A tonsillar sinus or fossa is a space that is bordered by the triangular fold of the palatoglossal and palatopharyngeal arches in the lateral wall of the oral cavity. The palatine tonsils are in these sinuses.

The glossopharyngeal nerve is the main sensory nerve for the tonsillar fossa. The tonsillar branches of the glossopharyngeal nerve supply the palatine tonsils forming a plexus around it. Filaments from this plexus are distributed to the soft palate and fauces where they communicate with the palatine nerves. A lesser contribution is made by the lesser palatine nerve. Because of this otalgia may occur following tonsillectomy.

The inferior mesenteric artery arises from the abdominal aorta at the level of the L3 vertebrae and supplies blood to the final third of the transverse colon, the descending colon, the sigmoid colon and the uppermost part of the rectum.

It is the artery most likely to affect the left colon.

Cardiac output = stroke volume x heart rate

Left ventricular ejection fraction = (stroke volume / end diastolic LV volume ) x 100%

Stroke volume = end diastolic LV volume – end systolic LV volume

Pulse pressure = Systolic Pressure – Diastolic Pressure

Systemic vascular resistance = mean arterial pressure / cardiac output
Factors that increase pulse pressure include:
-a less compliant aorta (this tends to occur with advancing age)
-increased stroke volume

Professor Mapleson classified non-rebreathing circuits based on the position of the APL valve, which controls fresh gas flow.

The Mapleson A (Magill) circuit is most effective in spontaneous breathing, requiring only 70-100 ml/kg (the patient’s minute volume) of fresh gas flow. The patient inhales fresh gas from the reservoir bag and tubing during inspiration. During expiration, the patient adds dead space gas (gas that hasn’t been exchanged) to the tubing and reservoir bag in addition to the fresh gas flow. At the patient’s end, alveolar gas is vented through the APL valve. During the expiratory pause, the fresh gas flow causes more gas to be released.

The Mapleson A is inefficient during controlled ventilation. Venting occurs during inspiration rather than during the expiratory phase, as it does during spontaneous ventilation. As a result, unless a high fresh gas flow of >20 L/minute is used, alveolar gas is rebreathed.

During spontaneous ventilation, the Mapleson D circuit is inefficient.

The oxygen concentration in a Hudson mask is insufficient to allow for adequate pre-oxygenation.

Based on the presenting symptoms, this is the case of bacterial meningitis. The treatment of choice for bacterial meningitis is a cephalosporin. Cephalosporin acts by inhibiting bacterial cell wall synthesis.

The liver receives blood supply from two sources.
1. Hepatic artery proper
It arises from the celiac trunk via the common hepatic artery and brings oxygenated blood to the liver.
It contributes to approximately 30% of the blood supply of the liver.
2. Hepatic portal vein – supplies the liver with partially deoxygenated blood, carrying nutrients absorbed from the small intestine. It gets tributaries from the inferior mesenteric vein, splenic vein, and superior mesenteric vein

The inferior mesenteric artery supplies the hindgut.
The superior mesenteric artery supplies the pancreas and intestine up to the proximal two-thirds of the transverse colon.
The inferior phrenic artery supplies the inferior surface of the diaphragm and oesophagus.

Being the part of a meta analysis, forest plots are more valued as evidence then randomised control trials.

The notion that forest plots can only be used if the results are substantial is not true. They are good indicators of the significance of the data. If the diamond intersects the central line, the data is rendered significant. It also aggregates means and confidence intervals from studies conducted in the past which makes the study much more reliable as errors associated with individual studies tend to have less of an impact in this way.

The suggestion that forest plots are primarily used for qualitative data is factually incorrect. Forest plots require numerical values to function.

All in all, forest plots help us in determining whether or not there is a significant trend in that particular field of study.

The diaphragm has three opening through which different structures pass from the thoracic cavity to the abdominal cavity:

Inferior vena cava passes at the level of T8.

Oesophagus, oesophageal vessels and vagi at T10.

Aorta, thoracic duct and azygous vein through T12.

Sympathetic trunk and pulmonary branches of vagus nerve form a posterior pulmonary plexus at the root of the lung. Fibres continue posteriorly from superficial cardiac plexus to form Anterior pulmonary plexus. It contains vagi nerves and superficial cardiac plexus. These fibres then follow the blood vessel and bronchi into the lungs.

The lower border of the pleura is at the level of:

8th rib in the midclavicular line

10th rib in the lower level of midaxillary line

T12 at its termination.

Both lungs have oblique fissure while right lung has transverse fissure too.

The trachea expands from the lower edge of the cricoid cartilage (at the level of the 6th cervical vertebra) to the carina.

Direct laryngoscopy are performed using laryngoscopes and they can be classed according to the shape of the blade as curved or straight.

Miller, Soper, Wisconsin and Seward are examples of straight blade laryngoscopes. Straight blades are commonly used for intubating neonates and infants but can be used in adults too.

The tip of the miller blade is advanced over the epiglottis to the tracheal entrance then lifted in order to view the vocal cords.

The RIGHT-SIDED Macintosh blade is used in adults while the left-sided blade may be used in conditions that make intubation with standard blade difficult e.g. facial deformities.

The McCoy laryngoscope is based on the STANDARD MACINTOSH blade not Robertshaw’s. It has a lever operated hinged tip, which improves the view during laryngoscopy.

Polio blade is mounted at an angle of 120-135 degrees to the handle. Originally designed for use during the polio epidemic ​in intubation patients within iron lung ventilators, it is now useful in patients with conditions like breast hypertrophy, barrel chest, and restricted neck mobility.

The bifurcation of the abdominal aorta into common iliac arteries occurs at the level of L4. The bifurcation is a common site for atherosclerotic plaques as it is an area of high turbulence.

Leriche Syndrome is an aortoiliac occlusive disease and affects the distal abdominal aorta, iliac arteries, and femoropopliteal vessels. It has a triad of symptoms:
1. Claudication (cramping lower extremities pain that is reproducible by exercise)
2. Impotence (reduced penile arterial flow)
3. Absent/weak femoral pulses (hallmark)

T12 – aorta enters the diaphragm with the thoracic duct and azygous veins

L2 – testicular or ovarian arteries branch off the aorta

L3 – inferior mesenteric artery