黄帝问于伯高曰。脉度言经脉之长短。何以立之。伯高曰。先度其骨节之大小广狭长短。而脉
度定矣。（脉度叶肚先度叶铎）
此言经脉之长短。从骨节之大小广狭长短。而定其度数。故曰骨为干。脉为营。如藤蔓之营附
于木干也。
黄帝曰。愿闻众人之度。人长七尺五寸者。其骨节之大小长短各几何。伯高曰。头之大骨。围
二尺六寸。
此言头之大骨度数。众人。谓天下之大众。长七尺五寸者。上古适中之人也。适中之人。则头
骨亦适中矣。头骨适中。通体之骨皆适中矣。
胸围四尺五寸。腰围四尺二寸。
此胸骨腰骨。围转一周之总数也。
发所覆者。颅至项尺二寸。发以下至颐。长一尺。君子终折。
此言头颅前后上下之骨度。发所覆者。谓从前额颅之发际。上至巅顶。以至后项之发际。计发
所覆者。度一尺二寸。发以下至颐者。谓从前额颅之发际。以下至于两颐。计长一尺。君子终折者。
谓从发际之始。以至发际之终。可折中而度量。盖君子之人。面方广而发际高。发所覆者。从颅至
项度一尺一寸。发以下至颐长一尺一寸也。此言天下之众。有君子小人不同。有太过不及不等。
结喉以下至缺盆中长四寸。缺盆以下至 长九寸。过则肺大。不满则肺小。 以下至天枢
长八寸。过则胃大。不及则胃小。天枢以下至横骨长六寸半。过则回肠广长。不满则狭短。横骨长
六寸半。横骨上廉以下至内辅之上廉长一尺八寸。内辅之上廉以下至下廉长三寸半。内辅下廉下至
内踝长一尺三寸。内踝以下至地长三寸。膝 以下至跗属长一尺六寸。跗属以下至地长三寸。故骨
围大则太过。小则不及。（ 音吉 叶 踝叶瓦去声）
此仰面之骨度也。结喉下两旁巨骨陷中为缺盆。盖形如缺盆。因以为名。 。骨名。一名尾
翳。即鸠尾骨也。自两旁缺盆而下至 。计长九寸。过则肺大。不满则肺小。盖 之内。心肺
之所居也。天枢在脐旁二寸。乃足阳明之穴。从两旁 而下至天枢。计长八寸。过则胃大。不及
则胃小。盖自鸠尾以至于脐。胃腑之所居也。横骨在毛际横纹中。自天枢而下至于横骨。计长六寸
半。过则回肠广大。不满则狭短。盖自脐以至少腹。大肠之部分也。横骨横长亦六寸半。内辅者。
内之辅骨也。内辅之上廉。长一尺八寸者。在上之腿度也。内辅之上廉。以下至下廉长三寸半者。
膝之连骸。一名膝盖骨也。内辅下廉。下至内踝长一尺三寸者。在下之腿度也。曰内辅内踝者。以
足八字分立。则内骨偏向于面也。踝者。下廉之腿骨。与足骨相连之凹处。在内者为内踝。在外者
为外踝。内踝以下至地长三寸者。足跟骨也。膝 者。膝前下之腿骨。跗者。足面上之跗骨。即
足阳明之动脉处。自膝前而下至于跗面。计长一尺六寸也。属者。概足面而言也。跗属以下至地
长三寸者。从足面而下至足底之骨也。骨围大者。骨之粗大也。小者。骨之细小也。
角以下至柱骨长一尺。行腹中不见者长四寸。腋以下至季胁长一尺二寸。季胁以下至髀枢长六寸。
髀枢以下至膝中长一尺九寸。膝以下至外踝长一尺六寸。外踝以下至京骨长三寸。京骨以下至地
长一寸。
此侧身之骨度。皆纵而数之也。耳上之旁为角。肩胛上之颈骨为柱骨。自角以下至柱骨长一尺。
肋下 内为腋。自柱骨至腋中计长四寸。胁骨之下为季胁。自腋以下至季胁。计长一尺二寸。捷骨
之下为髀枢。一名髀厌。在臀之两旁。即足少阳之环跳穴处。自季胁以下至髀枢。计长六寸。髀枢
以下至膝盖骨内之中分。计长一尺九寸。即上之腿数也。膝以下至外踝长一尺六寸。即下之腿数也。
京骨。足太阳膀胱经穴名。在足外侧大骨下。赤白肉际陷中。外踝骨以下至京骨长三寸。京骨以下
至地长一寸。此侧身之骨度也。按、胁骨名扁骨。横于胁下。有渗理而无髓空。此节不度胁骨之长
短。而只以腋下至季胁长一尺二寸者。盖以形身之度数。概皮肉脉骨而量其长短。经脉循骨度而直
行于上下也。耳后当完骨者。广九寸。耳前当耳门者。广一尺三寸。两颧之间。相去七寸。
此头侧之横度也。耳后高骨为完骨。入发际四分。广者横阔也。耳后当完骨者。从耳以至于
脑后也。耳前当耳门者。从耳而至于鼻准也。此头侧之横度也。两颧之间。相去七寸者。此当面之
横度也。按、手足少阳阳明之脉。纵横经络于头面左右。故复度头面之广数。两乳之间。广九寸半。
此形身前面之横度也。
两髀之间。广六寸半。
此形身背面之横度也。
足长一尺二寸。广四寸半。
此两足之纵横数也。
肩至肘长一尺七寸。肘至腕长一尺二寸半。腕至中指本节长四寸。本节至节其末长四寸半。
此两臂两手之骨度也。本节者。指掌交接之骨节。末者。指尖也。
头发以下至背骨长二寸半。膂骨以下至尾 二十一节长三尺。上节长一寸四分分之一。奇分在
下。故上七节至于膂骨。九寸八分分之七。（ 叶底）
此脊背之骨度也。项发以下至背骨者。自顶后之发际。至背骨之大椎。计长二寸五分。膂骨。
脊骨也。自背骨之大椎。循膂骨以下至于尾 。计二十一节。共长三尺。上节每节长一寸四分一厘。
其奇分之九厘。在下节计算。故膂骨以上。计有七节。每节长一寸四分一厘。则七得七寸。四七二
寸八分。共九寸八分。又每节一厘。共计九寸八分七厘。故曰九寸八分分之七也。玉师问曰。
脊椎二十一节。只详论上七节之度数何也。曰。七节之旁。乃膈俞也。脏腑之气。皆从内膈而出。
如逆伤脏气则死。刺伤腑气。皆为伤中。故曰七节之旁。中有小心。而本经论五脏之背俞。亦兼论
七节之膈俞。不可妄刺者也。
此众人骨之度也。所以立经脉之长短也。是故视其经脉之在于身也。其见浮而坚。其见明而大
者多血。细而沉者多气也。
此总结骨之度数。定经脉之长短也。经脉之浮而坚。明而大者多血。细而沉者多气。此篇论骨
气而结经脉之血气者。血脉资始于肾。骨之精气盛。则经脉之血气亦盛矣。尚御公曰。肾藏精气
而主骨。血者。神气也。此六篇论筋骨血脉。本于少阴之阴阳。张开之曰。肾藏之精液。奉心神
化赤而为血。气者。精气也。故浮为阳而主血。沉为阴而主气。
黄帝向伯高问道：《脉度》篇中论述了经脉的长短，依据什么标准来确定呢？伯高回答说：首先测量人体骨节的大小、宽窄、长短，那么经脉的长度就确定了。（“度”音duó，意为测量；“叶”为古音韵助词，此处指读音关联）
这段文字说明，经脉的长短是根据骨节的大小、宽窄、长短来确定的。所以说，骨骼是主干，经脉是营气运行的通道，就像藤蔓依附于树木的主干一样。
黄帝说：我希望了解普通人的身体尺度。身高七尺五寸的人，其各个骨节的大小和长度各是多少？伯高回答说：头部大骨（指头围最大的部位）的周长是二尺六寸。
这里讲述的是头部大骨的尺度。“众人”指的是天下的普通人。身高七尺五寸的人是上古时期中等身材的人。中等身材的人，其头骨也是适中的。头骨适中，全身骨骼也就都适中了。
胸部周长四尺五寸，腰部周长四尺二寸。
这是指胸骨和腰骨环绕一周的总长度。
头发覆盖的范围，从颅顶到后项部为一尺二寸；从前额发际线以下至下巴颏，长一尺。对于君子（指面容方正、发际较高的人），最终取折中值。
这里讲述的是头颅前后上下的骨度。“头发覆盖的范围”，是指从前额头发的边缘，向上至头顶，再向后项部的头发边缘，计算头发所覆盖的区域，长度为二尺二寸。“发以下至颐”，是指从前额发际线向下至两侧脸颊下颌处，长度为一尺。“君子终折”，是指从发际线的起始到发际线的终结，可以取中间值进行度量。大概君子的脸型方正宽阔且发际线较高，其头发覆盖范围从颅顶到后项为一尺一寸，发际线以下至下巴为一尺一寸。这里指出天下之人有君子和小人之别，体型有太过和不足的不等差异。
喉结下方至缺盆穴（锁骨上窝中央凹陷处）长四寸；缺盆穴下方至鸠尾骨（剑突）长九寸。如果超过这个尺寸，则肺脏偏大；不足这个尺寸，则肺脏偏小。鸠尾骨下方至天枢穴（脐旁两寸）长八寸。如果超过这个尺寸，则胃脏偏大；不足则胃脏偏小。天枢穴下方至横骨（耻骨联合上缘）长六寸半。如果超过这个尺寸，则回肠宽大且长；不足则狭短。横骨本身的长度也是六寸半。从横骨上缘向内辅骨（胫骨内侧髁）上缘长一尺八寸；内辅骨上缘至下缘长三寸半；内辅骨下缘至内踝长一尺三寸；内踝下方至地面长三寸；膝腘窝下方至足背连接处长一尺六寸；足背连接处下方至地面长三寸。所以，骨骼围度大则为太过，小则为不及。（“ ”音jí，同“髌”，即膝盖骨；“叶”为古音韵助词，此处指读音关联“踝”、“瓦”去声）
这是仰卧面测量的骨度。喉结下方的两旁，巨骨陷中的位置称为缺盆，因其形状像缺口的盆而得名。“ ”是骨名，又名尾翳，即鸠尾骨。从两旁缺盆向下至鸠尾骨，计长九寸。超过则肺大，不足则肺小。因为鸠尾骨内部是心肺所在之处。天枢穴位于脐旁两寸，属于足阳明胃经穴位。从两旁鸠尾骨向下至天枢穴，计长八寸。超过则胃大，不足则胃小。因为从鸠尾骨到脐部是胃腑所在之处。横骨位于阴毛际的横纹中，从天枢穴向下至横骨，计长六寸半。超过则回肠广大，不足则狭短。因为从脐部到小腹是大肠的部分区域。横骨横向长度也是六寸半。“内辅”是指内侧的辅骨。内辅骨上缘长一尺八寸，这是大腿上部的长度。内辅骨上缘至下缘长三寸半，这是连接膝盖的部位，又名膝盖骨（髌骨）。内辅骨下缘至内踝长一尺三寸，这是小腿下部的长度。之所以称为内辅和内踝，是因为当双脚呈八字形分立时，内侧骨骼偏向面部方向。“踝”是指小腿下段骨头与足骨相连的凹陷处，在内侧的为内踝，在外侧的为外踝。内踝下方至地面长三寸，这是足跟骨。膝前下方的腿骨称为 ，足面上的骨头称为跗骨，也就是足阳明经动脉搏动处。从膝前向下至足背，计长一尺六寸。“属”泛指足面。足背下方至地面长三寸，这是从足面向下到足底的骨头。骨骼围度大的，表示骨骼粗壮；小的，表示骨骼细小。
耳角上方至柱骨（第七颈椎棘突）长一尺；在腹中行走不可见的部分长四寸；腋下至季胁（第十二肋骨末端）长一尺二寸；季胁下方至髀枢（股骨大转子）长六寸；髀枢下方至膝中（膝关节中部）长一尺九寸；膝下方至外踝长一尺六寸；外踝下方至京骨（足外侧第五跖骨粗隆）长三寸；京骨下方至地面长一寸。
这是侧面测量的骨度，都是纵向计数的。耳朵上方的旁侧为角，肩胛上方的颈骨为柱骨。从角下方至柱骨长一尺。肋下内侧为腋，从柱骨至腋中计长四寸。肋骨之下为季胁，从腋下至季胁计长一尺二寸。捷骨（髋关节）之下为髀枢，又名髀厌，位于臀部两旁，即足少阳胆经环跳穴处。从季胁下方至髀枢计长六寸。髀枢下方至膝盖骨内侧的中分处，计长一尺九寸，这是大腿上部的长度。膝下方至外踝长一尺六寸，这是小腿下部的长度。京骨是足太阳膀胱经的穴位名，位于足外侧大骨下，赤白肉际的凹陷中。外踝骨下方至京骨长三寸，京骨下方至地面长一寸。这是侧面测量的骨度。按：胁骨名为扁骨，横置于胁下，有纹理而无骨髓空腔。这一节不测量胁骨本身的长短，而只以腋下至季胁长一尺二寸来计算，这是因为根据身形尺度，概略测量皮、肉、脉、骨的长短，经脉沿着骨度直行于上下之间。耳后正当完骨（乳突）处，宽度为九寸；耳前正当耳门处，宽度为一尺三寸；两颧骨之间，相距七寸。
这是头部侧面的横向尺度。耳后的高骨为完骨，深入发际四分。“广”指横向宽度。耳后正当完骨处，是从耳朵直到脑后。耳前正当耳门处，是从耳朵直到鼻准。这是头部侧面的横向尺度。两颧之间相距七寸，这是面部的横向尺度。按：手足少阳、阳明经脉纵横交错分布于头面左右，所以再次测量头面的宽度。两乳头之间，宽度为九寸半。
这是身体前面的横向尺度。
两髀（大腿根部/胯部）之间，宽度为六寸半。
这是身体背面的横向尺度。
足长一尺二寸，宽四寸半。
这是双足的纵向和横向数值。
肩部至肘部长一尺七寸，肘部至腕部长一尺二寸半，腕部至中指本节（掌指关节）长四寸，本节至指尖长四寸半。
这是双臂双手的骨度。本节是指手指与手掌交接的骨节，末是指指尖。
头发以下至背骨（大椎穴处）长二寸半；脊骨（膂骨）以下至尾骨二十一节长三尺。每节长一寸四分又四分之一分，奇数部分在下节计算。所以上七节至膂骨，共长九寸八分又七分之七。（“ ”音dǐ，同“底”）
这是脊背的骨度。项部发际以下至背骨，是从头顶后方发际线至背部的大椎穴，计长二寸五分。膂骨即脊骨。从背骨的大椎穴沿脊骨向下至尾骨，共计二十一节，总长三尺。上节每节长一寸四分一厘，其奇分的九厘在下节计算。所以膂骨以上，计有七节，每节长一寸四分一厘，则七节得七寸，四七二寸八分，共九寸八分。加上每节的一厘，共计九寸八分七厘，所以说“九寸八分分之七”。玉师问道：脊椎二十一节，为什么只详细论述上七节的尺度呢？回答说：七节旁边，是膈俞穴所在。脏腑之气，都从内膈而出。如果逆伤脏气则会致死，刺伤腑气，都属于伤及中焦。所以说“七节之旁，中有小心”。而且本经在论述五脏的背俞穴时，也兼论了七节处的膈俞穴，不可随意针刺。
这是普通人的骨骼尺度。用来确立经脉的长短。因此，观察人身上的经脉，如果显现出浮起而坚实、明亮而粗大的，说明多血；显现出细弱而沉隐的，说明多气。
这是总结骨骼的尺度，以确定经脉的长短。经脉显现浮起而坚实、明亮而粗大的，说明多血；细弱而沉隐的，说明多气。本篇论述骨气，最后归结于经脉的血气。血脉起源于肾，骨骼的精气旺盛，则经脉的血气也旺盛。尚御公说：肾藏精气而主司骨骼。血，是神气的表现。这六篇论述筋骨血脉，根本在于少阴经的阴阳。张开之说：肾所藏的津液，奉心神化赤而为血。气，是精气。所以浮象属阳而主血，沉象属阴而主气。
Huangdi asked Bo Gao, "The *Mai Du* (Measure of Vessels) chapter discusses the lengths of the meridians. On what basis are these measurements established?" Bo Gao replied, "First measure the size, width, and length of the bone joints, and then the lengths of the vessels will be determined." (*Du* means to measure; *Ye* is an ancient phonetic particle).
This passage explains that the lengths of the meridians are determined by the size, width, and length of the bone joints. Therefore, it is said that bones are the trunk, and the vessels are the channels through which Ying Qi (Nutritive Qi) circulates, much like vines attaching themselves to the trunk of a tree.
Huangdi said, "I wish to hear about the body measurements of ordinary people. For a person who is seven chi five cun tall, what are the sizes and lengths of their various bone joints?" Bo Gao replied, "The circumference of the largest part of the skull is two chi six cun."
This describes the measurement of the skull. "Ordinary people" refers to the general population. A height of seven chi five cun represents the average stature in ancient times. For those of average stature, the skull is also average. If the skull is average, the bones of the entire body are average.
The chest circumference is four chi five cun, and the waist circumference is four chi two cun.
These figures represent the total circumference around the chest and lumbar vertebrae.
The area covered by hair, from the top of the skull to the nape of the neck, measures one chi two cun. From the anterior hairline down to the chin, the length is one chi. For gentlemen (those with square faces and high hairlines), a median value is taken.
This describes the anterior-posterior and superior-inferior dimensions of the skull. "The area covered by hair" refers to the region from the anterior hairline, up to the vertex, and back to the posterior hairline at the nape, measuring one chi two cun. "From the hairline down to the chin" refers to the distance from the anterior hairline to the mandibular angles on both sides, measuring one chi. "Gentlemen take the median" means that for individuals with high hairlines, the measurement from the start to the end of the hairline can be averaged. Typically, for such individuals, the hair-covered area from the skull to the nape is one chi one cun, and the area from the hairline to the chin is also one chi one cun. This indicates that among the population, there are differences between gentlemen and commoners, and variations ranging from excess to deficiency.
From the laryngeal prominence below to the Quepen (Locket Basin, central depression of the supraclavicular fossa) is four cun. From Quepen below to the Jiuwei (Tail Shield, xiphoid process) is nine cun. If this exceeds the standard, the lungs are large; if it is less, the lungs are small. From Jiuwei below to the Tianshu (Heavenly Pivot, 2 cun lateral to the umbilicus) is eight cun. If this exceeds the standard, the stomach is large; if it is less, the stomach is small. From Tianshu below to the Henggu (Horizontal Bone, upper border of the pubic symphysis) is six and a half cun. If this exceeds the standard, the ileum is wide and long; if it is less, it is narrow and short. The Henggu itself is six and a half cun long. From the upper border of the Henggu to the upper border of the Neifu (Inner Accessory Bone, medial condyle of the tibia) is one chi eight cun. From the upper border of the Neifu to its lower border is three and a half cun. From the lower border of the Neifu to the medial malleolus is one chi three cun. From below the medial malleolus to the ground is three cun. From below the popliteal fossa to the dorsum-foot junction is one chi six cun. From the dorsum-foot junction to the ground is three cun. Therefore, if the bone circumference is large, it indicates excess; if small, it indicates deficiency. (*Ji* sounds like 'patella'; *Ye* is an ancient phonetic particle).
This describes the bone measurements taken while supine. The depressions on either side of the laryngeal prominence, near the clavicle, are called Quepen because their shape resembles a basin with a missing section. The *Jiuwei* is a bone name, also known as Wei Yi, referring to the xiphoid process. From the bilateral Quepen down to the Jiuwei measures nine cun. Excess implies large lungs; deficiency implies small lungs, as this internal area houses the heart and lungs. Tianshu is located two cun lateral to the umbilicus and belongs to the Foot-Yangming Stomach Meridian. From the bilateral Jiuwei down to Tianshu measures eight cun. Excess implies a large stomach; deficiency implies a small stomach, as this region from the xiphoid to the umbilicus houses the stomach organ. The Henggu is located in the transverse crease of the pubic hair line. From Tianshu down to the Henggu measures six and a half cun. Excess implies a wide ileum; deficiency implies a narrow one, as this region from the umbilicus to the lower abdomen corresponds to the large intestine. The transverse length of the Henggu is also six and a half cun. "Neifu" refers to the accessory bone on the medial side. The upper border of the Neifu being one chi eight cun long refers to the upper leg measurement. The distance from the upper to the lower border of the Neifu is three and a half cun, referring to the knee connection, also known as the patella. The distance from the lower border of the Neifu to the medial malleolus is one chi three cun, referring to the lower leg measurement. They are called Neifu and medial malleolus because when the feet stand in a splayed position, the inner bones face inward. The "malleolus" refers to the concave area where the lower leg bone connects with the foot bone; the inner one is the medial malleolus, and the outer one is the lateral malleolus. The distance from below the medial malleolus to the ground is three cun, representing the calcaneus. The bone below the knee is referred to as *Xi*, and the bone on the dorsum of the foot is the tarsal bone, specifically the site of the Foot-Yangming artery pulse. From the front of the knee down to the dorsum measures one chi six cun. "Shu" generally refers to the dorsum of the foot. The distance from the dorsum to the ground is three cun, representing the bones from the dorsum down to the sole. Large bone circumference indicates robust bones; small indicates slender bones.
From the ear angle above to the Zhugu (Pillar Bone, spinous process of C7) is one chi. The portion running within the abdomen and not visible is four cun. From the axilla to the Ji Xie (Seasonal Costal Margin, end of the 12th rib) is one chi two cun. From the Ji Xie to the Bitshu (Hip Pivot, greater trochanter of the femur) is six cun. From the Bitshu to the middle of the knee is one chi nine cun. From the knee to the lateral malleolus is one chi six cun. From the lateral malleolus to the Jinggu (Capital Bone, tuberosity of the fifth metatarsal) is three cun. From the Jinggu to the ground is one cun.
This describes the bone measurements taken from the side, counted longitudinally. The side above the ear is the angle; the cervical bone above the scapula is the Zhugu. From the angle below to the Zhugu measures one chi. The interior of the ribs below the armpit is the axilla. From the Zhugu to the center of the axilla measures four cun. Below the rib cage is the Ji Xie. From the axilla to the Ji Xie measures one chi two cun. Below the Jiegǔ (hip joint) is the Bitshu, also known as Biyan, located on both sides of the buttocks, corresponding to the Huantiao point of the Foot-Shaoyang Gallbladder Meridian. From the Ji Xie to the Bitshu measures six cun. From the Bitshu to the mid-point of the inner side of the patella measures one chi nine cun, which is the upper leg measurement. From the knee to the lateral malleolus is one chi six cun, which is the lower leg measurement. Jinggu is a point name in the Foot-Taiyang Bladder Meridian, located in the depression between red and white flesh below the large bone on the lateral side of the foot. From the lateral malleolus to the Jinggu is three cun; from the Jinggu to the ground is one cun. This is the lateral bone measurement. Note: The costal bones are flat bones lying horizontally under the ribs, having texture but no marrow cavity. This section does not measure the length of the costal bones themselves but uses the distance from the axilla to the Ji Xie (one chi two cun) as a proxy. This is because body measurements generally assess the skin, flesh, vessels, and bones together, with meridians running vertically along the bone structures. Behind the ear, at the Wangu (Complete Bone, mastoid process), the width is nine cun. In front of the ear, at the Ermen (Ear Gate), the width is one chi three cun. Between the two zygomatic arches, the distance is seven cun.
This describes the horizontal dimensions of the side of the head. The high bone behind the ear is the Wangu, extending four fen into the hairline. "Guang" refers to transverse width. "Behind the ear at the Wangu" extends from the ear to the back of the head. "In front of the ear at the Ermen" extends from the ear to the tip of the nose. This is the horizontal dimension of the side of the head. The distance between the two zygomatic arches is seven cun, which is the horizontal dimension of the face. Note: The meridians of the Hand and Foot Shaoyang and Yangming traverse the head and face horizontally and vertically, so the width of the head and face is measured again. The distance between the two nipples is nine and a half cun.
This is the horizontal dimension of the anterior body.
The distance between the two thighs (groin) is six and a half cun.
This is the horizontal dimension of the posterior body.
The foot is one chi two cun long and four and a half cun wide.
These are the longitudinal and transverse measurements of the feet.
From the shoulder to the elbow is one chi seven cun. From the elbow to the wrist is one chi two and a half cun. From the wrist to the root knuckle of the middle finger is four cun. From the root knuckle to the fingertip is four and a half cun.
These are the bone measurements of the arms and hands. The "root knuckle" refers to the joint connecting the finger and palm; the "tip" refers to the fingertip.
From below the hairline to the back bone (Dazhui) is two and a half cun. From the Lügu (Spinal Bone) down to the twenty-one segments of the coccyx is three chi. Each segment is one cun four fen and one-quarter fen long, with the fractional part calculated in the lower segment. Thus, the upper seven segments up to the Lügu measure nine cun eight fen and seven-eighths of a fen. (*Di* sounds like 'bottom').
This describes the bone measurements of the spine and back. From the posterior hairline to the back bone (Dazhui point) measures two cun five fen. The Lügu is the spinal column. From the Dazhui along the spine down to the coccyx comprises twenty-one segments, totaling three chi. Each upper segment is one cun four fen one li long. The remaining nine li of the fraction are calculated in the lowest segment. Therefore, above the Lügu, there are seven segments. At one cun four fen one li per segment, seven segments yield seven cun. Four times seven yields two cun eight fen, totaling nine cun eight fen. Adding one li per segment totals nine cun eight fen seven li. Hence, it is stated as "nine cun eight fen and seven-eighths." Master Yu asked, "Why are only the upper seven segments detailed among the twenty-one vertebral segments?" The answer is, "Beside the seventh segment lies the Ge Shu (Diaphragm Shu) point. The Qi of the zang and fu organs emerges from the internal diaphragm. Injury to Zang Qi from above is fatal; injury to Fu Qi is considered injury to the Middle Jiao. Therefore, it is said, 'Beside the seventh segment, there is the Small Heart.' Furthermore, this chapter discusses the Back-Shu points of the Five Zang organs and also mentions the Diaphragm Shu at the seventh segment, which must not be needled recklessly."
These are the bone measurements of ordinary people, used to establish the lengths of the meridians. Therefore, observing the meridians in the body: those that appear floating, firm, bright, and large indicate abundant Blood; those that appear thin and deep indicate abundant Qi.
This summarizes the bone measurements to determine meridian lengths. Meridians appearing floating, firm, bright, and large indicate abundant Blood; those thin and deep indicate abundant Qi. This chapter discusses Bone Qi and concludes with the Blood and Qi of the meridians. Blood vessels originate from the Kidney; when the essence and Qi of the bones are vigorous, the Blood and Qi of the meridians are also vigorous. Shang Yugong said, "The Kidneys store Essence and govern the bones. Blood is the manifestation of Shen Qi." These six chapters discuss tendons, bones, blood, and vessels, rooted in the Yin and Yang of the Shaoyin channel. Zhang Kaizhi stated, "The fluids stored in the Kidneys are transformed by the Heart Spirit into red Blood. Qi is Essence. Therefore, floating indicates Yang and governs Blood; sinking indicates Yin and governs Qi."