psoas minor muscle
{{short description|Long, slender skeletal muscle located anterior to the psoas major muscle}}
{{Infobox muscle
| Name = Psoas minor muscle
| Latin = musculus psoas minor
| Image = Musculus psoas minor.png
| Caption = Muscles of the iliac and anterior femoral regions (psoas minor visible near top right)
| Origin = Lateral surface bodies of T12 and L1 vertebrae and intervening intervertebral disc
| Insertion = Pectineal line and iliopubic eminence
| Action = Weak trunk flexor
| Blood =
| Nerve = Anterior ramus of nerve L1
| Antagonist = Erector spinae
}}
The psoas minor muscle ({{IPAc-en|ˈ|s|oʊ|.|ə|s}} or {{IPAc-en|ˈ|s|oʊ|.|æ|s}}; from {{langx|grc|ψόᾱ|psóā|muscles of the loins}}) is a long, slender skeletal muscle. When present, it is located anterior to the psoas major muscle.Tank (2005), p 93Gray (2008), p 1372
Structure
The psoas minor muscle originates from the vertical fascicles inserted on the last thoracic and first lumbar vertebrae. From there, it passes down onto the medial border of the psoas major, and is inserted to the innominate line and the iliopectineal eminence. Additionally, it attaches to and stretches the deep surface of the iliac fascia and occasionally its lowermost fibers reach the inguinal ligament.Bendavid (2001), p 58 It is posteriolateral to the iliopsoas muscle.{{Citation|last=Zwingenberger|first=Allison|title=Chapter 14 - Musculoskeletal System|date=2015-01-01|url=http://www.sciencedirect.com/science/article/pii/B9781416048671000143|work=Small Animal Diagnostic Ultrasound (Third Edition)|pages=517–540|editor-last=Mattoon|editor-first=John S.|place=St. Louis|publisher=W.B. Saunders|language=en|isbn=978-1-4160-4867-1|access-date=2021-01-22|last2=Benigni|first2=Livia|last3=Lamb|first3=Christopher R.|editor2-last=Nyland|editor2-first=Thomas G.}} Variations occur, however, and the insertion on the iliopubic eminence sometimes radiates into the iliopectineal arch.Platzer (2004), p 234
The psoas minor muscle receives oxygenated blood from the four lumbar arteries (inferior to the subcostal artery) and the lumbar branch of the iliolumbar artery.{{citation needed|date=February 2018}}
= Innervation =
The psoas minor muscle is innervated by direct branches of the lumbar spinal nerves.{{Citation|last=Gardner|first=ERNEST D.|title=Chapter 2 - Gross Anatomy of the Peripheral Nervous System|date=2005-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780721694917500053|work=Peripheral Neuropathy (Fourth Edition)|pages=11–33|editor-last=Dyck|editor-first=Peter J.|place=Philadelphia|publisher=W.B. Saunders|language=en|isbn=978-0-7216-9491-7|access-date=2021-01-22|last2=Bunge|first2=RICHARD P.|editor2-last=Thomas|editor2-first=P. K.}}
=Variation=
The psoas minor muscle is considered inconstant and is often absent, only being present in about 40% of human specimens studied.Mcg Farias (1 Jan. 2012). Morphological and morphometric analysis of Psoas Minor Muscle in cadavers. ResearchGate. Retrieved from https://www.researchgate.net/publication/280236296_Morphological_and_morphometric_analysis_of_Psoas_Minor_Muscle_in_cadavers It has an average length of about 24 cm, of which about 7.1 cm is muscle tissue and about 17 cm is tendon.
Function
The psoas minor is a weak flexor of the lumbar vertebral column.
Other animals
The psoas minor muscle is present in other mammals, such as horses.{{Citation|last=Haussler|first=Kevin K.|title=21 - Back and pelvis|date=2014-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780702047718000211|work=Equine Sports Medicine and Surgery (Second Edition)|pages=419–456|editor-last=Hinchcliff|editor-first=Kenneth W.|publisher=W.B. Saunders|language=en|isbn=978-0-7020-4771-8|access-date=2021-01-22|last2=Jeffcott|first2=Leo B.|editor2-last=Kaneps|editor2-first=Andris J.|editor3-last=Geor|editor3-first=Raymond J.}} In horses, it may be palpated during rectal exams to check for causes of back pain.
Additional images
File:Gray236.png|Right hip bone, internal surface
File:Gray245.png|Right femur, posterior surface
File:Slide4nn.JPG|Psoas minor muscle
File:Slide9pp.JPG|Psoas minor muscle
File:Slide6ppp.JPG|Psoas minor muscle
Notes
{{Reflist}}
References
{{Commons category|Psoas minor muscles}}
- {{cite book
| url = https://books.google.com/books?id=ai6fOllPH44C&pg=RA1-PA58
| title = Abdominal Wall Hernias: Principle and Management
| first = Robert | last = Bendavid |author2=Abrahamson, Jack |author3=Arregui, Maurice E.
| publisher = Springer | year = 2001
| isbn = 0-387-95004-4
}}
- {{cite book
| title = Color Atlas of Human Anatomy, Vol 1: Locomotor system
| first = Werner | last = Platzer
| edition = 5th | publisher = Thieme
| isbn = 3-13-533305-1 | year = 2004
}} (ISBN for the Americas 1-58890-159-9.)
- {{cite book
| first = Patrick W. | last = Tank
| title = Grant's Dissector
| publisher = Lippincott Williams & Wilkins | location = Hagerstown, MD
| year = 2005 | edition = 13th
| isbn = 0-7817-5484-4
}}
- {{cite book
| title = Gray's Anatomy - The Anatomical Basis of Clinical Practice
| first = Henry | last= Gray |author2=Standring, Susan
| edition = 40th | publisher = Churchill Livingstone - Elsevier
| year = 2008
| isbn = 978-0-443-06684-9
}}
{{Muscles of lower limb}}
{{Authority control}}