Block 5 Endo Anat Embryo Thryoid Mix MCQ's

The space described in the question is located between the buccopharyngeal fascia anteriorly and the prevertebral fascia posteriorly. This space is known as the retropharyngeal space. The other options mentioned in the question (supraternal space, lateral pharyngeal space, axillary space, and masticator space) do not match the description given in the question.

After a thyroid surgery, a patient may experience a hoarse voice due to a lesion of the recurrent laryngeal nerve. The recurrent laryngeal nerve controls the movement of the vocal cords, and any damage to this nerve can result in vocal cord paralysis or weakness, leading to hoarseness. This is a common complication of thyroid surgery, as the recurrent laryngeal nerve is in close proximity to the thyroid gland and can be accidentally injured during the procedure. The other options, such as chronic glottis edema, compression of the trachea, removal of the parathyroid glands, or lesion of the inferior laryngeal artery, are less likely to cause hoarseness in this scenario.

When there is an infection at the tip of the tongue, the lymph node that is most likely to be initially enlarged and tender is the sub-mental lymph node. The sub-mental lymph node is located under the chin and drains the tongue, floor of the mouth, and lower lip. Therefore, it is the closest lymph node to the site of infection and is likely to be the first to respond to the infection by becoming enlarged and tender.

During the tonsillectomy, the glossopharyngeal nerve was likely damaged. The glossopharyngeal nerve provides sensory innervation to the posterior third of the tongue, so its damage would result in the loss of sensation in that area. The other nerves listed do not provide sensory innervation to the posterior third of the tongue, making them less likely to be the cause of the loss of sensation.

The correct answer is that neuroectoderm gives rise to the neurohypophysis. During embryonic development, the neurohypophysis, also known as the posterior pituitary, is derived from the neuroectoderm. The neuroectoderm forms a downgrowth from the diencephalon, which eventually gives rise to the posterior pituitary. The anterior pituitary, on the other hand, is derived from Rathke's pouch, which is an outgrowth of the oral ectoderm. Therefore, the statement that the neuroectoderm gives rise to the neurohypophysis is correct.

The correct answer is that the oral ectoderm gives rise to the anterior pituitary. This means that during embryonic development, the cells that form the anterior pituitary gland originate from the oral ectoderm layer.

During a tonsillectomy, the surgeon may inadvertently damage the glossopharyngeal nerve (CN IX), which innervates the back of the tongue. This can result in numbness or loss of sensation in the affected area. The other nerves listed, such as the chorda tympani, CN V3, CN X, and internal laryngeal nerve, do not primarily innervate the back of the tongue, making CN IX the most likely nerve to be damaged in this scenario.

The correct answer is cricothyroid joint. The cricothyroid muscle is innervated by the external laryngeal nerve and is responsible for controlling the tension of the vocal cords. It helps to adjust the pitch and tension of the vocal cords by moving the cricothyroid joint, which is located between the cricoid cartilage and the thyroid cartilage in the larynx. The other joints listed (cricoarytenoid joint, cricotracheal joint, sternoclavicular joint, and acromioclavicular joint) are not involved in the movement of the cricothyroid muscle.

Damage to the internal laryngeal nerve during a partial thyroidectomy would result in loss of general sensation in the larynx above the vocal cord. The internal laryngeal nerve provides sensory innervation to the mucosa of the larynx above the vocal cord, including the epiglottis, aryepiglottic folds, and false vocal cords. Therefore, the other options (over the epiglottis only, larynx below the vocal cord, ventricle of the larynx only, saccule of the larynx only) are incorrect as they do not involve the specific area innervated by the internal laryngeal nerve.

The lingual nerve is most likely damaged during the extraction. The lingual nerve innervates the anterior two-thirds of the tongue and is responsible for taste and general sensation in that area. Therefore, damage to the lingual nerve can result in loss of taste and sensation in the anterior two-thirds of the tongue, which is consistent with the patient's symptoms.

The correct answer is the auricular nerve (of Arnold). This nerve is responsible for providing sensory innervation to the posterior side of the external ear canal. It is a branch of the cranial nerve of the fourth pharyngeal arch.

The statement that the swelling is located superficial to the sternothyroid muscle would least likely suggest a diagnosis of thyroid gland swelling because the thyroid gland is located deep to the sternothyroid muscle. Therefore, if the swelling is superficial to this muscle, it is unlikely to be related to the thyroid gland.

The most likely diagnosis is a lateral cervical cyst because the patient presented with a painless swelling on the right side of her neck, and the CT scan revealed a well-defined cystic mass at the angle of the mandible just anterior to the sternocleidomastoid muscle. This location and presentation are consistent with a lateral cervical cyst, which is a common type of cyst that forms in the neck.

The incorrect placement of the intubation tube into the thyrohyoid membrane instead of the cricothyroid membrane would not put the thyroid ima artery at risk of injury. The thyroid ima artery is a rare anatomical variation that is not present in all individuals. It arises from the brachiocephalic trunk or the arch of the aorta and supplies blood to the thyroid gland. Since it is not a structure that is commonly found, it would not be at risk of injury in this scenario.

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The correct answer is the median cricothyroid ligament. In an allergic glottis edema, an incision needs to be made on the median cricothyroid ligament to relieve the swelling and open up the airway. This ligament connects the cricoid cartilage to the thyroid cartilage and is located in the front of the neck. By making an incision on this ligament, it allows for better airflow and can help alleviate the symptoms of the allergic reaction.

The parietal bone of the skull is formed through intramembranous ossification. This process involves the direct ossification of mesenchymal cells without the presence of a cartilage model. The parietal bone is one of the flat bones of the skull and is formed by the ossification of membranous connective tissue. In contrast, the other options listed, such as the ethmoid, sphenoid, base of occipital, and petrous portion of temporal bones, are formed through endochondral ossification, which involves the initial formation of a cartilage model that is later replaced by bone tissue.

The styloglossus muscle is not derived from a pharyngeal arch. The styloglossus muscle is a muscle of the tongue, responsible for retracting and elevating the tongue. It is derived from the occipital somites, not from a pharyngeal arch. The other muscles mentioned (stylopharyngeus, stylohyoid, levator veli palatine, and tensor veli palatini) are all derived from pharyngeal arches.

After protraction of the mandible, the posterior fibers of the temporalis muscle are responsible for retracting it. The temporalis muscle is a powerful muscle that is involved in the movement of the mandible. The posterior fibers specifically help to pull the mandible back towards its original position after it has been pushed forward. This muscle plays an important role in chewing and biting movements.

The inferior laryngeal nerve is responsible for innervating the muscles of the larynx, including the vocal folds. Damage to this nerve can result in paralysis or weakness of the vocal folds, leading to difficulty speaking in a normal voice.