- Male reproductive system
- Lymphatic system
- Skeletal system
- Blood vessels
- Respiratory system
- Digestive system
- Endocrine glands
- Nervous system
- Female reproductive system
The neck connects the head with the rest of the body, and it contains various tissue, blood vessels, nerves, lymphatics and organs, including many skeletal muscles. The neck muscles are responsible for movements of the neck and head. Also, these muscles provide structural support for the head.
The muscles of the neck are usually divided into three groups according to their location:
- Anterior group
- Lateral group
- Posterior group
All these groups contain muscles that share the same compartment of the neck and have similar functions. For example, posterior neck muscles are located in the posterior aspect of the neck, and they are responsible for the extension of the neck.
The mentioned groups can be further subdivided into even smaller divisions that share the same depth and function. The anterior neck muscle group covers the anterior aspect of the neck, and it includes the following divisions:
- Superficial neck muscles
- Suprahyoid muscles
- Infrahyoid muscles
- Anterior vertebral (prevertebral) muscles
The superficial neck muscles are the most external muscles of the anterior neck, including the platysma and the sternocleidomastoid. The suprahyoid muscles are a group of muscles that elevates the hyoid bone and are located above it. In contrast, the infrahyoid muscles are situated below the hyoid bone and depress it. The suprahyoid muscles include the mylohyoid, geniohyoid, digastric and stylohyoid. The infrahyoid muscles are the sternohyoid, omohyoid, sternothyroid and thyrohyoid.
The anterior vertebral muscles are the deepest muscles of the anterior group. They got their name because of their location - they are situated anterior to the spine. Additionally, these muscles are surrounded by the prevertebral layer of the deep cervical fascia, so they are also called the prevertebral muscles. This group includes the longus colli, longus capitis, rectus capitis anterior and rectus capitis lateralis.
The lateral group muscles are positioned in the lateral compartment of the neck. This group includes three scalene muscles, and therefore the lateral neck muscle group is also known as the scalene muscles. All scalene muscles are named by their location - anterior, middle and posterior scalene.
Finally, the posterior neck muscles include four paired suboccipital muscles, and they are located in the upper posterior aspect of the neck below the occipital bone. These muscles can also be categorized among the deep muscles of the back, and they include the following - rectus capitis posterior major and minor and obliquus capitis superior and inferior muscles.
Several back muscles also extend up to the neck region and are partly connected with the cervical part of the vertebral column. These muscles include the trapezius, levator scapulae, splenius cervicis, iliocostalis, longissimus, rotatores, semispinalis, interspinales, and intertransversarii muscles. However, usually, they are not classified as neck muscles.