Semispinalis muscle

Semispinalis muscle
	Back muscles of humans ; (M. semispinalis thoracis and M. semispinalis cervicis only shown on the left, M. semispinalis capitis only shown on the right)
origin
	Transverse and teat processes of the thoracic and cervical vertebrae
approach
	Spinous processes of the vertebrae , occiput
function
	Stretching and sideways bending of the spine
Innervation
	Spinal nerves ( rami dorsales )

Musculus semispinalis (plural: Musculi semispinales; Latin for "half thorn muscle") is the name of three skeletal muscles lying on the spine that belong to the " local back muscles ", more precisely to their transversospinal system ( Systema transversospinale ). It forms the superficial layer of the Systema transversospinale. The name is derived from their position on the side of the spinous processes of the vertebrae ( processus spinosi ), on the outside the longissimus muscle lies against them. In humans, a distinction is made between a semispinalis thoracis muscle ("half thorn muscle of the chest"), cervicis ("half thorn muscle of the neck") and capitis ("half thorn muscle of the head"). The innervation takes place through the dorsal branches of the corresponding spinal nerves (Th4-Th6, C3-C6 and C1-C5). They act as a straightener, with one-sided effect as a sideways bender of the corresponding spinal column sections.

Semispinalis thoracis muscle

The semispinalis thoracis muscle (from the Latin thorax , thorax ) arises from the teat processes ( processus mamillares ) of the 6th to 12th thoracic vertebrae and attaches to the spinous processes of the first four thoracic and last two cervical vertebrae .

In carnivores and ruminants , the chest and neck part of the semispinalis muscle are completely fused with the spinalis muscle , which is why the muscle is referred to here as the spinalis et semispinalis thoracis et cervicis muscle . In horses and pigs , no semispinalis thoracis muscle is developed.

Semispinalis cervicis muscle

The semispinalis cervicis muscle (from Latin cervix " neck ") arises from the transverse processes of the first 5 to 6 thoracic vertebrae and attaches to the spinous processes of the 2nd to 7th cervical vertebrae.

While it is not developed as an independent muscle in predators and ruminants (see above), it is completely absent in horses and pigs.

Semispinalis capitis muscle

The semispinalis capitis muscle (from Latin caput "head") arises from the transverse processes of the 3rd cervical to the 6th thoracic vertebra and attaches between the neck lines of the occiput . Laterally it is covered by the splenius muscle . The occipital lymph nodes lie above the insertion .

In predators, ruminants, and pigs, the semispinalis capitis muscle is divided into two muscles called the complexus and biventer cervicis muscles .

Individual evidence

↑ ^a ^b ^c ^d Michael Schünke: Functional Anatomy - Topography and Function of the Movement System . Georg Thieme, Stuttgart 2000, ISBN 978-3-13-118571-6 , p. 174 .
^ Werner Platzer: Pocket Atlas of Anatomy . tape 1 . Georg Thieme, Stuttgart 2009, ISBN 978-3-13-492010-9 , p. 74 .
↑ ^a ^b ^c Hermann Bragulla: Anatomy of domestic mammals: Textbook and Color Atlas of study and practice . Schattauer, Stuttgart 2009, ISBN 978-3-7945-2650-5 , p. 129 .
↑ Detlev Drenckhahn (Ed.): Anatomy, macroscopic anatomy, embryology and human histology . Elsevier, Urban & Fischer, 16th ed. 2004, p. 176.

[Schünke-1] Michael Schünke: Functional Anatomy - Topography and Function of the Movement System . Georg Thieme, Stuttgart 2000, ISBN 978-3-13-118571-6 , p. 174 .

[2] Werner Platzer: Pocket Atlas of Anatomy . tape 1 . Georg Thieme, Stuttgart 2009, ISBN 978-3-13-492010-9 , p. 74 .

[Bragulla-3] Hermann Bragulla: Anatomy of domestic mammals: Textbook and Color Atlas of study and practice . Schattauer, Stuttgart 2009, ISBN 978-3-7945-2650-5 , p. 129 .

[4] Detlev Drenckhahn (Ed.): Anatomy, macroscopic anatomy, embryology and human histology . Elsevier, Urban & Fischer, 16th ed. 2004, p. 176.