啄木鸟头颈部解剖结构分析

Analysis of the anatomical structure of woodpecker head and neck

啄木鸟(Picidae)能够高速有力地啄木而不发生颈部损伤,相比之下,人在汽车碰撞事故引起的头颈部后仰与前屈运动中易引发挥鞭样损伤.本文利用组织学解剖和椎骨逆向建模等方法对啄木鸟头颈部解剖结构进行分析,绘制出啄木鸟头颈部主要肌肉解剖图谱,从头颈部软组织解剖结构和椎骨形态角度将其与戴胜鸟以及人类进行对比,分析其特殊解剖结构所发挥的抗震作用.通过对比发现,啄木鸟的头腹直肌跨度较戴胜鸟更小,头侧直肌为一整片肌肉不与头半棘肌分开,颈前没有连接上节腹突与下节侧突的斜向肌肉,这些均导致啄木鸟的头颈部旋转活动度小于戴胜鸟,这表明啄木鸟颈部损失了一定的头颈部活动度以增强稳定性,进而避免啄木过程中的颈部损伤.此外,啄木鸟的头夹肌连接颅骨与上段颈椎起到增加颅颈连接稳定性的作用,颈椎间没有椎间盘颈部旋转活动度相对较小,这些可能是其较人类更不易发生颈部损伤的原因.

Woodpeckers are able to peck wood at great force and high speed without sustaining neck injury. Unlike woodpeckers, humans are prone to whiplash injury during vehicle collisions as a result of hypsokinesis and anteflexion of the head and neck. In this study, the anatomical structure of woodpecker head and neck was analyzed based on histological evaluation of anatomy and reverse modeling of vertebrae, and an atlas of the anatomy of the primary muscles of woodpecker head and neck was constructed. The anatomical structure of the head and neck soft tissue and morphology of the cervical vertebrae were compared among woodpeckers, humans, and hoopoes to assess the shock resistance of the woodpecker head and neck special structure. We found that the span of the woodpecker rectus capitis ventralis is smaller than that of the hoopoe, the woodpecker rectus capitis lateralis is a single muscle tissue and is not separated from the complexus, and the oblique muscles that connect the ventral process of the upper vertebrate and the lateral process of the lower vertebrate do not exist in woodpeckers. These differences result in woodpeckers having more restricted head and neck rotation compared with hoopoes. Thus, woodpeckers sacrifice some range of motion to ensure greater stability, thereby avoiding neck injury during pecking. In addition, the woodpecker splenius capitis, which connects the os supraoccipitale and the upper cervical vertebra, increases the stability of the cranial-cervical connection, and the absence of the cervical intervertebral disc leads to a reduced range of cervical rotation. These anatomical differences may explain why woodpeckers are less prone to neck injury than humans.