大则应指满溢，既大且长，按似少力。凡浮芤洪长，皆属大类。不似长脉但长不大，洪脉既大且
数也。（张璐）大有虚实阴阳之异，不可一律。如见大而有力，则为阳气有余，其病则进；大而无力，则为正
气不足。大偏于左，则为邪盛于经；大偏于右，则为热盛于阴。大而兼涩兼芤，则为血不内营；大而兼实兼沉，
则为实热内炽。大而浮紧，则为病甚于外；大而沉短，则为痞塞于内。大实而缓，虽剧且生；大实而迫，虽静
即死。故凡脉大，必得症与脉应，方云无碍。若使久虚而见脉大，利后而见脉大，喘止而见脉大，产后而见脉
大，皆为不治之症矣。（张璐曰∶诸脉皆小，中有一部独大者，诸脉皆大，中有一部独小者，便以其部断其病
之虚实。）
小则三部皆小，而指下显然。凡微细短弱，
皆属小类。不似微脉之微弱依稀，细脉之微细如发，弱脉之软弱不前，（按之乃得）短脉之首尾不及也（张璐）
。小为元气不足，及病已退之势，如因病损小，其脉兼弱，见于人迎，则为胃气衰也；见于气口，则为肺气弱也；
见于寸口，则为阳不足也；见于尺内，则为阴不足也；此皆无力之象。若使小而有力，脉兼滑实，则为实热
固结。然脉不至急强，四肢不逆，犹云胃气之未绝。若胃气既无，生气已失，其奚济乎。（经曰∶切其脉口滑
小紧益沉者，病益甚在中。又曰∶温病大热而脉反细小，手足逆者死。显微曰∶前大后小，则头痛目眩；前小
后大，则胸满短气。）
大脉表现为搏动充实满溢，既宽大又长，重按时感觉力量稍显不足。凡是浮脉、芤脉、洪脉、长脉，都属于大脉这一类。它们不像单纯的长脉那样仅长而不宽大，也不像洪脉那样既宽大又快速。（张璐）大脉有虚证和实证、阴证和阳证的区别，不能一概而论。如果脉象大而有力，说明阳气有余，病情正在进展；如果脉象大而无力，说明正气不足。脉象偏于左手（寸关尺），说明邪气盛于经络；脉象偏于右手，说明热邪盛于阴分。脉象大且兼见涩脉或芤脉，说明血液不能内养脏腑；脉象大且兼见实脉或沉脉，说明实热在体内炽盛。脉象大且浮紧，说明病邪严重在体表；脉象大且沉短，说明气机痞塞在体内。脉象大实而缓，虽然病情剧烈但有生机；脉象大实而急迫，虽然表面安静但预后死亡。所以凡是遇到大脉，必须症状与脉象相应，才能说没有危险。如果是久病体虚却出现大脉，泻下后出现大脉，喘息停止后出现大脉，产后出现大脉，都是不治之症了。（张璐说：各种脉象都小，其中有一部独大的，各种脉象都大，其中有一部独小的，就根据该部位来判断疾病的虚实。）
小脉表现为寸、关、尺三部脉象都细小，指下感觉明显。凡是微脉、细脉、短脉、弱脉，都属于小脉这一类。它们不像微脉那样微弱隐约，不像细脉那样细微如发丝，不像弱脉那样软弱无力且需重按才得，也不像短脉那样首尾不及本位。（张璐）小脉代表元气不足，以及疾病即将消退的趋势。如果因病导致脉小，且脉象兼见弱脉，出现在人迎穴部位，说明胃气衰败；出现在气口部位，说明肺气虚弱；出现在寸口部位，说明阳气不足；出现在尺内部位，说明阴气不足；这些都是无力的征象。如果脉象小而有力，且兼见滑脉或实脉，说明是实热固结。然而只要脉象不急促强劲，四肢没有逆冷，还可以说是胃气未绝。如果胃气已经消失，生气已经丧失，那又能有什么帮助呢？（《内经》说：切诊脉口，如果脉象滑小紧益沉，说明病邪加重且在体内。又说：温病高热却脉象反而细小，手足逆冷的，预后死亡。显微说：前大后小，则头痛目眩；前小后大，则胸满短气。）
The Da (Large) pulse manifests as full and overflowing under the fingers, being both large and long, yet feeling slightly weak upon deep pressure. The Fu (Floating), Kou (Hollow), Hong (Surging), and Chang (Long) pulses all belong to this category of Da pulses. They differ from the Chang pulse, which is merely long without being large, and from the Hong pulse, which is both large and rapid. (Zhang Lu) The Da pulse presents differences between deficiency and excess, yin and yang, and cannot be generalized. If the pulse is large and forceful, it indicates an excess of Yang Qi, suggesting the disease is progressing; if it is large but forceless, it indicates a deficiency of Zheng Qi (Upright Qi). A Da pulse biased towards the left suggests pathogenic excess in the meridians; a Da pulse biased towards the right suggests heat excess in the Yin. A Da pulse accompanied by Se (Choppy) or Kou (Hollow) pulses indicates that Blood fails to nourish internally; a Da pulse accompanied by Shi (Excess) or Chen (Deep) pulses indicates blazing internal Excess-Heat. A Da pulse with Fu-Jin (Floating-Tight) characteristics indicates severe external pathology; a Da pulse with Chen-Duan (Deep-Short) characteristics indicates internal obstruction/stagnation. A Da-Shi (Large-Excess) pulse that is Huan (Slow) indicates虽有剧疾仍有生机 (severe condition but with potential for survival); a Da-Shi pulse that is Po (Rapid/Impetuous) indicates虽静即死 (apparent calm but impending death). Therefore, whenever a Da pulse is observed, symptoms must correspond with the pulse to rule out danger. If a Da pulse appears after prolonged deficiency, after purgation, after the cessation of wheezing, or postpartum, these are all signs of untreatable conditions. (Zhang Lu stated: Among various small pulses, if one position is uniquely large; among various large pulses, if one position is uniquely small, diagnose the deficiency or excess of the disease based on that specific position.)
The Xiao (Small) pulse manifests as smallness across all three positions (Cun, Guan, Chi), clearly perceptible under the fingers. The Wei (Minute), Xi (Fine), Duan (Short), and Ruo (Weak) pulses all belong to this category of Xiao pulses. They differ from the Wei pulse, which is faint and indistinct; from the Xi pulse, which is minute like a hair; from the Ruo pulse, which is soft and weak, requiring deep pressure to feel; and from the Duan pulse, which does not extend to its beginning and end. (Zhang Lu) The Xiao pulse signifies insufficiency of Yuan Qi (Original Qi) and the trend of disease receding. If the pulse becomes small due to illness damage and is accompanied by weakness, appearing at the Renying point, it indicates decline of Stomach Qi; appearing at the Qikou point, it indicates weakness of Lung Qi; appearing at the Cun Kou point, it indicates insufficiency of Yang; appearing at the Chi Nei area, it indicates insufficiency of Yin. These are all manifestations of forcelessness. However, if the pulse is small yet forceful, and accompanied by Hua (Slippery) or Shi (Excess) qualities, it indicates solidified Excess-Heat. Nevertheless, as long as the pulse is not urgent and strong, and the limbs are not cold/reversed, it can still be said that Stomach Qi has not perished. If Stomach Qi is gone and Sheng Qi (Vital Qi) is lost, what help can there be? (The Classic states: Palpating the Mai Kou, if the pulse is Slippery, Small, Tight, and increasingly Deep, the disease worsens and resides in the interior. It also states: In Warm Disease with high fever, if the pulse is unexpectedly small and fine, and the hands and feet are reversed/cold, death ensues. Xianwei stated: Large anteriorly and small posteriorly leads to headache and vertigo; small anteriorly and large posteriorly leads to chest fullness and shortness of breath.)