pinna

1. any leaflet of a pinnate compound leaf

2. Zoology a feather, wing, fin, or similarly shaped part

3. another name for auricle

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

pinna

[′pin·ə]

(anatomy)

The cartilaginous, projecting flap of the external ear of vertebrates. Also known as auricle.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Pinna

(also auricle or auricula), the external part of the human and mammalian auditory analyser, consisting of elastic cartilage and a skin covering. The cartilage determines the pinna’s shape and its various elevations and depressions, such as the helix (the pinna’s incurved margin), the antihelix (located parallel to the helix), the tragus (the anterior protuberance), the antitragus (located behind the tragus), and the fossa triangularis. The lobe has no cartilage. Deep within the pinna, directly behind the tragus, is the opening of the external auditory canal. The pinna’s skin is covered with minute hairs and contains sebaceous and sudoriferous glands.

In some mammals, the pinna is endowed with special musculature and is capable of movement; in others, individual parts of the pinna are capable of movement; and in still others, for example, humans, movement is severely limited. The pinna is secondarily simplified or completely reduced in many aquatic mammals, such as whales, manatees, seals, and walruses, and in many burrowing animals, such as desmans and moles. It is well developed in nocturnal animals, for example, bats, in some forest ungulates, and in desert canids.

The pinna has many functions. It receives sound and amplifies or reflects it according to frequency. It makes possible the determination of the spatial location of a sound source. It also protects the auditory organs from mechanical injury during digging and diving, as well as from excessive noise, by means of special protective hairs, by the overlapping of the auditory canal, or by the involution of the entire pinna, as in some bats.

G. N. SIMKIN

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References in periodicals archive

indica eggs and motiles per pinna were analyzed through covariance analysis and Tukey separation tests (Proc ANCOVA SAS Inc.).

Effect of Amblyseius largoensis (Acari: Phytoseiidae) on Raoiella Indica (Acari: Tenuipalpidae) by predator exclusion and predator release techniques

The position of the pinna can be affected by incisions used to access the mastoid [13], but the effect of this and the scar site itself are rarely considered.

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Pinna has another word of advice for those headed to Sardinia.

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Application: Ian Butterworth, an engineer at NPL, said: "Having a 2D pinna in an artificial ear has some inherent frequency limitations.

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There are up to 70-80 pinna pairs, 18-30 well developed pairs with sizes as indicated above, 10 or more basal pairs gradually reduced, and 30 or more apical also reduced pairs (Figs.

Sporophyte morphology and gametophyte development of the fern Blechnum sprucei (Pteridophyta: Blechnaceae)

12, fig.2) illustrated a pinna fragment with three pinnules clearly showing the venation characteristic of the species.

Floras en las capas rojas de la cuenca permica de Lodeve (Sur de Francia)

Among the 35 siluriform families (Ferraris & De Pinna, 1999), the Pimelodidae, with more than 300 species, is one of the largest and most diverse Neotropical groups (De Pinna, 1998; Shibatta, 2003).

Osteology and myology of the cephalic region and pectoral girdle of Heptapterus mustelinus, comparison with other heptapterins, and discussion on the synapomorphies and phylogenetic relationships of the Heptapterinae and the Pimelodidae (Teleostei: Siluriformes)/Osteologia y miologia de la region cefalica y de la cintura pectoral del Heptapterus mustelinus, comparacion con otros heptapterinos ..

A cat's ear consists of the external ear, which includes the ear flap (pinna) and ear canal; the middle ear, including the eardrum and auditory ossicles (small bones); and the inner ear, which contains the semicircular canals to regulate balance and the cochlea, the organ of hearing.

Your cat's sense of hearing: this highly effective sense is particularly useful for wild cats, but our indoor pets make use of their superior hearing, as well