There are 6 pharyngeal arches, the fifth does not contribute any useful structures and often fuses with the sixth arch. The structures arising from the aortic arches are as follows:First aortic arch: It regresses except for a very small part that gives rise to the maxillary artery.Second aortic arch: It regresses except for a very small part giving rise to the stapedial artery.Third aortic arch: This arch is the source of the common carotid artery and the proximal part of the internal carotid artery, and the external carotid which arises as a bud from this arch.Right Fourth aortic arch: Is the genesis of the proximal part of the right subclavian artery.Left Fourth aortic arch: Gives rise to the medial portion of the arch of the aorta.Fifth aortic arch: The fifth aortic arch regresses completely and very early in the development.Sixth aortic arch: Either of the sixth aortic arches divides into ventral and dorsal segments, and therefore, their derivatives also divide into these two segments.Right Sixth Arch:Ventral: Gives rise to the right pulmonary artery.Dorsal: It degenerates completely and loses its connection with the dorsal aorta.Left Sixth ArchVentral: It gives rise to the left pulmonary artery that goes to the left pulmonary bud.Dorsal: It forms a vital connection during intrauterine life between the left pulmonary artery and the arch of the aorta. This structure is called ductus arteriosus.

Management of acute otitis media should begin with adequate analgesia. Antibiotic therapy can be deferred in children two years or older with mild symptoms. Antibiotics should be prescribed immediately if:- Symptoms lasting more than 4 days or not improving- Systemically unwell but not requiring admission- Immunocompromise or high risk of complications secondary to significant heart, lung, kidney, liver, or neuromuscular disease- Younger than 2 years with bilateral otitis media- Otitis media with perforation and/or discharge in the canaHigh-dose amoxicillin (80 to 90 mg per kg per day) is the antibiotic of choice for treating acute otitis media in patients who are not allergic to penicillin, otherwise erythromycin or clarithromycin should be given.

The swelling and bruising on the mandible needs to be checked for fractures. A facial X-ray can adequately visualize this.

At least seven episodes in the previous year, five episodes in each of the previous two years, or three episodes in each of the previous three years are indications for tonsillectomy. Antibiotics should be administered in the conventional dosage for proved or suspected streptococcal episodes. For now the child should be treated on a case by case basis.

The parotid duct (Stensen’s duct), which provides an exit for the gland’s secretions, passes through the anterior edge of the gland in the superficial lobe, turns medially at the anterior border of the masseter, penetrates the buccinator, then enters the oral cavity lateral to the second maxillary molar.

For Otorhinolaryngologist, removal of foreign bodies (FB) from the ear, nose and throat is one of the common emergency procedures done. Most of the cases especially of the ear and nose can be managed without General Anaesthesia (GA). But in some cases GA may be needed. As the child is mentally unstable, he is unlikely to be able to hold still while the foreign body (pea) is being removed with a forceps, which could result in instrumental damage to the ear canal. Pea is an organic foreign body and not metallic hence the use of magnets would not be of any help either. From the options provided, general anaesthesia would be the best option in this child.

Adenoid tissue sometimes swell as a result of fighting off the infection as germs are trapped in the adenoids. Adenoid enlargement is suspected.

NICE does not recommend the use of antibiotics or tonsillectomy in this case. Paracetamol/Ibuprofen are indicated as they provide antipyretic action and analgesia. Indications for tonsillectomy are 5 or more episodes of acute sore throat/year, symptoms present for at least 2 years, symptoms are severe enough to disrupt a child’s social life. Indications for antibiotics are features of marked systemic upset secondary to the acute sore throat, unilateral peritonsillitis, history of rheumatic fever, an increased risk from acute infection, acute tonsillitis with 3 or more of the following: history of fever, tonsillar exudates, no cough and tender anterior cervical lymphadenopathy.

The most appropriate next step in the management would be to refer the patient for an ENT opinion. Rationale:This child has clinical signs of adenotonsillar hypertrophy, symptoms of persistent snoring and features of obstructive sleep apnoea (OSA). Suspected OSA warrants referral to an ENT specialist. Other options:- Capillary blood gas: The investigation consists of overnight oxygen saturation monitoring or polysomnography.- Chest X-ray: A chest x-ray is not indicated.- Phenoxymethylpenicillin (Penicillin V) is the first-line treatment for tonsillitis. However, with a history of several months and no suggestion of fever or sore throat, acute tonsillitis is unlikely.- Weight loss advice: Obesity is a risk factor for obstructive sleep apnoea (OSA) amongst other health problems. The child’s weight should be highlighted and advice and support for weight loss provided however referral to ENT is warranted for further investigation.

The child has Chronic suppurative otitis media (CSOM) which is defined as a perforated tympanic membrane with persistent drainage from the middle ear for more than 2-6 weeks.CSOM differs from chronic serous otitis media in that chronic serous otitis media may be defined as a middle ear effusion without perforation that is reported to persist for more than 1-3 months. Patients with chronic suppurative otitis media (CSOM) present with a draining ear of some duration and a premorbid history of recurrent acute otitis media, traumatic perforation, or the placement of ventilation tubes. Typically, they deny pain or discomfort. A common presenting symptom is hearing loss in the affected ear. Reports of fever, vertigo, and pain should raise concerns about infratemporal or intracranial complications. A history of persistent CSOM after appropriate medical treatment should alert the physician to consider cholesteatoma.The external auditory canal may or may not be oedematous and is not typically tender. The discharge varies from fetid, purulent, and cheese like to clear and serous. Granulation tissue is often seen in the medial canal or middle ear space. The middle ear mucosa visualized through the perforation may be oedematous or even polypoid, pale, or erythematous.

Omega-shaped epiglottis is a characteristic feature in the X-ray of a patient with laryngomalacia.

Epistaxis is common in younger children usually due to nose picking. After the episode is over no active management is required and reassurance should be given to the patient and his attendants.

Removal of foreign bodies from the ear is indicated whenever a well-visualized foreign body is identified in the external auditory canal. Insects are better extracted with suction than with forceps or hooks. From the given answers, irrigation with warm water is the most suitable answer.

Based on the clinical scenario, the most probable diagnosis for this patient is maxillary sinusitis.The maxillary sinus drains from its superior aspect, leaving it prone to infections. It is the most commonly affected sinus in sinusitis.Common symptoms of maxillary sinusitis include postnasal discharge, pain, headache and toothache.Radiological imaging may show a fluid level in the antrum.Common organisms causing maxillary sinusitis include Haemophilus influenzae or Streptococcus pneumoniae.Treatment with antral lavage may facilitate diagnosis and relieve symptoms. Antimicrobial therapy has to be continued for long periods. Antrostomy may be needed.Other options:- Frontal sinusitis more commonly causes intracranial complications, but it is still less frequent than maxillary sinusitis.- The petrosal sinus is not a cavity within bone| rather, it is a venous structure located beneath the brain.- Frontoethmoidal sinusitis: It usually presents with frontal headache, nasal obstruction and altered sense of smell. Inflammation may progress to involve periorbital tissues. Ocular symptoms may occur, and secondary CNS involvement brought about by infection entering via emissary veins. CT scanning is the imaging modality of choice. Early cases may be managed with antibiotics. More severe cases usually require surgical drainage.

Lung buds are formed by 4-5 weeks of gestation.Development of the respiratory tract has five stages:- Embryonic (at 4 – 5 weeks of gestation):Formation of lung buds, trachea and mainstem bronchi occur. These structures are formed from a ventral outpouching of foregut pharynx. At this stage, the beginnings of the five lung lobes are present.- Pseudoglandular (at 5 – 16 weeks of gestation):Formation of terminal bronchioles, cartilage and smooth muscles occur in this stage. Adult numbers of airways proximal to acini are in place.- Canalicular (at 16-24 weeks gestation): Differentiation of type I and II epithelial cells can be done in this stage. There is also an increase in the size of proximal airways).- Saccular (at 24 – 40 weeks of gestation): Terminal saccule formation occurs. Production of surfactant takes place at this stage with an increase in the number of goblet cellsUp to half the adult number of alveoli are in place by this stage.- Alveolar (occurs between 32 weeks of gestation till the post-natal age 8): Formation of alveoli and septation occurs with the expansion of air spaces.

Thyroglossal cyst is the most common congenital thyroid anomaly which is clinically significant and affects women more than men. It is a vestigial remnant of developing thyroid. Although the thyroglossal cyst can develop anywhere along the thyroglossal duct, the most common site is in the midline between the isthmus of thyroid and hyoid bone, or just above the hyoid. Thyroglossal cysts are also associated with ectopic thyroid tissue. Clinically, the cyst moves upward with protrusion of the tongue. Rarely, the persistent duct can become malignant (thyroglossal duct carcinoma) where the cancerous cells arise in the ectopic thyroid tissue that are deposited along the duct. Exposure to radiation is a predisposing factor.

The external auditory canal (EAC) extends from the auricle to the tympanic membrane. Its lateral portion is fibrocartilaginous and its medial portion is bony. Its bony portion is formed by the tympanic portion of the temporal bone.

Upper respiratory tract infection when not treated accordingly can lead to otitis media and the patient presents with severe earache and fever.

Not uncommonly, children insert a foreign body in their ear canal and do not mention it to their parents. If any pain accompanies purulent drainage, the possibility of a foreign body in the ear canal should be considered. A patient with a foreign body in place will not improve until it is removedOrganic foreign bodies tend to elicit inflammatory reactions. In the ear, they predispose to otitis externa, suppurative otitis media and hearing loss

A lymphangioma is a swelling or mass that occurs mainly in the head, neck, and mouth. Lymphangiomas are the result of a congenital condition and are usually apparent at birth, or at least by the time a person is 2 years old. It is rare in adult population and when detected, it can be treated with surgical excision. Branchial cyst in most cases does not transilluminate which lymphangioma does.