Intertransversarii muscle group

The intertransversarii muscles are small and short muscles found in the deepest layer of the intrinsic back muscles that stretchextending between the transverse processes of the adjacentadjacent cervical and lumbar vertebrae. Most intertransversarii pairs are located within the cervical and lumbar regions of the spine with some small muscular slips present in the lower thoracic region.

Cervical intertransversarii

The cervical intertransversarii are comprised ofsubdivided into seven pairs of anterior and posterior muscles that extend along the sides of the cervical spine. These muscles are better developed thanwhile the lumbar intertransversarii are subdivided into four pairs of medial and lateral muscles.

SummaryCervical intertransversarii

• origin:

  • anterior cervical intertransversarii: anterior tubercles of transverse processes of cervical vertebrae (C1 - T1)

  • posterior cervical intertransversariiinsertion: superior borders of transverse processes of cervical vertebrae

• insertion

  • anterior cervical intertransversarii: anterior tubercles of transverse processes of adjacent cervical vertebrae

  • posterior cervical intertransversarii: inferior borders of transverse processes of adjacent cervical vertebrae above(C1 - T1)

• action: lateral flexion and stabilisation of the cervical spine

• blood supply: vertebral, deep cervical, ascending cervical, and occipital arteries

• innervation

  • anterior cervical intertransversarii: ventral rami of cervical spinal nerves

  • posterior cervical intertransversarii: ventralanterior and dorsalposterior rami of cervical spinal nerves

  Lumbar intertransversarii

  • origin: transverse and accessory processes of contiguous lumbar vertebrae (L1 - L4)

  • insertion: mammillary and transverse processes of contiguous lumbar vertebrae (L1 - L4)

  • action: lateral flexion of cervical spine,and stabilisation of cervical spine

  Gross anatomy

  Origin

  Each anterior cervical intertransversarii muscle originates from the anterior tubercle of the transverse process of the cervical vertebra. Each posterior cervical intertransversarii muscle originates from the superior border of the transverse process of the cervical vertebra.

  Insertion

  Each anterior cervical intertransversarii muscle inserts on the anterior tubercle of the adjacent cervical vertebra, while each posterior cervical intertransversarii muscle inserts on the inferior border of the transverse process of the adjacent cervical vertebra above.

  Arterial supply

  The anterior cervical intertransversarii muscles receive arterial blood supply from the occipital, deep cervical and vertebral arteries. The occipital artery arises from the external carotid artery, the deep cervical artery originates from the costocervical trunk, while the vertebral artery is a branch of the subclavian artery. The posterior cervical intertransversarii muscles are supplied by the ascending cervical artery of the thyrocervical trunk.

  Innervation

  The anterior cervical intertransversarii muscles are innervated by the ventral rami of the cervical spinal nerves, while the posterior cervical intertransversarii are supplied by the ventral and dorsal rami of the cervical spinal nerves.

  Action

  The anterior and posterior cervical intertransversarii muscles aid in lateral flexion of the cervical spine in addition to stabilising the cervical spine.

  Lumbar intertransversarii

  The lumbar intertransversarii are composed of four pairs of muscles located on either side of the lumbar spine extending between the transverse processes of two adjacent lumbar vertebrae. Each pair consists of a medial and lateral component, namely, the medial and lateral lumbar intertransversarii muscles.

  Summary

  • origin

    • medial lumbar intertransversarii: accessory processes of L1 - L4 vertebrae

    • lateral lumbar intertransversarii: transverse and accessory processes of L1 - L4 vertebrae

  • insertion

    • medial lumbar intertransversarii: mammillary processes of adjacent lumbar vertebrae

    • lateral lumbar intertransversarii: transverse processes of adjacent lumbar vertebrae

  • blood supply: branches of lumbar arteries

  • innervation: ventralanterior and posterior rami of lumbar spinal nerves

  Gross anatomy

  Relations

  Cervical intertransversarii

  • actionanterior cervical intertransversarii: deep to the posterior cervical intertransversarii, posterior to the longus colli, and medial to the scalene muscles

  • posterior cervical intertransversarii lateral flexion: lie superficially to the anterior cervical intertransversarii with the anterior rami of lumbar spine, stabilisation of lumbar spinecervical spinal nerves running in between

  Gross anatomy

  Origin

  Lumbar intertransversarii

  • Themedial lumbar intertransversarii: lateral to the lumbar vertebral bodies and medial to the lateral lumbar intertransversarii muscles

  • lateral lumbar intertransversarii: located anterior to the multifidus and rotator longus, posterior to the iliopsoas, and medial to the quadratus lumborum and intertransverse ligaments

  Origin

  Cervical intertransversarii

  • anterior cervical intertransversarii: originate from the anterior tubercle of the transverse processes of the C1 (atlas) to T1 vertebrae

  • posterior cervical intertransversarii: originate from the superior aspect of the transverse processes of the C1 to T1 vertebrae

  Lumbar intertransversarii

  • medial lumbar intertransversarii: originate from the accessory processes of the L1 to L4 vertebrae

  • lateral lumbar intertransversarii: arise from the transverse and accessory processes of the 1^stL1 to 4^thlumbarL4 vertebrae (L1

  Insertion

  Cervical intertransversarii

  • anterior cervical intertransversarii: insert onto the anterior tubercle of the corresponding adjacent transverse process (C1 - L4T1). The

  • posterior cervical intertransversarii: attach to the inferior aspect of the transverse process of the corresponding superior vertebra (C1 - T1)

  Lumbar intertransversarii

  • medial lumbar intertransversarii muscles arise from: insert onto the accessory processesmammillaryprocess of the first fourassociated lumbar vertebrae (L1 - L4).

    Insertion

  • The muscle fibreslateral lumbar intertransversarii: insert onto the transverse process of the lateralassociated lumbar vertebra (L1 - L4)

  Action

  The intertransversarii insert onmuscle group assist the transverse processeserector spinae, multifidus, and semispinalis in ipsilateral flexion of the adjacent lumbar vertebraeneck and trunk when contracting unilaterally. The medial lumbar intertransversarii muscles insert onAdditionally, they play a supportive role during body movement by stabilising the mammillary processes of the adjacent lumbar vertebraespine when contracting bilaterally.

  Arterial supply

  Cervical intertransversarii

  • anterior cervical intertransversarii: recieve blood supply from the occipital artery (a branch of the external carotid), the deep cervical artery (a branch of the costocervical trunk), and the vertebral arteries (a branch of the subclavian artery)

  • posterior cervical intertransversarii: supplied by the ascending cervical artery, which arises from the inferior thyroid artery (a branch of the thyrocervical trunk)

  Lumbar intertransversarii

  The medial and lateral lumbar intertransversarii muscles receive arterial blood supply from the dorsal branches of thelumbar arteries that arise (arising from theabdominal aorta).

  Innervation

  Cervical intertransversarii

  • Theanterior cervical intertransversarii: innervated by the anterior rami of the cervical spinal nerves (C1 - C7)

  • posterior cervical intertransversarii: innervated by the anterior and posterior rami of the cervical spinal nerves (C1 - C7)

  Lumbar intertransversarii

  Both medial and lateral lumbar intertransversarii muscles are innervated by the ventralanterior rami of the lumbar spinal spinal nerves (L1 - L4).

  Action

  The lumbar intertransversarii muscles aid in lateral flexion and stabilisation of the lumbar spine.