Soft Tissues of the Back - Deep

Soft Tissues of the Back - Deep

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Deep Tissues

A. Deep or intrinsic muscles

1.Muscles of the superficial layer: spinotransverse group

• Consist of the splenius capitis and the splenius cervicis .
• Originate from the spinous processes and insert into the transverse processes (splenius cervicis) and on the mastoid process and the superior nuchal line (splenius capitis).
• Are innervated by the dorsal primary rami of the middle and lower cervical spinal nerves.
• Extend, rotate , and laterally flex the head and neck.

2. Muscles of the intermediate layer: sacrospinalis group

• Consist of the erector spinae (sacrospinalis) , which is divided into three columns: iliocostalis (lateral column), longissimus (intermediate column), and spinalis (medial column).
• Originate from the sacrum, ilium, ribs, and spinous processes of lumbar and lower thoracic vertebrae.
• Insert on the ribs (iliocostalis); on the ribs, transverse processes, and mastoid process (longissimus); and on the spinous processes (spinalis).
• Are innervated by the dorsal primary rami of the spinal nerves.
• Extend, rotate , and laterally flex the vertebral column and head.
  

3.Muscles of the deep layer: transversospinalis group

• Consist of the semispinalis (capitis, cervicis, and thoracis), the multifidus , and the rotators
• The semispinalis muscles originate from the transverse processes and insert into the skull (semispinalis capitis) and the spinous processes (semispinalis cervicis and thoracis).
• The rotators run from the transverse processes to spinous processes two vertebrae above (longus) and one vertebra above (brevis).
  The multifidus originates from the sacrum, ilium, and transverse processes and inserts on the spinous processes. It is best developed in the lumbar region.
• Are innervated by the dorsal primary rami of the spinal nerves.
• Extend and rotate the head, neck, and trunk.

B. Segmental muscles

• Are innervated by the dorsal primary rami of the spinal nerves.
• Consist of the following:

1.Interspinals

• Run between adjacent spinous processes and aid in extension of the vertebral column.

2. Intertransversarii

• Run between adjacent transverse processes and aid in lateral flexion of the vertebral column.

3. Levatores costarum (longus and brevis)

• Extend from the transverse processes to ribs and elevate the ribs.

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