|
The squamous part of occipital bone, is situated above and behind the foramen magnum, and is curved from above downward and from side to side. == External surface == The external surface is convex and presents midway between the summit of the bone and the foramen magnum a prominence, the external occipital protuberance (or inion). Extending lateralward from this on either side are two curved lines, one a little above the other. The upper, often faintly marked, is named the highest nuchal line, and to it the galea aponeurotica is attached. The lower is termed the superior nuchal line. That area of the squamous part, which lies above the highest nuchal lines is named the ''planum occipitale'' and is covered by the ''occipitalis muscle''. That below, termed the ''planum nuchale'', is rough and irregular for the attachment of several muscles. From the external occipital protuberance, an often faintly marked ridge or crest, the median nuchal line, descends to the foramen magnum and affords attachment to the ligamentum nuchæ. Running from the middle of this line across either half of the nuchal plane is the inferior nuchal line. Several muscles are attached to the outer surface of the squamous part, thus the superior nuchal line gives origin to the occipitalis and trapezius, and insertion to the sternocleidomastoideus and splenius capitis. Into the surface between the superior and inferior nuchal lines the Semispinalis capitis and the Obliquus capitis superior are inserted, while the inferior nuchal line and the area below it receive the insertions of the Recti capitis posteriores major and minor. The posterior atlantoöccipital membrane is attached around the postero-lateral part of the foramen magnum, just outside the margin of the foramen. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Squamous part of occipital bone」の詳細全文を読む スポンサード リンク
|