Musculature surrounding the spine

Dru Yoga is an excellent way to help look after your back. In today’s blog, I’m looking at some of the muscles that surround the spine.

The muscles of the back play a key role in the flexibility and mobility of the spine and can be divided into superficial and deep muscles 1. The deep muscles are associated with support and movement of the spine, whereas the superficial muscles are also responsible for the movement of the upper arms and shoulders 1.

Superficial muscles

Figure 1 shows key superficial muscles of the back 5.

Figure 1: Superficial back muscles

Trapezius: the trapezius is a tripartite muscle that originates at the base of the skull and inserts at the lateral third of the clavicle, Acromion process and the spine of the scapula 6. It helps to rotate and hold the head in an upright position and also moves the shoulder blades (scapula) up and down, and rotates the shoulders forward and back 1,6.

Latissimus dorsi : the largest muscle of the back is the latissimus dorsi 1. It originates from the lower six thoracic vertebrae and the sacral and lumbar vertebrae – extending from the trapezius to the pelvis 1,6. The insertion point of the latissimus dorsi is just below the shoulder joint (in the bicipital groove of the humerus) 6. The latissimus dorsi is used when extending the arm or pulling the arm back towards the body – even against resistance, and when forcefully breathing in 1,6.

Levator scapulae, rhomboids (major and minor): the smaller superficial muscles of the back are the levator scapulae and the rhomboids (major and minor) 1. These muscles attach to the spine and the scapula. The levator scapula originates from the first three or four cervical vertebrae, whereas the rhomboids originate from the seventh cervical and upper five thoracic vertebrae. The insertion point is at the vertebral edge of the scapula for all of these muscles 1,6. They control the movement of the arms up and inwards 1,6.

Serratus posterior inferior: this muscle originates form the thoracolumbar vertebrae and inserts at the ribs. It acts to move the ribcage down when breathing out1. The serratus posterior superior (not shown in Figure 5) is positioned in the area of the rhomboids, underneath the shoulder blade and attaches to multiple ribs. It is responsible for the upwards movement of the upper ribs when breathing in.

Erector spinae: these muscles are also known as the sacrospinalis and are comprise the iliocostalis, iliocostalis, and the spinalis) (Figure 6). They originate from the sacrum, iliac crest, the vertebrae, and the ribs. They insert at the vertebrae, ribs, and the skull 6. The erector spinae help keep the spine upright and act to move the spine backwards and sideways 1,6.

 

Deep muscles

Figure 2 shows some of the deep muscles of the back 5.

Figure 2: Deep muscles of the back

Semispinalis (capitis, thoracis, cervicis):  The semispinalis originates from cervical and thoracic vertebrae and insert at the skull, cervival and upper thoracic vertebrae 6. The semispinalis capitis helps to support and rotate the head, whereas the thoracis and cervicis extend the spine and head and assist with rotation of vertebrae 1,6.

Levatores costarum: these muscles originate from the seventh cervical and upper  thoracic vertebrae and insert into the ribs. The levatores costarum elevate the ribs during breathing 1,6.

Splenius capitas and cervicis: the splenius capitas originates from the seventh cervivcal vertebra and inserts at the temporal bone and the sternocleidomastoideus6. The splenius cervicus originates from the thoracic vertebrae and inserts at the cervical vertebrae 6. These muscle act to extend the head and neck and individually laterally flex the neck and turn the face 6.

Figure 2: Quadratus lumborum

Quadratus lumborum: the quadratus lumborum lies below the thoracolumbar fascia and originates from the iliac crest and the fifth lumbar vertebrae 6. Its insertion point is at the twelfth rib and the upper four lumbar vertebrae 6. This muscle cause lateral flexion of the spine and helps maintain an upright posture 1,6.

Obliques and rectus abdominis: the obliques and the rectus abdominus do not attach to the spine but form part of the major core muscles which are essential for maintaining a healthy spine. I’ll look at core stability another time.

Hope you’re enjoying the anatomy blogs! Namaste.

References

  1. Abrahams PH. How the Body Works. London: Amber Books; 2012.
  2. Key S. Sarah Key’s Back Sufferers’ Bible. London: Vermilion; 2007.
  3. Kaminoff L, Matthews A, Ellis S. Yoga Anatomy. Champaign, IL: Human Kinetics; 2007.
  4. Sullivan K, Royal College of General Practitioners. 5-minute Back Relief. London: Collins; 2007.
  5. Long R, Macivor C. The Key Muscles of Yoga: Your Guide to Functional Anatomy in Yoga. [S.l.]: Bandha Yoga Publications; 2006.
  6. Jarmey C. The Concise Book of Muscles. Chichester, England; Berkeley, Calif.: Lotus Pub. ; North Atlantic Book; 2008.