Posterior auricular muscle

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Posterior auricular muscle
Gray906.png
The muscles of the auricula
Auricularis posterior.png
Auricula in context.
Details
Origin Mastoid process of temporal bone
Insertion Posterior part of auricle of outer ear
Artery Posterior auricular artery
Vein Posterior auricular vein
Nerve Posterior auricular nerve of facial nerve (VII)
Actions Pulls ear backward
Identifiers
Latin musculus auricularis posterior
TA98 A04.1.03.022
TA2 2091
FMA 46857
Anatomical terms of muscle

The posterior auricular muscle is a muscle behind the auricle of the outer ear. It arises from the mastoid part of the temporal bone, and inserts into the lower part of the cranial surface of the auricle of the outer ear. It draws the auricle backwards, usually a very slight effect.

Contents

Structure

The posterior auricular muscle is found behind the auricle of the outer ear. [1] It consists of two or three fleshy fasciculi. These arise from the mastoid part of the temporal bone by short aponeurotic fibers. [1] They insert into the lower part of the cranial surface of the auricle of the outer ear. [1]

The posterior auricular muscle is supplied by branches of the posterior auricular artery, which continues deep to the muscle. [2] It is drained by the posterior auricular vein that accompanies the artery. [2]

Nerve supply

The posterior auricular muscle is supplied by the posterior auricular nerve, a branch of the facial nerve (VII). [2] [3]

Function

The posterior auricular nerve draws the auricle of the outer ear backwards. [2] This effect is usually very slight, although some people can wiggle their ears due to a more significant muscle movement. [2] Electromyographic signals in humans suggest the posterior auricular muscle may be part of an ancient system for monitoring sounds we can't see. [4]

Postauricular reflex

The postauricular reflex is a vestigial myogenic [5] muscle response in humans that acts to pull the ear upward and backward. [6] Research suggests neural circuits for auricle orienting have survived in a vestigial state for over 25 million years. It is often assumed the reflex is a vestigial Preyer reflex (also known as the pinna reflex). [7] [8]

A study on auriculomotor activity found that in the presence of sudden, surprising sounds, the muscles around the ear closest to the direction of the sound would respond by moving involuntarily, causing the pinna to be pulled backwards and flatten. [9]

Clinical significance

If the posterior auricular muscle inserts into an unusual part of the auricle of the outer ear, this can cause protruding ears. [1] In one study, the muscle was found to be absent in 5% of people. [10]

See also

References

  1. 1 2 3 4 Yotsuyanagi, Takatoshi; Yamauchi, Makoto; Yamashita, Ken; Sugai, Asuka; Gonda, Ayako; Kitada, Ayaka; Saito, Tamotsu; Urushidate, Satoshi (July 2015). "Abnormality of Auricular Muscles in Congenital Auricular Deformities" . Plastic and Reconstructive Surgery . 136 (1): 78e –88e. doi:10.1097/PRS.0000000000001383. ISSN   0032-1052. PMID   26111335. S2CID   23651843.
  2. 1 2 3 4 5 Niamtu, Joseph (2018). "8 - Cosmetic Otoplasty and Related Ear Surgery". Cosmetic Facial Surgery (2nd ed.). Edinburgh: Elsevier. pp. 473–532. doi:10.1016/B978-0-323-39393-5.00008-X. ISBN   978-0-323-39402-4. OCLC   976037123.
  3. ↑ Barral, Jean-Pierre; Croibier, Alain (2009). "25 - Ear". Manual Therapy for the Cranial Nerves. Edinburgh: Churchill Livingstone / Elsevier. pp. 227–238. doi:10.1016/B978-0-7020-3100-7.50028-8. ISBN   978-0-7020-3736-8. OCLC   460904284.
  4. ↑ Schroeer, Andreas; Corona-Strauss, Farah I.; Hannemann, Ronny; Hackley, Steven A.; Strauss, Daniel J. (2025). "Electromyographic correlates of effortful listening in the vestigial auriculomotor system". Frontiers in Neuroscience. 18. doi: 10.3389/fnins.2024.1462507 . ISSN   1662-453X. PMC   11825814 .
  5. ↑ Benning, Stephen D. (2018-04-05). "The Postauricular Reflex as a Measure of Attention and Positive Emotion" . Oxford Handbooks Online. doi:10.1093/oxfordhb/9780199935291.013.74. ISBN   978-0-19-993529-1.
  6. ↑ Benning, Stephen D. (2011-03-01). "Postauricular and superior auricular reflex modulation during emotional pictures and sounds". Psychophysiology. 48 (3): 410–414. doi:10.1111/j.1469-8986.2010.01071.x. ISSN   1469-8986. PMC   2962877 . PMID   20636290.
  7. ↑ Hackley, Steven A. (2015-10-01). "Evidence for a vestigial pinna-orienting system in humans". Psychophysiology. 52 (10): 1263–1270. doi:10.1111/psyp.12501. ISSN   1469-8986. PMID   26211937.
  8. ↑ "ZFIN Behavior Ontology: pinna reflex". zfin.org. Retrieved 2020-01-05.
  9. ↑ Strauss, Daniel J; Corona-Strauss, Farah I; Schroeer, Andreas; Flotho, Philipp; Hannemann, Ronny; Hackley, Steven A (2020-07-03). "Vestigial auriculomotor activity indicates the direction of auditory attention in humans". eLife. 9: e54536. doi: 10.7554/eLife.54536 . ISSN   2050-084X. PMC   7334025 . PMID   32618268.
  10. ↑ Benning, Stephen D. (2018-04-05). "The Postauricular Reflex as a Measure of Attention and Positive Emotion". Oxford Handbook Topics in Psychology. Vol. 1. Oxford University Press. doi:10.1093/oxfordhb/9780199935291.013.74. ISBN   978-0-19-993529-1.
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