Hearing - Outer Ear Development

From Embryology
Revision as of 11:54, 15 April 2018 by Z8600021 (talk | contribs)
Embryology - 20 Jan 2020    Facebook link Pinterest link Twitter link  Expand to Translate  
Google Translate - select your language from the list shown below (this will open a new external page)

العربية | català | 中文 | 中國傳統的 | français | Deutsche | עִברִית | हिंदी | bahasa Indonesia | italiano | 日本語 | 한국어 | မြန်မာ | Pilipino | Polskie | português | ਪੰਜਾਬੀ ਦੇ | Română | русский | Español | Swahili | Svensk | ไทย | Türkçe | اردو | ייִדיש | Tiếng Việt    These external translations are automated and may not be accurate. (More? About Translations)


Adult hearing embryonic origins.
Adult external ear

The external ear is derived from 6 surface hillocks (auricular hillocks), three on each of pharyngeal arch 1 and 2.

The external auditory meatus is derived from the 1st pharyngeal cleft.

The postnatal human external ear structure also selectively boosts frequencies around 3 kHz, by a sound pressure level of 30 to 100-fold, that correspond to frequencies associated with speech. The anatomical position, on either side of the head, also allows exquisite localization of sounds in space by neural comparison of signals reaching each ear.

Hearing Links: Introduction | inner ear | middle ear | outer ear | balance | placode | hearing neural | Science Lecture | Lecture Movie | Medicine Lecture | Stage 22 | hearing abnormalities | hearing test | sensory | Student project

  Categories: Hearing | Outer Ear | Middle Ear | Inner Ear | Balance

Historic Hearing 
Historic Embryology: 1880 Platypus cochlea | 1892 Vertebrate Ear | 1902 Development of Hearing | 1906 Membranous Labyrinth | 1910 Auditory Nerve | 1913 Tectorial Membrane | 1918 Human Embryo Otic Capsule | 1918 Cochlea | 1918 Grays Anatomy | 1922 Human Auricle | 1922 Otic Primordia | 1931 Internal Ear Scalae | 1932 Otic Capsule 1 | 1933 Otic Capsule 2 | 1936 Otic Capsule 3 | 1933 Endolymphatic Sac | 1934 Otic Vesicle | 1934 Membranous Labyrinth | 1938 Stapes - 7 to 21 weeks | 1938 Stapes - Term to Adult | 1940 Stapes | 1942 Stapes - Embryo 6.7 to 50 mm | 1943 Stapes - Fetus 75 to 150 mm | 1946 Aquaductus cochleae and periotic (perilymphatic) duct | 1946 aquaeductus cochleae | 1948 Fissula ante fenestram | 1948 Stapes - Fetus 160 mm to term | 1959 Auditory Ossicles | 1963 Human Otocyst | Historic Disclaimer

Some Recent Findings

  • Movement of the external ear in human embryo[1] "In all, 171 samples between Carnegie stage (CS) 17 and CS 23 were selected from MR image datasets of human embryos obtained from the Kyoto Collection of Human Embryos. The three-dimensional absolute position of 13 representative anatomical landmarks, including external and internal ears, from MRI data was traced to evaluate the movement between the different stages with identical magnification. Two different sets of reference axes were selected for evaluation and comparison of the movements. ...The results indicate that movement of all anatomical landmarks, including external and internal ears, can be explained by differential growth. Also, when the external ear is recognized as one of the facial landmarks and having a relative position to other landmarks such as the eyes and mouth, the external ears seem to move cranially."
  • Age- and sex-related changes in the normal human ear[2] "All ear dimensions were significantly larger in men than in women (p<0.001). A significant effect of age was found (p<0.001), with larger values in older individuals. The ear width-to-length ratio and the sagittal angle of the auricle significantly decreased as a function of age (p<0.001) but without sex-related differences. On average, the three-dimensional position of ears was symmetric, with symmetry coefficients ranging between 92% and 96%. Asymmetry was found in the sagittal angle of the auricle (both sexes), in the ear width-to-length ratio and ear width (men only)."
More recent papers
Mark Hill.jpg
PubMed logo.gif

This table allows an automated computer search of the external PubMed database using the listed "Search term" text link.

  • This search now requires a manual link as the original PubMed extension has been disabled.
  • The displayed list of references do not reflect any editorial selection of material based on content or relevance.
  • References also appear on this list based upon the date of the actual page viewing.

References listed on the rest of the content page and the associated discussion page (listed under the publication year sub-headings) do include some editorial selection based upon both relevance and availability.

More? References | Discussion Page | Journal Searches | 2019 References | 2020 References

Search term: Outer Ear Development'

<pubmed limit=5>Outer Ear Development</pubmed>

Pinna- Auricle

External ear stages-14-23-adult.jpg

Embryonic External Ear

Images of the lateral view of the human embryonic head from week 5 (stage 14) through to week 8 (stage 23) showing development of the auricular hillocks that will form the external ear. The adult ear is also shown indicating the part of the ear that each hillock contributes.

  • develops from six aural hillocks: 3 on first pharyngeal arch and 3 on the second pharyngeal arch.
  • originally on neck, moves cranially during mandible development

Human embryo head week 6 to 8.jpg

Movement of the external ear in human embryo (week 6 to 8)[1]

Pharyngeal Contributions

External ear simplified anatomy
Pharyngeal Arch Hillock Auricle Component
Arch 1 1 tragus
2 helix
3 cymba concha
Arch 2 4 concha
5 antihelix
6 antitragus
  • Outer- external auditory meatus
  • derived from first pharyngeal cleft
  • ectodermal diverticulum
  • week 5 - extends inwards to pharynx
  • until week 18 has ectodermal plug - plug forms stratified squamous epithelia of canal and outer eardrum

Human Timeline

Time EAM Appearance
Embryonic period Ectodermal cells proliferate and fill the entire lumen forming a meatal plug
10 weeks Meatal plug extends in a disc-like fashion. In the horizontal plane the meatus is boot-shaped with a narrow neck and the sole of the meatal plug spreading widely to form the future tympanic membrane medially. Proximal portion of the neck starts to be resorbed.
13 weeks Disc-like plug innermost surface in contact with the primordial malleus, contributes to the formation of the tympanic membrane.
16.5 week Meatus is fully patent throughout its length, lumen is still narrow and curved.
18 week Meatus is already fully expanded to its complete form.

Based on data from[3]

Auricular Cartilage

Streeter1922-06-07.jpg Image shows the embryonic and fetal growth of the auricular cartilage within the pinna.[4]

Fig. 6. Lateral views of left auricular cartilage, taken from reconstructions of human embryos of the Carnegie Collection: No. 460 (21 mm.), No. 417 (32 mm.), No. 886 (43 mm.). X14.

Fig. 7. Reconstruction of left auricular cartilage of a 50 mm. fetus (No. 84, Carnegie Collection). X 14. A model of the external form of the auricle was made, in conjunction with the cartilage, to give the topographical relations. The edge of the helix in contact with the ectoderm is indicated by cross-lines.

Human Auricle Development

External Auditory Meatus


External auditory meatus and the outer ear.


The auriculotemporal nerve supplies a large part of the pinna, some innervation may also arise from the trigeminus.

Postnatal Growth

Postnatally, human ears continue to grow throughout the entire lifetime and have a sexually dimorphic pattern, described in a large study.[5] Three anatomical features of the ear were found to not grow at all after birth; Concha auriculae width, Incisura intertragica width, and the helical brim diameter of the auricle.

  • birth - external ear bigger than the large head in proportion to the body
  • childhood - large yearly increases decrease by 8 or 10 years of age.
  • adult - male increases in all parameters were greater than for female ears.
Ear Length (mm +/-SD) Data[5]
Age Female Male
Birth 52 (4.3) 52 (4.1)
20 yrs 61 (3.9) 65 (4.0)
Older than 70 yrs 72 (4.6) 78 (4.8)

Ear Features

  • Darwin's tubercle - (Woolnerian tip) is a tubercle is seen along the upper, posterior portion of the helix (upper and middle thirds).
  • "railroad track" - associated with fatal alcohol syndrome, the curve at top part of outer ear is underdeveloped and folded over parallel to curve beneath.

Lobe Attachment

In the normal population, free earlobes have been described as dominant.[6] With some researchers suggesting that "attached" would be better described as "lobeless". There have been several historic studies identifying attached ear lobes in some population groups (Indian[7], Malaysian). There are a number of syndromes and genetic disorders associated with variation in lobe attachment.

Links: OMIM 128900 | PMID 14277139


Outer Ear Genes

  • controlled by genes that regulate arch 1 and 2 development
  • related to hindbrain segmentation (rhombomere 4)
  • Mouse - Hoxa1/Hoxb1, goosecoid, Endothelin1, dHAND


Facial appearance of fetal alcohol syndrome. Ear curve at top part of outer ear is underdeveloped and folded over parallel to curve beneath and gives the appearance of a "railroad track"

There are a range of external ear abnormalities relate to final structure, size and position. In some cases these abnormalities relate directly to pharyngeal arch development or may be part of a wider spectrum of abnormalities associated with a genetic or environmental (fetal alcohol syndrome) disorders. Some known abnormalities include: anotia, microtia, prominent ear, lop ear, cup ear, cryptotia and Stahl's ear. Other associated external ear abnormalities include the formation of the external auditory meatus (canal) and pre-auricular fistulae (pits) and appendages. Finally, a range of abnormalities can be found associated with the overlying skin of both the external ear and the ear canal.{#pmid:18261212|PMID18261212}}

Minor structural anomalies have been shown to be corrected by appropriate splinting in the early neonatal period.{#pmid:18490209|PMID18490209}}

Links: Sensory - Hearing Abnormalities


Anotia 01.jpg

Upper Auricular Detachment

Upper auricular detachment 02.jpg Upper auricular detachment 01.jpg



Microtia (autosomal-recessive) - A mutation has been identified in HoxA2 (https://www.omim.org/entry/604685 HOXA2] 7p15.2){#pmid:18394579|PMID18394579}}

Links: Hox

Cleft Lobule

Oculo-auricular syndrome - A mutation in the NKX5-3 (HMX3 10q26.13) human homeobox gene.{#pmid:18423520|PMID18423520}}

Stahl's Ear

A rare ear abnormality, where the rim of the ear is flattened and the upper portions deformed. More common in Oriental background and can occur from mild to severe. The skin and cartilage are both folded to different degrees that can result in a pointed upper edge. This pointed ear has been said to resemble the Star Trek television character "Vulcan" ear shape.

External Auditory Meatus

The external auditory meatus (canal) can also fail to canalise leading to a range of malformation including membranous and/or bony atresia and stenosis.

External Auditory Meatus Stenosis[8]

  • Type A - a marked narrowing of the canal with an intact skin layer.
  • Type B - a partial development of the canal with an atresia plate at the medial part.
  • Type C - a complete bony canal atresia.

Pre-auricular Fistulae and Appendages

Preauricular sinus
Preauricular tag
Preauricular tag

There are also a range of pre-auricular fistulae (pits) and appendages that generally occur in a specific region beside the tragus and crus helicis.

Pre-auricular fistulae and appendage locations.jpg

Auricular Pit

Beckwith-Wiedemann syndrome posterior helix pit.jpg

Posterior helix pit associated with Beckwith-Wiedemann syndrome.

Links: Sensory - Hearing Abnormalities

Additional Images

Historical Images


  1. 1.0 1.1 Kagurasho M, Yamada S, Uwabe C, Kose K & Takakuwa T. (2012). Movement of the external ear in human embryo. Head Face Med , 8, 2. PMID: 22296782 DOI.
  2. Sforza C, Grandi G, Binelli M, Tommasi DG, Rosati R & Ferrario VF. (2009). Age- and sex-related changes in the normal human ear. Forensic Sci. Int. , 187, 110.e1-7. PMID: 19356871 DOI.
  3. <pubmed>1441991</pubmed>
  4. Streeter GL. Development of the auricle in the human embryo. (1922) Carnegie Instn. Wash. Publ. 277, Contrib. Embryol., 14: 111-138.
  5. 5.0 5.1 Niemitz C, Nibbrig M & Zacher V. (2007). Human ears grow throughout the entire lifetime according to complicated and sexually dimorphic patterns--conclusions from a cross-sectional analysis. Anthropol Anz , 65, 391-413. PMID: 18196763
  6. DUTTA P & GANGULY P. (1965). FURTHER OBSERVATIONS ON EAR LOBE ATTACHMENT. Acta Genet Stat Med , 15, 77-86. PMID: 14277139
  7. Sharma A, Sidhu NK, Sharma MK, Kapoor K & Singh B. (2007). Morphometric study of ear lobule in northwest Indian male subjects. Anat Sci Int , 82, 98-104. PMID: 17585565 DOI.
  8. Kösling S, Omenzetter M & Bartel-Friedrich S. (2009). Congenital malformations of the external and middle ear. Eur J Radiol , 69, 269-79. PMID: 18054456 DOI.


Alasti F & Van Camp G. (2009). Genetics of microtia and associated syndromes. J. Med. Genet. , 46, 361-9. PMID: 19293168 DOI.

Torban E & Goodyer P. (2009). The kidney and ear: emerging parallel functions. Annu. Rev. Med. , 60, 339-53. PMID: 18976115 DOI.

Wood-Jones F & I-Chuan W. (1934). The Development of the External Ear. J. Anat. , 68, 525-33. PMID: 17104502


Sforza C, Grandi G, Binelli M, Tommasi DG, Rosati R & Ferrario VF. (2009). Age- and sex-related changes in the normal human ear. Forensic Sci. Int. , 187, 110.e1-7. PMID: 19356871 DOI.

Search PubMed

May 2010 "Outer Ear Development" All (1478) Review (120) Free Full Text (215)

Search Pubmed: Outer Ear Development | Pinna Development

External Links

External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name. Links to any external commercial sites are provided for information purposes only and should never be considered an endorsement. UNSW Embryology is provided as an educational resource with no clinical information or commercial affiliation.

Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link

Cite this page: Hill, M.A. (2020, January 20) Embryology Hearing - Outer Ear Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Hearing_-_Outer_Ear_Development

What Links Here?
© Dr Mark Hill 2020, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G