目的　观察测量前锯肌间隙美兰溶液扩散范围及神经分布, 为该间隙神经阻滞提供解剖学依据。   方法　选用4具尸体，应用超声引导技术，采用Blanco穿刺入路，在胸壁两侧腋中线4、5肋间，注入含美兰染料的液体（0.4 ml/kg）至前锯肌间隙，约10 min后逐层分离至该间隙，观察美兰液体的扩散范围、染料沉积后界限以及该范围内的神经分布。   结果　观察8侧前锯肌，逐层掀开胸大肌和胸小肌后，清晰显露前锯肌间隙的蓝染区域及区域内蓝染的2~6肋间神经的外侧皮支、胸长神经和胸背神经。中位数M(P25, P75)描述8个前锯肌筋膜间隙注射扩散范围测量结果，腋前线11.35（10.45,12.15）cm，腋中线12.6(12.12,13.15)cm，腋后线11.1(10.70,12.05)cm，平乳头线9.8(9.12,10.65)cm。头侧扩散至第2肋腋前线占75%,腋中线占87.5%,腋后线占87.5%；扩散至第3肋腋前线占25%,腋中线占12.5%,腋后线占12.5%。  结论　前锯肌间隙美兰溶液扩散范围解剖测量研究提示临床应用此方法进行前锯肌间隙神经阻滞，可阻滞前锯肌间隙内的2~6肋间神经外侧皮支、胸长神经和胸背神经，满足胸前外侧壁手术的麻醉和镇痛。

Objective　This study was conducted to investigate extent of spread of injecting methylene blue and nerve involvement in serratus anterior space.　Method　The ultrasound scans were performed with a GE(Venue 40) 9~13 MHz linear array transducer. Cadavers were placed in the prone position. Ribs were counted by ultrasound to locate the space between the 4th and 5th rib in the midaxillary line, and from there to the serratus anterior muscle. Under real-time ultrasound guidance, a needle was inserted within the serratus plane between the 4th and 5th rib in the midaxillary line by the Blanco method for administration of 0.4 ml/kg methylene blue. There were a total of 8 injections. After injection of 10 min, layers were separated into the anterior serratus muscle space. The extent of dye spread was measured in the serratus space, and the nerves stained were documented.　Results　Afterpectoralis major and minor muscles were removed respectively, structuresstained by the dye within serratus space wereidentified, including lateral cutaneous branches of 2~6 intercostal nerves, long thoracic nerve and thoracodorsal nerve stained. Spread of dye within eight serratus planes was identified by expressed in medians(P25, P75). They are 11.35(10.45,12.15)cm in the anterior axillary line,12.6(12.12,13.15)cm in the midaxillary line, 11.1(10.70,12.05)cm in the posterior axillary line, and 9.8(9.12,10.65) in the nipple line. Cephalad spread of contrast was noted in 2nd and 3rd intercostal space (75% and 25%) at anterior axillary line,(87.5% and 12.5%) at the midaxillary line, and (87.5% and 12.5%)at the anterior axillary line respectively.　Conclusion　This study describes that the injection spread in serratus space can be determined with the help to provide analgesia to the anterolateral chest wall.