foramen

n., pl., -ram·i·na (-răm'ə-nə), or -ra·mens.
An opening or orifice, as in a bone or in the covering of the ovule of a plant.

[Latin forāmen, an opening, from forāre, to bore.]

foraminal fo·ram'i·nal (-răm'ə-nəl) or fo·ram'i·nous (-nəs) adj.

(fôrā′mən)
n

1. a natural opening in a bone or other structure. 2. a natural opening in the root, usually at or near the apical end.

Foramen. (Liebgott, 2001)

A round or oval hole or opening in a bone or between bone cavities through which nerves and blood vessels pass.

Pl. foramina [L.] a natural opening or passage, especially one into or through a bone.

• alar f. — a foramen which perforates the wing of the atlas in some species and transmits the vertebral artery; appears as a notch in dogs.
• apical f. — the opening at or near the apex of the root of a tooth and into the dental cavity.
• auditory f. (external) — the external acoustic meatus.
• auditory f. (internal) — the passage for the auditory (vestibulocochlear) and facial nerves in the pars petrosa of the temporal bone. Called also internal acoustic meatus.
• caudal palatine f. — the caudal opening into the greater palatine canal.
• caval f. — one of the three openings in the diaphragm; situated in the central tendinous part of the diaphragm; called also vena caval foramen, foramen venae cavae.
• cecal f., f. cecum — a blind opening between the frontal crest and the crista galli.
• f. cecum linguae — an occasional finding in humans; marks the boundary of the caudal and rostral contributions to the tongue, the site of the origin of the thyroid gland; called also cecum foramen.
• condyloid f. (anterior) — hypoglossal canal.
• condyloid f. (posterior) — condylar canal.
• epiploic f. — an opening connecting the omental bursa with the rest of the abdominal cavity; situated on the visceral surface of the liver dorsal to the portal fissure. Called also foramen of Winslow.
• e. f. hernia strangulation — rare cause of acute intestinal obstruction in horses.
• incisive f. — one of the openings of the incisive canals into the incisive fossa of the hard palate.
• infraorbital f. — the facial opening of the infraorbital canal, a prominent feature of the lateral aspect of the face; provides a point of emergence for the infraorbital nerve.
• interventricular f. — a passage from the third to the lateral ventricle of the brain.
• intervertebral f. — a passage for a spinal nerve and vessels formed by notches on the pedicles of adjacent vertebrae.
• jugular f. — an opening formed by the jugular notches of the temporal and occipital bones.
• f. lacerum — the irregular gap between the basioccipital, petrous temporal and sphenoid wing bones, making up a large, membrane-covered foramen in horses, but reduced to a slit in other domestic mammals.
• f. magnum — a large opening in the occipital bone, between the cranial cavity and spinal canal.
• f. magnum herniation — see transtentorial herniation.
• mandibular f. — in the medial surface of the mandible; inferior alveolar vessels and nerve enter here.
• maxillary f. — one of the foraminae ventral to the orbit; leads to the infraorbital canal.
• mental f. — foramina on the lateral aspect of the mandible from which the inferior alveolar nerve and blood vessels emerge to supply the chin.
• mastoid f. — an opening in the temporal bone behind the mastoid process.
• f. of Monro — interventricular foramen.
• nutrient f. — the entrance for the nutrient artery of a bone.
• obturator f. — the large opening between the pubic bone and the ischium.
• optic f. — the opening into the optic canal.
• orbital f. — transmits ophthalmic branch of trigeminal, oculomotor, abducent and trochlear nerves. Called also orbital fissure.
• orbitorotundum f. — the copy, in pigs and ruminants, of the orbital foramen in other species.
• f. ovale — 1. the septal opening in the fetal heart that provides a communication between the atria. The opening closes at birth; failure to close results in atrial septal defect.
— 2. an aperture in the great wing of the sphenoid for vessels and nerves.
• palatine f. (anterior) — greater and lesser foramina in the hard palate for conduction of palatine vessels.
• pneumatic f. — apertures in avian bones which connect with air sacs making pneumatization of bone marrow cavities possible.
• f. primum — opening in the septum primum between the two atria of the embryonic heart; called also ostium primum.
• retroarticular f. — the external opening of the temporal canal just caudal to the zygomatic arch; this foramen provides an exit for a large vein, the transverse sinus which drains the cranial cavity.
• f. rotundum, round f. — a round opening in the great wing of the sphenoid for the exit of the maxillary branch of the trigeminal nerve from the cranial cavity; in ruminants it is combined with the orbital fissure.
• round f. — see foramen rotundum (above).
• sacral f. (dorsal) — passage on the dorsal surface of the sacrum for the dorsal branches of the sacral nerves.
• sacral f. (ventral) — passage on the pelvic surface of the sacrum for the ventral branches of the sacral nerves.
• Scarpa's f. — an opening behind the upper medial incisor, for the nasopalatine nerve.
• sciatic f. — either of two foramina, the greater and the lesser sciatic foramina, formed by the sacrotuberal and sacrospinous ligaments in the sciatic notches of the hip bone.
• f. secundum — the second of the two orifices to perforate the septum primum between the cardiac atria; forms through cell death. Called also ostium secundum.
• sphenopalatine f. — a space between the orbital and sphenoidal processes of the palatine bone, opening into the nasal cavity and transmitting the sphenopalatine artery and the nasal nerves.
• spinous f. — a hole in the great wing of the sphenoid for the middle meningeal artery.
• stylomastoid f. — the opening of the facial canal, adjacent to the ear from which the facial nerve emerges.
• supracondylar f. — a fissure in the mediodistal part of the humerus in cats through which the median nerve and vessels pass.
• supraorbital f. — passage in the frontal bone for the supraorbital vessels and nerve; often present as a notch bridged only by fibrous tissue.
• thebesian f. — minute openings in the walls of the heart through which the smallest cardiac veins (thebesian veins) empty into the cardiac chambers.
• transverse f. — the passage in either transverse process of a cervical vertebra that, in the first six vertebrae, transmits the vertebral vessels.
• f. triosseum — the hole between the ends of the avian clavicle, coracoid and scapula that transmits the tendon of the supracoracoid muscle and serves as a fulcrum to lever the wing upwards.
• vena cava f. — an opening in the diaphragm for the caudal vena cava.
• vertebral f. — 1. the large opening in a vertebra formed by its body and its neural arch.
— 2. transverse foramen.
• f. of Vesalius — an occasional opening medial to the foramen ovale of the sphenoid, for passage of a vein from the cavernous sinus.
• f. of Winslow — epiploic foramen.

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