zygo-, zyg-, -zygous; zygomatico- +

The descending intercepting trunk for the upper, often the fourth through the eighth, left posterior intercostal veins: The accessory hemiazygos vein lies on the left side, and at the eighth thoracic vertebra it joins the hemiazygos vein, or crosses to the right side to join the azygos vein directly.

Pertaining to genes in a homozygote that are copies of the same ancestral gene as a result of a mating between related individuals: When two alleles at a locus come from a common predecessor by inbreeding, the genotype is termed autozygous.

The region below the azygos vein arch in which the right lung intrudes into the mediastinum (the space in the thoracic cavity behind the sternum and amidst the two pleural sacs containing the lungs) between the heart and the vertebral column, bordered on the left by the esophagus, which is the long hollow muscular tube that connecting the pharynx (cavity at the back of the mouth) to the stomach.

Pertaining to or located between the azygos vein and esophagus (long hollow muscular tube that connects the pharynx [cavity at the back of the mouth] to the stomach).

The azygos vein is the single vein going up in the abdomen from the right ascending lumbar vein (part of the back between the thorax and the pelvis) or the vena cava (large vein which returns blood to the heart), enters the thorax (between the neck and the abdomen) through the aortic orifice (opening) in the diaphragm, and terminates or ends in the superior vena cava (major blood vessel that returns blood from the head, neck, upper extremities and chest and feeds into the right atrium or thin-walled chamber of the heart which pumps blood into the right ventricle for ejection into the pulmonary or lung circulation).

The radiographic record or image obtained by azygography (radiography of the azygos venous system after injection of a contrast medium).

Azygos refers to an unpaired anatomical structure.

Radiography or a radiographic examination of the aygos venous system following its opacification with contrast material; usually employed for evaluation of abnormal tumor masses in the mediastinum, as evidenced by extrinsic pressure upon, or complete obstruction of, the visualized azygos vein.

Pertaining to or located between the azygos vein and mediastinum (the region of the chest between the lungs that contains the heart and its large veins and arteries, the trachea [tube that leads from the larynx or voice box to two major air passages that bring oxygen to each lung], the esophagus [tube connecting the throat to the stomach], the bronchi [several large air passages in the lungs through which inhaled air and exhaled air go], and the lymph nodes).

The lymph nodes consist of tissue scattered along the lymphatic system that act as filters and immune monitors, removing fluids, bacteria, or cancer cells that travel through the lymph system.

An unpaired anatomical part: Most structures of anatomy show bilateral symmetry, while such a single element is unusual. such as the vena azygos.

Referring to a part of the anatomy that appears only once: Judy learned in her medical book that an azygos is a biological structure that occurs singly. and not as a pair.

One of a system of veins, also termed "vena azygos", that drain the thoracic and abdominal walls which goes up from the right curving upward lumbar vein or the vena cava (large vein which returns blood to the heart), enters the thorax through the aortic orifice (largest artery) in the diaphragm, and terminates or ends in the superior vena cava (major blood vessel that returns blood from the head, neck, upper extremities and chest and feeds into the right atrium or chamber of the heart which pumps blood into the right ventricle for ejection into the pulmonary or lung circulation).

An asexually formed zygospore, also known as "azygosperm" or "parthenospore", in fungi or a spore developed directly from a gamete without joining together.

A zygospore remains dormant while it waits for environmental cues, such as light, moisture, heat, or chemicals secreted by plants.

When the environment is favorable, the zygospore germinates, meiosis (cell division) occurs, and haploid (chromosome) vegetative cells are released.

1. A reference to an anatomical part occurring singly; not occurring as one of a pair, such as a vein or muscle: The medical students learned that the superior vena cava (one of two very large veins) receives blood from the azygous vein, which drains blood from the chest.

The physicians examined Richard's azygos veins to make sure that the three unpaired veins of the abdomen and thorax emptied properly into the inferior vena cave.

2. Etymology: from Greek meaning "unyoked" or "not a pair"; from a-, "without" + zygon, "a yoke".

1. A cell containing more than one zygote: Jane learned in her biology book that the coenozygote is the fusion of two such coenogametes.
2. A zygote formed by coenogametes or multinucleate gametes which are male or female cells that unite with cells of the opposite sex to produce zygotes that can develop into embryos (animals or humans before they are born, when they are beginning to develop and grow) and then into babies.

Descriptive of a narrow face as compared with the width of the cranium (head), so that when the skull is viewed from above, the zygomatic arches are not visible.

The "zygomatic arches" are formed by the temporal process of the zygomatic bone (bone which forms the prominence of the cheek) that joins the zygomatic process (arch of bone beneath the orbit) of the temporal bone or the large irregular bone situated in the base and side of the skull.

A reference to twins derived from two separately fertilized eggs: The probability of a mother giving birth to two offspring at the same time, or dizygotic twins, increases with age and the number of babies the mother has given birth to.