Chp 4 Spine and Thorax AOIN

About Transversospinalis Group

Deep to the erector spinea muscle group is the transversospinalis muscle group. the transversospinalis is composed of three branches- multifidi, rotators and semispininalis--and extends the length of the vertebral column. unlike the long, vertical erector fibers, the branches of the transversospinalis consist of many short fibers. These fibers form an intricate stitch like design that links the veterbrae together. The name transversospinalis refers to the fact that the fibers of this muscle group extend at varying lengths from the transverse and spinous processes of the vertebrae.

Abdominals The four abdominal muscles expand beyond the stomach region. * form a muscular girdle that reaches around the side of the thorax to the thoracolumbar aponeurosis, superiorly to the middle of the ribs and inferior to the inguinal ligament. the immense span of these muscles, with its unique overlapping arrangement and varying fiber direction, helps stabilize the entire abdominal region.

Rectus Abdominis, External Oblique, Internal Oblique, Transverse Abdominis

Suboccipitals The Suboccipitals are the deepest muscles. They are located at the base of the head.

Rectus Capitis Posterior Major, Rectus Capitis Posterior Minor, Oblique Capitis Superior, Oblique Capitis Inferior

Erector Spinae Group The large Erector Spinae group is the most superficial of the spinal muscles and has three major branches.

Spinalis, Longissimus, Iliocostalis. Action- Unilaterally: Laterally flex vertebral column to the same side. Bilaterally: Extend the vertebral column. Origin- Common tendon (thoracolumbar aponeurosis) that attaches to the posterior surface of sacrum, iliac crest, spinous processes of lumbar and last two thoracic vertebrae. Insertion-Various attachments at the posterior ribs, spinous processes of the lumbar and last two thoracic vertebrae. Nerve- Spinal

Semispinalis Capitis located along the thoracic and cervical vertebrae and ultimately reaches the cranium. both semispinalis muscles form the twin "speed bumps" easily seen on the posterior neck when the neck is extended against resistance.

Action- Extend the vertebral column and head Origin- TVP of C-4 to T-5 Insertion- Between the superior and inferior nuchal lines of the occiput Nerve- Cervical

Rectus Abdominis The revered "washboard belly" is formed by the multiple superficial bellies of the rectus abdominis

Action- Flex the vertebral column. Tilt pelvis posteriorly. Origin- Pubic crest, Pubic Symphysis. Insertion- Cartilage of fifth, sixth, and seventh ribs and xiphoid process. Nerve: T7-11

Intertransversarii As their name suggests, these small, short muscles span between the transverse processes. They are the deepest muscles in the cervical and lumbar regions and, for this reason, are nearly impossible to detect, let alone access.

Action- Unilaterally: Laterally flex the vertebral column to the same side. bilaterally extend the vertebral column Nerve: Spinal

Internal Oblique The thin internal oblique fibers are deep and perpendicular to the external oblique fibers and can be difficult to distinguish.

Action- Unilaterally: Laterally flex vertebral column to the same side. Rotate vertebral column to the same side. Bilaterally: Flex the vertebral column. Compress abdominal contents. O: Lateral inguinal ligament, iliac crest and thoracolumbar fascia. I: Internal surface of lower 3 ribs, abdominal aponeurosis to linea alba. Nerve- T9-12, L1,

Iliocostalis The long tendons of the iliocostalis extend laterally beneath the scapula. Branches of the Iliocostalis group: Iliocostalis Lumborum, Iliocostalis Thoracis, Iliocostalis Cervicis.

Action- Unilaterally: Laterally flex vertebral column to the same side. Bilaterally: Extend the vertebral column. Iliocostalis Lumborum O: Common tendon. I: TVP of lumbar vertebrae 1-3 and posterior surface of ribs 6-12. Iliocostalis thoracis and Cervicis O: Posterior surface of ribs. Iliocostalis Thoracis I: Posterior Surface of ribs 1-6. Iliocostalis Cervicis I: Transverse processes of lower cervicals. Nerve: Spinal

Longissimus The thick Longissimus and lateral iliocostalis form a visible mound alongside the lumbar and thoracic spine. Branches of the erector Longissimus group: Longissimus Thoracis, Longissimus Cervicis, Longissimus Capitis

Action- Unilaterally: Laterally flex vertebral column to the same side. Bilaterally: Extend the vertebral column. Longissimus Thoracis O: Common Tendon. I: Lower nine ribs and TVP of thoracic vertebrae. longissimus Cervicis and Capitis O: TVP of upper five thoracic vertebrae. Longissimus Cervicis I: Transverse processes of cervical vertebrae. Longissimus Capitis I: Mastoid process of temporal bone. Nerve: Spinal

Spinalis is the smallest of the three muscles and lies closest to the spine and lamina groove. Branches of the erector spinea group: Spinalis Thoracis, Spinalis Cervicis

Action- Unilaterally: Laterally flex vertebral column to the same side. Bilaterally: Extend the vertebral column. Spinalis Thoracis O: Spinous processes of the upper lumbar and lower thoracic vertebra. I: Spinous processes of upper thoracic Spinalis Cervicis O: Ligmentum Nuchae, Spinous process of C-7. Insertion: Spinous process of cervical except C-1 Nerve: Spinal

Quadratus Lumborum the deepest muscle of the abdomen. Stretching from the posterior ilium to the transverse processes of the lumbar vertebrae and the twelfth rib, this squat muscle is simply an abdominal muscle located on the posterior surface of the thorax. while the medial portion of the quadratus lumborum is buried beneath the thoracolumbar aponeurosis and the thick erector spinea, its lateral edge is accessible from the side of the torso.

Action- Unilaterally: Laterally tilt (elevate) the pelvis. Laterally flex the vertebral column to the same side. Assist to extend the vertebral column. Bilaterally: Fix the last rib during forced inhalation and exhalation. Origin- Posterior iliac crest. Insertion- Last rib and TVP of 1st through 4th lumbar vertebrae. Nerve: Lumbar Plexus

Splenius capitis and Splenius Cervicis The long splenius capitis and the splenius cervicus muscles are located along the upper back and posterior neck. On contrast to the other back muscles that run parallel to the spine, the splenii fibers run obliquely. The Splenius Capitis is deep to the trapezius and rhomboids. its fibers angle toward the mastoid process and are superficial between the trapezius and the sternocleidomastoid. The splenius cervicis is deep to the splenius capitis and is not easily isolated; however, its general location can be outlined in the lamina groove of the upper thoracic and cervical spine.

Action- Unilaterally: Rotate head and neck to the same side. Laterally flex the head and neck to the same side. Splenius Capitis O: Inferior one-half of ligamentum nuchae and spinous processes of c-7 to T-4. I: Mastoid process and lateral portion of superior nuchal line. Splenius Cervicis O: Spinous processes of T-3 to T-6. Insertion: TVP of C-1 to C-3 Nerve: Cervical

Multifidi and Rotatores The surprisingly thick multifidi are directly accessible to the lumbar spine. they are the only muscles with fibers that lie across the posterior surface of the sacrum. The shorter smaller rotatores lie deep to the multifidi.

Action- Unilaterally: Rotate the vertebral column to the opposite side Bilaterally: Extend the vertebral column. Multifidi O: Sacrum and TVP of lumbar through cervical vertebrae Rotatores O: TVP of lumbar through cervical vertebrae I:- Spinous processes of lumbar vertebra through second cervical vertebrae (multifidi span two to four vertebrae) (Rotatores span one or two vertebrae) Nerve- Spinal

External Oblique Lateral to the rectus abdominis is the external oblique. the external oblique is a broad, superficial muscle best palpated at its attachments to the lower ribs.

Action-Unilaterally: Lateral flex vertebral column to the same side. Rotate vertebral column to the opposite side. Bilaterally: Flex the vertebral column. Compress abdominal contents. Origin- External surfaces of 5th to 12th ribs. Insertion- Anterior part of the iliac crest, abdominal aponerosis to linea alba. Nerve- T7-11

Intercostals Are small, slender muscles between the ribs. They are divided into two groups; the external and internal intercostals. the fibers of these two groups run perpendicular to each other and can be visualized as extensions of the external and internal oblique muscles. The intercostals help: * stabilize the rib cage * assist in respiration

Action: External Intercostals- Draw the ribs superiorly (increasing the space of the thoracic cavity) to assist with inhalation. Internal Intercostals- Draw the ribs inferiorly (decreasing the space of the thoracic cavity) to assist with exhalation. Nerve: Thoracic

Transverse Abdominis The transverse abdominis, the deepest muscle of the group, plays a major role in forced exhalation. It cannot be specifically palpated.

Action: Compress abdominal contents. O: Lateral inguinal ligament, iliac crest, thoracolumbar fascia and internal surface of lower six ribs. I: Abdominal aponeurosis to line alba. Nerve: T7-12, L1,

Serratus Posterior Inferior Although they are sandwiched between the shoulder muscles and the erector spinae group, these two broad muscles only affect movement of the ribs. The inferior is deep to the thoracolumbar aponerosis and, during exhalation, can stabilize the ribs against the pull of the diaphragm.

Action: Depress the ribs during exhalation. Nerve: T9, 10, 11, (12)

Diaphragm The diaphragm is the primary muscle of respiration. Its broad umbrellalike shape separates the upper and lower thoracic cavities. the diaphragm's muscle fibers attach to the inner surface of the ribs and the lumbar vertebrae and converge at the central tendon. the diaphragm creates inspiration (inhalation) when its muscle fibers contract and pull at the central tendon inferiorly. Because the central tendon is attached to the connective tissue that surrounds the lungs, a vacuum is created in the upper thoracic cavity, pulling air into the lungs. On exhalation, the muscle fibers of the diaphragm relax, releasing the central tendon and allowing the lungs to deflate.

Action: Draw down the central tendon of the diaphragm. Increase the volume of the thoracic cavity during inhalation. Nerve: Phrenic c3, 4, 5

Serratus Posterior Superior Although they are sandwiched between the shoulder muscles and the erector spinae group, these two broad muscles only affect movement of the ribs. The belly of the Superior is partially deep to the scapula and has fibers that parallel the superficial rhomboids.

Action: Elevate the ribs during inhalation. Nerve: T1,2,3,4

Interspinalis Extending from the spinous processes in the cervical and lumbar regions, these short muscles help extend the spine. The cervical muscles are deep to the ligamentum nuchae while the lumbar muscles are deep to the interspinous ligament. like the intertransversarii, these muscles are too deep to isolate.

Action: Extend the vertebral column. Nerve: Spinal

Oblique Capitis Superior

Action: Laterally flex the head to the same side. Rock and tilt the head into extension. Nerve: Suboccipital

Rectus Capitis Posterior Minor

Action: Rock and tilt head back into extension. Nerve: Suboccipital

Oblique Capitis Inferior

Action: Rotate the head to the same side. Nerve: Suboccipital

Rectus Capitis Posterior Major

Action: Rotate the head to the same side. Rock and tilt the head back into extension. Nerve: Suboccipital

Transversospinalis Group Transversospinalis Group has three major branches and lies deep to the erectors. Its name refers to its muscle fibers, which extend at varying lengths from the transverse, and spinous processes of the vertebrae.

Multifidi, Rotatores, Semispinalis Capitis can be felt along the lamina groove of the thoracic and lumbar vertebrae.

About the Suboccipitals: Rectus Capitis Posterior major, Rectus capitis Posterior Minor, Oblique Capitis Superior, Oblique Capitis Inferior

The eight small suboccipitals are the deepest muscles of the upper posterior neck. they are involved in stabilizing the axis and the atlas and in creating intrinsic movements such as rocking and tilting of the head.

The erector spinae group: Spinalis, Logissimus, Iliocostalis

The erector spine group runs from the sacrum to the occiput along the posterior aspect of the vertebral column. Its musculature has a dense layered arrangement and can be difficult to visualize. In the lumbar region, the erectors lie deep to the thin but dense thoracolumbar aponerurosis. In the thoracic and cervical areas, they are deep to the trapezius, the rhomboids, and the serratus posterior superior, and inferior. As a group the erectors are easily palpated along the entire length of the back and neck.

Longissimus cervicus, Longissimus Capitis, iliocostalis cervicis

The upper fibers of longissimus and iliocostalis muscles assist in extension, lateral flexion, and rotation of the neck to the same side. IL-ee-o-kos-TA-lis (L.) from hip to hip. longissimus lon-JIS-i-mus (L.) longest