Ligamentum venosum is an anterior relation of the liver: The ligamentum venosum, the fibrous remnant of the ductus venosus of the fetal circulation, lies posterior to the liver. It lies in the fossa for ductus venosus that separates the caudate lobe and the left lobe of the liver. The portal triad contains three important tubes: 1. Proper hepatic artery 2. Hepatic portal vein 3. Bile ductules It also contains lymphatic vessels and a branch of the vagus nerve. The bare area of the liver is a large triangular area that is devoid of any peritoneal covering. The bare area is attached directly to the diaphragm by loose connective tissue. This nonperitoneal area is created by a wide separation between the coronary ligaments. The porta hepatis is a fissure in the inferior surface of the liver. All the neurovascular structures (except the hepatic veins) and hepatic ducts enter or leave the liver via the porta hepatis. It contains the sympathetic branch to the liver and gallbladder and the parasympathetic, hepatic branch of the vagus nerve. The caudate lobe (segment I) lies in the lesser sac on the inferior surface of the liver between the IVC on the right, the ligamentum venosum on the left, and the porta hepatis in front

The paired sublingual glands are major salivary glands in the mouth. They are the smallest, most diffuse, and the only unencapsulated major salivary glands. They provide only 3-5% of the total salivary volume. The gland receives its blood supply from the sublingual and submental arteries. The sublingual artery is a branch of the lingual artery, thus damage to the lingual artery will decrease the blood flow to the sublingual gland.

The sternocleidomastoid muscle divides the neck into anterior and posterior triangles on both sides of the neck. The posterior triangle has the following boundaries: anteriorly – sternocleidomastoid muscle posteriorly – trapezius roof – investing layer of deep cervical fascia floor – prevertebral fascia overlying splenius capitis, levator scapulae, and the scalene muscles The contents of the posterior triangle are: 1. fat 2. lymph nodes (level V) 3. accessory nerve 4. cutaneous branches of the cervical plexus (A major branch of this plexus is the phrenic nerve, which arises from the anterior divisions of spinal nerves C3-C5) 5. inferior belly of omohyoid 6. branches of the thyrocervical trunk (transverse cervical and suprascapular arteries) 7. third part of the subclavian artery 8. external jugular vein

The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. A large number of muscles attach to the hyoid: Superiorly – the middle pharyngeal constrictor muscle, hyoglossus muscle, genioglossus, intrinsic muscles of the tongue and suprahyoid muscles. Inferiorly – the thyrohyoid muscle, omohyoid muscle and sternohyoid muscle.

Based on the aforementioned findings in this case, the most likely diagnosis is medullary carcinoma of the thyroid associated with multiple endocrine neoplasia (MEN). Medullary thyroid cancer is a tumour of the parafollicular cells (C cells) of the thyroid and is neural crest in origin. It may be familial and occur as part of the MEN 2A disease spectrum. Less than 10% of thyroid cancers are of this type with patients typically presenting as children or young adults. Diarrhoea occurs in 30% of the cases. In association with MEN syndromes, medullary thyroid cancers are always bilateral and multicentric. Spread may either be lymphatic or haematogenous, and as these tumours are not derived primarily from thyroid cells, they are not responsive to radioiodine. Toxic nodular goitre is very rare. In sporadic medullary carcinoma of the thyroid, patients typically present with a unilateral solitary nodule and it tends to spread early to the lymph nodes in neck.

The glossopharyngeal nerve provides parasympathetic innervation for the parotid salivary gland via the auriculotemporal nerve. The facial nerve supplies the parasympathetic innervation of the lacrimal, nasal, sublingual and submandibular glands.

The middle meatus is a nasal passageway located inferior to the middle concha and superior to the inferior concha. On the superior aspect of this meatus is a bulge produced by the middle ethmoidal cells known as the bulla ethmoidalis. Below this bulge is a curved fissure, the hiatus semilunaris, which is also bordered inferiorly by the edge of the uncinate process of the ethmoid. It is through this curved fissure, hiatus semilunaris, that the middle meatus communicates with the frontal sinus. It first forms a communication with a curved passage way known as the infundibulum. The infundibulum anteriorly communicates with the anterior ethmoidal cells and continues upward as the frontonasal duct into the frontal sinus.

The sternocleidomastoid muscle is an important landmark in the neck as it divides the neck into two; anterior and posterior triangles. These triangles help in the location of the structures of the neck including the carotid artery, head and neck lymph nodes, accessory nerve and the brachial plexus. It originates from the manubrium and medial portion of the clavicle and inserts on the mastoid process of the temporal bone, superior nuchal line. The sternocleidomastoid receives blood supply from the occipital artery and the superior thyroid artery. It is innervated by the accessory nerve (motor)and cervical plexus (sensory).

Acute otitis media (AOM) is a painful type of ear infection. It occurs when the area behind the eardrum, the middle ear, becomes inflamed and infected.The following behaviours in children often mean they have AOM:- fits of fussiness and intense crying (in infants)- clutching the ear while wincing in pain (in toddlers)- complaining about a pain in the ear (in older children).Perforation of the tympanic membrane is not unusual as the process advances, most frequently in posterior or inferior quadrants. Before or instead of a single perforation, an opaque serum like exudate is sometimes seen oozing through the entire tympanic membrane.With perforation and in the absence of a coexistent viral infection, the patient generally experiences rapid relief of pain and fever. The discharge initially is purulent, though it may be thin and watery or bloody; pulsation of the otorrhea is common. Otorrhea from acute perforation normally lasts 1-2 days before spontaneous healing occurs. Otorrhea may persist if the perforation is accompanied by mucosal swelling or polypoid changes, which can act as a ball valve.

In adults, the spinal cord typically ends between L1/L2 whereas the subarachnoid space extends to approximately the lower border of vertebra S2. Lumbar puncture is performed in the intervertebral space L4/L5 or L3/L4.

The cricoid cartilage is a hyaline cartilage ring surrounding the trachea. It provides support for key phonation muscles. The inferior border of the cricoid cartilage is attached to the thyroid cartilage and the inferior border is attached to the first tracheal ring through the cricotracheal ligament. Application of pressure to the cricoid cartilage to reduce risk of aspiration of gastric contents (Sellick manoeuvre) does not stop tracheal aspiration and cannot stop regurgitation into the oesophagus. A force of 44 newtons to the cricoid cartilage is needed to control regurgitation.

Bell’s palsy is facial muscle weakness or paralysis that arises from idiopathic damage to the facial nerve. It can occur at any age but is commonly associated with some conditions: 1. pregnancy 2. diabetes 3. upper respiratory ailment 4. GBS 5. Toxins The common symptoms of Bell’s palsy are: 1. Abnormal corneal reflex as the facial nerve controls the motor aspect of the corneal reflex. 2. The loss of control of facial muscles and eyelids leads to decreased tear production. 3. mild weakness to total paralysis on one side of the face, occurring within hours to days. 4. Bell’s palsy is a lower motor neuron lesion that usually spares the forehead while the upper motor near lesions, like stroke, involves the entire face. 5. The anterior two-thirds of the tongue is supplied by the chorda tympani branch of the facial nerve, thus resulting in loss of taste. 6. Ptosis can be a feature of Bell’s palsy but Bell’s palsy would typically show unilateral symptoms rather than bilateral.

The most common cause of hypoparathyroidism is injury or removing the parathyroid glands. They can be injured accidentally during surgery to remove the thyroid as they are located posterior to the thyroid gland. A result of both low parathyroid hormone and low calcium is likely to mean that the parathyroid glands are not responding to hypocalcaemia. The hypocalcaemia can cause confusion, and the stay in the hospital is likely to refer to her surgery. While a parathyroid adenoma is fairly common and can cause hypoparathyroidism, it much more likely causes hyperparathyroidism. Chronic kidney disease is likely to cause hypocalcaemia, which would increase parathyroid hormone production in an attempt to increase calcium levels, causing hyperparathyroidism. Vitamin D is activated by the kidneys and then binds to calcium to be absorbed in the terminal ileum so that a deficiency would cause hyperparathyroidism.

The descending thoracic aorta begins at the lower border of T4 near the midline as a continuation of the arch of the aorta. It descends and ends at the level of T12 at the aortic hiatus in the diaphragm, where it becomes the abdominal aorta. The aorta gives off the following branches: (descending order) 1. Bronchial arteries 2. Mediastinal arteries 3. Oesophageal arteries 4. Pericardial arteries 5. Superior phrenic arteries The posterior intercostal arteries are branches that originate throughout the length of the posterior aspect of the descending thoracic aorta. The inferior thyroid artery is usually derived from the thyrocervical trunk, a branch of the subclavian artery.

Ludwig’s angina is life-threatening cellulitis of the soft tissue involving the floor of the mouth and neck. It involves three compartments of the floor of the mouth: the sublingual, submental, and submandibular. Ludwig’s angina usually originates as a dental infection of the second or third mandibular molars. The infection begins in the subgingival pocket and spreads to the musculature of the floor of the mouth. It progresses below the mylohyoid line, indicating that it has moved to the sublingual space. As the roots of the second and third mandibular molars lie below this line, infection of these teeth will predispose to Ludwig’s angina. The infection spreads lingually rather than buccally because the lingual aspect of the tooth socket is thinner. It initially spreads to the sublingual space and progresses to the submandibular space. The disease is usually polymicrobial, involving oral flora, both aerobes, and anaerobes. The most common organisms are Staphylococcus, Streptococcus, Peptostreptococcus, Fusobacterium, Bacteroides, and Actinomyces.

In the setting of cervical radiculopathy, because the nerve root of a spinal nerve is compressed or otherwise impaired, the pain and symptomatology can spread far from the neck and radiates to arm, neck, chest, upper back and/or shoulders. Often muscle weakness and impaired deep tendon reflexes are noted along the course of the spinal nerve. Cervical radiculopathy is almost always unilateral, although, in rare cases, both nerves at a given level may be impacted. Those rare presentations can confound physical diagnosis and require acceleration to advanced imaging especially in cases of trauma. If there is nerve impingement, the affected side will be reduced relative to the unaffected side. Reduction in strength of muscles innervated by the affected nerve is also significant physical finding. For a C4-C5 injury, the following symptoms may present: Weakness in the deltoid muscle (front and side of the shoulder) and upper arm Shoulder pain Numbness along the outside of the upper arm

The ophthalmic nerve is the smallest of the three trigeminal divisions. The cutaneous branches of the ophthalmic nerve supply the conjunctiva, the skin over the forehead, the upper eyelid, and much of the external surface of the nose.

The lingual nerve wraps around Wharton’s duct, and thus, is at risk of injury as the submandibular gland is mobilised. The lingual nerve provides sensory supply to the anterior 2/3 of the tongue.Note:- Submandibular duct (Wharton’s duct): It opens lateral to the lingual frenulum on the anterior floor of the mouth. It is around 5 cm in length.- Lingual nerve wraps around Wharton’s duct. As the duct passes forwards, it crosses medial to the nerve, above it and then crosses back, lateral to it, to reach a position below the nerve.

The lateral rectus muscle is one of the 6 extra-ocular muscles that control eye movements. It is responsible for abduction and is the only muscle that is innervated by the abducens nerve (CN VI).

Cholesteatoma is a special form of chronic otitis media in which keratinizing squamous epithelium grows from the tympanic membrane or the auditory canal into the middle ear mucosa or mastoid. The presence of abnormal epithelium in an abnormal location triggers an inflammatory response that can destroy surrounding structures such as the ossicles. Cholesteatomas may be congenital or acquired later in life. Acquired cholesteatomas are usually associated with chronic middle ear infection. Cardinal symptoms are painless otorrhea and progressive hearing loss. Important diagnostic procedures include mastoid process x-rays, temporal bone CT scans, and audiometric tests. Left untreated, erosion of the surrounding bone by a cholesteatoma can lead to facial nerve palsy, extradural abscess, and/or sigmoid sinus thrombosis. Therefore, even if a cholesteatoma is asymptomatic, surgery is always indicated. Surgical treatment involves tympanomastoidectomy to excise the cholesteatoma, followed by repair of the damaged middle ear structures.

Nasal discharge of clear fluid and a recent head injury makes basal skull fracture the most likely underlying cause for facial nerve palsy.Facial palsy is a neurological condition in which function of the facial nerve (cranial nerve VII) is partially or completely lost. It is often idiopathic (Bell’s palsy) but in some cases, specific causes such as trauma (e.g. temporal bone fracture), infections, or metabolic disorders can be identified. Two major types are distinguished: 1. Central facial palsy—lesion occurs between cortex and nuclei in the brainstem2. Peripheral facial palsy—lesion occurs between nuclei in the brainstem and peripheral organs Diagnosis can usually be made clinically while patient’s history often helps in evaluating the underlying aetiology.Patients with basal skull fracture following head injury (as in this case) exhibit Battle’s sign on examination. It is an indication of fracture of middle cranial fossa of the skull and consists of bruising over the mastoid process as a result of extravasation of blood along the path of the posterior auricular artery. Clinical presence of CSF leak further supports the diagnosis.Assessment options for basal skull fracture include CT and MRI scan. Idiopathic facial nerve palsy is treated with oral glucocorticoids and, in severe cases, with antivirals. Treatment of the other types depends on the underlying cause. Prophylactic antibiotics are given in cases of CSF leak.

The oculomotor nerve controls most of the eye muscles. It also controls the constriction of the pupils and thickening of the lens of the eye. This can be tested in two main ways. By moving a finger toward a person’s face to induce accommodation, their pupils should constrict or shining a light into one eye should result in equal constriction of the other eye. The neurons in the optic nerve decussate in the optic chiasm with some crossing to the contralateral optic nerve tract. This is the basis of the swinging-flashlight test. Loss of accommodation and continued pupillary dilation can indicate the presence of a lesion of the oculomotor nerve.

All of the muscles of the larynx are innervated by the recurrent laryngeal nerve, except the cricothyroid muscle. Cricothyroid muscle is located deep in the anterior neck, between the cricoid and thyroid cartilage and is innervated by the external laryngeal nerve. Any injury to this muscle can cause paralysis and lead to hoarseness. When cricothyroid muscle contracts, it leads to tightening, stretching and thinning of the vocal folds. This produces higher-pitched sounds during vocalization. A patient experiencing hoarseness due to possible injury to the external laryngeal nerve should be reassured that the hoarseness will resolve in time due to increased compensation from the other muscles.

The otic ganglion is a small (2–3 mm), oval shaped, flattened parasympathetic ganglion of a reddish-grey colour, located immediately below the foramen ovale in the infratemporal fossa and on the medial surface of the mandibular nerve. The preganglionic parasympathetic fibres originate in the inferior salivatory nucleus of the glossopharyngeal nerve. They leave the glossopharyngeal nerve by its tympanic branch and then pass via the tympanic plexus and the lesser petrosal nerve to the otic ganglion. Here, the fibres synapse, and the postganglionic fibres pass by communicating branches to the auriculotemporal nerve, which conveys them to the parotid gland. They produce vasodilator and secretomotor effects.

Elevation of the mandible is generated by the temporalis, masseter and medial pterygoid muscles.

The following structures arise from each branchial pouch: 1st pouch – eustachian tube, middle ear, mastoid, and inner layer of the tympanic membrane2nd pouch – middle ear, palatine tonsils3rd pouch – inferior parathyroid glands, thymus 4th pouch – superior parathyroid glands, ultimobranchial body which forms the parafollicular C-cells of the thyroid gland, musculature and cartilage of larynx (along with the sixth pharyngeal pouch)5th pouch – rudimentary structure6th pouch – along with the fourth pouch, contributes to the formation of the musculature and cartilage of the larynx.

Diphtheria is an infection caused by the bacterium Corynebacterium diphtheriae. Signs and symptoms may vary from mild to severe. They usually start two to five days after exposure. Symptoms often come on fairly gradually, beginning with a sore throat and fever. In severe cases, a grey or white patch develops in the throat. This can block the airway and create a barking cough as in croup. The neck may swell in part due to enlarged lymph nodes.The disease may remain manageable, but in more severe cases, lymph nodes in the neck may swell, and breathing and swallowing are more difficult. People in this stage should seek immediate medical attention, as obstruction in the throat may require intubation or a tracheotomy. Abnormal cardiac rhythms can occur early in the course of the illness or weeks later, and can lead to heart failure. Diphtheria can also cause paralysis in the eye, neck, throat, or respiratory muscles. Patients with severe cases are put in a hospital intensive care unit and given a diphtheria antitoxin (consisting of antibodies isolated from the serum of horses that have been challenged with diphtheria toxin). Since antitoxin does not neutralize toxin that is already bound to tissues, delaying its administration increases risk of death. Therefore, the decision to administer diphtheria antitoxin is based on clinical diagnosis, and should not await laboratory confirmation.Antibiotics are used in patients or carriers to eradicate C. diphtheriae and prevent its transmission to others. The Centres for Disease Control and Prevention recommends either:MetronidazoleErythromycin is given (orally or by injection) for 14 days (40 mg/kg per day with a maximum of 2 g/d), orProcaine penicillin G is given intramuscularly for 14 days (300,000 U/d for patients weighing 10 kg); patients with allergies to penicillin G or erythromycin can use Rifampicin or clindamycin.

The pterygoid hamulus is a hook-like process at the lower extremity of the medial pterygoid plate of the sphenoid bone around which the tendon of the tensor veli palatini passes.

A posterolateral herniation of the disc at the L4 – L5 level would be most likely to damage the fifth lumbar nerve root, not the fourth lumbar nerve root, due to more oblique descending of the fifth lumbar nerve root within the subarachnoid space.

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 muscles Organs: thyroid gland, parathyroid glands, larynx, trachea, esophagus, submandibular gland, caudal part of the parotid gland Arteries: superior and inferior thyroid, common carotid, external carotid, internal carotid artery (and sinus), facial, submental, lingual arteries Veins: anterior jugular veins, internal jugular, common facial, lingual, superior thyroid, middle thyroid veins, facial vein, submental vein, lingual veins Nerves: vagus nerve (CN X), hypoglossal nerve (CN XII), part of sympathetic trunk, mylohyoid nerve The 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 nodes Nerves: accessory nerve (CN XI), the trunks of the brachial plexus, fibers of the cervical plexus