骨科英文书籍精读（66）｜肩关节前脱位（1）
DISLOCATION OF THE SHOULDER
Of the large joints, the shoulder is the one that most commonly dislocates. This is due to a number of factors: the shallowness of the glenoid socket; the extraordinary range of movement; underlying conditions such as ligamentous laxity or glenoid dysplasia; and the sheer vulnerability of the joint during stressful activities of the upper limb.
In this chapter, acute anterior and posterior dislocations are described. Chronic instability is described in Chapter 13.
ANTERIOR DISLOCATION
Mechanism of injury
Dislocation is usually caused by a fall on the hand. The head of the humerus is driven forward, tearing the capsule and producing avulsion of the glenoid labrum (the Bankart lesion). Occasionally the posterolateral part of the head is crushed. Rarely, the acromion process levers the head downwards and the joint dislocates with the arm pointing upwards (luxatio erecta); nearly always the arm then drops, bringing the head to its subcoracoid position.
Clinical features
Pain is severe. The patient supports the arm with the opposite hand and is loathe to permit any kind of examination. The lateral outline of the shoulder may be flattened and, if the patient is not too muscular, a
bulge may be felt just below the clavicle. The arm must always be examined for nerve and vessel injury before reduction is attempted.
X-Ray
The anteroposterior x-ray will show the overlapping shadows of the humeral head and glenoid fossa, with the head usually lying below and medial to the socket. A lateral view aimed along the blade of the scapula will show the humeral head out of line with the socket.
If the joint has dislocated before, special views may show flattening or an excavation of the posterolateral contour of the humeral head, where it has been indented by the anterior edge of the glenoid socket, the Hill–Sachs lesion.
---from 《Apley’s System of Orthopaedics and Fractures》
重点词汇整理：
shallow /ˈʃæloʊ/n. [地理] 浅滩adj. 浅的；肤浅的vt. 使变浅vi. 变浅
glenoid /'glinɔɪd/n. 关节盂adj. 像浅窝的，有浅窝的；关节盂的
socket /ˈsɑːkɪt/n. 插座；窝，穴；牙槽vt. 给…配插座
ligamentous laxity 韧带松弛
dysplasia /dɪs'pleʒə/n. 发育不良；发育异常；异常结构
sheer /ʃɪr/adj. 绝对的；透明的；峻峭的；纯粹的adv. 完全；陡峭地
vulnerability /ˌvʌlnərəˈbɪləti/n. 易损性；弱点
avulsion /ə'vʌlʃən/n. 扯开，撕裂；扯离的部分
labrum /'lebrəm/n. [无脊椎] 上唇
levers /'levəz/n. 杠杆；手段（lever的复数）v. 用杠杆撬动（lever的第三人称单数）
is loathe to permit any kind of examination厌恶是否允许任何形式的检查
loathe /loʊð/vt. 讨厌，厌恶
flatten /ˈflætn/vt. 击败，摧毁；使……平坦vi. 变平；变单调
bulge /bʌldʒ/n. 胀；膨胀；凸出部分vt. 使膨胀；使凸起vi. 膨胀；凸出
overlapping shadows 重叠影
glenoid fossa关节窝
indent /ɪn'dɛnt/v. 缩排；印凹痕；切割成锯齿状；定货，申请；
百度翻译：
肩关节脱位
在大关节中，肩关节是最常脱臼的关节。这是由许多因素造成的：关节盂窝很浅；活动范围非常大；潜在条件如韧带松弛或盂盂发育不良；以及在上肢紧张活动期间关节的极度脆弱性。
在这一章，急性前脱位和后脱位的描述。慢性不稳定在第13章中有描述。
前脱位
损伤机制
脱臼通常是由于手上摔了一跤而造成的。肱骨头部向前推进，撕裂包膜，造成盂唇撕脱（Bankart病变）。偶尔头部的后外侧部分被压碎。很少情况下，肩峰突将头部向下撬起，关节脱臼，手臂向上（luxatio erecta）；几乎总是手臂下降，使头部回到其胸骨下的位置。
临床特征
疼痛很严重。病人用另一只手支撑手臂，不允许做任何检查。肩部外侧轮廓可能变平，如果患者肌肉不太发达，则锁骨下方可能会感觉到隆起。在试图复位前，必须检查手臂是否有神经和血管损伤。
X射线
前后位的x光片显示肱骨头和关节盂窝的重叠阴影，头部通常位于关节窝的下方和内侧。沿着肩胛骨刀片的侧视图将显示肱骨头与关节窝不一致。
如果关节曾经脱位，特殊视图可能显示肱骨头的后外侧轮廓变平或被挖出，在那里它被关节盂窝的前缘凹陷，希尔-萨克斯损伤。