Albl's ring

ring (ring)

1. any annular or circular organ or area.

2. in chemistry, a collection of atoms united in a continuous or closed chain.

---

Albl's ring  a ring-shaped shadow in radiographs of the skull, caused by aneurysm of a cerebral artery.

Bandl's ring  pathologic retraction r.; see retraction r.

benzene ring  the closed hexagon of carbon atoms in benzene, from which different benzene compounds are derived by replacement of hydrogen atoms.

Benzene ring structure represented as a hybrid of two possible ring structures; sometimes called a resonance hybrid.

Cannon's ring  a focal contraction seen radiographically at the mid-third of the transverse colon, marking an area of overlap between the superior and inferior nerve plexuses.

common tendinous ring  the annular ligament of origin common to the recti muscles of the eye, attached to the edge of the optic canal and the inner part of the superior orbital fissure.

conjunctival ring  a ring at the junction of the conjunctiva and cornea.

constriction ring  a contracted area of the uterus, where the resistance of the uterine contents is slight, as over a depression in the contour of the fetus, or below the presenting part.

femoral ring  the abdominal opening of the femoral canal, normally closed by the crural septum and peritoneum.

fibrous rings of heart  see anulus fibrosus (1).

greater ring of iris  the less coarsely striated outer concentric circle on the anterior surface of the iris.

inguinal ring, deep  an aperture in the transverse fascia for the spermatic cord or the round ligament.

inguinal ring, superficial  an opening in the aponeurosis of the external oblique muscle for the spermatic cord or the round ligament.

Kayser-Fleischer ring  a gray-green to red-gold pigmented ring at the outer margin of the cornea, seen in progressive lenticular degeneration and pseudosclerosis.

Landolt's rings  broken rings used in testing visual acuity.

lesser ring of iris  the more coarsely striated inner concentric circle on the anterior surface of the iris.

mitral ring  see anulus fibrosus.

retraction ring  a ringlike thickening and indentation occurring in normal labor at the junction of the isthmus and corpus uteri, delineating the upper contracting portion and the lower dilating portion (physiologic retraction r.), or a persistent retraction ring in abnormal or prolonged labor that obstructs expulsion of the fetus (pathologic retraction r.) .

Schwalbe's ring  a circular ridge composed of collagenous fibers surrounding the outer margin of Descemet's membrane.

scleral ring  a white ring seen adjacent to the optic disk in ophthalmoscopy when the retinal pigment epithelium and choroid do not extend to the disk.

tracheal rings  tracheal cartilages: the 16 to 20 incomplete rings which, held together and enclosed by a strong, elastic, fibrous membrane, constitute the wall of the trachea.

tricuspid ring  see anulus fibrosus.

tympanic ring  the bony ring forming part of the temporal bone at birth and developing into the tympanic plate.

umbilical ring  the aperture in the fetal abdominal wall through which the umbilical cord communicates with the fetus.

vascular ring  a developmental anomaly of the aortic arch wherein the trachea and esophagus are encircled by vascular structures, many variations being possible.

---

Albl's ring,

a calcified ring-shaped shadow visible on a skull radiograph of a cerebral aneurysm.

---

ring [ring]

1. any annular or circular organ, structure, or area.

2. in chemistry, a collection of atoms united in a continuous or closed chain.

abdominal ring, external an opening in the aponeurosis of the external oblique muscle for the spermatic cord or round ligament.

abdominal ring, internal an aperture in the transverse fascia for the spermatic cord or round ligament.

Albl's ring a ring-shaped shadow in radiographs of the skull, caused by aneurysm of a cerebral artery.

Bandl's ring see bandl's ring.

benzene ring the hexagon representing the arrangement of carbon atoms in a molecule of benzene, different compounds being derived by replacement of the hydrogen atoms by different elements or compounds.

Cannon's ring a focal contraction seen radiographically at the mid-third of the transverse colon, marking an area of overlap between the superior and inferior nerve plexuses.

conjunctival ring a ring at the junction of the conjunctiva and cornea.

constriction ring a contracted area of the uterus, where the resistance of the uterine contents is slight, as over a depression in the contour of the fetus, or below the presenting part.

fibrous ring of heart anulus fibrosus.

halo ring a metal orthosis used for traction in the treatment of spinal cord injuries. The halo apparatus can maintain stability and alignment of the cervical vertebrae while the patient is out of bed.

inguinal ring, deep an aperture in the transverse fascia for the spermatic cord or the round ligament.

inguinal ring, external superficial inguinal ring.

inguinal ring, internal deep inguinal ring.

inguinal ring, superficial an opening in the aponeurosis of the external oblique muscle for the spermatic cord or the round ligament.

Kayser-Fleischer ring a golden brown or green discoloration in the zone of Descemet's membrane in the limbic region of the cornea seen in wilson's disease and other liver disorders.

pathologic retraction ring a complication of prolonged labor marked by failure of relaxation of the circular fibers at the internal opening of the cervix, obstructing delivery of the infant. See also bandl's ring.

physiologic retraction ring the demarcation between the upper, contracting portion of the uterus in labor and the lower, dilating part.

Schwalbe's ring a circular ridge composed of collagenous fibers surrounding the outer margin of Descemet's membrane.

tympanic ring the bony ring forming part of the temporal bone at birth and developing into the tympanic plate.

umbilical ring the orifice in the abdominal wall of the fetus for transmission of the umbilical vein and arteries.

vascular ring a congenital anomaly of the aortic arch and its tributaries, the vessels forming a ring about the trachea and esophagus and causing varying degrees of compression.