脑疽之证，前言从外感受者轻，从五脏蕴结内发于外者重，兹复举而申明之。由外感发
者，多生于正中，属督脉所主。督脉起于尾闾穴，贯脊而上，气血交会，毒瓦斯得之，乃能外
发，故易于高肿溃脓，生肌收口，此为易治之证。从内发者，多生于偏旁，属太阳膀胱经所
主。太阳膀胱主司寒水，性质多沉，起于巅顶，贯项两旁，夹脊而下，此处发疽，气血与疮
毒交会下流，故疮多平塌，根脚走散，两肩漫肿，膊项难转，背如负石，难以成脓，难溃难
敛，此不易治之证。夫所谓从五脏蕴结而成者，其源有五∶心绪烦扰，煽动不宁，以致火旺
而沸腾，行于项间，与寒水交滞而为脓者一也；恼怒伤肝，项乃三阳经统筋之所，肝伤则血
脉不潮，筋无荣养，凝结为肿，故项紧急强痛，不能转侧，其患未溃前，肉色紫暗，坚硬漫
肿，破流血水，木痛无肿者二也；思虑伤脾，脾气日损，又或膏粱损胃，胃汁干枯，以致中
脘痞塞，气不营运，逆于肉里，乃生壅肿，其患外皮虽腐，内坚不溃，口燥舌干，饮食不进
，根脚走散，脓秽色散者三也；忧郁伤肺，肺伤则毛窍闭塞，腠理不通，气不舒畅，纵横经
络，结而为肿，其疮形多平陷，色淡不荣华，皮腐脂流，形如汤泼，气粗短促，鼻煤鼻 ，
漉漉生痰，殷殷发嗽者四也；恣欲伤肾，肾伤则真阴之气败，真阴一败，相火即生，此火最
能自升自降，或动或静，疮形紫黑，脉数乖度，烦躁口干，随饮随渴者五也。故云内发者重
。
外疡中脑疽为第一险证，易成易败，变化多端，故再细论之，特揭篇首。
脑疽这一病症，前文提到由外感邪气引发的较轻，由五脏蕴结、内发于外的较重，这里再次列举并加以阐明。由外感引发的，多生于头部正中，属于督脉所主司。督脉起于尾闾穴，贯穿脊柱向上，气血在此交会，毒邪得以依附，才能向外发出，所以容易高肿、溃破流脓、生肌收口，这是容易治疗的证候。由内发的，多生于头部偏侧，属于足太阳膀胱经所主司。足太阳膀胱主司寒水，性质多沉滞，经脉起于头顶，贯穿颈部两侧，夹着脊柱向下，此处发生疽病，气血与疮毒交会后向下流注，所以疮面多平塌，根脚扩散，双肩漫肿，胳膊和脖子难以转动，背部感觉像背负重物一样，难以成脓，难溃难敛，这是不容易治疗的证候。所谓由五脏蕴结而成的，其根源有五种：一是心绪烦扰，煽动心神不宁，导致火旺而沸腾，热气行于项间，与寒水交滞而化为脓，这是第一种情况；二是恼怒伤肝，颈部是三阳经统摄筋脉的地方，肝受伤则血脉不能充盈濡养，筋脉失去荣养，凝结为肿胀，所以颈部紧急强痛，不能转头，在患处在未溃破前，肉色紫暗，坚硬漫肿，破溃后流出血水，疼痛如木且无红肿，这是第二种情况；三是思虑伤脾，脾气日渐损耗，或者因过食肥甘厚味损伤胃气，导致胃中津液干枯，以致中脘部位痞塞不通，气机不能运行，逆阻于肌肉之中，从而产生壅滞肿胀，患处外皮虽然腐烂，但内部坚硬不溃，口干舌燥，饮食不进，根脚扩散，脓液污秽颜色淡散，这是第三种情况；四是忧郁伤肺，肺受伤则毛孔闭塞，腠理不通畅，气机不舒畅，纵横阻滞于经络，凝结而成肿胀，疮形多平陷，颜色淡白不荣华，皮肤腐烂脂液流出，形状像被热水泼过一样，呼吸粗重短促，鼻孔干燥或黑，鼻涕漉漉，频繁咳嗽，这是第四种情况；五是纵欲伤肾，肾受伤则真阴之气败坏，真阴一旦败坏，相火就会滋生，这种火最能自升自降，无论动静，疮形呈紫黑色，脉搏数乱失常，烦躁口干，喝水后立即又渴，这是第五种情况。所以说内发者病情严重。
在外疡中，脑疽是第一危险的证候，容易形成也容易败坏，变化多端，所以再详细论述它，特意放在篇首揭示。
The condition of Naoju (Brain Carbuncle), as mentioned previously, is mild when caused by external pathogenic factors and severe when originating internally from the accumulation and stagnation of the Five Zang organs manifesting outwardly. Here, we reiterate and clarify this point. Those arising from external infections often occur in the center of the head, governed by the Du Mai (Governing Vessel). The Du Mai originates at the Weili acupoint (Tailbone), penetrates the spine upward, where Qi and Blood intersect. When toxic pathogens attach to this intersection, they can manifest outwardly; thus, it is prone to high swelling, suppuration, tissue regeneration, and wound closure, making it an easily treatable syndrome. Those arising internally often occur on the sides of the head, governed by the Foot-Taiyang Bladder Meridian. The Foot-Taiyang Bladder governs cold water and its nature is often sinking. Its meridian starts at the vertex, passes through both sides of the neck, and descends flanking the spine. When a carbuncle develops here, Qi and Blood intersect with the sore toxin and flow downward. Consequently, the sore tends to be flat and collapsed, with spreading roots, diffuse swelling on both shoulders, difficulty turning the arms and neck, a sensation of carrying a heavy stone on the back, difficulty in forming pus, difficulty in ulcerating, and difficulty in healing. This is a difficult-to-treat syndrome.
As for those formed by internal accumulation of the Five Zang organs, there are five sources: First, mental agitation stirs the mind, causing Fire to flare up and boil. Heat travels to the neck region, stagnates with Cold Water, and transforms into pus. This is the first type. Second, anger injures the Liver. The neck is where the Three Yang meridians converge to govern the sinews. Liver injury leads to insufficient blood circulation and lack of nourishment to the sinews, resulting in凝结 (coagulation) and swelling. Thus, the neck becomes stiff and painful, unable to turn. Before ulceration, the flesh appears purple-dark, hard, and diffusely swollen; upon rupture, bloody fluid drains out, accompanied by numb pain without significant redness or swelling. This is the second type. Third, excessive thinking injures the Spleen, daily depleting Spleen Qi. Alternatively, rich and greasy foods damage the Stomach, drying up Stomach fluids. This leads to fullness and obstruction in the Zhongwan area, preventing Qi movement. Qi reverses and obstructs within the muscles, causing stagnation and swelling. Although the outer skin may rot, the interior remains hard and un-ulcerated; symptoms include dry mouth and tongue, loss of appetite, spreading roots, and foul, pale-dispersed pus. This is the third type. Fourth, melancholy injures the Lungs. Lung injury causes pore closure and blockage of Couli (interstices), leading to stagnant Qi that obstructs the meridians longitudinally and transversally, coagulating into swelling. The sore shape is often flat and depressed, color pale and lacking luster, with rotting skin and flowing fat-like exudate, resembling scalding by hot water. Symptoms include coarse, short breathing, dry or blackened nostrils, dripping nasal discharge, and frequent coughing. This is the fourth type. Fifth, excessive sexual desire injures the Kidneys. Kidney injury leads to the failure of True Yin Qi. Once True Yin fails, Ministerial Fire arises. This fire rises and descends freely, whether in motion or stillness. The sore appears purple-black, the pulse is rapid and irregular, accompanied by irritability, dry mouth, and thirst immediately after drinking. This is the fifth type. Therefore, it is said that internally originated cases are severe.
Among external sores, Naoju (Brain Carbuncle) is the most dangerous syndrome. It is easy to form and easy to deteriorate, with numerous variations. Therefore, it is discussed in detail here and placed at the beginning of the chapter for emphasis.