📚 Question Bank

Type I collagen is present in fibrocartilage.

• Fibrocartilage (also known as white fibrocartilage) contains both type I and type II collagen.
• Hyaline and elastic cartilage contains only type II collagen

Each bundle of muscle fibres is surrounded by the perimysium. Organization of skeletal muscle:

• Muscle fibre or myocyte - made up of myofibrils and consists of several elongated nuclei, which lie along the periphery of the fibre just under the cell membrane. The cell membrane of the muscle fibre is called the sarcolemma, while the cytoplasm is called sarcoplasm. Each muscle fibre is surrounded by a delicate connective tissue called endomysium.
• Fascicle - Group of muscle fibres together form fascicle. Each fascicle is surrounded by the perimysium. The perimysium serves as a pathway for nerves and blood vessels.
• Muscle - Group of fascicles together form a skeletal muscle. The entire skeletal muscle is surrounded by epimysium. Epimysium contains larger nerves, blood vessels and lymphatics of the muscle.

The taste pathway for circumvallate papillae of the tongue goes through the glossopharyngeal nerve.

Taste sensation from the anterior 2/3rd of the tongue except the circumvallate papillae is carried by the chorda tympani branch of the facial nerve.

Areas innervated by glossopharyngeal nerve:

• The circumvallate papillae
• Posterior 1/3rd of the tongue
• Palatoglossal arches
• The oropharynx

Taste buds in the extreme posterior part of the tongue and epiglottis receive fibres from the internal laryngeal branch of the vagus.

Pain sensation at the tip of the tongue is carried by the lingual nerve which is a branch of the mandibular nerve.

The submental lymph node will be biopsied first as it is the sentinel lymph node. The sentinel node is the first node that the tumor site drains into.

In squamous cell carcinoma of the tongue, submental lymph nodes are involved in lesions of the tip and submandibular lymph nodes are involved in lesions of the sides of the tongue. Bilateral neck lymph node spread is common due to the crossing of lymph vessels in the tongue.

Lymphatic drainage of the to ngue

Marginal

Lateralmargin of the tongue Central

Dorsal

Area

Tipof the tongue

Unilateralsubmandibularnod es

Central part of the anterior 2/ 3rd of the tongue

Posterior 1/3rd of the tongue and circumvallate papillae

Lymph nodes

Bilateral submental nodes

Bilateraljugulodigastric and j ugulo-omohyoidnodes

Bilateraljugulodigastricandju gulo-omohyoidnodes

The sensory fibers from the taste buds in the hard and soft palate travel along the trigeminal nerve.

The taste sensation from taste buds in the oral surface of the soft palate is carried by the lesser palatine nerve.

The taste fibers initially travel in the greater petrosal nerve (a branch of the facial nerve) and pass through the pterygopalatine ganglion without synapsing.

The tonsillar branch of facial artery supplies the palatine tonsil and not the palate.

Blood supply of the palate:

• Hard palate - greater (descending) palatine artery which is a branch of the third part of the maxillary artery.
• Soft palate - ascending palatine branch of the facial artery, ascending pharyngeal artery, and lesser palatine arteries.

Piriform fossa is a structure present in the laryngopharynx and not the nasopharynx.

The nasopharynx is present above the soft palate and is made up of the roof, floor, posterior wall, and two lateral walls. Important structures seen in the nasopharynx are:

• Pharyngeal opening of the eustachian tube
• Torus tubarius- tubal elevation which is present behind the opening of the eustachian tube.
• çossa of Žosenmuller- A lateral pharyngeal recess that is present behind the torus tubarius. It is the most common site for nasopharyngeal carcinoma
• Pharyngeal tonsil which is present in the roof and posterior wall
• Passavant's ridge.

Passavant's ridge is formed by palatopharyngeus and superior constrictor muscles.

Some fibers of the palatopharyngeus muscle pass deep to the mucous membrane of the pharynx and form an internal sphincter to the superior constrictor. These muscles contract and cause a ridge on the posterior wall of the nasopharynx which is †nown as Passavant's ridge.

The given image shows purulent inflammation of the tonsils and the case scenario is suggestive of acute tonsillitis. Passavant's ridge is not seen in the oropharynx as it is present on the posterior wall of the nasopharynx.

The oropharynx extends from below the soft palate to the upper border of the epiglottis. Structures seen in the oropharynx:

• Palatoglossal folds
• Palatopharyngeal folds
• Palatine tonsils - between the palatoglossal and palatopharyngeal folds
• Lingual tonsils
• Valleculae - mucosal pouches between the tongue and the epiglottis.

Sinus of Morgagni is a gap present between the base of the s†ull and the upper border of superior constrictor muscle.

Structures passing through the sinus of Morgagni are as follows:

• Palatine branch of ascending pharyngeal artery
• Ascending palatine artery
• Levator veli palatini muscle
• Eustachian tube

Note: Sinus of Morgagni syndrome/Trotter's triad is seen in nasopharyngeal carcinoma which spreads laterally to involve the sinus of Morgagni. It is characteriˆed by:

• Conductive hearing loss
• Ipsilateral immobility of the palate
• Neuralgic pain.

Stylopharyngeus is not supplied by the pharyngeal plexus. It is supplied by the glossopharyngeal nerve.

The pharyngeal plexus is formed by the pharyngeal branches of the glossopharyngeal nerve and the vagus nerve with contributions from the superior cervical sympathetic ganglion. It supplies:

• All muscles of the soft palate
• Except tensor veli palatini - supplied by the mandibular nerve
• All the muscles of the pharynx
• Except stylopharyngeus - supplied by the glossopharyngeal nerve.

Cricoid is not a paired cartilage.

Cricoid cartilage forms a complete ring around the airway and this is the only laryngeal cartilage to do so.

Clinical significance:

• Sellick's maneuver - Cricoid pressure is applied to occlude the esophagus without occluding the airway. It prevents regurgitation of gastric contents during intubation and rapid induction of anesthesia.
• The cricoid cartilage is the narrowest part of the pediatric airway.

The given image shows the histology of hyaline cartilage. Apex of arytenoid is made up of elastic cartilage, not hyaline cartilage.

Cricothyroid is the component of the intrinsic laryngeal membrane of the larynx.

The cricothyroid ligament is present between the cricoid and thyroid cartilage of the larynx. It consists of three parts: the right and the left lateral parts and the thickened median portion. The lateral parts are called conus elasticus and the median thickened part is called the median or the anterior cricothyroid ligament.

The extrinsic ligaments and membranes of the larynx are:

• Thyrohyoid membrane
• Hyoepiglottic ligament
• Cricotracheal ligament

The intrinsic ligaments and membranes of the larynx are:

• Quadrangular membrane - present between the epiglottis and the arytenoid cartilage
• Cricothyroid membrane
• Thyroepiglottic ligament.

Rima glottidis is present between the vocal folds of the larynx.

The cavity of the larynx can be divided into upper, middle, and lower parts. Upper part:

• It extends from the laryngeal inlet to the vestibular folds.
• The laryngeal inlet is made of the upper edge of the epiglottis, aryepiglottic fold, arytenoids,
• and posterior commissure.
• The vestibule is the region between the laryngeal inlet and the vestibular folds.
• Middle part:
• It extends from rima vestibuli to the rima glottidis.
• Rima vestibuli is the aperture between the two vestibular folds.
• Rima glottidis is the aperture between the two vocal folds.
• Ventricle is the space bounded by rima vestibuli above and rima glottidis below.
• Saccule is a pouch from the anterior end of the ventricle. It contains mucous glands.
• Lower part:
• The lower part is also called the infraglottic cavity or subglottic cavity and extends from the
• vocal cords to the lower border of the cricoid cartilage.

The larynx is covered by the pseudostratified ciliated columnar epithelium except at three sites where it is covered by non-keratinized stratified squamous epithelium. These are:

• Vocal folds
• Lingual surface of epiglottis
• Upper part of aryepiglottic folds

The nerve supply of larynx above the level of vocal cords is by internal laryngeal nerve which is a branch of the superior laryngeal nerve.

• Sensory innervation of the larynx above the level of vocal cords is by the internal laryngeal
• nerve.
• Sensory innervation of the larynx below the level of vocal cords is by the recurrent laryngeal nerve.
• At the level of vocal cords, it is supplied both by the internal laryngeal and recurrent laryngeal nerves.

All the intrinsic muscles of the larynx are supplied by the recurrent laryngeal nerve except for cricothyroid, which is supplied by the external laryngeal nerve.

The external laryngeal nerve supplies the cricothyroid muscle. All other intrinsic muscles of the larynx are supplied by the recurrent laryngeal nerve.

The larynx contains three paired cartilages (arytenoid, corniculate, cuneiform) and three unpaired cartilages (epiglottis, thyroid, and cricoid).

Sometimes the triticeal cartilage (TC) may be present. This is a small, oval-shaped cartilage found within the lateral border of the thyrohyoid membrane between the greater horn of the hyoid bone and the superior horn of the thyroid cartilage (SHTC). The TC is not a constant structure; it may be present unilaterally, bilaterally, or absent.

Injury to the recurrent laryngeal nerve will cause vocal cord paralysis.

All the intrinsic muscles of the larynx except for the cricothyroid are supplied by the recurrent laryngeal nerve. Cricothyroid is supplied by the external laryngeal nerve which is a branch of the superior laryngeal nerve.

Since most of the laryngeal muscles are supplied by the recurrent laryngeal nerve, the most appropriate answer would be recurrent laryngeal nerve.

Supraglottic tumors spread to the pre-epiglottic space via the perforations in the epiglottic cartilage.

Pre-epiglottic space: It lies anterior to the epiglottis. Its relations are as follows:

• Superior - Hyoepiglottic membrane median hyoepiglottic ligament
• Inferior - Thyroepiglottic ligament
• Anterior - Thyrohyoid membrane and median thyrohyoid ligament
• Posterior - Epiglottis
• Lateral - Greater cornua of the hyoid bone in the upper part, continuous with the paraglottic space in the lower part.

The laryngeal tumors can spread to the pre-epiglottic space through the multiple perforations present in the epiglottis.

Para-glottic space: This space contains the laryngeal nerve. Its relations are:

• Superior - Para-glottic space is continuous with the pre-epiglottic space.
• Inferior- Cricothyroid joint
• Posterior- Piriform fossa
• Lateral - Thyroid cartilage and thyrohyoid membrane
• Medial- Quadrangular membrane in the upper part and conus elasticus in the lower part.

The internal laryngeal nerve is accompanied by the superior laryngeal vessels, not the superior thyroid vessels. Along with superior laryngeal vessels, it pierces the thyrohyoid membrane.

The vagus nerve arises as several rootlets from the medulla which unite to form a single nerve and emerges via the intermediate compartment of the jugular foramen.

Galen's anastomosis is the connecting branch between the inferior laryngeal nerve (a branch of the recurrent laryngeal nerve) and the internal laryngeal nerve (a branch of the superior laryngeal nerve).

Right recurrent laryngeal nerve winds around the lower and posterior part of 1st part of the right subclavian artery and left recurrent laryngeal nerve winds around the arch of the aorta.

The clavicle is the first bone to ossify in the human body. It occurs by the 5th- 6th weeks of intrauterine life.

The clavicle is a band of condensed mesenchyme in the early embryonic phase.

At the terminal ends of this band, early cartilage transformation (pre-cartilage) takes place. Intramembranous centers of ossification appear and fuse in the mesenchyme between them. Hence, it ossifies partly in the membrane and partly in cartilage.

Fractures of the clavicle typically occur at the junction of the medial 3/5 th and lateral 2/5 th.

Middle-third or midshaft region of the clavicle is the most common site for a fracture, especially the junction of medial 3/5 th and lateral 2/5 th.

It is the junction where the 2 primary ossification centers meet. It is also where the transition from antecurve to retro curve begins and is prone to be at high risk for fractures.

The fracture causes the upward displacement of the proximal fragment (sternocleidomastoid) and downward displacement of the distal fragment (pectoralis major and gravity).