* Operculum ( animal ), a stiff structure resembling a lid or a small door that opens and closes

* Operculum ( dentistry ), a small flap of tissue which may cover an erupting or partially erupted molar

** Operculum ( gastropod ), a lid on the shell of some gastropods

** Operculum ( bryozoa ), a lid on the orifice of some bryozoans

** Operculum ( bird ), a structure which covers the nares of some birds

The dried leaves and twigs of the yerba mate plant ( Ilex paraguariensis ) are placed in a small cup, also called mate, usually made from a gourd, but also from bone or horn.

The prehistory of arithmetic is limited to a small number of artifacts which may indicate conception of addition and subtraction, the best-known being the Ishango bone from central Africa, dating from somewhere between 20, 000 and 18, 000 BC although its interpretation is disputed.

It has been hypothesized that this is a result of bone's piezoelectric properties, which cause bone to generate small electrical potentials under stress.

In 2008, archaeologists working at the site of Denisova Cave in the Altai Mountains of Siberia uncovered a small bone fragment from the fifth finger of a juvenile member of a population now referred to as Denisova hominins, or simply Denisovans.

The nut is a small strip of bone, plastic, brass, corian, graphite, stainless steel, or other medium-hard material, at the joint where the headstock meets the fretboard.

There are a number of surgical approaches to the removal of the thymus gland: transsternal ( through the sternum, or breast bone ), transcervical ( through a small neck incision ), and transthoracic ( through one or both sides of the chest ).

* Excess alcohol: Although small amounts of alcohol are probably beneficial ( bone density increases with increasing alcohol intake ), chronic heavy drinking ( alcohol intake greater than three units / day ) probably increases fracture risk despite any beneficial effects on bone density.

Pictish art appears on stones, metalwork and small objects of stone and bone.

During the recovery process, small fragments were identified from some passengers on Flight 175, including a six-inch piece of bone belonging to Peter Hanson, and small bone fragments of Lisa Frost.

In severe infection, the virus production inside the body is greatly increased, and many more organs ( such as the liver and the bone marrow ) can be affected, and fluid from the bloodstream leaks through the wall of small blood vessels into body cavities.

Free flaps of skin, muscle, bone, fat, or a combination may be removed from the body, moved to another site on the body, and reconnected to a blood supply by suturing arteries and veins as small as 1 to 2 millimeters in diameter.

The cheeks of the coelacanths are unique because the opercular bone is very small and holds a large soft-tissue opercular flap.

For instance a bone folder allows sharp creases to be made in the paper easily, paper clips can act as extra pairs of fingers, and tweezers can be used to make small folds.

The cypriniformes ( family Cyprinidae ) are traditionally grouped with the Characiformes, Siluriformes and Gymnotiformes to create the superorder Ostariophysi, since these groups have certain common features, such as being found predominantly in fresh water and that they possess Weberian ossicles ( an anatomical structure originally made up of small pieces of bone formed from four or five of the first vertebrae ); the most anterior bony pair is in contact with the extension of the labyrinth and the posterior with the swimbladder.

Several adaptations combine to protect the woodpecker's brain from the substantial pounding that the pecking behaviour causes: it has a relatively thick skull with relatively spongy bone to cushion the brain ; there is very little cerebrospinal fluid in its small subarachnoid space ; the bird contracts mandibular muscles just before impact, thus transmitting the impact past the brain and allowing its whole body to help absorb the shock ; its relatively small brain is less prone to concussion than other animals '.

Computed tomography shows a small, soft-tissue mass with bone erosion.

The term " ossicles " literally means " tiny bones " and commonly refers to the auditory ossicles, though the term may refer to any small bone throughout the body.

The incus or anvil is the anvil-shaped small bone or ossicle in the

The malleus or hammer is a hammer-shaped small bone or ossicle of the middle ear which connects with the incus and is attached to the inner surface of the eardrum.

The stapes is the stirrup-shaped small bone or ossicle in the

The small skull cap evolved into a bigger true helmet, the bascinet, as it was lengthened downward to protect the back of the neck and the sides of the head.

The facial region of skull is relatively small, with pinnae very small or lacking, and the vibrissae are well developed.

In 2006 the European Food Safety Authority ( EFSA ) stated that the SSC opinion was confirmed, that the BSE risk of bone-derived gelatin was very small, and removed support for the 2003 request of excluding the skull and vertebrae of bovine origin older than 12 months from the material used in gelatin manufacturing.

"); where a calaverita is a small skull made of sugar or chocolate.

One Velociratoptor mongoliensis skull bears two parallel rows of small punctures that match the spacing and size of Velociraptor teeth.

In November 1935, under Moniz's direction, surgeon Pedro Almeida Lima drilled a series of holes on either side of a woman's skull and injected ethanol to destroy small areas of subcortical white matter in the frontal lobes.

T. horridus-T. prorsus-T. brevicornus was now thought to be the most conservative lineage, with an increase in skull size and a decrease in nasal horn size, and T .- elatus-T. calicornis was defined by large brow horns and small nasal horn.

The skull is large, with a narrow foramen magnum, and relatively small skull base.

In addition to their small size and big feet, the skull and arm bones of Homo floresiensis differ from those of modern humans.

He was so exceedingly terrified, that it is said that he wet himself when he saw Thor ..... But the hammer Mjölner hit Hrungner right in the head, and crushed his skull in small pieces.

Males tend to have slightly thicker and longer limbs and digit bones ( phalanges ), while females tend to have narrower rib cages, smaller teeth, less angular mandibles, less pronounced cranial features such as the brow ridges and external occipital protuberance ( the small bump at the back of the skull ), and the carrying angle of the forearm is more pronounced in females.

The skull of Machairodus was noticeably narrow compared with the skulls of modern pantherine big cats, and the orbits were relatively small.

The long and narrow skull was small in proportion to the body.

* At birth, the skull features a small posterior fontanelle, an open area covered by a tough membrane, where the two parietal bones adjoin the occipital bone ( at the lambda ).

The massive blue-gray bill is the largest of any living accipiterid, a feature enhanced by the relatively small skull of the species.

Going by the species name, it was probably relatively small ; his skull was 2 cm in length indeed.

This creature was a small multituberculate with a 2 cm skull.

Derived characteristics of the taxon ( apomorphies ) include: " snout short and wide with anterior part of zygomatic arches directed transversely, resulting in a square-like shape of the skull ( shared with Kogaionidae ); frontals small, pointed posteriorly, almost or completely excluded from the orbital rim ," ( Kielan-Jaworowska and Hurum 2001, p. 417 ).

These include small brain size, the orientation of the brain within the skull ( which maximises the area of contact between the brain and the skull ) and the short duration of contact.

The sophistication of positronic circuitry renders a brain so small that it could comfortably fit within the skull of an insect.