The anterior triangle is the triangular area of the neck found anteriorly to the sternocleidomastoid muscle. It is formed by the anterior border of sternocleidomastoid laterally, the median line of the neck medially and by the inferior border of the mandible superiorly. The apex of the anterior triangle extends towards the manubrium sterni. The anterior triangle contains:Muscles: thyrohyoid, sternothyroid, sternohyoid musclesOrgans: thyroid gland, parathyroid glands, larynx, trachea, esophagus, submandibular gland, caudal part of the parotid glandArteries: superior and inferior thyroid, common carotid, external carotid, internal carotid artery (and sinus), facial, submental, lingual arteriesVeins: anterior jugular veins, internal jugular, common facial, lingual, superior thyroid, middle thyroid veins, facial vein, submental vein, lingual veinsNerves: vagus nerve (CN X), hypoglossal nerve (CN XII), part of sympathetic trunk, mylohyoid nerveThe posterior triangle is a triangular area found posteriorly to the sternocleidomastoid muscle. It has three borders; anterior, posterior and inferior borders. The anterior border is the posterior margin of the sternocleidomastoid muscle. The posterior border is the anterior margin of the trapezius muscle, while the inferior border is the middle one-third of the clavicle. The investing layer of deep cervical fascia and integument forms the roof of the space, while the floor is covered with the prevertebral fascia along with levator scapulae, splenius capitis and the scalene muscles. The inferior belly of omohyoid subdivides the posterior triangle into a small supraclavicular, and a large occipital, triangle.Contents:Vessels: the third part of the subclavian artery, suprascapular and transverse cervical branches of the thyrocervical trunk, external jugular vein, lymph nodesNerves: accessory nerve (CN XI), the trunks of the brachial plexus, fibers of the cervical plexus

Patients with hypertension are only eligible for the seasonal influenza vaccination if they have co-existent cardiac complications.The UK national policy is that the seasonal influenza vaccine should be offered to the following groups:All those aged 65 years and olderChildren aged 2 to 15 yearsResidents of nursing and residential homes for the elderly (and other long-stay facilities)Carers of persons whose welfare may be at risk if the carer falls illAll those aged 6 months or older in a clinical risk groupThe following table outlines the clinical risk groups that are considered eligible for the vaccine:CategoryExamples of eligible groupsRespiratory diseaseCOPDInterstitial lung diseaseCystic fibrosisAsthma (requiring oral or inhaled steroids)Heart diseaseCongenital heart diseaseChronic heart failureCoronary heart disease (requiring medication and/or follow-up)Hypertension with cardiac complicationsKidney diseaseChronic kidney diseaseNephrotic syndromeRenal transplant patientsLiver diseaseLiver cirrhosisChronic hepatitisBiliary atresiaNeurological diseaseCerebrovascular accidentTransient ischaemic attackEndocrine diseaseType 1 and 2 diabetesImmunosuppressionPatients undergoing chemotherapyPatients taking immunosuppressive drug therapy (including systemic steroids)Asplenia or splenic dysfunctionHIV infectionPregnancyAll pregnant women

Cortisol levels fluctuate throughout the day, with the greatest levels occurring around 0900 hours and the lowest occurring at 2400 hrs during sleep.The diurnal swing of cortisol levels is lost in Cushing’s syndrome, and levels are greater throughout the 24-hour period. In the morning, levels may be normal, but they may be high at night-time, when they are generally repressed.

Oxygen saturation should be 94 – 98% in most acutely ill patients with a normal or low arterial carbon dioxide (PaCO2). In some clinical situations, however, like cardiac arrest and carbon monoxide poisoning, it is more appropriate to aim for the highest possible oxygen saturation until the patient is stable.

Homeostasis is the property of a system in which variables are regulated so that internal conditions remain relatively constant and stable. Homeostasis is achieved by a negative feedback mechanism.Negative feedback occurs based upon a set point through receptors, comparators and effectors. The ‘set point’ is a NARROW range of values within which normal function occurs.The two body systems that regulate homeostasis are the Nervous system and the Endocrine system. The smooth muscle of the uterus becomes more active towards the end of pregnancy. This is a POSITIVE feedback.

Escherichia coli O157 is a serotype of Escherichia coli.The Escherichia coliO157 strain is ‘enterohaemorrhagic’ and causes severe forms of acute haemorrhagic diarrhoea. It can also cause non-haemorrhagic diarrhoea. Incubation period of Escherichia coli O157 is usually 3-4 days and bloody diarrhoea usually begins on the 3rd or 4th day of the infection.Infections with Escherichia coliO157 are more common during the warmer months than in winter.Haemolytic uraemic syndrome develops in approximately 6% of patients. It is commonly seen in children and in the elderly. Escherichia coli O157 can also cause:Haemorrhagic colitisHaemolytic uraemic syndromeThrombotic thrombocytopenic purpura but not immune thrombocytopenic purpura.

Relative risk (RR) is a ratio of the probability of an event occurring in the exposed group versus the probability of the event occurring in the non-exposed group.RR can be computed as the absolute risk of events in the treatment group (ART), divided by the absolute risk of events in the control group (ARC).RR = ART/ARCRR = (30/300) / (20/500)RR = 2.5Recall that:If RR < 1, then the intervention reduces the risk of the outcome.If RR = 1, then the treatment has no effect on the outcome.If RR > 1, then the intervention increases the risk of the outcome.

Extensor digitorum is a long muscle located in the posterior compartment of the forearm. Together with the extensor carpi ulnaris and extensor digiti minimi, extensor carpi radialis longus and brevis as well as the brachioradialis, it belongs to the group of superficial extensors of the forearm. These muscles can be easily palpated in the lateral aspect of the posterior forearm, especially during the extension of hand when they are contracted.Extensor digitorum runs from the lateral epicondyle of humerus to the medial four phalanges of the hand. In this way, it generates the pull for the extension of the four medial fingers in their metacarpophalangeal and both interphalangeal joints. Extensor digitorum also participates in the extension of the wrist.Extensor digitorum is innervated by posterior interosseous nerve which is a continuation of a deep branch of radial nerve (root value C7 and C8).Extensor digitorum is vascularized by the branches of three different arteries: (1) posterior interosseous artery, (2) radial recurrent artery, and (3) anterior interosseous artery. Anterior and posterior interosseous arteries are the branches of the common interosseous artery that arises from the ulnar artery. The radial recurrent artery is a branch of the radial artery.

Amiodarone is an anti-arrhythmic medication that can be used to treat both ventricular and atrial arrhythmias.The use of amiodarone is contraindicated in the following situations:Conduction disturbances that are severe (unless pacemaker fitted)Sinus node disease is a condition that affects the lymph nodes in (unless pacemaker fitted)Sensitivity to iodineBlockage of the Sino-atrial heart valve (except in cardiac arrest)Bradycardia in the sinuses (except in cardiac arrest)Thyroid disorders

Lithium is the drug of choice for bipolar disorders but is commonly associated with side effects and toxicity. Fine hand tremor is very commonly seen and reported in as many as 50% of patients during the first week of therapy with Lithium. The tremor tends to reduce with time and is only present in around 5% of patients taking the medication two years or longer. Lithium tremors are more common with older age, presumably due to the additive effects of age-related essential tremors.Option The normal therapeutic range is 2.0-2.5 mmol/l: Lithium should be carefully monitored as it has a very low therapeutic index. The normal therapeutic range is 0.4-0.8 mmol/l. Levels should be checked one week after starting therapy and one week after every change in dosage. (Option Levels should be checked one month after starting therapy) Option It can induce hyperthyroidism: Lithium has a known effect on thyroid function. Lithium decreases the production of T4 and T3 and commonly causes hypothyroidism. More rarely, lithium causes hyperthyroidism due to thyroiditis.Option It can induce diabetes mellitus: Lithium can induce nephrogenic diabetes insipidus but not diabetes mellitus.