TMJs are not just TMJs

TMJs與其它Axial skeleton 最大的不同是TMJs幾乎不直接受地球重力的影響,當人類站立或坐下時.由頭顱,脊椎,骨盆,一直到腳,關節面會受到重力的施力,相對的,TMJs的關節介面不會受到重力的壓迫,當TMJs的關節面或disk有結構上的損傷時,如果沒有強大外力的傷害或疾病,幾乎可以說TMJs的 internal derangement or pathology 都是來自於咀嚼肌群的過度施力. 肌肉造成的microtrauma,長期累積下來,才是TMJs pathology 的元凶,大多數的TMD(顳顎關節障礙)是肌肉來源的疼痛,即使是TMJ pathology產生的疼痛,也大多數來自於肌肉的overloading所產生的pathology.骨骼肌可說是人体單一最大器官,約佔体重的50%,肌肉酸痛幾乎是所有人都曾有過的經驗,在英文中,酸痛的表達是soreness 或aching,肌肉的疼痛最常見也最不為醫界所知的是myofascial trigger point .近幾年來醫界對它的認識已有改善,其定義如下:Clinical definition of a centraltrigger point : A hyperirritable spot in skeletal muscle that is associated with a hypersensitive palpable nodule in a taut band. The spot is painful on compression and can give rise to characteristicic referred pain, referred tenderness, motor dysfunction, and autonomic phenomena. Types of myofascial trigger point include: active , associated, attachment, central , key, latent, primary, and satellite (Note especially the distinction between central and attachment myofascial trigger point). Any myofascial trigger point is to be distinguished from a cutaneous, ligmentous, periosteal, or any other nonmuscular trigger point. 雖然myofascial trigger point 通常是直接造成肌肉疼痛的來源,但有許多已知或未知因素才是形成myofascial trigger point 的原因.到目前為止,要完全消除myofascial trigger point 幾乎是不可能達到的目標,但是有些治療模式確實是可以降低trigger point的活性,進而緩解疼痛,到目前為止的醫療文獻,對肌肉的疼痛治療,幾乎都是緩解(relief),),幾乎未曾見到cure(治癒)這個字眼. 任何一個單一關節的運動,幾乎都是由多組肌肉共同完成,當然TMJs 亦不例外. 牙齒與上下顎骨的連接,使得masticatory system 易於執行咀嚼,發音,及吞嚥等主要功能,當然,沒有牙齒,這些功能一樣能夠執行,只是成效較差而已. 牙齒與齒槽骨的連結,可視為一種關節. 事實上,在關節分類學上,牙齒與齒槽骨所構成的關節稱為gomphosis,如果去除微生物,化學傷害,疾病,及巨大外力創傷,大多數的關節都是因為長期的受力而受傷,如果沒有肌力的Overloading,及 Ground reaction force 的作用,關節是很難受傷的. TMJs及牙齒雖然不受地反作用力影響,但masticatory muscle loading force 長期作用下來,就易於造成關節的損害. 同樣,肌肉長期過度的使用,也造成肌肉本身的傷害. 肌肉需接受到神經系統傳來的訊號,才能產生收縮,因此,肌肉如何協調作用,是受到CNS(中樞神經系統)的控制,在牙醫學界,有一個觀念稱為Muscle Engram, 其定義如下: Within the brain stem is a pool of neuron that controls rhythmic muscle activities such as breathing , walking , and chewing. This pool of neurons is collectively known as the central pattern generator (CPG). For the CPG to be most efficient, it must receive constant sensory input from the masticatory structures. Therefore, the tongue, lips, teeth, and periodontal ligaments are constantly feeding back information that allows CPG to determine the most appropriate and efficient chewing stroke. Once an efficient chewing pattern that minimizes damage to any structure is found , it is learned and repeated. This learned pattern is called a muscle engram. Chewing therefore can be thougugught of as an extremely complex activity that is primarily controlled by CPG. With input from numerous sensory receptors, like many other reflex activities, chewing is a subconscious activity yet can be brought to conscious control at any time. Breathing and Walking are other CPG reflex activities that generally occur at subconscious level but can be brought under voluntary control at will. Muscle Engram 這個名詞幾乎不曾在其他領域見到,這個觀念所闡述的是幾乎人類的動作都有一個固定重複的模式,而且這個模式是最有效率的,意即要執行一 個功能,使用最少的能量消耗,即使這個動作看起來非),幾乎未曾見到cure(治癒)這個字眼. 任何一個單一關節的運動,幾乎都是由多組肌肉共同完成,當然TMJs 亦不例外. 牙齒與上下顎骨的連接,使得masticatory system 易於執行咀嚼,發音,及吞嚥等主要功能,當然,沒有牙齒,這些功能一樣能夠執行,只是成效較差而已. 牙齒與齒槽骨的連結,可視為一種關節. 事實上,在關節分類學上,牙齒與齒槽骨所構成的關節稱為gomphosis,如果去除微生物,化學傷害,疾病,及巨大外力創傷,大多數的關節都是因為長期的受力而受傷,如果沒有肌力的Overloading,及 Ground reaction force 的作用,關節是很難受傷的. TMJs及牙齒雖然不受地反作用力影響,但masticatory muscle loading force 長期作用下來,就易於造成關節的損害. 同樣,肌肉長期過度的使用,也造成肌肉本身的傷害. 肌肉需接受到神經系統傳來的訊號,才能產生收縮,因此,肌肉如何協調作用,是受到CNS(中樞神經系統)的控制,在牙醫學界,有一個觀念稱為Muscle Engram,