Ilayperuma Isurani, Nanayakkara B G, Hasan R, Uluwitiya S M, Palahepitiya K N
Department of Anatomy, Faculty of Medicine, University of Ruhuna, P.O. Box 70, Galle, Sri Lanka.
Department of Anatomy, Faculty of Medicine, University of Kelaniya, Kelaniya, Sri Lanka.
Surg Radiol Anat. 2016 Apr;38(3):335-40. doi: 10.1007/s00276-015-1564-y. Epub 2015 Oct 13.
Coracobrachialis (CBM) is a complex muscle with a wide range of variations in its morphology and innervation. The goal of this study was to elucidate the morphology, morphometry, gender differences of CBM and precise anatomical position of the musculocutaneous nerve (MCN) with reference to surrounding anatomical landmarks in an adult Sri Lankan population.
Cadaveric upper limbs (n = 312) were examined for the proximal and distal attachments, length, width, thickness of CBM and its relationship with the MCN.
The CBM originated from the tip of the coracoid process of the scapula and lateral, posterior and medial aspects of the tendon of short head of biceps brachii. Gender differences were observed in all morphometrical parameters of CBM. In 83.33 %, MCN perforated the CBM. In 50 % the MCN pierced the middle one-third of CBM while none pierced the lower one-third. The distance from the coracoid process to the point of entry of MCN into CBM (distance P) was 50.62 mm. A positive correlation was observed between the arm length and distance P indicating that arm length provides an accurate and reliable means of gauging the distance P of an individual.
The present study provides new evidence pertaining to the origin of CBM. Further, it was revealed that the predicted distance P of any upper extremity can be calculated by dividing the arm length by 5. Precise anatomical location of MCN in relation to CBM using unequivocal and well-defined anatomical landmarks will be imperative in modern surgical procedures.
肱二头肌短头腱（CBM）是一块形态和神经支配存在广泛变异的复杂肌肉。本研究的目的是阐明成年斯里兰卡人群中CBM的形态、形态测量、性别差异以及肌皮神经（MCN）相对于周围解剖标志的精确解剖位置。
对312例尸体上肢进行检查，观察CBM的近端和远端附着点、长度、宽度、厚度及其与MCN的关系。
CBM起于肩胛骨喙突尖以及肱二头肌短头腱的外侧、后侧和内侧。在CBM的所有形态测量参数中均观察到性别差异。83.33%的MCN穿过CBM。50%的MCN穿过CBM的中1/3，而无一穿过下1/3。从喙突到MCN进入CBM的点的距离（距离P）为50.62mm。观察到臂长与距离P之间呈正相关，表明臂长为测量个体距离P提供了一种准确可靠的方法。
本研究提供了有关CBM起源的新证据。此外，研究表明，任何上肢的预测距离P可通过将臂长除以5来计算。在现代外科手术中，使用明确且定义良好的解剖标志来确定MCN相对于CBM的精确解剖位置至关重要。
