NEET MDS Synopsis
Muscles of the Soft Palate
AnatomyMuscles of the Soft Palate
The Levator Veli Palatini (Levator Palati)
Superior attachment: cartilage of the auditory tube and petrous part of temporal bone.
Inferior attachment: palatine aponeurosis.
Innervation: pharyngeal branch of vagus via pharyngeal plexus.
This cylindrical muscle runs inferoanteriorly, spreading out in the soft palate, where it attaches to the superior surface of the palatine aponeurosis.
It elevates the soft palate, drawing it superiorly and posteriorly.
It also opens the auditory tube to equalise air pressure in the middle ear and pharynx.
The Tensor Veli Palatini (Tensor Palati)
Superior attachment: scaphoid fossa of medial pterygoid plate, spine of sphenoid bone, and cartilage of auditory tube.
Inferior attachment: palatine aponeurosis.
Innervation: medial pterygoid nerve (a branch of the mandibular nerve).
This thin, triangular muscle passes inferiorly, and hooks around the hamulus of the medial pterygoid plate.
It then inserts into the palatine aponeurosis.
This muscle tenses the soft palate by using the hamulus as a pulley.
It also pulls the membranous portion of the auditory tube open to equalise air pressure of the middle ear and pharynx.
The Palatoglossus Muscle
Superior attachment: palatine aponeurosis.
Inferior attachment: side of tongue.
Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.
This muscle, covered by mucous membrane, forms the palatoglossal arch.
The palatoglossus elevates the posterior part of the tongue and draws the soft palate inferiorly onto the tongue.
Superior attachment: hard palatThe Palatopharyngeus Musclee and palatine aponeurosis.
Inferior attachment: lateral wall of pharynx.
Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.
This thin, flat muscle is covered with mucous membrane to form the palatopharyngeal arch.
It passes posteroinferiorly in this arch.
This muscle tenses the soft palate and pulls the walls of the pharynx superiorly, anteriorly and medially during swallowing.
The Musculus Uvulae
Superior attachment: posterior nasal spine and palatine aponeurosis.
Inferior attachment: mucosa of uvula.
Innervation: cranial part of accessory through the pharyngeal branch of vagus, via the pharyngeal plexus.
It passes posteriorly on each side of the median plane and inserts into the mucosa of the uvula.
When the muscle contracts, it shortens the uvula and pulls it superiorly.
The Lateral Pterygoid Muscle
AnatomyThe Lateral Pterygoid Muscle
This is a short, thick muscle that has two heads or origin.
It is a conical muscle with its apex pointing posteriorly.
Origin: superior head—infratemporal surface and infratemporal crest of the greater wing of the sphenoid bone, inferior head—lateral surface of lateral pterygoid plate.
Insertion: neck of mandible, articular disc, and capsule of temporomandibular joint.
Innervation: mandibular nerve via lateral pterygoid nerve from anterior trunk, which enters it deep surface.
Acting together, these muscles protrude the mandible and depress the chin.
Acting alone and alternately, they produce side-to-side movements of the mandible.
Embrasures
PeriodontologyClassification of Embrasures
Type I Embrasures:
Description: These are characterized by the
presence of interdental papillae that completely fill the embrasure
space, with no gingival recession.
Recommended Cleaning Device:
Dental Floss: Dental floss is most effective in
cleaning Type I embrasures. It can effectively remove plaque and
debris from the tight spaces between teeth.
Type II Embrasures:
Description: These embrasures have larger spaces
due to some loss of attachment, but the interdental papillae are still
present.
Recommended Cleaning Device:
Interproximal Brush: For Type II embrasures,
interproximal brushes are recommended. These brushes have bristles
that can effectively clean around the exposed root surfaces and
between teeth, providing better plaque removal than dental floss in
these larger spaces.
Type III Embrasures:
Description: These spaces occur when there is
significant loss of attachment, resulting in the absence of interdental
papillae.
Recommended Cleaning Device:
Single Tufted Brushes: Single tufted brushes
(also known as end-tuft brushes) are ideal for cleaning Type III
embrasures. They can reach areas that are difficult to access with
traditional floss or brushes, effectively cleaning the exposed root
surfaces and the surrounding areas.
Cricothyroidotomy
General SurgeryCricothyroidotomy
Cricothyroidotomy is a surgical procedure that involves making an incision
through the skin over the cricothyroid membrane, which is located between the
thyroid and cricoid cartilages in the neck. This procedure is performed to
establish an emergency airway in situations where intubation is not possible or
has failed, such as in cases of severe airway obstruction, facial trauma, or
anaphylaxis.
Indications
Cricothyroidotomy is indicated in the following situations:
Acute Airway Obstruction: When there is a complete
blockage of the upper airway due to swelling, foreign body, or trauma.
Failed Intubation: When attempts to secure an airway
via endotracheal intubation have been unsuccessful.
Facial or Neck Trauma: In cases where traditional
airway management is compromised due to injury.
Severe Anaphylaxis: When rapid airway access is needed
and other methods are not feasible.
Anatomy
Cricothyroid Membrane: The membrane lies between the
thyroid and cricoid cartilages and is a key landmark for the procedure.
Surrounding Structures: Important structures in the
vicinity include the carotid arteries, jugular veins, and the recurrent
laryngeal nerve, which must be avoided during the procedure.
Procedure
Preparation
Positioning: The patient should be in a supine position
with the neck extended to improve access to the cricothyroid membrane.
Sterilization: The area should be cleaned and
sterilized to reduce the risk of infection.
Anesthesia: Local anesthesia may be administered, but
in emergency situations, this step may be skipped.
Steps
Identify the Cricothyroid Membrane: Palpate the thyroid
and cricoid cartilages to locate the membrane, which is typically located
about 1-2 cm below the thyroid notch.
Make the Incision: Using a scalpel, make a vertical
incision through the skin over the cricothyroid membrane, approximately 2-3
cm in length.
Incise the Membrane: Carefully incise the cricothyroid
membrane horizontally to create an opening into the airway.
Insert the Airway Device:
A tracheostomy tube or a large-bore cannula (e.g., a 14-gauge
catheter) is inserted into the opening to establish an airway.
Ensure that the device is positioned correctly to allow for
ventilation.
Secure the Airway: If using a tracheostomy tube, secure
it in place to prevent dislodgment.
Post-Procedure Care
Ventilation: Connect the airway device to a
bag-valve-mask (BVM) or ventilator to provide oxygenation and ventilation.
Monitoring: Continuously monitor the patient for signs
of respiratory distress, oxygen saturation, and overall stability.
Consider Further Intervention: Plan for definitive
airway management, such as a formal tracheostomy or endotracheal intubation,
once the immediate crisis is resolved.
Complications
While cricothyroidotomy is a life-saving procedure, it can be associated with
several complications, including:
Infection: Risk of infection at the incision site.
Hemorrhage: Potential bleeding from surrounding
vessels.
Damage to Surrounding Structures: Injury to the
recurrent laryngeal nerve, carotid arteries, or jugular veins.
Subcutaneous Emphysema: Air escaping into the
subcutaneous tissue.
Tracheal Injury: If the incision is not made correctly,
there is a risk of damaging the trachea.
Ofloxacin
Pharmacology
Ofloxacin : It is a quinolone antibiotic and similar in structure to levofloxacin. It is an alternative treatment to ciprofloxacin for anthrax.
Itraconazole
Pharmacology
Itraconazole:
The drug may be given orally or intravenously.
Cori Cycle
Biochemistry
Cori Cycle
The Cori Cycle operates during exercise, when aerobic metabolism in muscle cannot keep up with energy needs.
For a brief burst of ATP utilization, muscle cells utilize ~P stored as phosphocreatine. For more extended exercise, ATP is mainly provided by Glycolysis.
Lactate, produced from pyruvate, passes via the blood to the liver where it is converted to glucose. The glucose may travel back to the muscle to fuel Glycolysis.
The Cori Cycle costs 6 P in liver for every 2P made available in muscle. The net cost is 4 P Although costly in terms of "high energy" bonds, the Cori Cycle allows the organism to accommodate to large fluctuations in energy needs of skeletal muscle between rest and exercise.
MAXILLARY FIRST MOLAR
Dental Anatomy
MAXILLARY FIRST MOLAR
The first molars are also known as 6-year molars, because they erupt when a child is about 6 years
Facial Surface:-The facial surface has a facial groove that continues over from the occlusal surface, and runs down to the middle third of the facial surface.
Lingual Surface:-In a great many instances, there is a cusp on the lingual surface of the mesiolingual cusp. This is a fifth cusp called the cusp of Carabelli, which is in addition to the four cusps on the occlusal surface.
Proximal: In mesial perspective the mesiolingual cusp, mesial marginal ridge, and mesiobuccal cusp comprise the occlusal outline. In its distal aspect, the two distal cusps are clearly seen; however, the distal marginal ridge is somewhat shorter than the mesial one.
Occlusal Surface:- The tooth outline is somewhat rhomboidal with four distinct cusps. The cusp order according to size is: mesiolingual, mesiobuccal, distobuccal, and distolingual. The tips of the mesiolingual, mesiobuccal, and distobuccal cusps form the trigon, Cusp of Carabelli located on the mesiolingual cusp.
Contact Points; The mesial contact is above, but close to, the mesial marginal ridge. It is somewhat buccal to the center of the crown mesiodistally. The distal contact is similarly above the distal marginal ridge but is centered buccolingually.
Roots:-The maxillary first molar has three roots, which are named according to their locations mesiofacial, distofacial, and lingual (or palatal root). The lingual root is the largest.