申斗垣曰∶膝眼毒，先必膝眼酸痛，乃成此证，乃肾经感受风邪，寒湿相侵而成。（《启玄》）
汪省之曰∶膝外痈是足少阳胆经，膝内痈是足太阴脾经，俱多气少血，乃膝间
枢纽，骨节行动之处，宜仔细治之，免成废疾。（《理例》）
王肯堂曰∶托疽生于膝傍腿侧，乃足少阳胆经，多气少血。阳关穴、阳陵泉穴
肿作痛，半月有脓可治；如不痛出鲜血，或出青黑脓，及长出头渐多，或肿无定处者，不治。（《准绳》）
《灵枢》云∶发于膝名曰 疽，其状大，痈色不变，寒热而坚，勿石之，石之者死。
须其柔乃石之者生。（坚如石者，用生樟六根擦之效。）书曰∶诸痈疽之发于节而相应者，（刘涓
子云∶应者内发透外也。）不可治也。发于阳者，百日死。（阳谓诸节之背。）发于阴者，三十日死。（阴谓诸节之 间。）
《心法》曰∶膝眼风生于膝眼穴，（又名鬼眼穴，在膝盖之下，左右两骨空陷中。）由下焦素虚，
外邪易于侵袭，先从膝眼隐隐作痛，如风胜则其痛走注不定，寒胜则痛如锥刺，湿
胜则胖肿曲不能伸，其病在筋，伸不能曲，其病在骨，动移不遂，沉寒锢冷之候也。惟
在临证详辨∶单膝生者轻，双膝生者重。若左膝方愈，复病右膝；右膝方愈，复病左膝者，名过膝风，属险。
申斗垣说：膝眼毒，起初必定是膝眼部位酸痛，然后才形成这种病症，这是肾经感受风邪，寒湿相互侵袭而形成的。（出自《启玄》）
汪省之说：膝外侧的痈属于足少阳胆经，膝内侧的痈属于足太阴脾经，这两条经脉都是多气少血。这里是膝关节的枢纽，也是骨节活动的地方，应当仔细治疗，以免变成残疾。（出自《理例》）
王肯堂说：托疽生长在膝盖旁边的大腿侧面，属于足少阳胆经，该经多气少血。如果阳关穴、阳陵泉穴肿胀疼痛，半个月后化脓还可以治疗；如果不痛却流出鲜血，或者流出青黑色的脓液，以及疮头逐渐增多，或者肿处位置不固定的，则无法治疗。（出自《准绳》）
《灵枢》说：发生在膝盖部位的疽叫做“疵疽”（注：原文此处似有脱字或异体，通常指膝部疽），它的症状是肿块大，痈的颜色没有改变，伴有寒热感且质地坚硬，不能用石针切开，如果用石针切开会致死。必须等到患处变软才能用石针切开，这样才会生还。（对于坚硬如石的，使用六根生樟木擦拭效果显著。）书上说：各种痈疽发生在关节部位并且内外相应的，（刘涓子说：相应是指内部病邪透发至外部。）是无法治疗的。发生在阳面的，一百天死亡。（阳面指的是各个关节的背面。）发生在阴面的，三十天死亡。（阴面指的是各个关节的间隙。）
《心法》说：膝眼风生长在膝眼穴，（又名鬼眼穴，位于膝盖下方，左右两块骨头之间的凹陷处。）由于下焦原本虚弱，外邪容易侵袭，先从膝眼隐隐作痛开始，如果风邪偏胜，则疼痛游走不定；寒邪偏胜，则疼痛像锥子刺一样；湿邪偏胜，则肢体胖肿弯曲不能伸直。病在筋脉的，只能伸展不能弯曲；病在骨骼的，活动转移不便，这是沉寒固冷的证候。只有在临诊时详细辨别：单侧膝盖发病的较轻，双侧膝盖发病的较重。如果左侧膝盖刚痊愈，右侧膝盖又发病；右侧膝盖刚痊愈，左侧膝盖又发病的，名叫过膝风，属于险症。
Shen Douyuan stated: For *Xiyan Du* (Knee Eye Toxin), there must first be soreness and pain in the knee eye area before this syndrome forms. It is caused by the Kidney Meridian contracting wind pathogens, with cold and dampness invading together. (From *Qixuan*)
Wang Shengzhi stated: An abscess on the lateral side of the knee belongs to the Foot-Shaoyang Gallbladder Meridian, while an abscess on the medial side belongs to the Foot-Taiyin Spleen Meridian. Both meridians are characterized as having abundant Qi but scarce Blood. This area serves as the pivot of the knee joint and the site of bone-and-joint movement; therefore, it should be treated carefully to avoid resulting in disability. (From *Lili*)
Wang Kentang stated: *Tuo Ju* (Supporting Carbuncle) arises on the lateral thigh beside the knee, belonging to the Foot-Shaoyang Gallbladder Meridian, which has abundant Qi but scarce Blood. If the Yangguan (Yang Pass, GB33) and Yanglingquan (Yang Mound Spring, GB34) acupoints swell and become painful, and pus forms within half a month, it is treatable. However, if there is no pain but bright red blood flows out, or if green-black pus appears, or if the number of sores gradually increases, or if the swelling has no fixed location, it is untreatable. (From *Zhunsheng*)
The *Ling Shu* states: A carbuncle occurring at the knee is named "Ci Ju" (Carbuncle at the Knee). Its presentation involves a large mass, unchanged skin color over the abscess, accompanied by chills and fever, and a hard texture. Do not puncture it with a stone needle; doing so will lead to death. One must wait until the hardness softens before puncturing with a stone needle for survival. (For hardness like stone, rubbing with six roots of fresh Camphor Wood [Cinnamomum camphora] is effective.) The text further states: When various abscesses and carbuncles occur at joints and correspond internally and externally... they are untreatable. Liu Juanzi explained that "correspondence" refers to internal pathogens manifesting externally. Those occurring on the Yang aspect die within one hundred days. (The Yang aspect refers to the dorsal side of all joints.) Those occurring on the Yin aspect die within thirty days. (The Yin aspect refers to the interstices between all joints.)
The *Xin Fa* states: *Xiyan Feng* (Knee Eye Wind) arises at the Xiyan (Knee Eye) acupoint (also known as Guiyan [Ghost Eye] acupoint, located in the depressions below the kneecap, between the bones on both left and right sides). Due to inherent deficiency in the Lower Jiao, external pathogens easily invade. It begins with vague pain in the knee eye. If Wind pathogen predominates, the pain wanders without a fixed location; if Cold predominates, the pain feels like being pierced by an awl; if Dampness predominates, the limb becomes swollen and cannot bend. If the pathology is in the sinews, extension is possible but flexion is not; if the pathology is in the bones, movement and shifting are difficult. This represents a condition of deep-seated cold and entrenched chill. Clinical differentiation is essential: cases involving only one knee are mild, while those involving both knees are severe. If the left knee heals but the right knee subsequently becomes diseased, or vice versa, it is named Guoxi Feng (Passing-Knee Wind), which is considered a dangerous condition.