. Its roots are:-
Sensory root:-By Auriculotemporal nerve.
Sympathetic root:-By sympathetic plexus around middle meningeal artery.
Parasympathetic (secretomotor) root: - This root is by lesser petrosal nerve. Preganglionic fibres begin in inferior salivatory nucleus, pass through glossopharyngeal nerve, then its tympanic branch, tympanic plexus, and the lesser petrosal nerve and relay in otic ganglion.
Postganglionic fibers pass through auriculotemporal nerve and supplies parotid gland.
Motor root :- It is derived from nerve to medial pterygoid which passes unrelayed through ganglion and supplied tensor veli palatini and tensor tympani (Note :- Otic ganglion has a motor root, beside three standard roots of parasympathetic ganglion of head and neck: sensory, sympathetic and parasympathetic).
Submandibular Ganglion
Functionally, submandibular ganglion is connected to facial nerve, while topographically it is connected to lingual branch ofmandibular nerve. Its roots are :-
Sensory root: - It is from lingual nerve.
Sympathetic root: - It is from sympathetic plexus around facial artery, which contains postganglionic fibers from superior cervical ganglion of sympathetic trunk.
Secretomotor (parasympathetic) root: - Preganglionic fibers arise from superior salivatory nucleus pass through facial nerve then its chorda tympani branch which joins lingual nerve and relay in submandibular ganglion.
Postganglionic fibers supply :-Directly submandibulargland.
Through lingual nerveSublingual salivary gland and glands in oral cavity.
Pterygopalatine Ganglion (Sphenopalatine Ganglion)
It is the largest parasympathetic ganglion, suspended by two roots to maxillary nerve. Functionally, it is related to facial nerve. It is called ganglion of "hay fever". Its roots are:-
Sensory root:-It is from maxillary nerve.
Sympathetic root:-It is sympathetic plexus around internal carotid artery through deep petrosal nerve.
Secretomotor (parasympathetic) root:-Preganglionic fibers arise from lacrimatory nucleus, pass through facial nerve, then to its greater petrosal branch. Greater petrosal nerve unites with deep petrosal nerve (sympathetic fibers) to form nerve to pterygoid canal (Vidian nerve). Fibers reach to pterygopalatine ganglion; only fibers of greater petrosal nerve relay in the ganglion, not of deep petrosal nerve.
Postganglionic fibers supply lacrimal gland and palatal glands, and pharyngeal glands.
Branches of the pterygopalatine ganglion are :-
For lacrimal gland: - Postganglionic fibers pass through zygomatic nerve (branch of maxillary nerve), its zygomaticotemporal division which gives communicating branch to lacrimal nerve for supplying lacrimal gland.
Nasopalatine nerve:-For nasal and palatal glands.
Nasal branches: - For mucous membrane and glands oflateral wall of nasal cavity.
Palatine branches: - One greater palatine and 2-3 lesser palatine branches for glands of soft palate and hard palate.
Orbital branches: - For orbital periosteum.
Pharyngeal branches:-For glands of pharynx.
Ciliary Ganglion
Topographically, ciliary ganglion is related to nasociliary nerve (a branch of ophthalmic division of trigeminal nerve), but functionally it is related to oculomotor nerve. Its roots are:-
Sensory root:-It is from nasociliary nerve.
Sympathetic root: - It is from plexus around ophthalmic artery.
Parasympathetic root: - It is from a branch to inferior oblique muscle. These fibers arise from Edinger – Westphalnucleus, join oculomotor nerve and then to its branch to inferior oblique to relay in ciliary ganglion.
Postganglionic fibers pass through short ciliary nerves to supply sphincter pupillae and ciliary muscles.
Nutrition and tooth development
Dental Anatomy
Nutrition and tooth development
As in other aspects of human growth and development, nutrition has an effect on the developing tooth. Essential nutrients for a healthy tooth include calcium, phosphorus, fluoride, and vitamins A, C, and D. Calcium and phosphorus are needed to properly form the hydroxyapatite crystals, and their levels in the blood are maintained by Vitamin D. Vitamin A is necessary for the formation of keratin, as Vitamin C is for collagen. Fluoride is incorporated into the hydroxyapatite crystal of a developing tooth and makes it more resistant to demineralization and subsequent decay.
Deficiencies of these nutrients can have a wide range of effects on tooth development. In situations where calcium, phosphorus, and vitamin D are deficient, the hard structures of a tooth may be less mineralized. A lack of vitamin A can cause a reduction in the amount of enamel formation. Fluoride deficency causes increased demineralization when the tooth is exposed to an acidic environment, and also delays remineralization. Furthermore, an excess of fluoride while a tooth is in development can lead to a condition known as fluorosis.
Dental Indices
Public Health Dentistry
Plaque index (PlI)
0 = No plaque in the gingival area.
1 = A thin film of plaque adhering to the free gingival margin and adjacent to the area of the tooth. The plaque is not readily visible, but is recognized by running a periodontal probe across the tooth surface.
2 = Moderate accumulation of plaque on the gingival margin, within the gingival pocket, and/or adjacent to the tooth surface, which can be observed visually.
3 = Abundance of soft matter within the gingival pocket and/or adjacent to the tooth surface.
Gingival index (GI)
0 = Healthy gingiva.
1= Mild inflammation: characterized by a slight change in color, edema. No bleeding observed on gentle probing.
2 = Moderate inflammation: characterized by redness, edema, and glazing. Bleeding on probing observed.
3 = Severe inflammation: characterized by marked redness and edema. Ulceration with a tendency toward spontaneous bleeding.
Modified gingival index (MGI)
0 = Absence of inflammation.
1 = Mild inflammation: characterized by a slight change in texture of any portion of, but not the entire marginal or papillary gingival unit.
2 = Mild inflammation: criteria as above, but involving the entire marginal or papillary gingival unit.
3 = Moderate inflammation: characterized by glazing, redness, edema, and/or hypertrophy of the marginal or papillary gingival unit.
4 = Severe inflammation: marked redness, edema, and/or hypertrophy of the marginal or papillary gingival unit, spontaneous bleeding, or ulceration.
Community periodontal index (CPI)
0 = Healthy gingiva.
1 = Bleeding observed after gentle probing or by visualization.
2 = Calculus felt during probing, but all of the black area of the probe remains visible (3.5-5.5 mm from ball tip).
3 = Pocket 4 or 5 mm (gingival margin situated on black area of probe, approximately 3.5-5.5 mm from the probe tip).
4 = Pocket > 6 mm (black area of probe is not visible).
Periodontal screening and recording (PSR)
0 = Healthy gingiva. Colored area of the probe remains visible, and no evidence of calculus or defective margins is detected.
1 = Colored area of the probe remains visible and no evidence of calculus or defective margins is detected, but bleeding on probing is noted.
2 = Colored area of the probe remains visible and calculus or defective margins is detected.
3 = Colored area of the probe remains partly visible (probe depth between 3.5-5.5 mm).
4 = Colored area of the probe completely disappears (probe depth > 5.5 mm).
Multiple myeloma
General Pathology
Multiple myeloma.
Blood picture:
- Marked rouleaux formation.
- Normpcytic normochromic anaemia.
- There may be leucopenia or leucoery!hrohlastic reaction.
- Atypical plasma cells may be seen in some patients
- Raised ESR
- Monoclonal hypergammaglobulinaemia
- If light chains are produced in excess, they are excreted in urine as bence jones protein
Bone marrow
- Hyper cellular
- Plasma cells from at least 15 – 30% atypical forms and myeloma cells are seen.
Clarithromycin
Pharmacology
Clarithromycin Used to treat pharyngitis, tonsillitis, acute maxillary
sinusitis, acute bacterial exacerbation of chronic bronchitis, pneumonia (especially atypical pneumonias associated with Chlamydia pneumoniae or TWAR), skin and skin structure infections, and, in HIV and AIDS patients to prevent, and to treat, disseminated Mycobacterium avium complex or MAC.
Unlike erythromycin, clarithromycin is acid-stable and can therefore be taken orally without being protected from gastric acids. It is readily absorbed, and diffused into most tissues and phagocytes.
Clarithromycin has a fairly rapid first-pass hepatic metabolism, i.e it is metabolised by the liver. However, this metabolite, 14-hydroxy clarithromycin is almost twice as active as clarithromycin.
Contraindications Clarithromycin should be used with caution if the patient has liver or kidney disease, certain heart problems (e.g., QTc prolongation or bradycardia), or a mineral imbalance (e.g., low potassium or magnesium levels).