orbital fissure

orbital fissure

Etymology: L, orbita, wheel track, fissura, cleft

the space between the floor and lateral wall of the orbit, serving as a conduit for nerves and blood vessels.

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fissure

1. a narrow slit or cleft, especially one of the deeper or more constant furrows separating the gyri of the brain.

2. in dermatology a deep crack in the skin, often through a scab, which penetrates into the subcutis.

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abdominal fissure

a congenital cleft in the abdominal wall.

anal fissure, fissure in ano

a painful linear ulcer at the margin of the anus.

fissure of Bichat

transverse fissure (2).

branchial fissure

branchial cleft.

central fissure

fissure of Rolando.

collateral fissure

a longitudinal fissure on the ventral surface of the cerebral hemisphere between the fusiform gyrus and the hippocampal gyrus.

dorsal median fissure

1. a shallow vertical groove in the closed part of the medulla oblongata, continuous with the dorsal median sulcus of the spinal cord.

2. a shallow vertical groove dividing the spinal cord throughout its whole length in the midline dorsally. Called also dorsal median sulcus.

ear fissure

a split in the margin of the pinna which can gradually become larger from continued trauma.

hippocampal fissure

one extending from the splenium of the corpus callosum almost to the tip of the temporal lobe; called also hippocampal sulcus.

interhemispheric fissure

the fissure between the two cerebral hemispheres in birds.

interincisive fissure

fissure between the two incisive bones at the rostral end of the pig's face.

laryngeal fissure

the dorsal laryngeal furrow.

ligamentum teres fissure

on the diaphragmatic surface of the liver; houses the ligamentum teres.

fissure lines

in radiology, the variation in radiodensity indicating the division between lobes of the lung.

longitudinal fissure

the deep fissure between the cerebral hemispheres.

macropalpebral fissure

an enlarged palpebral fissure.

optic fissure

a ventral fissure in the developing optic cup through which blood vessels pass to the enclosed mesenchyme.

orbital fissure

see orbital foramen.

palatine fissure

a pair of fissures perforating the rostral extremity of the palate.

palpebral fissure

the opening between the eyelids.

perianal fissure

see perianal fistula.

petrotympanic fissure

the chorda tympani, on its way to merge with the lingual branch of the mandibular nerve, passes across the tympanic cavity and emerges at the petrotympanic fissure.

portal fissure

porta hepatis.

presylvian fissure

the ventral branch of the fissure of Sylvius.

reverse fissure

mediastinal fluid dissects into fissures between lung lobes causing fissure lines on radiographs to appear wide centrally and narrower peripherally.

Rolando's fissure, fissure of Rolando

a groove running obliquely across the superolateral surface of the cerebral hemisphere, separating the frontal from the parietal lobe. Called also central fissure and central sulcus.

round ligament fissure

one on the visceral surface of the liver, lodging the round ligament in the adult.

sylvian fissure, fissure of Sylvius

one extending laterally between the temporal and frontal lobes, and turning dorsally between the temporal and parietal lobes of the brain.

transverse fissure

1. porta hepatis.

2. the transverse cerebral fissure between the diencephalon and the cerebral hemispheres; called also fissure of Bichat.

tympano-occipital fissure

on the ventral surface of the skull, near the confluence of the osseous bulla and the occipital bone, this pair of fissures serve as conduits for the glossopharyngeal, vagal and accessory nerves in species without a jugular foramen.

ventral median fissure

a longitudinal furrow along the midline of the ventral surface of the spinal cord and medulla oblongata.

zygal fissure

a cerebral fissure consisting of two branches connected by a stem.