Skeletal muscles are particularly important for the human body, because they allow it to move freely. They are responsible for movements that the body performs voluntarily and actively, for example, the movement of the arms and legs. They also belong to the striated musculature, as they have fine transverse stripes, which gives a periodic, repetitive pattern. The rectus capitis lateralis muscle belongs to the striated musculature.
What is the rectus capitis lateralis muscle?
The term Musculus rectus capitis lateralis is Latin and stands for “lateral straight head muscle”. This muscle is small, short and flat, located to the side of the first upper cervical joint in the deep neck. It belongs to the secondary back musculature, but not to the autochthonous back musculature (“localized back musculature”), because it is intervened by the ramus anterior; however, the rectus capitis lateralis muscle also belongs to the neck musculature. The origin of the rectus capitis lateralis muscle is at the so-called transverse process of the first cervical vertebra. Transverse processes are paired bony tissues of a vertebra.
Anatomy and structure
The rectus capitis lateralis muscle belongs to the striated musculature and is thus lined with a sheath of connective tissue (fascia), this also encloses some flesh fibers. Each of these flesh fibers can be divided into several fiber bundles, which are also called primary bundles: These are stored in such a way that they can move each other, thus the muscle is flexible and adaptable. The primary bundle consists of twelve muscle fibers, which are connected by connective tissue and thin, fine blood vessels. The “lateral straight head muscle” becomes active by tensing, thus contracting and shortening. It then relaxes again and the muscle lengthens (relaxation). Muscle shortening is triggered by the brain or spinal cord transmitting electrical impulses via the nerves. A transversely striated muscle is also called a syncytium. This is a cell that consists of myoblasts and thus contains nuclei. The syncytium is incapable of division, which is why when muscle fibers are lost, no new ones grow back and adjacent fibers only thicken. At the nape of the neck, the rectus capitis lateralis muscle attaches to the processus jugularis, a bony process of the os occiptale (occipital bone), which forms the rearmost part of the cranial vault.
Function and Tasks
The function of the rectus capitis lateralis muscle is to assist in the movement of the head, especially in lateral movements. When the head tilts to one side, the small muscle shortens on one side and contraction occurs. When contracted on both sides, a slight dorsal reflection of the head takes place: The short muscle allows the head to bend forward dorsally, i.e., toward the back. When the head moves forward, the rectus capitis lateralis muscle stretches (extension). As a part of the secondary back as well as neck muscles, the rectus capitis lateralis muscle assists in the movement of the spine, especially in extension. Innervation is the supply of nerve tissue (for example, nerve fibers and cells) to an organ, connective tissue, or body. Innervation is used to control processes and reactions in the body through stimulus perception and excitation. The rectus capitis lateralis muscle is also innervated by special nerve tissue, the rami anteriores of the spinal nerves, which arise in pairs from the spinal cord. They belong to the peripheral nervous system, the nervous system that does not arise from the brain or spinal cord and is located outside the spinal canal or skull. The rami anteriores arise from spinal cord segments C1 and C2, these are the first two segments of the spinal cord. Through the C1 and C2, innervation occurs in the rectus capitis lateralis muscle and this muscle thus receives the necessary nervous tissue.
Diseases
As a part of the neck muscles, different complaints and diseases can occur in the rectus capitis lateralis muscle, such as neck tension, especially triggered by the small muscle. Nowadays, the biggest cause of neck tension is incorrect posture and stress in everyday life. Working permanently in the office can lead to muscular imbalance and manifest itself in the form of neck tension.In Repetitive Strain Injury Syndrome, there is a regular strain on the neck from repetitive movements, this can put all the more strain on the rectus capitis lateralis muscle and cause tension throughout the body. Occipital headaches can also originate from neck tension, which can be triggered by the rectus capitis lateralis muscle. The causes of occipital headaches can vary widely, but tension in neck muscles is likely. In case of tension, no medication is necessary, only heat and relaxation will help, so that the muscles can loosen up again and the tense position of the muscles will decrease. Cold as well as heat treatment may also prove helpful, as the rectus capitis lateralis muscle can come out of its shortened position, allowing the tension to subside.
