The nuchal lines are four curved lines on the external surface of the

occipital bone The occipital bone () is a neurocranium, 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 lobe ...

: * 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 The occipitalis muscle (occipital belly) is a muscle which covers parts of the skull. Some sources consider the occipital muscle to be a distinct muscle. However, Terminologia Anatomica currently classifies it as part of the occipitofrontalis muscl ...

. * From the

external occipital protuberance Near the middle of the squamous part of occipital bone is the external occipital protuberance, the highest point of which is referred to as the inion. The inion is the most prominent projection of the protuberance which is located at the posterioin ...

a ridge or crest, the

external occipital crest The external occipital crest is part of the external surface of the squamous part of occipital bone, squamous part of the occipital bone. It is a ridge along the midline, beginning at the external occipital protuberance and descending to the forame ...

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 oblon ...

, 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 proces ...

. * Running from the middle of this line is the inferior nuchal line. Attached are the

obliquus capitis superior muscle The obliquus capitis superior muscle () is a small muscle in the upper back part of the neck and is one of the suboccipital muscles and part of the suboccipital triangle. It arises from the lateral mass of the atlas bone. It passes superiorly and ...

rectus capitis posterior major muscle The rectus capitis posterior major (or rectus capitis posticus major, both being Latin for ''larger posterior straight muscle of the head'') arises by a pointed tendon from the spinous process of the axis, and, becoming broader as it ascends, is in ...

, and

rectus capitis posterior minor muscle The rectus capitis posterior minor (or rectus capitis posticus minor, both being Latin for ''lesser posterior straight muscle of the head'') arises by a narrow pointed tendon from the tubercle on the posterior arch of the atlas, and, widening as i ...

Additional images

File:Superior nuchal line.PNG, Posterior view of superior nuchal line (labeled in red) and muscles connecting to it.

References

External links

* {{Authority control Bones of the head and neck