Excel BDS · 2021. 1. 15. · Q.9Falx Cerebri Q.10Formation, blood supply and nerve supply of Nasal...

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I B.D.S Degree Examination - Nov 2020

Time: Three Hours Max. Marks: 70 Marks

HUMAN ANATOMY INCLUDING EMBRYOLOGY, OSTEOLOGY AND HISTOLOGY

Q.P. CODE: 1178 (RS3)

Your answers should be specific to the questions askedDraw neat, labeled diagrams wherever necessary

LONG ESSAYS 2X10=20 Marks

Q.1. Describe Parotid Gland under the following headings: (Aug 2017)

a) Situation b) Relations c) structures within the Gland d) Secretomotor Pathway

e) Applied Anatomy

Q.2. Describe Tongue under the following headings: (June 2016)

a) Gross features b) Nerve supply c) Lymphatic Drainage d) Development

SHORT ESSAYS 8X5=40 Marks

Q.3. Microscopic Anatomy of Thymus- explain with labeled diagram.

Q.4. Sphenoidal Air Sinus - boundaries, relations and applied Anatomy.

Q.5. Digastric Triangle boundaries and contents. (July 2018)

Q.6. Derivatives of Second Pharyngeal Arch. (June 2014)

Q.7. Parts and branches of Maxillary Artery.(June 2019)

Q.8. Dangerous layer of Scalp and its applied Anatomy. (Dec 2012)

Q.9. Submandibular Ganglion- situation, roots and branches.

Q.10. Orbicularis Oculi -parts, nerve supply and action. (June 2016)

SHORT ANSWERS 2X5=10 Marks

Q.11. Name any four Muscles supplied by Recurrent Laryngeal Nerve. (June 2016)

Q.12. Name the structures passing through Foramen Ovale. (Dec 2016)

Q.13. Labeled diagram of Histology of Trachea. (Aug 2017)

Q.14.Development of Upper Lip. (Dec 2017) (Dev of face)

Q.15.Pharyngobasilar Fascia.

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Q.3 Microscopic Anatomy of Thymus- explain with labeled diagram.

Ans.The thymus gland is lymphoid organ, which is lobulated and enclosed by a connective tissue capsule.

• Connective tissue with its trabeculae arises from it.

• These trabeculae extend into the interior of the organ.

• The thymus gland is subdivided into incomplete lobules by the trabeculae.

• Each lobule is made up of:

Outer cortex

Inner medulla

• The medulla shows continuity between the neighboring lobules, because the lobules are incomplete.

• With the age of the individual, there is variations seen in histology of the thymus gland.

• The thymus gland is reducing in size shortly after birth.

• The regression of thymus gland occurs at the time of puberty.

• The medulla of thymus gland has Hassall’s corpuscles become more prominent due to reduced lymphocyte production.

Q.4 Sphenoidal Air Sinus - boundaries, relations and applied Anatomy.

Ans. Sphenoidal Sinus

• It is also called as antrum sphenoidale.

• The sphenoidal sinuses are located in the sphenoid bone.

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• With the help of an apertureon the anterior aspect of sphenoid bone the sinus opens into the corresponding half of the nasal cavity.

• The sinus opens lies abovethe superior nasal concha along with a part of the nasal cavity

• T h i s o p e n i n g i s c a l l e d a s sphenoethmoidalrecess.

Measurements

Front to back: 2 cm.

Vertically: 2 cm.

Transverse: 1.5 cm.

Relations

Superiorly: Hypophysis cerebri and optic chiasma.

Inferiorly: Nasopharynx.

Lateral: Cavernous sinus

Posteriorly: Medulla oblongata.

Anteriorly: Sphenoethmoidal recess.

Q.9Submand ibu la r Gang l ion - situation, roots and branches.

Ans. It is also called as Langley’s Ganglion.

• It is a type of parasympathetic ganglion.

• It relays secretomotor fibres for submandibular and sublingual salivary glands.

• Topographically, it is related to the lingual nervebut functionally it is in connection with facial nerve.

Situation:

• External surface of hyoglossus muscle.

• It is suspending from the lingual nerve.

Relations:

Superiorly: Lingual nerve.

Inferiorly: Submandibular gland with its deeper parts.

Medial: Hyoglossus muscle.

Externally: Submandibular gland with its superficial part.

Roots of submandibular ganglion:

There are three roots of the submandibular ganglion such as the

i. Parasympathetic

ii. Sympathetic

iii. Sensory

i. Parasympathetic:

Superior salivatorynucleus (Pons)

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facial nerve

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Chorda tympani

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Lingual nerves

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Submandibular ganglion

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Postganglionic fibres

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Submandibular gland.

2. Sympathetic root:

Begin from first thoracic spinal segment (T1)

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Cervical sympathetic chain

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Superior ganglion.

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Forming plexus around the facialartery

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Passing ganglion without relay

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Supply the blood vessels in the submandibular andsublingual

salivary glands.

3. Sensory root: It is coming from lingual nerve.

Branches:

The branches of the submandibular ganglion are:

1. The submandibular gland has a total of 5-6 branches.

2. The sublingual and anterior lingual glands are supplied by the lingual nerve along with few other nerves.

Q.15 Pharyngobasilar Fascia.

Ans. The pharyngeal muscles are made up of muscles which are supported by two fascial layers which imparts strength and support to the pharyngeal muscles.

• The mucous membrane and the muscular layer of pharynx in between them there is a fascia.

• This fascia supports the mucous membrane which is present above the level of the superior constrictor muscle.

• The fascia thickened to become the pharyngobasilar fascia.

Attachments:

Superiorly: Skull base

Inferiorly: Into the pharynx

Median pharyngeal raphe is a fibrous band extending in the midline from the pharyngeal tubercle of the occipital bone which is forming the median pharyngeal raphe.

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I B.D.S Degree Examination –Nov 2020


HUMAN PHYSIOLOGY

Q.P. CODE: 1179



Q.1. Name the hormones of posterior pituitary. Explain the functions of each of them. (Dec 2014) Mention the features of Diabetes insipidus. (June 2016)


Q.2. Explain second phase of deglutition. (DADH) (Aug 2017)

Q.3. Describe oxygen hemoglobin dissociation curve. List the factors affecting it. (Dec 2016)

Q.4. Explain the Intrinsic mechanism of coagulation. (June 2019)


Q.5. List the functions of middle ear. (July 2018)

Q.6. Mention functions of testosterone. (Dec 2016)

Q.7. Define GFR. Mention its normal value. (Dec 2017)

Q.8. What is Referred pain. Mention the theories of referred pain. (Dec 2018)

Q.9. Draw and label ECG. (Dec 2017)

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I B.D.S Degree Examination – Nov 2020


BIOCHEMISTRY, NUTRITION & DIETICS

Q.P. CODE: 1180



Q.1. Describe Citric acid cycle (TCA cycle). Add a note on its energetics. (Aug 2017)


Q.2.Biochemical functions (July 2015)and deficiency manifestations (June 2016) of Vitamin C

Q.3. Renal regulation of acid base balance. (Dec 2013)

Q.4. Biologically important compounds formed from Phenyl alanine and tyrosine.(Dec 2013)


Q.5. Fluorosis. (July 2018)

Q.6. Dietary fibers. (June 2019)

Q.7. Essential fatty acids. (Dec 2014)

Q.8. mRNA. (Dec 2010) (Q.2 Type of RNA)

Q.9. Mention the normal serum levels of:

~ Phosphorus.

~ Alkaline phosphatase.

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Q.4Biologically important compounds formed from Phenyl alanine and tyrosine.(Dec 2013)

Ans. Phenylalanine is an essential α-amino acid.

• Phenol is an aromatic organic compound which is formed from phenylalanine.

• Phenylalanine is a precursor for tyrosine, the monoamine neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), and the skin pigment melanin.

Q.9Mention the normal serum levels of:

Ans.i. Phosphorus.

ii. Alkaline phosphatase.

i. Phosphorus:

• The phosphorus or phosphate level in the whole blood is 40 mg/dl.

• In serum it is about 3-4 mg/dl which is due to the RBC and WBC having increased content of phosphate.

ii. Alkaline phosphatase:

• The normal Alkaline phosphataselevel is around 3-13 KA units/dl.

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I B.D.S Degree Examination – Nov 2020


HUMAN ORAL AND DENTAL ANATOMY, EMBRYOLOGY, PHYSIOLOGY AND HISTOLOGY.


LONG ESSAY (2 X 10 = 20M)

Q.1. Classify salivary glands. Write in detail the ductal system. (Dec 2018)

Q.2. Describe in detail the morphology of mandibular 1" premolar. Add a note on its chronology (Refer table)

SHORT ESSAY (8 X 5= 40M)

Q.3 Dead tracts (Dec 2016)and sclerotic dentine. (Dec 2010)( Types of dentin in cross section.)

Q.4. Age changes in Enamel. (Aug 2017)

Q.5. Principle fibers of periodontal ligament. (Dec 2019)

Q.6. Theories mineralization. (June 2016)

Q.7. Functions (June 2019) and histology of maxillary sinus. (Dec 2019)

Q.8. Histo-physiological stages of tooth development. (Dec 2011)

Q.9. Development of tongue. (June 2016)

Q.10. Dento-gingival junction. (Dec 2017)

SHORT ANSWERS (5X2=10M)

Q.11. Non-Keratinocytes. (June 2019)

Q.12. Hyaline layer of Hopewell Smith. (July 2018) (Tomes granular layer)

Q.13. Enamel spindle. (July 2015)

Q.14. Meckel's cartilage. (June 2013)

Q.15. Cingulum. (June 2019)

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JUNE 2019 Anatomy

JUNE 2019

LONG ESSAYS 2 x10=20 Marks

Q.1Describe the commencement, course, termination and branches of external carotid artery.

Q.2Describe the Cavernous Sinus under the following headings:

a) Situation

b) Relations

c) Communications

d) Tributaries

e) Applied Anatomy

SHORT ANSWERS 8x5=40 Marks

Q.3Mention the midline structures of neck

Q.4Microscopic anatomy of Spleen – explain with labelled diagram

Q.5Derivatives of first pharyngeal arch

Q.6Boundaries and contents of Infra temporal fossa

Q.7Name the Muscles of tongue, their nerve supply and action

Q.8Branches of maxillary artery

Q.9Falx Cerebri

Q.10Formation, blood supply and nerve supply of Nasal septum

SHORT ANSWERS 5x2=10 Marks

Q.11Auditory tube

Q.12Boundaries and applied aspects of Pyriform fossa

Q.13Bones forming the orbital cavity

Q.14Formation and contents of Carotid sheath

Q.15 Medial Pterygoid muscle

Answers :

Q.1Describe the commencement, course, termination and branches of external carotid artery.

Ans.Commencement and course and terminationof external carotid artery:

?The common carotid artery lies deep within the neck and is divided into an external carotid artery and an internal carotid artery.

?The external carotid artery has 8 branches and ascends from the bifurcation of the common carotid artery along the line passing behind the angle and then the neck of the mandible.

?The internal carotid artery lies deeper than the external carotid within the carotid sheath along the line drawn from the head of the mandible to the bifurcation of the common carotid artery.

The 8 branches are as follows:

1. Superior thyroid artery: It is the first branch of external carotid artery arises from the anterior surface near or at the bifurcation, and reaches to supply the thyroid gland.

2. Ascending pharyngeal artery: It is the second and smallest branch of external carotid artery.

?It begins from the posterior aspect of the external carotid artery which reaches to supply the pharynx.

3. Lingual artery: It begins from the anterior surface of the external carotid artery.

?It is the main arterial supply for the tongue.

4. Facial artery: It is the third anterior branch of the

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?external carotid artery which begins just above the lingual artery.

?It is also called as the anaesthetist artery.

?It is the chief arterial supply of the face.

5. Occipital artery: It begins from the posterior surface of the external carotid artery at the level of origin of the facial artery.

?It supplies the sternocleidomastoid muscle.

6. Posterior auricular artery: It is a small branch of external carotid artery arising from the posterior surface which reaches to supply the scalp and ear.

7. Superficial temporal artery: It is one of the terminal branches of the external carotid artery.

?This artery divides into two parts the anterior and posterior.

8. Maxillary artery: It is the larger of the two terminal branches of external carotid artery.

? It begins in the posterior to the neck of

mandible which continues little medial to the mandible and reaches the pterygopalatine fossa.

Q.2 Describe the Cavernous Sinus under the following headings:

Ans.a)Situation b)Relations

c) Communications d) Tributaries

e) Applied Anatomy

Cavernous sinus

a. Situation:

• Cavernous sinus is a paired sinus that lies on each side of the body in the sphenoid.

• The sinus appears to have a spongy appearance resulting from the numerous fibrous trabeculae

• Each of this sinus is located between the endosteal layer of the dura mater enclosing the lateral aspect of the body of the sphenoid.

• A layer of the meningeal dura extends laterally from the side wall of the pituitary fossa and dorsum sellae to form the roof of the sinus that lies

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between the anterior and posterior clinoid process which in turn moves downwards to the floor of the middle cranial fossa thus forming the lateral walls of the sinus.

• The internal carotid artery, the nerves to the extraocular muscles and the first two divisions of the trigeminal nerve transverse the walls of the sinus.

• The middle cerebral vein drains the lateral surface of the hemisphere, the sphenoparietal sinus drains from the dura mater over the temporal region and the orbits are drained by the superior and inferior ophthalmic veins.

b. Relations

Superior

1. Optic chiasma.

2. Optic tract.

3. Part of Internal carotid artery.

4. Anterior perforated substance.

Inferior

1. The Foramen lacerum.

2. Junction of the body of sphenoid and the greater wing of the sphenoid.

Anterior

1. Superior orbital fissure.

2. Apex of the orbit.

Posterior

1. Crus cerebri of midbrain.

2. Apex of the petrous temporal bone.

Medial

1. Pituitary gland

2. Sphenoid air sinus.

Lateral

1. Temporal lobe of the cerebral hemisphere.

2. Trigeminal ganglion.

Lateral wall of the sinus has there structures:

From above downward these are as follows:

1. Oculomotor nerve.

2. Trochlear nerve.

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Branches of the trigeminal ganglion such as:

3. Ophthalmic nerve.

4. Maxillary nerve.

c. Communications

The communications of cavernous sinus are:

1. Internal jugular vein via inferior petrosal sinus.

2. Transverse sinus via superior petrosal sinus.

3. Pterygoid venous plexus

4. Facial vein.

5. Opposite to cavernous sinuses through anterior and posterior intercavernous sinuses.

6. Superior sagittal sinus

7. Internal vertebral venous

d. Tributaries

• The cavernous sinus receives blood from its three sources such as the orbit, meninges, and brain.

From orbit

1. Superior ophthalmic vein.

2. Inferior ophthalmic vein.

3. Rarely from the central vein of retina.

From meninges

1. Sphenoparietal sinus.

2. Frontal trunk of the middle meningeal vein.

From brain

1. Superficial middle cerebral vein.

2. Inferior cerebral veins (only few).

e) Applied Anatomy

Cavernous sinus thrombosis

• It is a syndrome, usually secondary to infections near the eye or nose, characterized by orbital edema, venous congestion of the eye, and

palsy of the nerves supplying the extraocular muscles.

• The infection may spread to involve the cerebrospinal fluid and meninges.

• Treatment involves antibiotics and sometimes anticoagulants.

• Cavernous sinus thrombosis has the following signs and symptoms

• Severe pain in the eye and forehead,

• Paralysis of ocular muscles occurs due to involvement of the 3rd, 4th, and 6th cranial nerves.

• Edema of the eyelids with exophth-almos.

Q.3 Mention the midline structures of neck

Ans.The structures present in the midline of the neck are:

• The 1 to 3 cm wide region from the chin to the sternum is the structure lying in the midline of the neck.

Skin

• It is the loose adherent structure which is present over the superficial fascia.

Superficial Fascia

It contains structures such as:

1. Muscle:

• Platysma.

Veins:

• Anterior jugular veins

• Jugular venous arch

Lymph Node:

• Submental lymph nodes.

Nerve:

• Anterior cutaneous nerve

Deep Fascia

• It is the investing layer of deep fascia

Deep Structures Lying above the

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Hyoid Bone

Muscle:

• Supra hyoid muscle.

• Mylohyoid muscle

• Anterior belly of digastric muscle.

• Hyoglossus muscle

• Digastric muscle

• Stylohyoid muscle

Glands:

• Submandibular salivary gland.

Nerve:

• Mylohyoid nerve.

Artery:

• Submental artery.

Structures Lying below the Hyoid Bone

Muscle:

• Infrahyoid muscles:

a. Sternohyoid

b. Sternothyroid

c. Thyrohyoid

d. Superior belly of omohyoid.

Pretracheal fascia and structures within it:

Muscle:

a. Thyrohyoid membrane muscle

b. Cricothyroid muscle

c. Thyroid cartilage.

c. Cricothyroid membrane

d. Arch of the cricoid cartilage.

e. Trachea

f. Carotid sheaths

Q.4 Microscopic anatomy of Spleen – explain with labeled diagram

Ans. The spleen is a lymphoid organ of the body.

• Its important actions are to filter blood, but engulfing RBCs and to provide T and B lymphocytes, and producing antibodies.

• The spleen is categorised as white and red pulps.

• White pulp is composed of lymphoid tissue which is organised to be consisting of T lymphocytes or B lymphocytes.

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Anatomy

• The red pulp is formed by pulp cords of billroth which are interposed by sinusoids.

• Reticular cells and reticular fibers extend into the pulp cords which consists of plasma cells macroph-ages, along with extravasated blood cells.

• Marginal zone is also seen which is an interface between the white and red pulps.

• Capillaries arising from the central arteries supply blood to sinusoids of the marginal zone.

• The splenic artery enters at the hilum of spleen which distributes blood to the interior of the organ as trabecular arteries.

• The paranchyma is enclosed by the periarterial lymphatic sheaths (PALS) and lymphoid nodules.

• After losing their periarterial lymphatic sheaths the central arteries enter the red pulp and divides into penicillar arteries.

• Penicillar arteries has three regions such as the

i) Pulp arterioles,

ii) Sheathed arterioles,

iii) Terminal arterial capillaries.

Q.5Derivatives of first pharyngeal arch

Ans.The rod-like thickenings of mesoderm are called pharyngeal arches.

• There are total of 6 pharyngeal arches out of which the 5th one disappears.

• The first pharyngeal arch is also called as the mandibular arch.

• The important cartilage of first pharyngeal arch is the Meckel’s cartilage which is associated with the

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f irst pharyngeal pouch which becomes the middle ear cavity.

• The mandible develops in close association with the Meckel's cartilage.

• The dorsal end of Meckel's cartilage finally ossifies to form the malleus

• Each arch consists of an artery, a skeletal element, striated muscle and a nerve.

The derivatives of the first pharyngeal arch are :

Skeletal derivatives:

• Malleus, incus, maxilla, mandible, zygomatic bone,sphenomandibular ligament.

Muscular derivatives:

• Muscles of mastication, Tensor tympani, Tensor vel i palatini, Mylohyoid, Anterior belly of digastric.

Nervous tissue derivatives:

• Mandibular nerve.

Arterial tissue derivative:

• Part of maxillary artery.

Q.6 Boundaries and contents of Infra temporal fossa

Ans.Infratemporal fossa is the area on the side of the cranium which is limited by structures superiorly, posteriorly, anteriorly, laterally.

• In the infratemporal fossa there is attachment of the lateral pterygoid muscle.

Anterior border: infratemporal surface of the maxilla.

Roof: Greater wing of sphenoid.

Medial border: The Lateral pterygoid plate.

Laterally: Zygomatic arch and ramus of mandible.

It consists of the following structures

• Medial pterygoid muscle

• Lateral pterygoid muscle

• Mandibular nerve with its branches

• Maxillary nerve with its branches

• Maxillary artery along with its branches

• Branch of facial nerve (Chorda tympani)

Q.7Name the Muscles of tongue, their nerve supplyand action

Ans. Tongue:

• The tongue is muscular organ which has an essential role in the mechanisms of swallowing and speech.

• There are the two muscular compon-ents of tongue

Intrinsic muscles &extrinsic muscles

A. Intrinsic muscles are the

i. Superior longitudinal muscle

ii. Inferior longitudinal muscle

iii. Transverse muscle

iv. Vertical muscle

B. Extrinsic muscles

i. Hyoglossus,

ii. Genioglossus,

iii. Styloglossus, and

iv. Palatoglossus.

Intrinsic muscles Action

Superior longitudinal Helps to shortening muscles the tongue and makes the dorsum concave

Inferior longitudinal contracts the tongue muscle

Transverse muscle Narrow the tongue

Vertical muscles Flattens the tongue

Extrinsicmuscles

Genioglossus muscle tongue out

Hyoglossus Lowers the muscle tongue

Styloglossus Pulls the muscle tongue back

Palatoglossus Elevates the tongue

Actions

Projects the

Nerve supply of tongue

Anterior 2/3rd of Posterior 1/3rd of Posterior mosttongue the tongue portion of the

tongue

Taste Chroda Tympani Glossopharyngeal Vagus- Internal laryngeal

Sensory Lingual nerve Glossopharyngeal Vagus – Internal Laryngeal

Motor All the extrinsic & intrinsic muscles supplied by hypoglossal nerve.Palatoglossus – Cranial root of accessory nerve.

Pharyngeal arch First Third Fourthdevelopment

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Intrinsic muscle of tongue

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Nerve supply:

• All the muscles both the intrinsic and extrinsic muscles of the tongue are supplied by the hypoglossal nerve.

• Palatoglossus is supplied by the cranial part of the accessory nerve.

Blood supply:

• Lingual branch of the external carotid artery.

• Ascending palatine and

• Ascending pharyngeal arteries.

Vein:

• Lingual and

• Deep lingual veins.

Q.8 Branches of maxillary artery

Ans. The maxillary artery is the terminal branches of the external carotid artery

• It begins in the parotid gland posterior to the neck of the mandible.

• The artery enters the infratemporal fossa by crossing the lower head of the lateral pterygoid to enter the pterygopalatine fossa.

• The maxillary artery is divided into three parts

Parts of maxillary artery:

1st Part: The first part of the maxillary artery is called as mandibular part

• It is present medially to the sphenomandibular ligament

• The first part also lies above to the auriculotemporal nerve.

2ndPart:The Second part of the maxillary artery is called as the pterygoid part.

• It is present in close relation with the lateral pterygoid muscle.

3rdPart: The third part of maxillary artery is called as pterygopalatine part.

• The maxillary artery passes from the upper border of the lateral pterygoid.

• In pterygopalatine fossa the maxillary artery lies in the anterior region of the pterygopalatine ganglion.

Branches of maxillary artery:

1st Part (Mandibular part)

1. Deep auricular artery: It enters the external acoustic meatus by piercing the floor and Supplies:

a. Part of external acoustic meatus, and

b. Exterior of tympanic membrane.

2. Anterior tympanic artery-It passes through petrotympanic fissure and supply the tympanic membrane.

3. Middle meningeal artery- supplies the meninges as and skull bone.

• Clinically it is the most important branch of the maxillary artery.

• The Middle meningeal artery divides into two branches the frontal and parietalbranches:

(a)Frontal branch: This branchmoves up till thepterion.

(b)Parietal branches: This branch travels over the squamous part of the temporal bone.

4. Accessory middle meningeal artery-It is a part of structures passing through foramen ovale.

After entering through the foramen, it supplies the meninges.

5. Inferior alveolar/dental artery: It moves between the sphenoma-ndibular ligament and mandible, to enters the mandibular foramen, giving off its branches to the premolar and molar teeth and the gingival structure around it.

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• Before it enters the mandibular foramen the inferior alveolar artery gives off two branches.

a) Lingual branch: It supplies the mucous membrane of the cheek.

b) Mylohyoid branch: It supplies the mylohyoid muscle.

Within the mandibular foramen:

It then divides into.

i) Mental: Supply the skin of the chin.

ii)Incisive branches: Supply canine and incisor.

II. 2nd Part Pterygoid part.

1. Deep temporal arteries: It supplies the temporalis muscle.

2. Pterygoid branches: It supply the medial and lateral pterygoid muscles.

3. Masseteric artery: It supplies the masseter muscle.

4. Buccal artery: It supplies buccinator muscle.

III. 3rd Part Pterygopalatine part.

1. Posterior superior alveolar artery: As it emerges from maxillary artery it divides into two or three branches to enter into the maxilla via the alveolar canals and supply the:

i) Molar and premolar teeth

ii) Mucus membrane of maxillaryair sinus.

2. Infraorbital artery: It passes through infraorbital foramen, gives off branches:

In the orbit:

(a)Branches to orbital contents.

(b)Middle superior alveolar artery: Maxillary premolar teeth.

(c)Anterior superior alveolar artery: Maxillary sinus, canine, Incisors.

3. Greater palatine artery it enters oral cavity through greater palatine foramen moving forward to enter the lateral incisive canal.

It supplies the roof of the mouth, soft palate and tonsil.

4. Pharyngeal artery: It supplies mucous membrane of the nasopharynx, auditory tube, and the sphenoidal air sinus.

5. Artery of pterygoid canal: it supplies the pharynx, auditory tube,and the tympanic cavity.

6. Sphenopalatine artery: It enters thr-ough sphenopalatine foramen.

Here it divides into:

(a)Posterior lateral nasal: it supplies the lateral wall of the nose and sphenoidal and ethmoidal air sinuses.

(b)Posterior septal branches: It anastomoses with the terminal branch of the greater palatine artery.

Q.9 Falx Cerebri

Ans.The falx cerebri is a sickle-shaped fold of dura it encloses the superior sagittal sinus and extends between the two cerebral hemispheres.

• It is made by the meningeal layer going down to reach back the mid sagittal line.

The falx cerebri occupies the great longitudinal fissure which is present between the two cerebral hemisp-heres.

Attachments:

Anteriorly: Crista gali

Posteriorly: Internal occipital crest and tentorium cerebelli.

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Within this dural fold: There is a presence of the two large venous sinuses

i) Superior sagittal sinus.

ii) Inferior sagittal sinus.

• The tentorium cerebelli extends throughout the cranium perpen-dicular to the falx cerebri.

• The falx cerebri also separates the cerebellar hemispheres from the cerebrum

• It even supports cerebrum and protects the occipital lobes.

• The falx cerebelli divides the two lobes of cerebral hemisphere.

• Lower end of the falx cerebri, the dura mater folds forming a free lower edge.

• Along the lower edge an oval space is left in the fold.

Q.10 Formation, blood supply and nerve supply of Nasal septum.

Ans. Nose is the primary pathway for the air to enter.

• Many other impurities of the air are trapped within the nose due to presence of hair and mucous secretion in the nostrils.

• The nasal septum is that structure that separates the two halves of the nasal cavity.

The nasal septum is made up of

i) Bony part.

ii) Cartilaginous part.

i) Bony Part: Made by fusion of the perpendicular plate of the ethmoid and the vomer.

ii) Cartilaginous part: It is made of hyaline cartilage.

• Both these structures play an

important role in supporting the nasal septum.

• The nasal cavity receives its secretion of mucus from the paranasal sinus and the tears which come through nasolacrimal duct.

• Septum mobile nasi is a mobile part of nasal septum.

• The part of the nasal septum at the apex of the nose, formed by skin, subcutaneous tissue, the greater alar cartilages, the membranous septum, and the columella.

Nerve Supply of Nasal Septum:

1. Olfactory nerves: one-third below the cribriform plate These nerves supply the.

2. Nasopalatine nerve: Supply the posteroinferior part of nasal septum.

3. Internal nasal branch: Supply anterosuperiorpart of nasal septum

4. Medial posterior superior nasal branches of pterygopalatine ganglion: Supply the posterosu-perior part of nasal septum.

5. Nasal branch of greater palatine nerve: Supply the posterior part of nasal septum.

6. Anterior superior alveolar nerve: Supply the anteroinferior part.

Arterial Supply of Nasal Septum

1. Septal branch of the sphenopalatine artery

2. Septal branch of the posterior ethmoidal artery

3. Septal branch of the greater palatine artery

4. Septal branch of the superior labial artery

5. Septal branch of the anterior ethmoidal artery

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Q.11 Pharyngotympanic Tube

Ans.Pharyngotympanic tube is a channel about 3.6 cm long, lined with mucous membrane.

• I t establ ishes communicat ion between the tympanic cavity and the nasopharynx.

• It serves to adjust the pressure of gas in the cavity to the external pressure, as well as for mucociliary clearance of the middle ear.

• It comprises a bony part (pars ossea), located in the temporal bone, and a cartilaginous part (pars cartilaginea), ending in the nasopharynx. eustachian canal or tube, oropharyngeal tube, and auditory tube.

Development of the Middle Ear

• The auditory tube and middle ear: Made from first pharyngeal pouch also from endodermal tubotympanic recess.

• First arch mesoderm gives rise to the malleus and incus.

• Second arch mesoderm gives rise to the stapes

• Tensor tympani muscle is attached to the cartilaginous part of the auditory tube

Q.12 Boundaries and applied aspects of Pyriform fossa

Ans. Also called as piriformis, piriform recess, piriform fossa or sinus

• It is a pear-shaped fossa in the wall of the laryngeal pharynx lateral to the arytenoid cartilage and medial to the lamina of the thyroid cartilage.

• It acts as a medium that directs solids and liquids from the oral cavity around the raised laryngeal inlet to help them to move into the esophagus.

Medially: Fossa is bounded by the aryepiglottic fold.

Floor: The piriform fossa is associated to the thyrohyoid membrane and thyroid cartilage.

Q.13 Bones forming the orbital cavity

Ans.The orbital cavity is a pyramidal shaped cavity containing the eyeballs along with its associated muscles, vessels, and nerves, the lacrimal apparatus that pass through to reach the face.

The parts of the orbit are:

i) Base

ii) Apex

iii) Roof

iv) Floor

v) Medial

vi) Lateral walls

Roof: Orbital part of the frontal bone and inferior surface of the lesser wing of the sphenoid.

Lateral wall: It is made by the orbital surfaces of the zygomatic bone and greater wing of thesphenoid.

Floor: Thin plate of bone forming the upper surface of the body of the maxilla forms the floor.

At the posteromedial corner of the orbital floor is a small triangular area formed by the orbital plate of the palatine bone.

Medial wall:It is made by the frontal process of the maxilla, the lacrimal, orbital plate of the ethmoidal labyrinth, body of the sphenoid.

Q.14Formation and contents of carotid sheath.

Ans.The carotid sheath is one of the layers of cervical fascia.

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•

•

•

•

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Anatomy

• It is the portion of the cervical fascia that encloses the carotid vessels and vagus nerve.

The contents of carotid sheath are:

a. Common carotid artery.

b. Internal carotid artery.

c. Internal jugular vein.

d. Vagus nerve.

Q.15Medial Pterygoid muscle

Ans. Medial pterygoid is a muscle of mastication.

Origin:

• Medial surface of the lateral pterygoid.

Insertion:

• Medial surface of the ramus of the mandible.

Action:

• It helps in elevation of the mandible.

• It helps in side to side movement of the mandible.

Nerve Supply:

• Mandibular branch of the trigeminal nerve.

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Excel BDS · 2021. 1. 15. · Q.9Falx Cerebri Q.10Formation, blood supply and nerve supply of Nasal...

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Transcript of Excel BDS · 2021. 1. 15. · Q.9Falx Cerebri Q.10Formation, blood supply and nerve supply of Nasal...