Editing Pectoralis minor

{{Short description|Human chest muscle that protracts the shoulder}}
{{Infobox muscle
| Name        = Pectoralis minor
| Latin       = musculus pectoralis minor
| Image       = Pectoralis minor.svg
| Caption     = Pectoralis minor (shown in red).
| Image2      = Pectoralis minor muscle and shoulder blade.png
| Caption2    = Pectoralis minor muscle (shown in red). The bone shown in blue is the [[shoulder blade]].
| Origin      = Third to fifth [[rib]]s, near the costochondral junction
| Insertion   = Medial border and superior surface of the [[coracoid process]] of the [[scapula]]
| Blood       = [[Pectoral branch]] of the [[thoracoacromial trunk]]
| Nerve       = [[Medial pectoral nerve]] (C8)
| Action      = Stabilizes the [[scapula]] by drawing it inferiorly and anteriorly against the [[thoracic wall]], raises ribs in inhalation
}}
'''Pectoralis minor muscle''' ({{IPAc-en|ˌ|p|ɛ|k|t|ə|ˈ|r|æ|l|ᵻ|s|_|ˈ|m|aɪ|n|ər}}) is a thin, triangular muscle, situated at the upper part of the [[chest]], beneath the [[pectoralis major]] in the human body. It arises from ribs III-V; it inserts onto the [[coracoid process]] of the [[scapula]]. It is innervated by the [[medial pectoral nerve]]. Its function is to stabilise the [[scapula]] by holding it fast in position against the [[Thoracic wall|chest wall]].

== Structure ==

=== Attachments ===
From the muscle's origin, the muscle's fibers pass superiorly and laterally, converging to form a flat tendon.

==== Origin ====
Pectoralis minor muscle arises from the upper margins and outer surfaces of the 3rd, 4th, and 5th [[rib]]s near their [[costal cartilages]], and from the [[Aponeurosis|aponeuroses]] covering the [[External intercostal muscles|intercostalis]].<ref name=":0">{{Cite book|last=Dommerholt|first=Jan|chapter-url=https://www.sciencedirect.com/science/article/pii/B9780702035289000340|title=Neck and Arm Pain Syndromes|publisher=[[Churchill Livingstone]]|year=2011|isbn=978-0-7020-3528-9|pages=430–438|language=en|chapter=Chapter 34 - Dry needling of trigger points|doi=10.1016/B978-0-7020-3528-9.00034-0}}</ref>

==== Insertion ====
Its tendon inserts onto the medial border and upper surface of the [[coracoid process]] of the [[scapula]].<ref name=":0" /><ref>{{Cite book|last1=Bentley|first1=J. Nicole|url=https://www.sciencedirect.com/science/article/pii/B9780124103900000123|title=Nerves and Nerve Injuries|last2=Yang|first2=Linda J. S.|publisher=[[Academic Press]]|year=2015|isbn=978-0-12-410390-0|pages=563–574|doi=10.1016/B978-0-12-410390-0.00012-3}}</ref>

=== Innervation ===
The muscle receives motor innervation from the [[medial pectoral nerve]].<ref name=":02">{{Citation |last1=Maldonado |first1=Kenia A. |title=Anatomy, Thorax, Medial Pectoral Nerves |date=2022 |url=http://www.ncbi.nlm.nih.gov/books/NBK556059/ |work=StatPearls |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=32310519 |access-date=2023-01-13 |last2=Tadi |first2=Prasanna}}</ref>

=== Relations ===

Pectoralis minor muscle forms part of the anterior wall of the [[axilla]].<ref>{{Cite book|last=Jacob|first=S.|chapter-url=https://www.sciencedirect.com/science/article/pii/B9780443103735500051|title=Human Anatomy|date=2008-01-01|publisher=[[Churchill Livingstone]]|isbn=978-0-443-10373-5|pages=5–49|language=en|chapter=Chapter 2 - Upper Limb}}</ref> It is covered anteriorly (superficially) by the [[clavipectoral fascia]]. The [[medial pectoral nerve]] pierces the pectoralis minor and the clavipectoral fascia. In attaching to the coracoid process, the pectoralis minor forms a 'bridge' - structures passing into the upper limb from the thorax will pass directly underneath.<ref>http://www.teachmeanatomy.com/muscles-of-the-pectoral-region/ {{dead link|date=March 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

[[Axillary lymph nodes|Axillary nodes]] are classified according to their positions relative to the pectoralis minor muscle. Level 1 are lateral, Level 2 are deep, Level 3 are medial. The pectoralis minor divides the axillary artery into three parts<ref>{{Cite journal |last1=Shi |first1=Dongning |last2=Bai |first2=Junwen |last3=Zhang |first3=Lu |last4=Wang |first4=Xia |date=February 2022 |title=The "Hand as Foot" teaching method in axillary artery anatomy |url=https://pubmed.ncbi.nlm.nih.gov/34973859/ |journal=Asian Journal of Surgery |volume=45 |issue=2 |pages=800–801 |doi=10.1016/j.asjsur.2021.12.001 |issn=0219-3108 |pmid=34973859|doi-access=free }}</ref> (in contrary sequence compared to the nodes) - first part medial, second part deep/posterior, third part lateral in relation to the pectoralis minor.

=== Variations ===
[[File:Braus 1921 137.png|thumb|right|An individual with an axillary arch as well as [[sternalis]] muscle and an accessory abdominal portion of the [[pectoralis major]].]]
The origin is from the second, third and fourth or fifth ribs. The tendon of insertion may extend over the coracoid process to the greater tubercle. It may be split into several parts. Absence of this muscle is rare but happens with certain uncommon diseases, such as the [[Poland syndrome]].<ref>{{Cite journal |last1=Al Faleh |first1=Khalid |last2=Al Saadi |first2=Muslim |last3=Khalid-Bantuas |first3=Shialinee |date=January 2014 |title=Poland's Syndrome with Absent Limb Anomalies |journal=Journal of Clinical Neonatology |volume=3 |issue=1 |pages=44–46 |doi=10.4103/2249-4847.128735 |doi-access=free |issn=2249-4847 |pmc=3982340 |pmid=24741541}}</ref>

== Function ==
Pectoralis minor muscle [[Depression (kinesiology)|depresses]] the point of the [[shoulder]], drawing the [[scapula]] superior, towards the [[thorax]], and throwing its [[inferior angle]] posteriorly.

<!-- == Additional images ==
<gallery>
File:Pectoralis minor muscle animation small.gif|Position of pectoralis minor muscle (shown in red).
File:Slide4por.JPG|Right pectoralis minor muscle. Deep dissection.
</gallery>
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==See also==
*[[Pectoralis minor syndrome]]

== References ==
{{Gray's}}
{{Reflist}}

== External links ==
{{Commons category|Pectoralis minor muscles}}
* {{MuscleUWash|upper-body/pectoralis-minor}}
* {{SUNYAnatomyFigs|04|04|05}}
* {{SUNYAnatomyFigs|05|02|08}}
* {{SUNYAnatomyLabs|05|ov|02|00}}
* {{SUNYAnatomyLabs|05|01|01|02}}
* [https://web.archive.org/web/20051123093450/http://faculty.ucc.edu/biology-potter/Musculature/sld014.htm Slide]

{{Muscles of thorax and back}}
{{Portal bar|Anatomy}}
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[[Category:Muscles of the upper limb]]

[[cs:Prsní svaly]]