arachno-, arachn- +

Relating to the eating of, or feeding on spiders: Many birds, amphibians, reptiles, and fish are arachnivourous creatures, that consume anthropods.

Long thin fingers and toes seen in certain dysplasias: Arachnodactylia is an abnormal development or growth of tissues, organs, or cells, specifically in the hand and foot bones.

A skeletal disorder where the patient has unusually long, thin bones, especially noticeable in the fingers and toes: The extreme length and slenderness of the fingers and toes are seen in arachnodactyly or in certain dysplasias, such as the Marfan syndrome.

The Marfan syndrome is a heritable condition that affects the connective tissue.

The primary purpose of connective tissue is to hold the body together and to provide a framework for growth and development. In the Marfan syndrome, the connective tissue is defective and does not act as it should.

Because connective tissue is found throughout the body, the Marfan syndrome can affect many body systems, including the skeleton, eyes, heart and blood vessels, nervous system, skin, fingers and toes, and the lungs.

A spider belly or the protuberant abdomen of an emaciated person with ascites, the accumulation of serous, or body fluid: Arachnogastria is the peritoneal cavity or transparent membrane that lines the abdominal cavity, most commonly encountered with heart failure and portal hypertension or the excessive tension of the large vein that carries blood from the stomach and intestines to the liver.

1. Covered with, or formed by long, delicate, entangled hairs or fibers: The fine layer of dust covering the old furniture in the attic looked like an arachnoid web of a spider.
2. Referring to the delicate serous membrane, or membranous sac, lining the dura mater, and enveloping the brain and spinal cord: Like a cobweb, a thin arachnoid membrane lies between two other membranes surrounding the brain and the spinal cord.

One of the tissue layers covering the brain and the spinal cord: Arachnoiditis is the name applied to inflammation of the arachnoid membrane.

In anatomy, numerous microscopic projections of the arachnoid membrane into some venous sinuses: Arachnoid villi refers to the minute hairlike projections, or tiny finger-like or vascular projections, on the mucous membranes.

Of the nature of, or pertaining to, the arachnoid: Dr. Smith diagnosed an arachnoidal cyst when Joseph went to the doctor's office for a check-up, but was told that he should consult a neurosurgeon for further information.

The middle of the three layers of the meninges or the membrances covering the brain and spinal cord.

The smooth external surface of the arachnoidea is closely applied between two other meninges, the more superficial "dura mater", while the inner roughened surface is separated from the "pia mater" by the subarachnoid space.

The delicate, spiderweb-like, or arachnoid layer, attached to the inside of the dura, surrounds the brain and spinal cord but does not line the brain down into its folds. In some locations the space is crossed by fine trabeculae.

An unnecessary variant of "arachnoid", or having the appearance or texture of a spider's web: The drawing of one of the meninges in Jane's biology book was a good representation of an arachnoideal membrane which envelops the brain and spinal cord.

Inflammation of the arachnoid membrane: Arachnoiditis can be any process of acute, subacute, or chronic inflammation, scarring, proliferative orgranulomatous process in the arachnoid membrane, whether primary or secondary, whether isolated or associated with damage to contiguous nervous tissues.

Types of arachnoiditis, designated according to their situation, include optochiasmatic, basal, spinal, and many other forms.

Referring to, or pertaining to arachnology: Floyd had to write a short essay on spiders and finally found some arachnological information on the internet that he could use.

A student of, or someone who is proficient in learning about spiders, scorpions, mites, and ticks: Jim's mother was an arachnologist and was an expert in the field of arachnids.

A department of zoology relating to spiders or the Arachnida generally: Peter was especially interested in zoology and chose the field of arachnolgy instead of the field of ornithology like he originally intended.

The active hemolytic component of spider venom: The hemolytic component, or arachnolysin, can lead to the destruction of the cell membranes of red blood cells, resulting in the release of hemoglobin from the damaged cells.