Anatomía - Hueso Esfenoides (Cuerpo, Alas Mayores y Menores, Procesos Pterigoideos)

Esfenoides: Anatomía y Funciones

Introducción al Hueso Esfenoides

• El esfenoides es un hueso impar, central y simétrico ubicado en la fosa craneal media. Se articula con varios huesos del cráneo: frontal y etmoides por delante, occipital por detrás, y temporal y parietales lateralmente.

• Su nombre significa "en forma de cuña", reflejando su posición entre otros huesos craneales.

Estructura del Esfenoides

Cuerpo del Esfenoides

• El cuerpo tiene forma cúbica con seis caras: superior, inferior, dos laterales, anterior y posterior.

• La cara superior presenta el "yugo esfenoidal" que contiene canales olfatorios conectados a la lámina horizontal del etmoides.

Elementos Clave de la Cara Superior

• La "Crista cribosa" sobresale para articularse con el etmoides; también se encuentra el canal óptico que aloja el quiasma óptico.

• Los agujeros ópticos permiten el paso del nervio óptico y la arteria oftálmica.

Silla Turca y Nervios Asociados

• Detrás del canal óptico está la fosa pituitaria o silla turca que aloja la glándula pituitaria.

• La silla turca tiene escotaduras laterales que permiten el paso de los nervios oculomotor (superior) y abducens (inferior).

Apófisis Clinoides

Descripción General

• Las apófisis clinoides son eminencias en los ángulos de la silla turca; hay anteriores (verdes), posteriores (rojas), y medias.

• Las apófisis clinoides medias pueden fusionarse con las anteriores formando un orificio carotid clinoideo para permitir el paso de la arteria carótida interna.

Cara Inferior del Esfenoides

Características Principales

• Presenta una cresta media llamada cresta inferior que aloja al canal del bommer; esta articulación es fibrosa tipo esquindilesis.

• Dos surcos a cada lado alojan bordes del bommer; uno externo forma un conducto junto a la apófisis esfenoidal del palatino.

Cara Anterior del Esfenoides

Elementos Notables

• Desde este punto de vista, se observa una lámina horizontal fina que se articula con el frontal y etmoides.

Anatomy of the Sphenoid Bone

Overview of the Sphenoid Bone Structure

• The sphenoid bone features semi-arid areas similar to those found on the posterior face of the ethmoid, which unite to form small air cavities.

• The dorsum sellae articulates with the occipital bone, forming a crucial anatomical point known as the clivus.

• A lateral view reveals sections of both lesser and greater wings, highlighting the dorsum sellae and Turkish saddle structure.

Cavernous Sinus and Associated Nerves

• The cavernous sinus contains critical elements such as internal carotid arteries and cranial nerves: abducens, oculomotor, trochlear, and ophthalmic branch of trigeminal nerve.

Lesser Wings of Sphenoid

• Lesser wings are also referred to as orbital wings due to their contribution to forming the roof of the orbit; they have a triangular shape.

• They feature an anterior sharp edge that articulates with the frontal bone and a posterior edge ending in an anterior clinoid process.

Greater Wings of Sphenoid

• Greater wings originate from lateral faces of sphenoid; they appear star-like and consist of three surfaces and three borders.

• The superior or posterior surface shows impressions left by brain lobes; it is important for understanding brain anatomy.

Important Openings in Greater Wings

• The anterior face forms part of the external wall of the orbit with significant borders contributing to various foramina including sphenoidal fissure.

• External surface divided by a crest into upper (temporal fossa contributor) and lower portions (zygomatic fossa contributor).

Key Foramina Related to Cranial Nerves

• The sphenoidal fissure allows passage for cranial nerves III (oculomotor), IV (trochlear), V1 (ophthalmic), along with ophthalmic vein.

• Foramen rotundum permits entry for maxillary nerve (V2); below it lies foramen ovale allowing mandibular nerve (V3).

Anatomical Structures of the Sphenoid Bone

Overview of Key Anatomical Features

• The Arnold's foramen (or currently known as the petrous foramen) allows passage for the lesser petrosal nerve, a branch of the facial nerve. Additionally, it features Vesalius' foramen, which connects intracranial circulation with the pterygoid venous plexus.

• The confluence of the external and internal borders forms an anatomical structure called the spine of the sphenoid, which serves as an attachment point for several ligaments including the sphenomandibular ligament and spinosum ligament.

• The term "pterygoid" translates to "wing-shaped." The pterygoid processes consist of a base, two wings, and a fossa. The base has a thick external root originating from the lower part of the greater wings.

• The internal base is thinner and arises from the lateral aspect of the inferior surface of the sphenoid body. It contains a canal known as Vidian canal or pterygoid canal, which transmits the vidian nerve.