The iliocostalis is the muscle immediately lateral to the longissimus

Longissimus

The longissimus is the muscle lateral to the semispinalis. It is the longest subdivision of the sacrospinalis that extends forward into the transverse processes of the posterior cervical vertebrae.-Longissimus thoracis:...

 that is the nearest to the furrow that separates the epaxial

Epaxial and Hypaxial muscles

Trunk muscles can be broadly divided into hypaxial muscle, which lie ventral to the horizontal septum of the vertebrae and epaxial muscles, which lie dorsal to the septum. Hypaxial muscles include some vertebral muscles, the diaphragm, the abdominal muscles, and all limb muscles...

 muscles from the hypaxial

Epaxial and Hypaxial muscles

Trunk muscles can be broadly divided into hypaxial muscle, which lie ventral to the horizontal septum of the vertebrae and epaxial muscles, which lie dorsal to the septum. Hypaxial muscles include some vertebral muscles, the diaphragm, the abdominal muscles, and all limb muscles...

. It lies very deep to the fleshy portion of the serratus ventralis

Serratus anterior muscle

The serratus anterior is a muscle that originates on the surface of the upper eight or nine ribs at the side of the chest and inserts along the entire anterior length of the medial border of the scapula.-Origin:...

 (serratus anterior).

Iliocostalis lumborum

The Iliocostalis lumborum (Iliocostalis muscle'; Sacrolumbalis muscle) is inserted, by six or seven flattened tendon

Tendon

A tendon is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension. Tendons are similar to ligaments and fasciae as they are all made of collagen except that ligaments join one bone to another bone, and fasciae connect muscles to other...

s, into the inferior borders of the angles of the lower six or seven rib

Rib

In vertebrate anatomy, ribs are the long curved bones which form the rib cage. In most vertebrates, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. They serve to protect the lungs, heart, and other internal organs of the thorax...

s.

Iliocostalis dorsi

The Iliocostalis dorsi (Musculus accessorius; Iliocostalis thoracis) arises by flattened tendons from the upper borders of the angles of the lower six ribs medial to the tendons of insertion of the Iliocostalis lumborum; these become muscular, and are inserted into the upper borders of the angles of the upper six ribs and into the back of the transverse process of the seventh cervical vertebra

Cervical vertebrae

In vertebrates, cervical vertebrae are those vertebrae immediately inferior to the skull.Thoracic vertebrae in all mammalian species are defined as those vertebrae that also carry a pair of ribs, and lie caudal to the cervical vertebrae. Further caudally follow the lumbar vertebrae, which also...

.

Iliocostalis cervicis

The Iliocostalis cervicis (Cervicalis ascendens) arises from the angles of the third, fourth, fifth, and sixth ribs, and is inserted into the posterior tubercles

Posterior tubercle of cervical vertebra

The posterior arch of a cervical vertebra forms about two-fifths of the circumference of the ring: it ends behind in the posterior tubercle, which is the rudiment of a spinous process and gives origin to the Recti capitis posteriores minores....

 of the transverse processes of the fourth, fifth, and sixth cervical vertebrae.

See also

• Semispinalis muscle
  Semispinalis muscle
  The semispinalis muscle is a transversospinalis muscle of the human body. More specifically, it is one of three muscles:* Semispinalis dorsi* Semispinalis cervicis* Semispinalis capitis...
  
  
• Erector spinae
• Longissimus
  Longissimus
  The longissimus is the muscle lateral to the semispinalis. It is the longest subdivision of the sacrospinalis that extends forward into the transverse processes of the posterior cervical vertebrae.-Longissimus thoracis:...
  
  
• Spinalis
  Spinalis
  The spinalis is the portion of the erector spinae, a bundle of muscles and tendons, located nearest to the spine. It is divided into three parts.-Spinalis dorsi:...
  
  

External links

- "Intrinsic muscles of the back."

• Dissection at ithaca.edu