条文：
经云：膀胱者州都之官，津液藏焉，气化则能出矣。
又云：膀胱当十九椎，居肾之下，大肠之前，有下口，无上口，
当脐上一寸水分穴处，为小肠下口，乃膀胱上际，水液由此别回肠随气泌渗而入，
其出入皆由气化，入气不化，则水归大肠，而为泄泻，出气不化，则闭塞下窍，
而为癃肿也，是经多血少气。
「难经」曰：膀胱重九两二铢，纵广九寸，盛溺九升九合，口广二寸半
（图五十六）。
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条文：
膀胱足太阳之脉，起于目内眦，上额交颠；
其直者，从颠入络脑，还出别下项，循肩髆，内侠脊，抵腰中，
入循膂络肾，属膀胱；
其直者，从腰中下挟脊，贯臀入腘中；
其支者，从髆内左右，别下贯胛，挟脊，内过髀枢，循髀外从后廉下合腘中，
以下贯□内，出外踝之后，循京骨至小趾外侧（见图五十七）。
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条文：
足太阳经膀胱脉，目内眦上起额尖；支者颠上至耳角，直者从颠脑后悬，
络脑还出别下项，仍循肩膊侠脊边，抵腰膂肾膀胱内，一支下与后阴连。
贯臀斜入委中穴，一支膊内左右别，贯胛侠脊过髀枢，臂内后廉腘中合，
下贯□内外踝后，京骨骨下趾外侧。
注：[1]足太阳之脉，起目内眦睛明穴，从睛明循行攒竹、曲差、五处，
上额交颠，入承光穴，从承光循行通天穴。
[2]其支者，从颠至耳上角，交于足少阳之经。
[3]其直者，从通天入络于大杼穴，从大杼循行肩髆内风门穴，
从风门循行肺俞穴，挟脊抵腰中厥阴俞穴，从厥阴俞穴、循行心俞、
鬲俞、肝俞、胆俞、脾俞、胃俞、三焦俞，入循膂络肾，
从肾俞穴循行气海俞，从腰中下挟脊大肠俞穴，从大肠俞循行关元俞、
膀胱俞、中膂俞、白环俞等穴，别行上□、次□、中□、下□等穴。
[4]其支者，又复上肩膊内，从附分穴循行贯胛魄户穴，
从魄户循行挟脊内膏盲、神堂、□嘻、鬲关、魂门、阳纲、意舍、胃仓、
肓门、志室、胞肓等穴，过髀枢秩边穴，从秩边穴循髀外从后廉、承扶、
浮□、委阳穴，下合腘中委中穴，从委中循行合阳穴，
从合阳下贯□内承筋穴，从承筋循行承山、飞扬、附阳等穴，
从附阳穴循行出外踝之后昆仑穴，从昆仑穴循行仆参、申脉、金门等穴，
循京骨即本经之京骨穴也。
[5]从京骨循行束骨、通谷穴，至小趾外侧至阴穴而终，
以交于足之少阴经也。
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The classic states: The Bladder is the official of the "Zhou Du" (the reservoir where fluids gather); it stores the Jin Ye (body fluids), and only through Qi transformation can they be excreted.
It further states: The Bladder is located at the level of the nineteenth thoracic vertebra, situated below the Kidneys and anterior to the Large Intestine. It has a lower orifice but no upper orifice. Its position corresponds to the Shuifen (Water Separation) acupoint, one cun above the umbilicus, which serves as the lower outlet of the Small Intestine and the upper boundary of the Bladder. Fluids separate from the ileum here and seep into the Bladder following the movement of Qi. Both entry and exit depend on Qi transformation; if the Qi for entry fails to transform, water flows into the Large Intestine, causing diarrhea; if the Qi for exit fails to transform, the lower orifices become obstructed, leading to strangury (difficulty in urination) or swelling. This meridian is characterized by abundant blood and scarce Qi.
The *Nan Jing* (Classic of Difficult Issues) records: The Bladder weighs nine liang and two zhu, measures nine cun in length and width, holds nine sheng and nine he of urine, and its opening is two and a half cun wide (Figure 56).
The Foot-Taiyang Bladder Meridian originates at the inner canthus of the eye, ascends to the forehead, and intersects at the vertex;
Its main straight branch enters from the vertex to connect with the brain, then emerges again to descend separately along the nape, follows the scapular region, runs parallel to the spine on both sides, reaches the middle of the waist,
enters the deep muscles of the back (Lu), connects with the Kidneys, and belongs to the Bladder;
Another straight branch descends from the middle of the waist, running parallel to the spine on both sides, passes through the buttocks, and enters the popliteal fossa;
A branch separates from the left and right sides of the scapular region, descends through the shoulder blade, runs parallel to the spine, passes medially through the hip joint (Bi Shu), follows the posterior-lateral aspect of the thigh, and merges with the main channel in the popliteal fossa,
continues downward through the calf muscle, emerges posterior to the lateral malleolus, follows the Jinggu point, and terminates at the lateral side of the little toe (see Figure 57).
The Foot-Taiyang Bladder Meridian originates at the inner canthus and ascends to the tip of the forehead; a branch ascends to the vertex and reaches the ear angle, while the straight branch descends from the vertex behind the head,
connects with the brain, emerges again to descend to the nape, still follows the scapula and runs parallel to the spine, reaching the lumbar paraspinal muscles, Kidneys, and interior of the Bladder, with one branch connecting downward to the genital and anal regions.
Passing through the buttocks, it obliquely enters the Weizhong acupoint; another branch separates from the medial arm, passes through the scapula, runs parallel to the spine, and passes through the hip joint, merging in the popliteal fossa along the posterior-medial aspect of the arm,
descends through the calf, posterior to the medial and lateral malleoli, passes below the Jinggu bone to the lateral side of the little toe.
Notes: [1] The Foot-Taiyang Bladder Meridian originates at the Jingming (BL1) acupoint at the inner canthus. From Jingming, it travels through Zanzhu (BL2) and Qucha (BL8),
ascends to the forehead and intersects at the vertex, enters Chengguang (BL9), and from Chengguang travels through Tongtian (BL7).
[2] Its branch extends from the vertex to the upper angle of the ear, intersecting with the Foot-Shaoyang Gallbladder Meridian.
[3] The main straight branch enters from Tongtian to connect with Dazhu (BL11). From Dazhu, it travels through Fengmen (BL12) in the medial scapular region,
from Fengmen travels through Feishu (BL13), runs parallel to the spine to reach Jueyinshu (BL14) in the middle of the waist. From Jueyinshu, it travels through Xinshu (BL15),
Geshushu (BL17), Ganshushu (BL18), Danshushu (BL19), Pishushu (BL20), Weishushu (BL21), and Sanjiaoshu (BL22), enters the deep muscles of the back to connect with the Kidneys,
from Shenshu (BL23) travels through Qihai Shu (BL24), descends from the waist parallel to the spine to Dachangshu (BL25). From Dachangshu, it travels through Guanyuan Shu (BL26),
Pangguang Shu (BL28), Zhonglü Shu (BL29), Baihuanshu (BL30), etc. Another path passes through Shangliao (BL31), Ciliao (BL32), Zhongliao (BL33), and Xialiao (BL34).
[4] A branch ascends again to the medial scapular region, traveling from Fufen (BL17) through Gehu (BL46) penetrating the scapula,
from Gehu travels through Gaohuang (BL43), Shen Tang (BL44), Yixi (BL45), Ge Guan (BL47), Hun Men (BL47 - *Note: standard numbering may vary, text implies sequence*), Yang Gang (BL48), Yi She (BL49), Wei Cang (BL50),
Huang Men (BL51), Zhi Shi (BL52), Baohuang (BL53), passing through the hip joint at Zhibian (BL54). From Zhibian, it follows the posterior-lateral aspect of the thigh through Chengfu (BL36),
Fupi (BL38), and Weiyang (BL39), merging downward into the popliteal fossa at Weizhong (BL40). From Weizhong, it travels through Heyang (BL57),
descends through the calf interior to Chengjin (BL56), from Chengjin travels through Chengshan (BL58), Feiyang (BL59), and Fuyang (BL60),
from Fuyang emerges posterior to the lateral malleolus at Kunlun (BL60), from Kunlun travels through Pucan (BL61), Shenmai (BL62), and Jinmen (BL63),
reaching Jinggu (BL64), which is the Jinggu acupoint of this meridian.
[5] From Jinggu, it travels through Shugu (BL65) and Tonggu (BL66), terminating at Zhiyin (BL67) on the lateral side of the little toe,
thereby intersecting with the Foot-Shaoyin Kidney Meridian.