View source for Thigh

{{Short description|Body part between pelvis and knee; upper leg}}
{{Other uses}}
{{More citations needed|date=April 2011}}
{{Infobox anatomy
| Name        = Thigh
| Latin       = femur
| Greek       = 
| Image       = File:Thigh.jpg
| Caption     = A woman's thighs
| Width       = 
| Image2      = Braus 1921 277.png
| Caption2    = Cross-section of the thigh showing muscles and bone (''latin terminology'')
| Precursor   = 
| System      = 
| Artery      = 
| Vein        = 
| Nerve       = 
| Lymph       = 
}}
In [[anatomy]], the '''thigh''' is the area between the [[hip]] ([[pelvis]]) and the [[knee]]. Anatomically, it is part of the [[leg|lower limb]].<ref>{{DorlandsDict|eight/000108279|thigh}}{{Dead link|date=November 2023}}</ref>

The single [[bone]] in the thigh is called the [[femur]]. This bone is very thick and strong (due to the high proportion of [[bone tissue]]), and forms a [[ball and socket joint]] at the [[hip]], and a modified [[hinge joint]] at the knee.<ref>{{cite web |url=https://dictionary.cambridge.org/dictionary/english/thigh
|title=Thigh|website=Cambridge Dictionary |access-date=2021-06-23}}</ref>

==Structure==
===Bones===
{{main|Femur}}
The [[femur]] is the only bone in the thigh and serves as an attachment site for all thigh muscles. The [[femur head|head of the femur]] articulates with the [[acetabulum]] in the [[pelvic bone]] forming the [[hip joint]], while the [[Lower extremity of femur|distal part of the femur]] articulates with the [[tibia]] and [[patella]] forming the [[knee]]. By most measures, the femur is the strongest and longest bone in the body.<ref>{{cite web|title=Facts About Bones in Your Skeleton|publisher=Hospital for Special Surgery|url=https://www.hss.edu/playbook/facts-about-bones-in-your-skeleton/}}</ref>

The femur is categorised as a [[long bone]] and comprises a [[diaphysis]], [[body of femur|the shaft (or body)]] and two [[epiphyses]], the [[lower extremity of femur|lower extremity]] and the [[upper extremity of femur]], that articulate with adjacent bones in the hip and knee.<ref name=Bojsen>{{cite book |last1=Bojsen-Møller |first1=Finn  |last2=Simonsen |first2=Erik B. |last3=Tranum-Jensen |first3=Jørgen| year=2001 |title=Bevægeapparatets anatomi |edition=12th |language=da |trans-title=Anatomy of the Locomotive Apparatus | isbn =978-87-628-0307-7|pages=239–241}}</ref>

===Muscular compartments===
{{main|Fascial compartments of thigh}}
In cross-section, the thigh is divided up into three separate compartments, divided by [[fascia]], each containing muscles. These compartments use the femur as an axis and are separated by tough [[connective tissue]] membranes (or [[septum|septa]]). Each of these compartments has its own [[blood]] and [[nerve]] supply, and contains a different group of [[muscle]]s.

* [[Medial fascial compartment of thigh]], adductor
* [[Posterior fascial compartment of thigh]], flexion, [[hamstring]]
* [[Anterior fascial compartment of thigh]], extension

Anterior compartment muscles of the thigh include [[sartorius muscle|sartorius]], and the four muscles that comprise the [[quadriceps muscles]] –  [[rectus femoris]], [[vastus medialis]], [[vastus intermedius]] and [[vastus lateralis]].

Posterior compartment muscles of the thigh are the [[hamstring muscles]], which include [[semimembranosus]], [[semitendinosus]], and [[biceps femoris]].

Medial compartment muscles are [[pectineus]], [[adductor magnus]], [[adductor longus]] and [[adductor brevis]], and also [[gracilis muscle|gracilis]].

Because the major muscles of the thigh are the largest muscles of the body, resistance exercises (strength training) of them stimulate blood flow more than any other localized activity.<ref>{{cite web|url=http://www.livestrong.com/article/406641-how-important-are-leg-workouts-for-muscle-gain/|title=How Important Are Leg Workouts for Muscle Gain?|first=Andrea|last=Cespedes}}</ref>

===Blood supply===
[[File:Common femoral and subsartorial artery and vein.jpg|thumb|Main blood vessels of the thigh.<ref>{{cite book|url=https://books.google.com/books?id=_3i_EAAAQBAJ&pg=PA1072|title=Comprehensive Textbook of Clinical Radiology – Volume III: Chest and Cardiovascular system|author=Amarnath C and Hemant Patel|year=2023|isbn=9788131263617|publisher=[[Elsevier]] Health Sciences |page =[https://books.google.com/books?id=_3i_EAAAQBAJ&pg=PA1072 1072]}}</ref>]]
The arterial supply is by the [[femoral artery]] and the [[obturator artery]]. The lymphatic drainage closely follows the arterial supply and drains to the lumbar lymphatic trunks on the corresponding side, which in turn drains to the [[cisterna chyli]].

The deep venous system of the thigh consists of the [[femoral vein]], [[common femoral vein]], [[deep femoral vein]], the proximal part of the [[popliteal vein]], and various smaller vessels; these are the site of proximal [[deep vein thrombosis]]. The [[Vein|perforating veins]] connect the deep and the superficial system, which consists of the [[Small saphenous vein|small]] and [[great saphenous vein]]s (the site of [[varicose vein]]s).<ref>{{cite web |url=https://www.lecturio.com/concepts/thigh/|title=Thigh|website=The Lecturio Medical Concept Library |access-date=2021-06-23}}</ref>

==Clinical significance==
Thigh weakness can result in a positive [[Gowers' sign]] on physical examination.<ref>{{cite journal |last1= Chang |first1=Richard F. |last2=Mubarak |first2=Scott J.|date=2011-12-28 |title=Pathomechanics of Gowers' Sign: A Video Analysis of a Spectrum of Gowers' Maneuvers
 |journal=Clinical Orthopaedics and Related Research |volume=470 |issue=7 |pages=1987–1991 |doi=10.1007/s11999-011-2210-6 |pmid=22203329 |pmc=3369091 }}</ref>

Thigh injury [[Sports injury|resulting from sports]], whether [[Acute injuries|acute]] or from [[overuse injuries|overuse]], can mean significant incapacity to perform. [[Soft tissue injury]] can encompass [[sprains]], [[Strain (injury)|strains]], [[bruising]] and [[tendinitis]].

[[Runner's knee]] ([[patellofemoral pain]]) is a direct consequence of the kneecap rubbing against the end of the thigh bone ([[femur]]). Tight hamstrings and weak thigh muscles, required to stabilize the knee, increase the risk of developing of runner's knee.<ref name=":2">{{Cite web|date=2020-08-31|title=Medically Sound: Field, Court, and Course Related Injuries – Sports Injuries|url=https://urmedlife.blogspot.com/2020/08/field-court-and-course-related-injuries.html|access-date=2020-11-01|website=Medically Sound}}</ref>

==Society and culture==
[[File:Thigh gap2.jpg|thumb|[[Thigh gap]]]]

Western societies generally tolerate clothing that displays thighs, such as [[short shorts]] and [[miniskirts]]. [[Beachwear]] and many [[athleisure]] styles often display thighs as well. Professional dress codes may require covering up bare thighs.

Many [[Islamic countries]] disapprove of or prohibit the display of thighs, especially by women.

Strategic covering or display of thighs is used in popular fashion around the world, such as [[thigh-high boots]] and ''[[zettai ryoiki]]''.

==Additional images==
<gallery>
Thigh muscles front.png|Front of thigh muscles from Gray's Anatomy of the human body from 1918.
Thigh muscles back.png|Back thigh muscles of the gluteal and posterior femoral regions from Gray's Anatomy of the human body from 1918.
File:Sobo 1909 573-574.png|Also showing major blood vessels and nerves.
Thigh_cross_section.svg|Cross-section through the middle of the thigh.
Gray436.png|The [[obturator externus]]
</gallery>

==References==
{{Wiktionary|position=left}}
{{Commons|position=left}}
{{Reflist}}

{{Human regional anatomy}}
{{Muscles of lower limb}}
{{Authority control}}

[[Category:Lower limb anatomy]]