Occipital bone : important viva questions and answers

 

Occipital

1.      Anatomical  points:

·        Occipital condyles are directed  downwards

·        Basilar part is directed forwards and upwards

·        External surface of squamous part is convex and directed backward

2.      Morphological type : Flat bone

3.      Structure of bone : inner and outer compact and middle diploie

4.      Ossification :  area of occipital bone above the highest nuchal line  is arisen from membranous ossification and rest of the parts of occipital bone is arisen from cartilaginous ossification

5.      Development : paraxial mesoderm

6.      Parts : Squamous part , basilar part and condylar part

Squamous part :

1.      Two surfaces : external and internal

External surface of squamous part

·        External occipital protuberance : gives attachment to the highest point of the ligamentum nuchae

·        Highest nuchal line : gives attachment to epicranial aponeurosis :

·        Superior nuchal line:  its medial part attached with origin of trapezius muscle and lateral part from before backwards attached with origin of occipital belly of occipito frontalis muscle and insertion of sternocleidomastoid and splenius capitis

·        Inferior nuchal line: medially:  rectus capitis posterior minor and

                                     Laterally rectus capitis posterior major  

·        External occipital crest : gives attachment of ligamentum nuchae

·        Area between superior and inferior nuchal line : medially insertion of semispinalis capitis and laterally obliquus capitis superior  

·        Area between inferior nuchal line and foramen magnum

·        Medially rectus capitis posterior minor and laterally rectus capitis posterior major

Internal surface of squamous part of occipital bone

Internal occipital protuberance : an irregular elevation opposite the external occipital protuberance

Sagittal sulcus : lodges superior sagittal sinus and its margin of sulcus attached with falx cerebri

Transverse sulcuses (right and left)  : lodges  transverse sinuses  and its margin of sulcuses attached with tentorium cerebella

Right transverse sinus is the continuous of superior sagittal sinus and left transverse sinus is the continuous of straight sinus

Internal occipital crest lodges occipital sinus and its margin attached with falx cerebelli.

Fossae :

Two upper triangular fossae : lodge occipital lobes of the cerebrum with meninges

Two lower quadrilateral fossae : lodge cerebellar hemispheres

Vermian fossa: a small depression which lodge vermis of the cerebellum

Angles:

Superior angle :  is meeting points of occipital bone and two parietal bone

Lateral angle : is the meeting points of occipital bone, parietal bone and mastoid part of temporal bone

 

Two lambdoid borders: they are articulates with posterior border of occipital bone

Two mastoid borders: they are articulates with mastoid part of temporal bone

Basilar part of occipital bones

Parts

2.       Three surfaces and three borders

3.      Anterior surface: articulate with body of sphenoid , forming primary cartilaginous joint , ossifies by the end of the 25^th years

4.      Smooth Superior surface (also known as clivus) it is related with meninges , ligament , lower part of pons and medulla oblongata , near the foramen magnum it is related with following structures above downward

·        Membrana tectoria

·        Upper band of crucial ligament

·        Apical ligament

·        Anterior atlanto –occipital membrane

Inferior surface of basilar part of occipital bone :

Pharyngeal tubercle: a small middle bony elevation attached with fibrous raphe of pharynx and superior constrictor muscle

Lateral to pharyngeal tubercle : insertion of longus capitis muscles

Behind the attachement of longus capitis or in front of occipital condyles : insertion of rectus capitis anterior

Borders of basilar part of occipital bones

Posterior border is formed the anterior margin of foramen magnum

Two Lateral borders : articulate with petrous part of temporal bone

Condylar part of occipital bone

Parts

Superior surface : contain jugular tubercle an oval eminence overlying the hypoglossal canal

Inferior surface:

Two Occipital condyles : articulate with superior articular processes of atlas forming atlanto –occipital joint

Hypoglossal canals : they are  situated anterior part of each condyle transmits :

Hypoglossal nerve

Meningeal branch of ascending pharyngeal artery 

Emissary vein connecting basilar venous plexus with pterygoid venous plexus

Condylar fossa : a depression behind the condyle

Condylar canal occationally a foramen present within the condylar fossa which transmit emissary vein connect sigmoid sinus with veins of suboccipital triangle

Jugular process : it is situated just lateral to occipital condyles

Anterior surface of jugular process bears jugular notch which form jugular foramen by articulating with petrous part of temporal bone

Jugular foramen : transmitted

Anterior compartment  :  inferior petrosal sinus

Middle compartment : glossopharyngeal

Vagus nerve , accessory nerve 

Meningeal branch of ascending pharyngeal artery

Emissary vein

Posterior compartment :

Sigmoid sinus continued as internal jugular vein

Foramen magnum:

Smaller anterior compartment transmits

Apical ligament

Upper band of cruciate ligament

Membrane tectoria

Larger posterior compartment transmits

Lower end of medulla oblongata

Right and left vertebral artery

Anterior and posterior spinal artery

Spinal root of accessory nerve

Sympathelic plexus of nerves

Veins joining the venous plexus of medulla oblongata

Lower part of tonsil of cerebellum

7.      Foramens and structure passing through them:

·        foramen magnum,

·         jugular foramen,

Jugular foramen:

• glossopharyngeal nerve : mixed nerve : sensory supply motor supply
• vagus nerve : mixed nerve : sensory supply  motor supply
• Cranial root of accessory nerves: motor nerve. supply
• Internal jugular vein

·         

·        hypoglossal foramen

8.      Joint related to this bone:

·        Joint between basilar part of occipital bone to body of sphenoid,: type, when it converted into bone lambdoid  suture: types

·        atlanto-occipital joint : type, movement

·        Posterior frontanelle/Lamda: location, formation, time of closer

9.      Muscular attachment on external surface of squmous part

10.   Structure related within the internal surface of squamous part

11.   Relation of posterior  surface of basilar part of occipital bone

12.  Sinuses: sup sagittal sinus, transverse sinus 

 

 

Maxilla important viva questions and answers

 

Maxilla

1.      Anatomical points:

·        Frontal process of maxilla is directed upward and medially

·        Palatine process is directed medially

·        Alveolar process is directed inferiorly  

2.      Morphological type:  Pneumatic irregular bone

3.      Ossification : intra membranous ossification

4.      Development: neural crest

5.      Parts:

·       four processes :

·        Frontal process of maxilla : it is directed upward and articulate with nasal notch of frontal bone, situated in between nasal bone and lacrimal bone

·        Zygomatic process of maxilla: is directed laterally  and articulate with zygomatic bone

·        Palatine process of maxilla: lies horizontally and directed medially. it is articulated with opposite palatine process of maxilla and formed anterior 2/3 of hard palate

·          Alveolar process of maxilla : it is directed downward , by uniting opposite maxilla it is formed alveolar arch forms upper jaw

·        Body of maxilla:

·        Anterior surface

·        Posterior surface

·        Orbital surface

·        Nasal surface

·        Foramen : infra orbital foramen : transmit infra orbital nerve and vessels

·        Identify following bony impression : maxillary hiatus , ethmoidal  and conchal crest and nasolacrimal groove, maxillary tuberosity ,

·        Show the attachment   of buccinator muscle  

6.      How maxillary hiatus is reduced in size?

·        It is reduced by

·        From above : Uncinate process of ethmoid and Descending process of lacrimal bone

·        From below : maxillary process of inferior nasal concha

·        From behind: maxillary process of perpendicular plate of palatine bone

7.      Dentoalveolar joint: Gomphosis variety of fibrous joint

8.      Related questions :

9.      Maxillary sinus: lining epithelium, functions, in which nasal meatus it is open? 

10.   What is intermaxillary segment? Mention its derivatives

 

Frontal bone : short description for viva exam

 

Frontal bone

1.    Anatomical points:

·  Squamous part of frontal bone lies vertically

·  Orbital plates are directed downward and horizontally

·  Nasal spine is directed downward and forward

 

2.   Morphological type: pneumatic flat bone   

3.    Structure of bone : Frontal bone is formed by inner and outer table (compact bone) and middle diploe (sgongy bone)

4.   Ossification : intramembranous ossification (it is ossify from membrane )

5.    Development : Neural crest ( derived from ectoderm)

 6.   Parts:  Identify

·       Squamous part:

-        External surface of squamous part : Frontal tuberosity / supercilliary arch / supraorbital margin/ superobital notch or foramen / glabella

-        

-        Internal surface of squamous part : impression for cerebral sulci and gyri / sagittal sulcus or groove for superior sagittal sinus / frontal crest / foramen caecum

-        ·       Orbital part,

·       ·       Zygomatic processes

·       Nasal notch : name of the bones articulate with nasal notch

·       Right side (from medial to lateral ) right nasal bone,  right frontal process of maxilla and right lacrimal bone

·       Left side (from medial to lateral ) left nasal bone,  left frontal process of maxilla and left lacrimal bone

·       

·       Ethmoidal notch:  name of the bone articulate with ethmoidal notch?

·        Ethmoid notch is situated in between two orbital plates and articulated by cibriform plate of ethmoid

 

7.   What is metopic suture?

8.   Which bones are articulated with nasal notch:

9.   Which bone is articulated with ethmoid notch 

10.                    coronal suture: which bones forms this suture,

11.                    Foramen related to this bone and structure passing through it

12.                   Show lacrimal fossa, what structure lodge within it:

13.                   Lacrimal gland: Nerve supply

 

Lecture note: Connective Tissue Fibers

 Connective Tissue Fibers

 are formed by proteins that polymerize into elongated structures.

Three main types of connective tissue fibers

i) Collagen fiber: Protein Collagen             

ii) Reticular fiber: Protein Collagen             

iii) Elastic fiber: Protein Elastin

Collagen Fiber:

•      It is the most abundant protein in the human body.

•      They are flexible & have a remarkably high tensile strength.

•      In light microscope, collagen fibers typically appear as wavy structures of variable width & stain readily with eosin & other acidic dyes.

•      When examined with TEM, collagen fibers appear as bundles of fine threadlike subunits. These subunits are collagen fibrils.

 Elastic Fiber

•      It allows tissues response to stretch and distension. EF are typically thinner than collagen fiber and are arranged in a branching pattern. EF stained with eosin but not well; therefore, they cannot be distinguished from collagen fiber in routine H& E preparations.

•      Elastic property of the elastin molecule is related to its unusual polypeptide backbone that causes random coiling.

•      EF are produced by many of the same cells that produce collagen and reticular fibers, particularly fibroblast and smooth muscle cells.

Elastic fiber is a major extracellular substance in vertebral ligaments, larynx, and elastic arteries.

Reticular fibers:

are named for their arrangement in a mesh like pattern or network. It provides a supporting framework for the cellular constituents of various tissues & organs. In light & electron microscope preparations, it can not be identified positively.

Lecture note : connective tissue summarized for viva examination

 Connective tissue

Connective tissue are composed mainly of intercellular elements with a limited number of cells

Composition of Connective tissue: Connective tissue is composed by connective tissue cells and extra-cellular matrix.

Connective tissue cells

Connective tissue cells	Functions	Figure
Permanent cells:
Fibroblasts/fibrocyte	Produce fibres of connective tissue
Macrophages	They phagocyte foreign substances, micro-organisms
Mast cells	Function in  immediate hypersensitivity reaction
Adipose cells	Energy storage, cushioning of vital organ organs
Mesenchymal stem cells

 

Wandering or transient cells:
Plasma cells	They are derived from B lymphocytes, produce antibodies
Lymphocytes: they are 3 types: T lymphocyte cells, B lymphocyte  cells & NK cells	They are involved in immune response
Monocytes	Macrophage derived from monocytes
Neutrophils	Take part in immune response
Eosinophils	Function in allergic reactions & parasitic reaction
Basophils	Take part in immune response

Extra cellular matrix: composed by connective tissue fibres and ground substanc

Connective tissue fibers: three types of fibres are present

i) Collagen fiber: formed by Collagen protein. location: bone, cartilage  

 ii) Reticular fiber: formed by Collagen protein: location : spleen, liver                

iii) Elastic fiber: formed by Elastin protein: location: vertebral ligaments, and elastic arteries.

Ground substance

·            Glycosaminoglycans (GAGs)

·         Proteoglycans

·         Multiadhesive glycoprotein

Macrophages are phagocytic cells derived from monocytes

Mononuclear phagocytotic system: cells of mononuclear phagocytotic system are derived from monocytes.

Cells of Mononuclear phagocytotic system

Name of cells	Location
Macrophage	Connective tissue, spleen
Kupffer cell	Liver
Alveolar macrophage	Lungs
Dendritic cells	Lymph node
Langerhans cells	Skin
Microglia	Central nervous system
Osteoclast	Bone

Classification of connective tissue

A. Embryonic connective tissue:

•         Mesenchymal

•         Mucous

B. Adult connective tissue:

Connective tissue proper:

Loose conne. tissue : lamina propria of GIT

Dense conne. tissue: they are two types : Regular: ex: tendon    Irregular: dermis of skin

Specialized conne. tissue:

Adipose tissue ,Elastic tissue ,Hematopoietic tissue, Blood

Supporting conne. tissue:

Cartilage, Bone

Cartilage: is a form of connective tissue composed of cells called chondrocytes and a highly specialized extracellular matrix

Types of cartilage: (according to the number of cells and the nature of the matrix) 

1. Hyaline cartilage 2.Elastic cartilage 3. Fibrocartilage

Features	Hyaline cartilage	Elastic cartilage	Fibrocartilage
Distribution	Tracheo-bronchial cartilage, costal cartilage of rib and nasal cartilage, most of the laryngeal cartilage	Epiglottis, external ear and ear canal, auditory tube, some laryngeal cartilage( corniculate, cuneiform etc.)	Intervertebral discs and pubic symphysis, articular discs of temporo-mandibular, sternoclavicular joint, menisci of the knee joint
Presence of perichondrium	Yes	Yes	No
Undergoes  calcification	Yes	No	Yes
Cell types	Chondroblast, chondrocyte	Chondroblast, chondrocyte	Chondrocytes, fibroblasts
Slide identification	*Cartilaginous matrix: is homogeneous *Cells: Lacunae (ovoid space within the matrix) contain chondrocyte *Perichondrium: present	*Cartilage matrix contain elastic fiber so it is not homogenous Lacunae contain chondrocyte *Perichondrium Present	Cartilaginous matrix: thick collagen fibres located between parallel rows of condrocytes *Cells: are arranged in  parallel rows between the bundles of  thick collagen fibers *Perichondrium: absent

 Mucous connective tissue

It is present in the umbilical cord. It consists of a specialized gelatin-like ground substance called wharton’s jelly. The spindle shaped mesenchymal cells occupies large intercellular spaces.

Topics	Loose  connective tissue:	Dense irregular connective tissue	Dense regular connective tissue
Cells	Large number of cells	Less number of cells	Less number of cells
Arrangement of cells	No definite pattern	No definite pattern	Arranged in definite pattern
Fibres	Less in amount	More in amount	More in amount
Arrangement of Fibres	No definite pattern	No definite pattern	Arranged in definite pattern
Examples:	Lamina propria of  GIT	Submucosa of GIT	Tendon