The Subcostales (singular: subcostalis) (Infracostales) consist of muscular and
aponeurotic
An aponeurosis (; plural: ''aponeuroses'') is a type or a variant of the deep fascia, in the form of a sheet of pearly-white fibrous tissue that attaches sheet-like muscles needing a wide area of attachment. Their primary function is to join muscl ...
fasciculi
Fascicle or ''fasciculus'' may refer to:
Anatomy and histology
* Muscle fascicle, a bundle of skeletal muscle fibers
* Nerve fascicle, a bundle of axons (nerve fibers)
** Superior longitudinal fasciculus
*** Arcuate fasciculus
** Gracile fas ...
, which are usually well-developed only in the lower part of the
thorax
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...
; each originates from the inner surface of one
rib, and is inserted into the inner surface of the second or third rib below, near its angle.
Their fibers run in the same direction as those of the
Intercostales interni
The internal intercostal muscles (intercostales interni) are a group of skeletal muscles located between the ribs. They are eleven in number on either side. They commence anteriorly at the sternum, in the intercostal spaces between the cartilages ...
.
Depresses the ribs to assist in expiration.
References
Muscles of the torso
{{muscle-stub