Longissimus

The longissimus (Latin for " longest muscle ") is a skeletal muscle of the back, the so-called " stationary standing back muscles ", or more precisely to the sacrospinous System ( Systema sacrospinous ) belongs. It extends across the whole length of the back, from the sacrum to the head. It lies between musculus iliocostalis and musculus semispinalis, these three muscles are summarized erector as muscle spinae ( " erector spine " ) and belong to the " epaxial " ordinary muscles, means they are located dorsal side (dorsal ) of the transverse processes of the vertebrae ( transverse processes ).

Structure

The longissimus is divided into four ( horses 5) sections that follow each other like a backdrop:

• Longissimus lumborum ( the "longest muscle of the loin " )
• Longissimus thoracis ( " longest muscle of the chest " )
• Longissimus cervicis ( " longest muscle of the neck " )
• Longissimus atlantis ( the "longest muscle of the Atlas " ): only in horses, occasionally in dogs
• Longissimus capitis ( the "longest muscle of the head " )

The longissimus lumborum originates at the ilium and to the spinous processes of the vertebrae ( spinous processes ). The grain direction of the muscle fibers is cephalad - side ( craniolateral ). From its strong fascia is a split between longissimus muscle and the iliocostalis lowers, which is referred to as Bogorodsky intermediate tendon. Both muscles, practically in the lumbar region are inseparable. The muscle fibers put on the transverse processes of the vertebrae, some muscle spikes also to the additional extensions ( processus accessorii ).

The longissimus thoracis also arises from the spinous processes and is applied to the additional and transverse processes and the ribbed edges ( tuberosity musculi longissimi ). In the upper chest area ( in animals according to the front ) of the muscle is narrower and the tendons put on the costal tubercle of the ribs.

The longissimus cervicis originates on the transverse processes of the first 5-8 thoracic vertebrae and goes to the transverse processes of the last 3 to 5 cervical vertebrae.

A longissimus atlantis is clearly only in horses, occasionally it also occurs in dogs. It runs below the longissimus capitis and sets the atlas wing (Ala atlantis ) on.

The longissimus capitis originates on the transverse processes of the first thoracic and the articular processes ( processus articulares ) of the last cervical vertebra and sets the processus of the mastoid of the temporal bone.

Function

When bilateral contraction of the muscle causes an erection ( stretching) of the spine ( a swayback, lordosis) and the lifting of the neck. In unilateral contraction of the spine is bent sideways (see a scoliosis).