Dorsal parts of lateral intertransversarii lumborum muscles
Partes dors. musculorum intertransversariorum lat. lumborum
The dorsal parts of the lateral lumbar intertransversarii are small slips linking the accessory process of one lumbar vertebra to the transverse process below.
At a glance
- English
- Dorsal parts of lateral intertransversarii lumborum muscles
- Latin (TA2)
- Partes dors. musculorum intertransversariorum lat. lumborum
- System
- Muscle
- Region
- Back
- Side
- Paired, left and right
About the dorsal parts of lateral intertransversarii lumborum muscles
The intertransversarii are short muscles between the transverse processes of neighbouring vertebrae. In the lumbar region they form two sets on each side. The medial set runs between the accessory and mamillary processes and belongs to the true back muscles. The lateral set fills the whole gap between two transverse processes, and each lateral muscle can be split further into a ventral part in front and a dorsal part behind.
Each dorsal part runs from the accessory process, the small knob at the back of the root of the transverse process, of one lumbar vertebra down to the next transverse process beneath. The slips are short and thin, lie in the angle between the transverse processes behind the ventral parts, and are covered behind by the deep back muscles.
Although small, the dorsal parts sit at the side of the lumbar spine and can bend it towards their own side, with quadratus lumborum and the larger muscles doing most of the work. They also help to steady each segment during movement. Like other very small spinal muscles they are packed with muscle spindles, so a large part of their value is probably in signalling the position of each vertebra to the nervous system.
Both the dorsal and ventral parts of the lateral lumbar intertransversarii are supplied by ventral rami of the lumbar spinal nerves. This places them, by development, with the body-wall muscles rather than with the true back muscles, whose supply comes from dorsal rami. Their blood comes from branches of the lumbar arteries.
Attachments, action and supply
- Origin
- Accessory process of a lumbar vertebra.
- Insertion
- Transverse process of the next lumbar vertebra down.
- Action
- Helps to bend the lumbar spine to the same side and steady each segment; supplies position sense.
- Nerve supply
- Ventral rami of the lumbar spinal nerves.
- Blood supply
- Dorsal branches of the lumbar arteries.
Anthromica
See the dorsal parts of lateral intertransversarii lumborum muscles where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
