Major muscles of the neck and back include the erector spinae, multifidus, rectus abdominus, transversus abdominus, internal obliques, external obliques, splenius, and quadratus lumborum.
The quadratus lumborum muscle is a common muscle involved in lower back pain.
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 external oblique muscle is situated on either side of the abdomen and aid in the twisting movement of the trunk and contract strongly when doing sit-ups.
The internal oblique muscles are opposite to the external oblique muscles and are responsible for movement on the side that it is situated, so the right internus abdominal muscle twists to the right and the left internus abdominal muscle twists to the right. Transversus Abdominus
Transversus Abdominus is often abbreviated to TVA. This is a very important core muscle that is vital in maintaining good posture. Activities such as Pilates focus on contraction of the TVA.
Rectus Abdominus is the most superficial of the abdominal muscles. It is this muscle that forms the six-pack shape!
Multifidus is a series of small muscles that travel up the length of the spine. It is an important muscle in the rehabilitation of Gilmore’s Groin.
The erector spinae (sometimes known as sacrospinalis) is often described as a group of different muscles called iliocostalis, longissimus, and spinalis.