Dissection of thoracic and lumbosacral regions of back from a posterior approach

Multifidus muscle in lumbar region

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Image #214-1
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Dissection of thoracic and lumbosacral regions of back from a posterior approach
Multifidus muscle in lumbar region
The iliocostalis and longissimus muscles have been retracted laterally and dissected to demonstrate nerves and blood vessels entering the muscles. The multifidus (8) has been exposed in the sacral, lumbar and lower thoracic regions. It should be noted that this muscle is more massive in the lumbosacral region and that its fascicles become progressively more slender in the thoracic area.
1 . Rib X
2 . Iliocostalis lumborum muscle (dissected to expose nerve and vascular supply)
3 . Longissimus thoracis muscle (dissected)
4 . Dorsal branches of lumbar arteries
5 . Internal oblique muscle
6 . Thoracolumbar fascia (cut off)
7 . Spinalis thoracis muscle
8 . Multifidus muscle
9 . Thoracolumbar fascia (posterior layer)
10 . Location of posterior superior iliac spine