The =superficial fascia= presents no special features. The =lumbo-dorsal
fascia= (Fascia lumbo-dorsalis) closely invests the muscles, but is
easily stripped off the longissimus. It is attached medially to the
supraspinous ligament and the spinous processes of the vertebræ;
laterally, it divides into two layers. The superficial layer is
practically the aponeurosis of the latissimus dorsi. The deep layer
gives origin to the serratus anticus and posticus, the lumbar part of
the obliquus externus abdominis, the transversus abdominis, and the
retractor costæ. Its lateral edge curves under the longissimus and is
attached to the ribs and lumbar transverse processes. Posteriorly, it is
continuous with the gluteal fascia. At the withers it forms an important
structure, the =dorso-scapular ligament=. This is a strong tendinous
sheet, attached to the third, fourth, and fifth thoracic spines. Its
upper part is very thick and gives origin by its superficial surface to
the rhomboideus dorsi, by its anterior part to the splenius. The lower
part is thin and elastic, and furnishes numerous lamellæ which intersect
the scapular part of the serratus and are attached with it to the
scapula. Three lamellæ are detached from the deep face of the ligament.
The deepest of these passes between the longissimus and spinalis and is
attached to the transverse processes of the first seven thoracic
vertebræ; it gives attachment to the complexus. The middle one dips in
between the longissimus and transversalis costarum. The superficial one
gives origin to the serratus anticus. A strong fascial layer, the
ilio-lumbar ligament, extends from the last rib to the external angle of
the ilium.
There are nine pairs of muscles in this region, arranged in four layers.