Refleks va uning turlari Reja Oliy nerv faoliyatini o’rganishda I. M. Sechenovning «Bosh miya reflekslari»

covered by muscles of the shoulder girdle and the upper extremity in addition
to the true muscles of the trunk (Figs. 4.18a, b and 4.19). These
gradually extended their origins to the trunk in the course of phylogenetic
development. The muscles of the trunk are arranged in individual
segments like the skeleton. With the exception of a few muscles
(e. g., the intercostal muscles), the segments are often not maintained
but rather fuse with neighboring segments into larger muscles. The
musculature of the trunk is divided into the muscles of the back, the
chest, and the abdomen together with the diaphragm and the pelvic
muscles (Figs. 4.18a, b and 4.19).
The Back
The muscles of the back proper are applied directly to the skeleton and
run in two great muscular columns on each side of the vertebral column
from the neck to the pelvis. This group of muscles has the collective
name erector spinae (see Fig. 4.21). It is the actual segmental musculature
of the back and it may be contrasted with the muscles covering it,
which encroach on the back from the upper limb and are usually
classified with the muscles of the upper extremity. These encroaching
muscles are the muscles of the shoulder girdle, including the trapezius,
the greater and lesser rhomboid muscles (rhomboideus major and minor),
the levator scapulae (elevator of the shoulder), and one of the muscles of
the free upper extremity, the latissimus dorsi (broad muscle of the back)