Anterior Crainal Fossa
Learning Objectives
 At the end of the lecture student will able:
 Describe the skull bone that forms the anterior cranial fossa.
 Demonstrate the foramina and openings present in anterior cranial fossa.
 Discuss the part of brain in relation to the anterior cranial fossa.
 Interior Of the skull
 Cranium is lined internally by endocranium
 The thickness of cranial vault is variable
 Most of the cranial bones are consist of:
 a) an outer table of compact bone which is thick and tough,
 b) an inner table of compact bone which is thin & brittle,
 c) Diploe which consist of spongy bone filled with Red marrow.
 Skull bones derived their blood supply mostly from meningeal arteries. Very little from arteries
of the scalp
 Internal Surface of the Cranium
 The interior of the base of the skull presents natural subdivision into anterior, middle and
posterior cranial fossae.
 Dura mater is firmly adherent to the floor of the fossae and is continuous with pericranium thru
the foramina and fissures.
 Internal or Superior Surface of
Base of Skull
 Forms floor of cranial cavity
 Divided into 3 fossae, called

Anterior

Middle

Posterior cranial fossae
 Anterior cranial Fossa
 Bounderies :
 Anteriorly--- Anteriorly and on the sides by the frontal bone.
 Posteriorly: It is separated from the middle cranial fossa by the free posterior border of lesser
wing of sphenoid, the anterior clinoid process and anterior margin of sulcus chiasmaticus.
 Floor: anteriorly by the cribriform plate of ethmoid bone, posteriorly by the superior surface of
anterior part of the sphenoid—jugum sphenoidale.
 On each side—orbital plate of frontal bone and is completed posteriorly by the lesser wing of
sphenoid.
 Anterior Cranial Fossa
 Cribriform Plate of the Ethmoid Bone
 Separates the anterior cranial fossa from the nasal cavity.
 It’s a quadrilateral shape.
 Anterior margin articulates with the frontal bone at the frontoethmoidal suture.
 Posterior margins articulates with the jugum sphenoidale—posteriolateral corners –posterior
ethmoidal canals.
 Lateral margins articulates with the orbital plate of the frontal bone: in b/w the suture the
anterior ethmoidal canal placed—behind the crista galli.
 Olfactory grooves of cribriform plate

Support olfactory bulb

Perforated by foramina for transmission of olfactory nerves &, more rostrally, by a slit
for nasociliary nerve
 Anterior Cranial Fossa
 Frontal crest (of frontal bone)

In midline most anteriorly, on which attaches falx cerebri
 Foramen cecum
-- The frontal crest of the frontal bone ends below in a small notch which is converted into a
foramen, by articulation with the ethmoid

Transmits a small vein from nasal cavity to superior sagittal sinus
 Crista galli

Upward continuation of perpendicular plate of ethmoid bone, to which attaches falx
cerebri
 The foramen cecum, between the frontal bone and the crista galli of the ethmoid, which usually
transmits a small vein from the nasal cavity to the superior sagittal sinus;
 Anterior Cranial Fossa
 Orbital plate of the frontal bone:
 It separates the anterior cranial fossa from the orbit, frontal air sinus may extend into its
anteriomedial part.
 Medial margins of the plate covers the lybrinth of the ethmoid and posterior margin
articultaes with the lesser wing of sphenoid.
 Lesser wing of sphenoid:
 Is broad medially where it is continuous with the jugum spenoidale and tapers alterally.
 Its free posterior borders fits into the stem of the lateral sulcus of brain.
 Medially it ends as anterior clinoid process.
 Inferiorly the posterior border forms the upper boundary of superior orbital fissure.

Jugum sphenoidale separates the anterior cranial fossa from the sphenoidal sinuses
 Anterior cranial Fossa
 It is traversed by the
frontoethmoidal suture
sphenoethmoidal suture
sphenofrontal sutures.
 Anterior Cranial Fossa
 Frontal lobes of brain rest on the fossa.
 Traversed by frontoethmoidal, sphenoethmoidal, & sphenofrontal sutures.
 The anterior clinoid process gives attachmant to the free margin of the tentorium cerebelli.
 Anterior cranial Fossa
 Anterior ethmoidal foramen

situated about the middle of the lateral margin of the olfactory groove,

Transmits the anterior ethmoidal vessels and the anterior ethmoidal nerve
 Posterior ethmoidal foramen

Opens at the back part of this margin under cover of the projecting lamina of the
sphenoid

transmits the posterior ethmoidal vessels and nerve
 Fracture anterior cranial fossa