骨科英文书籍精读（80）｜肱骨干骨折（1）
FRACTURED SHAFT OF HUMERUS
Mechanism of injury
A fall on the hand may twist the humerus, causing a spiral fracture. A fall on the elbow with the arm abducted exerts a bending force, resulting in an oblique or transverse fracture. A direct blow to the arm causes a fracture which is either transverse or comminuted. Fracture of the shaft in an elderly patient may be due to a metastasis.
Pathological anatomy
With fractures above the deltoid insertion, the proximal fragment is adducted by pectoralis major. With fractures lower down, the proximal fragment is abducted by the deltoid. Injury to the radial nerve is common, though fortunately recovery is usual.
Clinical features
The arm is painful, bruised and swollen. It is important to test for radial nerve function before and after treatment. This is best done by assessing active extension of the metacarpophalangeal joints; active extension of the wrist can be misleading because extensor carpi radialis longus is sometimes supplied by a branch arising proximal to the injury.
X-ray
The site of the fracture, its line (transverse, spiral or comminuted) and any displacement are readily seen. The possibility that the fracture may be pathological should be remembered.
Treatment
Fractures of the humerus heal readily. They require neither perfect reduction nor immobilization; the weight of the arm with an external cast is usually enough to pull the fragments into alignment. A ‘hanging cast’ is applied from shoulder to wrist with the elbow flexed 90 degrees, and the forearm section is suspended by a sling around the patient’s neck. This cast may be replaced after 2–3 weeks by a short (shoulder to elbow) cast or a functional polypropylene brace which is worn for a further 6 weeks.
The wrist and fingers are exercised from the start. Pendulum exercises of the shoulder are begun within a week, but active abduction is postponed until the fracture has united (about 6 weeks for spiral fractures but often twice as long for other types); once united, only a sling is needed until the fracture is consolidated.
---from 《Apley’s System of Orthopaedics and Fractures》
重点词汇整理：
oblique or transverse fracture.斜位或横位骨折
metastasis. /məˈtæstəsɪs/n. 转移；新陈代谢；[地质] 同质蜕变
deltoid insertion三角肌附着点
adducted by pectoralis major被胸大肌内收
adduct/'ædʌkt/n. [化学] 加合物vt. 使内收
pectoralis major 胸大肌
abduct /æbˈdʌkt/vt. 绑架；诱拐；使外展
deltoid /'dɛltɔɪd/n. 三角肌adj. 三角形的
metacarpophalangeal joints掌指关节
metacarpal/ˌmetəˈkɑːrpl/n. 掌骨adj. 掌部的
phalangeal/,felən'dʒiəl/adj. 指骨的，趾骨的
phalange/fə'lændʒ/n. 指骨；趾骨
extensor carpi radialis longus 桡侧腕长伸肌
readily /ˈredɪli/adv. 容易地；乐意地；无困难地
Fractures of the humerus heal readily.肱骨骨折容易愈合。
Pendulum exercises 钟摆运动/ˈpendʒələm/n. 钟摆；摇锤；摇摆不定的事态
百度翻译：
肱骨骨折
伤害机制
手上的跌倒可能会扭曲肱骨，导致螺旋骨折。手臂外展时肘部掉落会产生弯曲力，导致倾斜或横向骨折。对手臂的直接打击会导致横向或粉碎的骨折。老年患者的轴骨折可能是由于转移。
病理解剖
在三角肌插入上方骨折时，前壁片段由胸大肌内收。随着骨折向下，近端碎片被三角肌外展。桡神经损伤很常见，但幸运的是恢复很常见。
临床特征
手臂疼痛，瘀伤和肿胀。治疗前后测试桡神经功能非常重要。这最好通过评估掌指关节的主动伸展来完成；手腕的主动伸展可能会产生误导，因为桡侧腕伸肌有时由损伤近端的分支提供。
X射线
容易看到骨折部位，其线（横向，螺旋或粉碎）和任何位移。应记住骨折可能是病理性的可能性。
治疗
肱骨骨折容易愈合。它们既不需要完美的减少也不需要固定；带有外部铸件的手臂的重量通常足以将碎片拉对。在肘部弯曲90度的情况下，从肩部到腕部施加“悬挂式铸件”，并且通过围绕患者颈部的吊索悬挂前臂部分。这种铸件可以在2-3周后用短的（肩到肘）铸件或功能性聚丙烯支具更换，该支具再磨损6周。
手腕和手指从一开始就锻炼。肩部摆动练习在一周内开始，但主动外展被推迟到骨折愈合（螺旋骨折约6周，但其他类型通常长两倍）；一旦愈合，只需要吊带，直到骨折为止安慰。