The foramen rotundum is a circular hole in the

sphenoid bone The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of the occipital bone. The sphenoid bone is one of the seven bones that articulate to form the o ...

of the skull. It connects the

middle cranial fossa The middle cranial fossa, deeper than the anterior cranial fossa, is narrow medially and widens laterally to the sides of the skull. It is separated from the posterior fossa by the clivus and the petrous crest. It is bounded in front by the pos ...

and the

pterygopalatine fossa In human anatomy, the pterygopalatine fossa (sphenopalatine fossa) is a fossa in the skull. A human skull contains two pterygopalatine fossae—one on the left side, and another on the right side. Each fossa is a cone-shaped paired depression deep ...

. It allows for the passage of the

maxillary nerve In neuroanatomy, the maxillary nerve (V) is one of the three branches or divisions of the trigeminal nerve, the fifth (CN V) cranial nerve. It comprises the principal functions of sensation from the maxilla, nasal cavity, sinuses, the pala ...

(V₂), a branch of the

trigeminal nerve In neuroanatomy, the trigeminal nerve ( lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for sensation in the face and motor functions such as biting and che ...

Structure

The foramen rotundum is one of the several circular apertures (the

foramina In anatomy and osteology, a foramen (;Entry "foramen"
in

) located in the

base of the skull The base of skull, also known as the cranial base or the cranial floor, is the most inferior area of the skull. It is composed of the endocranium and the lower parts of the calvaria. Structure Structures found at the base of the skull are for ...

, in the anterior and medial part of the

. The mean area of the foramina rotunda is not considerable, which may suggest that they play a minor role in the dynamics of blood circulation in the venous system of the head.

Development

The foramen rotundum evolves in shape throughout the fetal period, and from

birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the f ...

to adolescence. It achieves a perfect ring-shaped formation in the fetus after the 4th fetal month. It is mostly oval-shaped in the fetal period, and round-shaped after birth (generally speaking). After birth, the rotundum is about 2.5 mm and in 15- to 17-year-olds about 3 mm in length. The average diameter of the foramen rotundum in adults is 3.55 mm.

Function

The foramen rotundum allows the passage of the

(V₂), a branch of the

. It also allows the passage of the artery of the foramen rotundum and an emissary vein.

History

Etymology

Foramen is the Latin term designating a hole-like opening. It derives from the Latin forare meaning to bore or perforate. Here, the opening is round as indicated by the Latin rotundum meaning round.

References

External links

* * ()
Superior view of the base of the skull at winona.edu
{{Authority control Foramina of the skull