nuchal lines

{{Short description|Part of the skull's occipital bone}}

{{Distinguish|Nuchal fluid line}}

{{Infobox bone

| Name = Nuchal lines

| Latin = linea nuchae

| Image = Nuchal lines.png

| Caption = Occipital bone. Outer surface.

| Image2 = Gray1193.svg

| Caption2 = Side view of head, showing surface relations of bones. (Superior and median lines visible at bottom right.)

}}

The nuchal lines are four curved lines on the external surface of the occipital bone:

• The upper, often faintly marked, is named the highest nuchal line, but is sometimes referred to as the Mempin line or linea suprema, and it attaches to the epicranial aponeurosis.
• Below the highest nuchal line is the superior nuchal line. To it is attached, the splenius capitis muscle, the trapezius muscle,{{Citation|last=Rea|first=Paul|title=Chapter 3 - Neck|date=2016-01-01|url=http://www.sciencedirect.com/science/article/pii/B978012803633400003X|work=Essential Clinically Applied Anatomy of the Peripheral Nervous System in the Head and Neck|pages=131–183|editor-last=Rea|editor-first=Paul|publisher=Academic Press|language=en|doi=10.1016/b978-0-12-803633-4.00003-x|isbn=978-0-12-803633-4|access-date=2020-11-02}} and the occipitalis.{{Citation|last1=Casteleyn|first1=Christophe|title=Chapter 2 - The Anatomy of the Common Marmoset|date=2019-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780128118290000029|work=The Common Marmoset in Captivity and Biomedical Research|pages=17–41|editor-last=Marini|editor-first=Robert|series=American College of Laboratory Animal Medicine|publisher=Academic Press|language=en|doi=10.1016/b978-0-12-811829-0.00002-9|isbn=978-0-12-811829-0|access-date=2020-11-02|last2=Bakker|first2=Jaco|s2cid=92754272 |editor2-last=Wachtman|editor2-first=Lynn|editor3-last=Tardif|editor3-first=Suzette|editor4-last=Mansfield|editor4-first=Keith}}
• From the external occipital protuberance a ridge or crest, the external occipital crest also called the median nuchal line, often faintly marked, descends to the foramen magnum, and affords attachment to the nuchal ligament.
• Running from the middle of this line is the inferior nuchal line. Attached are the obliquus capitis superior muscle, rectus capitis posterior major muscle, and rectus capitis posterior minor muscle.