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
The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristi ...
in the neck and upper
thorax
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the c ...
. It is involved in movements such as shaking the head.
Structure
It arises from the lower half of the
nuchal ligament, from the
spinous process of the
seventh cervical vertebra, and from the spinous processes of the upper three or four
thoracic vertebrae.
The fibers of the muscle are directed upward and laterally and are inserted, under cover of the
sternocleidomastoideus, into the
mastoid process
The mastoid part of the temporal bone is the posterior (back) part of the temporal bone, one of the bones of the skull. Its rough surface gives attachment to various muscles (via tendons) and it has openings for blood vessels. From its borde ...
of the
temporal bone
The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex.
The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears. ...
, and into the rough surface on 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 cer ...
just below the lateral third of the
superior nuchal line. The splenius capitis is deep to
sternocleidomastoideus at the mastoid process, and to the
trapezius
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 th ...
for its lower portion. It is one of the muscles that forms the floor of the posterior triangle of the neck.
The splenius capitis muscle is innervated by the
posterior ramus of spinal nerves
C3 and
C4.
Function
The splenius capitis muscle is a prime mover for head extension. The splenius capitis can also allow lateral flexion and rotation of the
cervical spine.
Additional images
File:Gray385.png, Muscles of the neck. Lateral view.
File:Slide2ccc.JPG, Splenius capitis muscle
See also
References
External links
* - "Superficial layer of the extrinsic muscles of the back."
* - "Intermediate layer of the extrinsic muscles of the back, deep muscles."
* - "Identification of the muscles associated with the
posterolateral triangle."
PTCentral
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Muscles of the torso