The nuchal lines are four curved lines on the external surface of the
occipital bone
The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the c ...
:
* 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
The epicranial aponeurosis (aponeurosis epicranialis, galea aponeurotica) is an aponeurosis (a tough layer of dense fibrous tissue). It covers the upper part of the skull in humans and many other animals.
Structure
In humans, the epicranial ...
.
* Below the highest nuchal line is the superior nuchal line. To it is attached, the
splenius capitis muscle
The splenius capitis () () is a broad, straplike muscle in the back of the neck. It pulls on the base of the skull from the vertebrae in the neck and upper thorax. It is involved in movements such as shaking the head.
Structure
It arises from th ...
, the
trapezius muscle
The trapezius is a large paired trapezoid-shaped surface muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae of the spine and laterally to the spine of the scapula. It moves the scapula and supports the ...
, and the
occipitalis.
* 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
The foramen magnum ( la, great hole) is a large, oval-shaped opening in the occipital bone of the skull. It is one of the several oval or circular openings (foramina) in the base of the skull. The spinal cord, an extension of the medulla oblonga ...
, and affords attachment to the
nuchal ligament
The nuchal ligament is a ligament at the back of the neck that is continuous with the supraspinous ligament.
Structure
The nuchal ligament extends from the external occipital protuberance on the skull and median nuchal line to the spinous pro ...
.
* 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.
Additional images
File:Superior nuchal line.PNG, Posterior view of superior nuchal line (labeled in red) and muscles connecting to it.
References
External links
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Bones of the head and neck