關於【Distal Biceps tendon】 骨科醫師也不知道的事，【肱二頭肌腱】超音波知識一次彙整給你 【PYSHEN-2025-048】
整理自高雄市立小港醫院沈柏因醫師（骨科/疼痛專科/超音波專科）
參考資料：
2025MSK Ultrasound Asian Meeting
█ Distal Biceps injury/tear發生率：
█ Distal Biceps injury好發族群/受傷機制
█ Distal Biceps injury臨床上可做哪些理學檢查
█Distal Biceps tendon 長短頭在超音波長軸底下有何不同？
█Distal biceps tendon在超音波底下掃描的四種方法(京都2025MSK Ultrasound Asian Meeting更新）
▐ Distal Biceps injury/tear發生率：
✓The incidence of injury ： averaged 1.2 ruptures per 100,000 patients per year
✓ 7.5 times greater risk of distal biceps tendon rupture in patients who smoke.
✓The incidence of distal biceps tendon ruptures is 1.2 per 100,000 patients, with the majority in the dominant elbow of men who smoke and who are in their fourth decade of life.
▐ 好發族群：
中年40~60 y/o/男性/慣用手
▐ 受傷機制：
在flexed＋supinated forearm的情況突然有eccentric load
▐ 臨床上可做哪些理學檢查：
➊Hook test((就勾不到一個cordlike structure就是positive )
Complete avulsion ⇢做 Hook test：是會abnormal
partial avulsion ⇢做 Hook test會很痛
➋passive forearm pronation(PFP test):
把前臂從supination轉到pronation的時候，biceps tendon是會動的(從proximal 跑到distal)⇢沒動要小心是rupture了
➌biceps crease interval test(BCI test)：看antecubital crease跟二頭肌的距離如果>6cm/變成對側的1.2倍以上⇢rupture
➍Reverse Popye deformity：Muscle belly retraction凸起
Weakness flexion and supination＋有的甚至還會busing
▐ Proposed sonographic characteristics distinguishing the long head and short head of the distal biceps brachii tendon
參考資料：Daoukas S, Galanis D. The Radial Arc technique: A systematic ultrasound method to imaging the distal biceps brachii tendon from a medial approach with anatomical insights. Ultrasound. Published online May 13, 2025. doi:10.1177/1742271X251337389
▐ 找Distal biceps tendon四種方法
方法 １（ant approach)
•很直覺
•缺點：
手臂壯很難掃：需壓大力避免anisotrophy
手臂不壯也很難掃：今日在京都的模擬病人其biceps用摸就摸得到，但掃起來也不容易，
推測是tendon斜且往深處接到Radial tuberosity上，probe很像很難平行其長軸，也因此很難做出tendon清楚＋tuberosity bone也清楚的程度
方法 2（Medial approach)
•elbow 90 探頭平行humerus由下往上掃
方法2-1(找肌肉）
Using the Pronator Window:找到pronator m後，Slide transducer inferior then anteriorly
隨著探頭往前走，pronator m下會出現brachial artery⇢ 可以讓其下接在radial tuberosity上的Distal Biceps Tendon更清楚(posterior enhacement效應)
方法2-2(找骨頭）
•會先看到U: Brachialis insertion(Deep head)
•再看到R: Biceps insertion
•缺點：打針角度困難，可能傷到ulnar a medial n ulnar n
方法2-3:Medial approach-Radial Are technique(找骨頭）有5大步驟
elbow 30 度+forearm in a near-neutral position
✓step01 :
Probe on medial epicondyle, aligned horizontally.
✓step02:
Gradually slide the probe distally in a strictly horizontal orientation until the medial epicondyle is no longer visible on the sonogram
✓step03:
•Sweep the probe anteriorly, towards the forearm's midline
•As you sweep anteriorly and the coronoid process fades from view, the radial head emerges, producing a distinct hyperechoic signal when the probe achieves a perpendicular angle to the bone.
•humeral trochlea⇢resembling a cliff
•pitfall :忘記調深：neglecting to increase the depth setting on the ultrasound machine.
✓step04:
•continue sliding the probe further distally in a true horizontal direction
•要注意的是radial tuberosity與head會隔一個山谷
radial head : resembling a hill
radial neck in the centre like a gentle slope resembling a valley
the radial tuberosity on the right side appearing as another hill – effectively displaying the sequential anatomical landmarks across the sonogram
✓step05
•keep the distal end of the probe stable while pivoting the proximal
end of the probe upwards by about 15degrees.
•This manoeuvre aligns the DBBT in its long axis view, through the pronator teres window
方法 ３（Lat approach)
•elbow 90,探頭平行humerus往遠端掃
方法 ４（Post approach)
•病人擺位很重要：Cobra view
需maximal pronation:可以請病人手背貼胸前
＃Distal Biceps Tendon Injury
＃Biceps Tendon Rupture Incidence
＃Ultrasound Scanning Techniques Biceps
＃Physical Examination Distal Biceps
＃Long Head Short Head Biceps Ultrasound
＃2025 MSK Ultrasound Asian Meeting
