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Mostración Cadavérica 2022 - Cráneo
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Mostración Cadavérica 2022 - Cráneo

Introduction to Cranial Anatomy

In this section, the speaker introduces the division of the skull into different regions and discusses the anatomical structures within each region.

Divisions of the Skull

  • The skull is divided into an anterior or rostral region known as the facial or viscerocranium, consisting of bones forming the face and muscles for facial expressions.
  • Another region is the caudal part called the neurocranium, housing the central nervous system except for the spinal cord.
  • The base of the skull includes anterior, middle, and posterior cranial fossae with specific bone boundaries and foramina.

Structure of Cranial Bones

This part delves into the internal structure of cranial bones and their functions in protecting vital organs.

Internal Structure of Cranial Bones

  • Cranial bones have a peripheral layer of compact tissue (external lamina) and inner compact tissue (internal lamina), with spongy bone in between known as diploe.
  • Some cranial bones contain pneumatic cavities like ethmoid cells serving various functions including resonance in speech.

Articulations in Cranial Bones

The discussion focuses on different types of articulations found in cranial bones based on tissue composition and mobility.

Types of Articulations

  • Fibrous joints without movement are sutures that can fuse into bony joints in adults.
  • Sutures vary based on surface articulation; coronal sutures resemble gear teeth while sagittal sutures are tooth-like.
  • Temporal-parietal junction lacks tooth-like structures but has serrated edges resembling scales, termed squamous structures.

Detailed Anatomy of the Cranial Fossae

In this section, the speaker delves into the detailed anatomy of the cranial fossae, focusing on the anterior, middle, and posterior fossae. The discussion includes boundaries, bones involved, and key structures within each fossa.

Anterior Cranial Fossa

  • The anterior cranial fossa is delimited anteriorly by the vertical portion of the frontal bone and posteriorly by the lesser wing of the sphenoid bone.
  • It comprises bones such as the frontal bone and ethmoid bone with its cribriform plate.
  • Key structures include the crista galli, cribriform plate foramina (foramen cecum), and olfactory nerve fibers.

Middle Cranial Fossa

  • Boundaries of the middle cranial fossa include the petrous part of temporal bone superiorly and dorsum sellae inferiorly.
  • Comprised of bones like temporal bone, parietal bone, and greater wing of sphenoid with structures such as sella turcica housing pituitary gland (hypophyseal fossa) and optic canal for optic nerve passage.

Posterior Cranial Fossa

  • Posterior cranial fossa is delineated by superior border of petrous part of temporal bone superiorly and dorsum sellae inferiorly.

Anatomy of the Skull

In this section, the speaker delves into the intricate details of the skull anatomy, focusing on various foramina and structures present in different regions.

Foramen Espinoso and Arteries

  • The Foramen Espinoso is highlighted as a significant structure where the arteria meníngea media enters.
  • In a living being, this foramen is closed by cartilage, allowing passage for nerves like nervio petroso mayor.

Nervio Petroso Mayor and Conducto Trigémino

  • The pathway of nervio petroso mayor towards nervio del conducto trigémino is discussed.
  • This journey involves forming connections that aid in communication within the skull.

Fosa de Gasé and Ganglio Trigémino

  • Details about Fosa de Gasé are provided, along with insights into Ganglio Trigémino impressions on bones.
  • Notable grooves related to nervio petroso mayor are identified on the left side of the skull.

Exploring Cranial Fossae

This segment focuses on exploring different cranial fossae, highlighting key landmarks and structures within each region.

Abertura Interna and Arteries

  • The opening for arteria carótida interna through conducto carotídeo is emphasized.
  • Various connections between cranial fossae and surrounding regions are discussed.

Fosa Craneal Posterior

  • Description of fosa craneal posterior boundaries involving occipital bone and temporal region.
  • Main features like cli bus occipital are pointed out within this region.

Neuroanatomy Insights

This part delves deeper into neuroanatomical aspects within the skull, shedding light on critical structures and their functions.

Foramen Occipital

  • Significance of foramen occipital in facilitating communication between different neural components is explained.
  • Details about conducto auditivo interno housing facial nerve (nervio facial), vestibulocochlear nerve (nervio vestíbulo coclear), and arteria laberíntica are shared.

Foramen Yugular

  • Exploration of foramen yugular reveals its role in accommodating important nerves like vago (décimo par craneal).

New Section

In this section, the speaker discusses the cranial nerves and their pathways through various structures in the head.

Cranial Nerves Pathway

  • The optic nerve passes through the optic canal along with the ophthalmic artery.
  • Cranial nerves III, IV, and VI exit towards the orbit through the superior orbital fissure.
  • The trigeminal nerve branches into three terminal nerves: ophthalmic (V1), maxillary (V2), and mandibular (V3).
  • Facial nerve (VII) and vestibulocochlear nerve (VIII) enter through the internal acoustic meatus.
  • Glossopharyngeal (IX), vagus (X), and accessory (XI) nerves exit via the jugular foramen alongside the internal jugular vein.

New Section

This part focuses on dividing the skull base into three zones based on specific landmarks.

Skull Base Division

  • Divide the skull base into anterior, middle, and posterior zones using horizontal lines.
  • The anterior zone corresponds to facial structures, while the middle zone is known as yugular region.
  • The posterior zone is termed occipital region; if divided into two zones only, it would be facial and temporal regions.

New Section

Detailed explanation of subdividing the yugular region of the skull base.

Subdividing Yugular Region

  • Subdivide yugular region into central quadrilateral and lateral triangles by marking bony landmarks like occipital condyles.

Anatomical Structures of the Skull

In this section, the speaker discusses various anatomical structures of the skull, focusing on different regions and features.

Office y Stereo Mix Dividiéndonos

  • The speaker divides the skull into an anterolateral triangle and a posterior triangle.
  • Key structures in the anterolateral triangle include the articular tubercle, mandibular fossa, and external auditory canal.
  • These structures are visible from the exobase and contain air columns without any dark nervous elements.

Forámenes and Triángulo Postal Interno

  • Discussion on foramen oval, foramen spinosum, and foramen rotundum.
  • Identification of the thyroid process within the next to thyroid cartilage region.
  • Exploration of structures in the posterior internal triangle such as jugular fossa, glossopharyngeal nerve canal, and carotid canal.

Posterior Zone Details

  • Examination of veins passing through venous sinuses in the occipital region.
  • Notable landmarks like occipital condyles, foramen magnum, external occipital crest with external occipital protuberance discussed.

Orbital Cavities

This part delves into orbital cavities or orbits within a skull model, highlighting their positioning relative to nasal cavities.

Orbital Configuration

  • Description of left and right orbits flanking nasal cavities in a skull model.
  • Orbits situated laterally to nasal cavity superiorly to maxillary bone and inferiorly to cranial base forming pyramidal shape with quadrangular base at front.

Lateral Wall Composition

  • Lateral wall composed sequentially by zygomatic bone portion followed by greater wing of sphenoid bone leading to lateral orbital margin formed by frontal bone's orbital part.

Superior Wall Structure

  • Superior wall consists mainly of frontal bone's orbital part anteriorly transitioning posteriorly into lesser wing of sphenoid bone.

Detailed Orbit Anatomy

Detailed exploration of orbit anatomy focusing on medial wall composition along with floor structure within a triangular pyramid framework.

Medial Wall Components

  • Medial wall formed by four bones: frontal process of maxilla, lacrimal bone's frontal process, orbital plate of ethmoid bone anteriorly; lateral body face portion of sphenoid bone posteriorly.

Inferior Wall Formation

  • Inferior wall comprises three bones: frontal process of maxilla anterior-laterally; orbital surface portion of palatine bone medially; small orbital process from palatine bone posteriorly.

Apex & Base Clarification

Understanding Orbital Anatomy

In this section, the speaker delves into the intricate details of orbital anatomy, highlighting key structures and their interconnections within the orbit.

Fissures in Orbital Anatomy

  • The superior orbital fissure connects the orbit with the middle cranial fossa. It houses structures like the lacrimal nerve, frontal nerve branches, and motor nerves.
  • The inferior orbital fissure links the orbit with the anterior cranial fossa, containing structures such as the infraorbital artery and vein, zygomatic nerve, and maxillary nerve.

Optic Nerve Pathway

  • The optic canal serves as a passage for the optic nerve and ophthalmic artery to connect the orbit with the middle cranial fossa.
  • Ethmoidal foramina (anterior and posterior) facilitate communication between the orbit and anterior cranial fossa for nerves and vessels.

Lacrimal System Connections

  • The inferior meatus houses the inferior orbital fissure leading to connections with infraorbital vessels and nerves.
  • The lacrimal duct communicates between the orbit and nasal cavity through its inferior portion.

Elements of the Nasal Cavity Roof

The discussion focuses on the components comprising the roof of the nasal cavity, detailing structures from anterior to posterior.

Components of the Nasal Cavity Roof

  • The nasal bones are located on both sides and articulate with the frontal bone's spine.
  • The inferior nasal concha ends anteriorly at the nasal crest of the maxilla.
  • Anatomical positioning is emphasized by rotating and identifying structures in relation to each other.

Floor and Inferior Boundary of Nasal Cavities

Exploring the floor and lower boundary of the nasal cavities, highlighting key anatomical features.

Floor and Lower Boundary Details

  • The floor consists of maxillary palatine processes and horizontal plates, forming the inferior limit.
  • Identification of maxillary processes and palatine bones aids in understanding nasal cavity structure.

Medial Wall Structures in Nasal Cavities

Discussing structures forming the medial wall within the nasal cavities for comprehensive anatomical insight.

Medial Wall Composition

  • The medial wall comprises cartilaginous nasal septum along with bony structures like perpendicular plates.
  • Detailed examination reveals superior, middle, and inferior conchae contributing to lateral wall formation.

Anatomy Overview

In this section, the speaker provides an overview of various anatomical structures and their relationships in the head region.

Structures and Communication Pathways

  • The inferior nasal meatus communicates with the nasolacrimal duct, connecting the nasal cavity to the exterior.
  • The lateral wall of the nasal cavity communicates with the pterygopalatine fossa through the sphenopalatine foramen.
  • The superior aspect of the nasal cavity connects to the anterior cranial fossa via multiple foramina, including anterior and posterior ethmoidal foramina.

Temporal Fossa Anatomy

This part focuses on detailing the boundaries and contents of the temporal fossa.

Boundaries and Contents

  • The temporal fossa's superior boundary consists of superior temporal lines on frontal and parietal bones.
  • The inferior limit is defined by the zygomatic arch at the level of zygomatic process articulation.
  • Medially, it includes temporal surfaces of frontal and parietal bones, along with temporal squama and greater wings of sphenoid bone.

Fossa Infra Temporalis Details

Exploring further into the infra-temporal fossa anatomy and its connections.

Fossa Components

  • Within this space, one can find muscles like temporalis, arteries (superficial/temporal), veins (temporal), as well as auriculotemporal nerve.

New Section

In this section, the speaker discusses the structure of the maxillary derivative fissure and its formation.

Maxillary Derivative Fissure Structure

  • The fissure is formed by the intersection of three walls: superior, anterior, and medial.
  • It is limited by the fusion walls for temporal and communicates with other regions such as the temporal fossa and pharynx.
  • Communication occurs with the temporal region, specifically with the medial temporal fossa and laterally with the infra-temporal fossa.
  • The infra-temporal fossa communicates with the pterygopalatine region through a space called "retro-jugular canal."

New Section

This section focuses on delineating elements in the lateral skull region and their importance in relation to other cranial regions.

Lateral Skull Region Elements

  • The lateral skull region contains numerous important bony elements crucial for interactions with other cranial regions.
  • The external auditory meatus has a triangular shape connecting to infra-temporal fossa.
  • Walls of external auditory meatus are formed by various structures like maxilla, zygomatic bone, and sphenoid bone components.
  • Specific structures like perpendicular plate of palatine bone form part of this region's boundaries.

New Section

This section delves into how structures within the external auditory meatus communicate with adjacent regions.

Communication Pathways

  • External auditory meatus communicates via various foramens like stylomastoid foramen linking to infra-temporal fossa.
  • Foramen located at junction between anterior wall of external auditory meatus connects to nasal cavity carrying vascular-nervous bundles.

New Section

Here, detailed information about contents passing through specific foramina within skull regions is provided.

Contents Passing Through Foramina

  • Foramen in superior part of external auditory meatus connects to nasal cavity housing artery bundles at junction points.

New Section

This segment explores additional conduits within skull regions facilitating communication between different cavities.

Conduits for Communication

Detailed Explanation of Fossa Tendina and Fossa Ethmoidal Palatine

In this section, the speaker provides a detailed explanation of the fossa tendina and fossa ethmoidal palatine, highlighting their anatomical features and boundaries.

Anatomical Features of Fossa Tendina

  • The fossa tendina is located by tilting and rotating the preparation to visualize its walls.
  • Walls include: anterior wall formed by maxillary tuberosity, posterior wall by anterior face of pterygoid process of sphenoid bone.
  • Superior/base formed by greater wing of sphenoid bone, ethmoid labyrinth, and medial pterygoid plate.

Boundaries of Fossa Ethmoidal Palatine

  • Lateral boundary: maxillary hiatus fissure communicating with infratemporal fossa.
  • Apex at angle formed by maxillary tuberosity and posterior wall (anterior face) of pterygoid process.
  • Location of greater palatine canal at tip of forceps; lesser palatine canal slightly posterior.

Detailed Description of Fossa Ethmoidal Palatine

  • Anterior due to presence of maxilla; posterior due to mastoid process; root removed for clarity.
  • Walls include: anterior - maxillary nature; posterior - anterior face pterygoid process; medial - perpendicular plate palatine bone; base - body ethmoid labyrinth, greater wings sphenoid bone; apex - angle between maxillary tuberosity and anterior face pterygoid process forming greater palatine canal.