8. Muscles of the Spine and Rib Cage



Muscles of the Spine and Rib Cage


The muscles of this chapter are primarily involved with movement of the trunk, neck, and head at the spinal joints. Some of these spinal muscles can also move the mandible at the temporomandibular joints (TMJs). In addition, muscles of the rib cage are presented in this chapter. These muscles move the ribs at the sternocostal and costospinal joints.


The following is an overview of the structure and function of the spinal joint muscles presented in this chapter.


The companion CD at the back of this book allows you to examine the muscles of this body region, layer by layer, and individual muscle palpation technique videos are available in the chapter 8 folder on the Evolve website.


OVERVIEW OF FUNCTION: MUSCLES OF THE SPINAL JOINTS


Muscles of the spinal joints may be categorized based on three factors: (1) the region of the spine, (2) their location, and (3) their depth. Regionally, they may be divided into three groups: (1) those that run the full length of the spine, (2) those that are primarily located only in the trunk, and (3) those that are primarily located only in the neck. Regarding location, they can be described as being anterior or posterior. Regarding their depth, they can be divided based on whether they are superficial or deep. Generally, the larger, more superficial muscles of the spine are important for creating motion; and the deeper, smaller muscles function to stabilize the spine.


The following general rules regarding actions can be stated for the functional groups of muscles of the spinal joints:



ent If a muscle crosses the spinal joints anteriorly with a vertical direction to its fibers, it can flex the trunk, neck, and/or head at the spinal joints by moving the insertion (superior attachment) down toward the origin (inferior attachment) in front.


ent If a muscle crosses the spinal joints posteriorly with a vertical direction to its fibers, it can extend the trunk, neck, and/or head at the spinal joints by moving the origin (superior attachment) down toward the insertion (inferior attachment) in back.


ent If a muscle crosses the spinal joints laterally, it can perform same-side lateral flexion of the trunk, neck, and/or head at the spinal joints by moving the insertion (superior attachment) down toward the origin (inferior attachment) on that side of the body.


ent Right and left rotators of the spine have a horizontal component to their fiber direction and wrap around the body part that they move.


ent Reverse actions of these muscles involve the lower spine (origin; inferior attachment) being moved toward the upper spine (insertion; superior attachment) at the spinal joints. These reverse actions usually occur when the client is lying down so the lower attachment is free to move. If the muscle attaches onto the pelvis, the reverse action involves movement of the pelvis at the lumbosacral spinal joint as well.


ent The reverse action of flexion of the upper spine relative to the lower spine is flexion of the lower spine relative to the upper spine, and posterior tilt of the pelvis if the muscle attaches to it.


ent The reverse action of extension of the upper spine relative to the lower spine is extension of the lower spine relative to the upper spine, and anterior tilt of the pelvis if the muscle attaches to it.


ent The reverse action of lateral flexion of the upper spine relative to the lower spine is lateral flexion of the lower spine relative to the upper spine, and elevation of the same side of the pelvis (and therefore depression of the opposite side of the pelvis) if the muscle attaches to it.


ent The reverse action of ipsilateral rotation of the upper spine relative to the lower spine is contralateral rotation of the lower spine relative to the upper spine, and contralateral rotation of the pelvis if the muscle attaches to it.


ent The reverse action of contralateral rotation of the upper spine relative to the lower spine is ipsilateral rotation of the lower spine relative to the upper spine, and ipsilateral rotation of the pelvis if the muscle attaches to it.


OVERVIEW OF MUSCLES THAT MOVE THE MANDIBLE*


Muscles that move the mandible at the TMJs attach to the mandible. The other attachment of these muscles is usually considered to be either superior or inferior to the mandible attachment.


The following general rules regarding actions can be stated for functional groups of muscles that move the mandible:



OVERVIEW OF FUNCTION: MUSCLES OF THE RIB CAGE


Muscles that move the rib cage attach to the rib cage. The other attachment of these muscles is usually considered to be either superior or inferior to the rib attachment. These muscles may be located anteriorly, posteriorly, and/or laterally.


The following general rules regarding actions can be stated for the functional groups of muscles of the rib cage:






SPINE AND RIB CAGE: Erector Spinae Group


Iliocostalis; Longissimus; Spinalis


Pronunciation IL-ee-o-kos-TA-lis • lon-JIS-i-mus • spy-NA-lis



The erector spinae group is a large muscle group that runs parallel to the spine from the pelvis to the head. It is composed of three subgroups. From lateral to medial, they are the iliocostalis, longissimus, and spinalis (Figure 8-6). The erector spinae is most massive in the lumbar and thoracic regions. In the lumbar region, it is deep to the latissimus dorsi; in the thoracic region, it is deep to the trapezius and rhomboids. Very little erector spinae is present in the neck. Other than a small amount of spinalis, its presence in the neck is the longissimus capitis that is located more laterally and goes up to the mastoid process of the temporal bone. It is deep to the trapezius, splenius capitis, and splenius cervicis.





ACTIONS



STABILIZATION


INNERVATION



PALPATION




TREATMENT CONSIDERATIONS



ent Each of the three subgroups of the erector spinae can be further subdivided into three subgroups: (1) iliocostalis lumborum, thoracis, and cervicis; (2) the longissimus thoracis, cervicis, and capitis; and (3) the spinalis thoracis, cervicis, and capitis. Note: The spinalis capitis often blends with and is therefore considered part of the semispinalis capitis of the transversospinalis group.


ent Inferiorly, the erector spinae blends into the thick thoracolumbar fascia.


ent The erector spinae is the principal musculature that works when we bend forward. It contracts eccentrically to guide our descent when we bend forward; it contracts isometrically when we hold a bentforward posture; and it contracts concentrically when we stand back up.


image

ent Tight erector spinae musculature pulls the pelvis into anterior tilt, which then increases the lordotic curve of the lumbar spine.



SPINE AND RIB CAGE: Transversospinalis Group


Semispinalis; Multifidus; Rotatores


Pronunciation SEM-ee-spy-NA-lis • mul-TIF-id-us • ro-ta-TO-reez



The transversospinalis group musculature is deep and makes up the mass of musculature that fills the laminar groove of the spine between the transverse and spinous processes. The transversospinalis muscle group can be divided into three subgroups: from superficial to deep, they are the semispinalis, the multifidus, and the rotatores (Figure 8-8). The rotatores attach superiorly to the vertebrae one to two levels above the inferior attachment; the multifidus attaches superiorly to vertebrae three to four levels above the inferior attachment; the semispinalis attaches superiorly to vertebrae five or more levels above the inferior attachment. The multifidus is the largest muscle of the low back; the semispinalis is the largest muscle of the neck. Of the three subgroups of the transversospinalis, only the multifidus attaches onto the pelvis, and only the semispinalis attaches onto the head. The term paraspinal musculature is used to describe the erector spinae and the transversospinalis groups together.





ACTIONS



STABILIZATION


INNERVATION



PALPATION



1. The client is prone. Place your palpating finger pads just lateral to the spinous processes of the lumbar spine within the laminar groove.


2. Ask the client to extend and rotate the trunk slightly to the opposite side of the body (contralaterally rotate) at the spinal joints. Feel for the contraction of the transversospinalis musculature of the lumbar spine (Figure 8-9).


3. Repeat this procedure superiorly up the spine.


4. To palpate the semispinalis group in the cervical region, have the client prone with the hand in the small of the back. Place your palpating fingers over the laminar groove of the cervical spine and ask the client to extend the head and neck slightly at the spinal joints. Feeling for the contraction of the semispinalis deep to the upper trapezius (Figure 8-10).


5. Once located, follow the semispinalis up to the attachment on the head by strumming perpendicular to the direction of fibers.




TREATMENT CONSIDERATIONS





ACTIONS


Interspinales



Intertransversarii



STABILIZATION

As a group, the interspinales and intertransversarii stabilize the cervical and lumbar spinal joints.


INNERVATION



PALPATION


Interspinales





Intertransversarii



TREATMENT CONSIDERATIONS





ACTIONS


The serratus posterior muscles move ribs at the sternocostal and costospinal joints.


Serratus Posterior Superior



Serratus Posterior Inferior



STABILIZATION

Stabilizes the rib cage.


INNERVATION



PALPATION


The serratus posterior superior and inferior are thin muscles that are located deep to other muscles; therefore they are difficult to palpate and discern. If palpation is done, the client is prone.


Serratus Posterior Superior



Serratus Posterior Inferior



TREATMENT CONSIDERATIONS




ATTACHMENTS


Origin (Proximal Attachment)



Insertion (Distal Attachment)



ACTIONS


The quadratus lumborum moves the trunk at the spinal joints, the pelvis at the lumbosacral joint, and the twelfth rib at the costospinal joint.



STABILIZATION

Stabilizes the pelvis, lumbar spinal joints, and twelfth rib.


INNERVATION



PALPATION



1. The client is prone. Place your palpating finger pads just lateral to the lateral border of the erector spinae in the lumbar region.



Note: Placing the fingers of other hand on the palpating fingers for extra support can be helpful.


2.  First locate the lateral border of the erector spinae musculature. (To do so, ask the client to raise the head and upper trunk from the table.) Then place your palpating finger just lateral to the lateral border of the erector spinae.


3. Direct palpating pressure medially, deep to the erector spinae musculature, and feel for the quadratus lumborum.


4. To engage the quadratus lumborum, ask the client to elevate the pelvis on that side at the lumbosacral joint and feel for its contraction (Figure 8-16, A).



Note: The pelvis should move along the plane of the table toward the head; in other words, the pelvis should not lift up in the air, away from the table.


5. Once located, palpate medially and superiorly toward the twelfth rib, medially and inferiorly toward the iliac crest, and directly medially toward the transverse processes of the lumbar spine (Figure 8-16, B).



TREATMENT CONSIDERATIONS



ent When working on the quadratus lumborum, you can position the client either prone, supine, or side lying. However, because much of this muscle is deep to the massive erector spinae musculature, it must be accessed with palpatory pressure from lateral to medial (i.e., come in from the side).


ent Keep in mind that the quadratus lumborum is not the only muscle in the lateral lumbar region and should not be blamed for all the pain in this area. The nearby erector spinae musculature is also likely to develop tension and pain.


ent If the quadratus lumborum is tight, it can pull up on the pelvic bone, causing the iliac crest on that side to elevate. This elevation can be seen during the postural assessment examination.


image

ent The quadratus lumborum is important for stabilizing the twelfth rib when the diaphragm contracts during inspiration. Stabilization increases the efficiency of the diaphragm during breathing.



SPINE AND RIB CAGE: Intercostal Group


External Intercostals; Internal Intercostals


Pronunciation EKS-turn-al in-ter-KOS-tals • IN-turn-al in-ter-KOS-tals



The intercostal group is composed of the external intercostals and the internal intercostals (Figure 8-17). These muscles are located in the anterior, lateral, and posterior thoracic region of the trunk. Depending on the specific location, they may be deep to other muscles or they may be superficial and easily palpable. The fiber directions of these two muscle groups are perpendicular to each other. The fiber direction of the external intercostals is the same as the fiber direction of the external abdominal oblique; the fiber direction of the internal intercostals is the same as the fiber direction of the internal abdominal oblique.





ACTIONS



External Intercostals



Internal Intercostals



STABILIZATION

Stabilize the rib cage.


INNERVATION



PALPATION




TREATMENT CONSIDERATIONS



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Aug 22, 2016 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on 8. Muscles of the Spine and Rib Cage

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