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
Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spinal ...
in the neck and upper
thorax. 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
In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebra (anatomy), vertebrae of intermediate size between the ce ...
.
The fibers of the muscle are directed upward and laterally and are inserted, under cover of the
sternocleidomastoideus, into the
mastoid process of the
temporal bone, and into the rough surface on 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 lies over the occipital lob ...
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 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
File:Braus 1921 56.png, Splenius muscle
File:Braus 1921 58.png, Splenius and Semispinalis
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
{{Authority control
Muscles of the torso
Human head and neck
Otorhinolaryngology
Muscles of the head and neck