Two very deep, connect right into skull and right into neck. On both the anterior side of the neck and lateral side. Calli muscles only work on the neck. Working together will flex head and straighten cervical spine. If working one at a time, they will assist in flexion and side-bending. These stabilize the neck during coughing.
You have three of these muscles. When working together, they act to flex the head and neck. When working separately, they will laterally flex the head and neck to the same side or rotate to the opposite side. Attachment area can cause it to pull in a different direction, that is why it's important to know the line of pull of a muscle. Go up into the occipital bone in the skull but on the anterior side. Attaches to different parts of the cervical spine.
Anterior on the cervical spine region. Have to do with the hyoid bone. Have four super-hyoids (2 on each side) and four infra-hyoids (2 on each side). GEeerally, what they do is to primarily keep the head and neck stabilized and are for swallowing. They resist you flexing forward as you are swallowing.
Anterior Head and Neck Muscles:
Longus Calli, Capitus, Hyoid-Strap Muscles
You have three of these: an anterior, a middle, and a posterior. Doesn't mean posterior on body, just means posterior in this group of muscles. Still on the lateral side of neck. They run from the cervical vertebrae into the first and second ribs. Together, they flex the cervical spine. Separately, they flex and laterally assist rotation to the same side.
Connection to sternum and mastoid. "Cleido" means clavicles. Has a little branch that starts on the manubrium where your clavicle meets, also have a little connection out at the calvicle as well. Goes up into the mastoid bone and connects behind and in front of hte ear. Can easily find this muscle, easily seen. The largest and more important anterior muscle!!! Together, performs flexion. Separately, laterally flex and also pulls like the capitus, will rotate to the opposite side.
Suboccipitals, Splenius Capitus, Splenius Cervius
Very short. You have four of these; two on each side: two obvliques capitus and two rectus capitus. Insert at the occipital bone in the back, originates in C1 and C2. Since it is only connected from C1 and C2 into the back of skull, it will only act on extension and hyperextension of hte head. Together, they extend/hyperextend the head. On one side, will laterally flex and rotate to the same side.
These are from C7 (last cervical vertebrae) as well as T3 and T4 (down into thoracic vertebrae) and insert into the mastoid bone/process of the skull. Acts more on the head. Works on lateral flexion and rotation of the head.
These run from C1, C3 down to T5 and T7. These do not involve the head. Has more to do with the cervical spine (only works cervical spine). Alone, these work in lateral flexion and rotation of the neck.
Deep Muscle Group of the Posterior Spine
This deep muscle group has many groups within it. These work very locally in a region of few spinous processes, but go very deep. These include Rotators, Interspinalous, Intertransversari, Levators Costera, etc. (know where theses are). They work locally in groups, but also work together to stabilize the entire spine. Symmetrically, they will perform extension and hyperextension when working together. Asymmetrically, they perform lateral flexion to the same side and some rotation to the opposite side, when working together. You need other things to counteract and aid in the movement. Have to assist each other
You have three of these. This is the layer more superficial to the layer of the deep muscle group (closer to skin). You have thoracic, cervicus, and capitus semispinalis. One involves head, one involves neck, and one involves more of the thoracic spine. This is a long strip of connection to these areas of the spine. Will extend, hyperextend the thoracic vertebrae, the cervical vertebrae. Alone, they will laterally flex and rotate to the same side.
Most superficial layer of muscle to the skin of the spine/Axial muscles. This has three branches, and they each have branches that connect out like fingers to different areas. The three branches are: Ilio-Pestalis, Longissimus, and Spinalis. These hyperextend the spine and head. Have one side with the anterior muscles, have lateral flexion. EAsier to feel because larger muscles. With cooperation of other muscles, same side and opposite side rotation of head and spine. Best exercise for strengthening these is hyperextension from a prone position, with arms and legs lifting (Superman exercise)
Ilio-Pestalis (Iliocostalis) branch of the Erector Spinae
Closer to Pelvis/Lumbar Region. Originate in a very large tendon in the lumbar, insert into the ribs of the thoracic region. Goes out to ribs. The most lateral muscles, coming from the ilium/lumbar region, and come out to ribs.
Longissimus branch of the Erector Spinae
Next layer inward from the iliopestalis. Appears as three muscles, but just one branch of Erector Spinae. Goes from lumbar into thoracic region, but also up to cervical region. There is a little siip of this that goes up into mastoid process.
Spinalis branch of the Erector Spinae
Most medial of Erector Spinae. Lies right against the vertebrae. Connects to the spinus processes of the entire spine. It is most significant in the thoracic region.
Best exercise for strengthening the Erector Spinae is ...
hyperextension from a prone position, with arms and legs lifting (Superman exercise)
Not a muscle, but a very large sheath. This is in the thoracolumbar region, where bottom of thoracic region meets the lumbar. A very deep sheath of fasciae. Binds your spinal muscles and your erector spinal muscles all together in the same area, so that they can work for stabilizing the spine. And separates them from your other back muscles, which have to do with the limbs.
Anterior Muscles of Trunk
There are four muscle groups that make up layers in trunk. A lot of pressure from the internal to the outside of the body. Transverse Abdominals, Internal Obliques, External Obliques, Rectus Abdominus. The three layers of flat muscles act to compress the abdominal contents during expiration, urination, and defecation. They assist in maintaining pressure on the curve of the lower back, resisting "sway back" and extension of the back.