Tibialis anterior muscle 2020477 225919803 2008-07-16T00:44:24Z Tigrress 284257 tense correction {{Infobox Muscle | Name = {{PAGENAME}} | Latin = musculus tibialis anterior | GraySubject = 129 | GrayPage = 480 | Image = Gray1240.png | Caption = Lateral aspect of right leg. | Image2 = Tibialis.png | Caption2 = Tibialis anterior | Origin = [[body of tibia]] | Insertion = [[medial cuneiform]] and [[first metatarsal]] bones of the [[foot]] | Blood = [[anterior tibial artery]]| Nerve = [[Deep fibular nerve| Deep Fibular (peroneal) nerve]] | Action = [[Dorsiflexion]] and [[Inversion_(kinesiology)|Inversion]] of the foot | Antagonist = [[Fibularis longus]], [[Gastrocnemius muscle|Gastrocnemius]], [[Soleus muscle|Soleus]], [[Plantaris muscle|Plantaris]], [[Tibialis posterior muscle|Tibialis posterior]] | DorlandsPre = m_22 | DorlandsSuf = 12551168 | }} In human anatomy, the '''tibialis anterior''' is a [[muscle]] in the shin that spans the length of the [[tibia]]. It originates in the upper two-thirds of the lateral surface of the [[tibia]] and inserts into the medial [[Cuneiform (anatomy)|cuneiform]] and first [[metatarsal]] bones of the [[foot]]. Its acts to [[dorsiflexion|dorsiflex]] and invert the foot. It is situated on the lateral side of the tibia; it is thick and fleshy above, tendinous below. This muscle overlaps the [[anterior tibial]] vessels and deep [[peroneal nerve]] in the upper part of the leg. The tibialis anterior muscle is the source of the common pain of '[[shin splints]]' affecting many runners, either because they are underconditioned or have not yet warmed up properly. ==Function== The tibialis anterior muscle is the most medial muscle of the [[anterior compartment of the leg]]. It functions to stabilise the ankle as the foot hits the ground during the contact phase of [[walking]] and acts later to pull the foot clear of the ground during the swing phase. It also functions to 'lock' the ankle, as in toe-kicking a ball, when held in an isometric contraction. Antagonists are [[plantar-flexors]] of the posterior compartment such as soleus and gastrocnemius. Essentially, the movements of tibialis anterior are [[dorsiflexion]] and [[Inversion (kinesiology)| inversion]] of the foot. However, actions of tibialis anterior are dependent on whether the foot is [[weight bearing]] or not (closed or open kinetic chain). When the foot is on the ground the muscle helps to balance the leg and talus on the other tarsal bones so that the leg is kept vertical even when walking on uneven ground. But, if you're walking on the beach it stays relaxed. This is because of less pressure pushing on it. ==Origin and insertion== It arises from the [[lateral condyle]] and upper half or two-thirds of the lateral surface of the [[body of the tibia]]; from the adjoining part of the [[interosseous membrane]]; from the deep surface of the fascia; and from the [[intermuscular septum]] between it and the [[Extensor digitorum longus]]. The fibers of this fusiform muscle are relatively parallel to the plane on insertion, ending in a tendon, apparent on the anteriomedial dorsal aspect of the foot close to the ankle. After passing through the most medial compartments of the [[transverse crural ligament| transverse]] and [[cruciate crural ligament]]s, it is inserted into the medial and under surface of the [[medial cuneiform bone]] and the base of the [[first metatarsal]] bone. ==Variations== A deep portion of the muscle is rarely inserted into the [[Talus bone|talus]], or a tendinous slip may pass to the head of the first metatarsal bone or the base of the first phalanx of the [[great toe]]. The [[Tibiofascialis anterior]], a small muscle from the lower part of the tibia to the transverse or [[cruciate crural ligament]]s or [[deep fascia]]. ==Additional images== <gallery> Image:Gray258.png|Bones of the right leg. Anterior surface. Image:Gray269.png|Bones of the right foot. Plantar surface. Image:Tibialis anterior 2.png|Anatomical terms of motion Image:Gray440_color.png|Cross-section through middle of leg. Image:Gray442.png|The mucous sheaths of the tendons around the ankle. Medial aspect. Image:Gray1241.png|The mucous sheaths of the tendons around the ankle. Lateral aspect. </gallery> ==External links== * {{MuscleLoyola|tiba}} * {{SUNYAnatomyLabs|15|st|04|15}} * http://www.wheelessonline.com/ortho/tibialis_anterior {{Gray's}} {{Muscles of lower limb}} [[Category:Calf muscles]] [[ca:Múscul tibial anterior]] [[de:Musculus tibialis anterior]] [[fr:Muscle tibial antérieur]] [[hr:Prednji goljenični mišić]] [[ja:前脛骨筋]] [[sv:Tibialis]]