Trunk & Spine Muscles
The spine consists of 24 vertibrae, 7 cervical (neck), 12 thoracic (chest), 5 lumbar (lower back), 5 fused bones of the sacrum and 4 fused bones in the coccyx or tailbone. The main muscles involved in moving the spine and neck are the rectus abdominus, internal and external obliques, quadratus lumborum, multifidus, sternocleidomastoid and errector spinae.
The internal obliques wrap around the waist and insert into the linea alba, a cord like strip of connective tissue running down the centre of the abdomen. They help to side bend and twist the body.
Transversus Abdominis is often abbreviated to TVA. This is a very important core muscle which is vital in maintaining good posture. Activities such as Pilates focus on contraction of the TVA.
Sternocleidomastoid (SCM) can clearly be seen when you turn your head to one side, on the opposite side of the neck.
Splenius is often divided into two muscles, splenius capitus (those fibres which insert on the skull) and splenius cervicis (those that insert onto the cervical transverse processes of the spine).
The obliques wrap around the trunk on each side to form our waists and join to the linea alba, a band of connective tissue running down the front of the abdomen. They help us to side bend and rotate the body.
Rectus Abdominis is the most superficial of the abdominal muscles. It is this muscle which forms the six-pack shape!
The quadratus lumborum or QL is a common cause of back pain which is to one side and comes on after lifting or twisting.
Multifidus is a series of small muscles which travel up the length of the spine. It is an important muscle in the rehabilitation of Gilmore's Groin and lower back pain.
The erector spinae (sometimes known as sacrospinalis) is often described as a group of different muscles called iliocostalis, longissimus and spinalis. Erector spinae consists of lots of small fibres which are situated very close to the spine.