Hanyar Corticospinal

**Hanyar corticospinal** hanya ce ta fararen kwayoyin jini (White matter) da ke motsa jiki, wadda ke farawa daga kwakwalwa kuma tana ƙarewa a kan ƙananan jijiyoyin motsa jiki da kuma jijiyoyin haɗin gwiwa(interneurons) a cikin kashin baya, tana kula da motsin hannaye da gaɓoɓi.  Akwai fiye da neurons miliyan ɗaya a cikin hanyar corticospinal, kuma sukan samu murfin kariya (myelin) a cikin shekaru biyu na farko rayuwa.

Sashen corticospinal yana ɗaya daga cikin sassan pyramidal, ɗayan kuma shine sashin corticobulbar.

## Ilimin Halittar Jiki
Hanyar corticospinal ta samo asali ne daga sassa da dama na kwakwalwa, ciki har da ba kawai wuraren motsa jiki ba, har ma da manyan sassan somatosensory da wuraren premotor.  Yawancin ƙwayoyin jijiyoyi sun samo asali ne daga ko dai manyan sassan motsa jiki (precentral gyrus, Brodmann area 4) ko kuma yankunan premotor.   Kimanin kashi 30% na ƙwayoyin jijiyoyi na corticospinal suna samo asali ne daga manyan sassan motsa jiki, kashi 30% kuma suna samuwa a cikin ƙananan sassan motsa jiki da kuma ƙarin sassan motsa jiki, tare da sauran kashi 40% da ke rarrabawa tsakanin ƙananan sassan somatosensory, parietal lobe, da cingulate gyrus.  Waɗannan ƙananan sassan motsa jiki na sama suna samo asali ne daga ƙwayoyin pyramidal na Layer V na neocortex,  kuma suna tafiya ta cikin sashin baya na ƙananan sassan cikin kwakwalwa a cikin kwakwalwa, domin shiga cikin kwakwalwar kwakwalwa a gindin tsakiyar kwakwalwa. Sannan duka sassan suna wucewa ta cikin tushen kwakwalwa, daga pons zuwa medulla.  Hanyar corticospinal, tare da hanyar corticobulbar, suna samar da dala biyu a kowane gefen medulla na tushen kwakwalwa - kuma suna ba da sunansu a matsayin hanyoyin pyramidal.  Kwayoyin halittar Corticospinal suna synapse kai tsaye akan ƙwayoyin halittar alpha domin kula da tsoka kai tsaye.

Kwayoyin Betz manyan ƙwayoyin halitta ne waɗanda ake iya gani sosai a ƙarƙashin na'urar hangen nesa, kuma yayin da suke wakiltar kusan kashi 5% kawai na ƙwayoyin da ke fitowa zuwa ga kashin baya, galibi ana ɗaukar su a matsayin mafi mahimmanci domin sadarwa da alamar motsi.  Waɗannan ƙwayoyin suna da mahimmanci saboda saurin watsa su, sama da mita 70/sec, mafi saurin watsa duk wani alamu daga kwakwalwa zuwa kashin baya. 

Akwai sassa biyu na hanyar corticospinal, sashin corticospinal na gefe da kuma sashin corticospinal na gaba. Kwayoyin halittar corticospinal na gefe suna ratsa tsakiyar layi a matakin medulla oblongata, kuma suna sarrafa gaɓoɓi da lambobi.   Yankin gefe yana samar da kusan kashi 90% na haɗin gwiwa a cikin hanyar corticospinal;  mafi yawansu suna ratsawa a cikin medulla, yayin da sauran (kimanin 2-3%) ke ci gaba da kasancewa a cikin tsaka. Kwayoyin halittar corticospinal na gaba, sauran kashi 10%, suna ci gaba da zama a cikin kashin baya amma suna raguwa a matakin jijiyar kashin baya inda suke fita, kuma suna sarrafa tsokoki na gangar jiki, kafada da wuya. 

## Aiki
Babban manufar hanyar corticospinal ita ce domin kula da jiki da gaɓoɓin jiki.

Duk da haka, alaƙa da haɗin gwiwa da kwakwalwan somatosensory yana nuna cewa hanyoyin pyramidal suma suna da alhakin daidaita bayanai daga jiki. 

Domin yawancin (75-80%) na haɗin suna ketare layin tsakiya a matakin medulla da wasu a matakin ƙashin baya, kowane ɓangaren kwakwalwa yana da alhakin sarrafa tsokoki a gefen jiki. 

Bayan marasa lafiya sun ji rauni a wani ɓangare na sassan jikinsu, sai su samu shanyewan ɓari a gefen jiki. Duk da haka, za su iya sake koyon wasu ƙananan motsi, ba tare da motsi mai kyau ba. 

Wannan yana nufin cewa haɗin waɗannan hanyoyin yana da mahimmanci domin motsi mai kyau, kuma kawai ɗan murmurewa ne kawai zai yiwu idan sun lalace.

## Manazarta