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Elbow anatomy: understanding the humerus, radius, and ulna – key to understanding elbow function and injury.

Updated Apr 2026
Isang guhit-kamay na ilustrasyon ng isang lektor sa anatomiya na tumuturo sa isang modelo ng balangkas.
Ang iyong siko ay isang hinge joint kasama ang maliit na pivot — ang humerus ay nagtatagpo sa ulna at radius upang payagan kang yumuko, tuwidin, at i-rotate ang forearm. Kieran Hirpara 4.0

Ang pahinang ito ay isinalin ng makina at hindi pa nasusuri ng isang doktor. Ang bersyong Ingles ang siyang opisyal.

Ang mga buto

Ang iyong siko ay hindi isang solong buto. Ito ay isang kumplikadong bisagra kung saan nagtatagpo ang tatlong buto. Ang buto ng itaas na braso ay ang humerus. Nagtatapos ito sa hugis na parang spool sa ibaba. Ang hugis na ito ay angkop sa mga buto ng babaeng braso sa ilalim.

Ang dalawang buto ng babaeng braso ay ang radius at ulna. Ang ulna ang mas malaking buto sa gilid ng maliit na daliri. Mayroon itong tuktok na parang kawit na tinatawag na olecranon. Maaari mong damhin ang matigas na puntong ito sa likod ng iyong siko. Ito ang tuktok ng ulna na nakapahinga sa isang guhit sa humerus.

Ang radius ang mas maliit na buto sa gilid ng hinlalaki. Ang ulo nito ay nasa malapit sa siko ngunit hindi bumubuo ng pangunahing bisagra. Sa halip, umiikot ito sa paligid ng ulna. Ang pagkakasunod-sunod na ito ay nagbibigay-daan sa pag-ikot ng iyong babaeng braso.

Isipin ang siko na parang bisagra ng pinto. Ang humerus ang frame ng pinto. Ang ulna ang pinto. Ang radius ay hiwalay na piraso na umiikot sa loob ng frame. Ang disenyo na ito ay nagbibigay sa iyong braso ng lakas at flexibility. Maaari mong damhin ang matigas na pagkakataon sa loob at labas ng iyong siko. Ito ang mga epicondyles. Hindi ito bahagi ng kasukasuan mismo. Sila ang mga punto ng pagdikit para sa mga kalamnan at ligamento.

Ang mga kasu-kasuan at kung paano ito gumagalaw

Ang iyong siko ay naglalaman ng tatlong hiwalay na kasu-kasuan na nagtatrabaho nang sabay-sabay. Ito ay nahahati sa dalawang pangunahing bahagi.

Una ay ang ulnohumeral joint. Ito ay isang hinge joint. Ito ay nag-uugnay ng humerus sa ulna. Pinapayagan nito ang iyong braso na yumuko at tuwid. Ang galaw na ito ay tinatawag na flexion at extension. Ginagamit mo ang galaw na ito kapag dinala mo ang kutsara sa iyong bibig. Pinapayagan din nito ang iyong itulak ang isang pinto para buksan. Matatag ang kasu-kasuan dahil mahigpit na magkaka-ugnay ang mga buto.

Pangalawa ay ang radioulnar joint. Ito ay isang pivot joint. Pinapayagan nito ang iyong forearms na umikot. Ang galaw na ito ay tinatawag na pronation at supination. Ang pronation ay nagpapahilig sa iyong palad pababa. Ang supination ay nagpapahilig sa iyong palad pataas. Ginagamit mo ito kapag ikinikot mo ang hawakan ng pinto o binubuhos ang tubig mula sa pitcher. Ang pag-ikot ay nangyayari nang halos pantay sa itaas at ibaba ng forearm. Hindi ito galaw ng siko lamang.

Mayroon ding maliit na kasu-kasuan sa pagitan ng radius at humerus. Tumutulong ito na gabayan ang radius habang umiikot. Magkakasama, pinapayagan ng mga kasu-kasuang ito na ilagay ang iyong kamay sa anumang posisyon sa espasyo. Ang iyong siko ay yumuyuko hanggang sa humigit-kumulang 145 degrees. Ang saklaw na ito ay sapat para sa karamihan ng mga pang-araw-araw na gawain.

Ang mga kalamnan, tendon, at ligamento

Ang mga kalamnan ay humihila sa mga buto upang lumikha ng galaw. Ito ay nakakabit sa mga buto sa pamamagitan ng mga tendon. Ang mga tendon ay matibay, tulad ng lubid na mga tisyu.

Ang biceps muscle ay nasa harap ng iyong itaas na braso. Ang kanyang tendon ay tumatawid sa siko. Tumutulong ito sa pagbaluktot ng iyong braso. Tumutulong din ito sa pag-ikot ng iyong forearms. Ang triceps muscle ay nasa likod ng iyong itaas na braso. Ang kanyang tendon ay nakakabit sa olecranon. Ito ang nagbubukas ng iyong braso. Ito ang pangunahing kalamnan para sa pagtutulak.

Ang mga ligamento ay nag-iikot ng mga buto. Nagbibigay ito ng katatagan. Ang medial collateral ligament ay nasa loob na bahagi ng siko. Pinipigilan nito ang siko na baluktotin palabas. Ang lateral collateral ligament ay nasa labas na bahagi. Pinipigilan nito ang siko na baluktotin paitaas. Mahalaga ang mga ligamentong ito para sa katatagan habang naglalaro ng sports.

Isipin ang mga ligamento bilang matibay na goma. Pinapanatili nito ang mga buto na nakaayos. Ang mga tendon ay gumagalaw tulad ng mga lubid. Ipinapasa nito ang lakas mula sa mga kalamnan patungo sa mga buto. Kapag nagtatayo ka ng isang mabigat na kahon, ang mga istrukturang ito ay nagtatrabaho nang sama-sama. Sinisipsip nila ang stress at pinipigilan ang pinsala.

Ang mga nerbiyo

Ang mga nerbiyo ay nagdadala ng mga signal sa pagitan ng iyong utak at katawan. Sila ang nagkontrol sa galaw at pakiramdam. Tatlong pangunahing nerbiyo ang dumaan sa rehiyon ng siko.

Ang ulnar nerve ay tumatakbo sa likod ng medial epicondyle. Ito ang loob na butong buntot ng iyong siko. Madalas itong tinatawag na "funny bone." Ang pagtama sa lugar na ito ay nagdudulot ng pakiramdam ng pamamanhid. Ito ay hindi sakit sa buto. Ito ay ang nerbiyo na pinipindot. Ang ulnar nerve ang nagkontrol sa pakiramdam sa anghas at maliit na daliri. Nagkontrol din ito sa maliliit na kalamnan sa kamay.

Ang median nerve ay tumatakbo sa gitna ng siko. Dumaan ito sa pagitan ng dalawang ulo ng biceps muscle. Tumatakbo ito pababa sa forearms papunta sa kamay. Nagkontrol ito sa pakiramdam sa hinirang, index, at middle fingers. Tumutulong din ito sa pagbaluktot ng pulso at mga daliri.

Ang radial nerve ay tumatakbo sa likod ng braso. Dumadalikot ito sa paligid ng humerus. Nagkontrol ito sa triceps muscle. Pinapayagan nito kang tuwidin ang iyong siko. Tumutulong din ito sa pagpapalawak ng iyong pulso at mga daliri.

Kung mararamdaman mo ang pamamanhid sa iyong mga daliri, maaari itong magkaugnay sa mga nerbiyong ito. Ang ulnar nerve ay nakakaapekto sa gilid ng pinky. Ang median nerve ay nakakaapekto sa gilid ng hinirang. Ang radial nerve ay nakakaapekto sa likod ng kamay. Ang pag-unawa sa mga landas na ito ay tumutulong sa pagpapaliwanag ng mga sintomas. Tinutukoy nito rin kung bakit ang mga partikular na sugat ay nagdudulot ng mga partikular na problema.


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