Intrinsic muscles of the back Flashcards
Iliocostalis cervicis
O: Angle of 3rd-6th ribs
I: Transverse processes of C4-C6
A:
Bilateral: Spine extension
Unilateral: Lateral flexion of spine (ipsilateral)
In: Lateral branches of posterior rami of spinal n. (C8-L1)
Iliocostalis thoracis
O: Angle of 7th-12th ribs
I: Angle of 1st-6th ribs, and TP of C7
A:
Bilateral: Spine extension
Unilateral: Lateral flexion of spine (ipsilateral)
In: Lateral branches of posterior rami of spinal n. (C8-L1)
Iliocostalis lumborum
O: Lateral crest of sacrum, medial end of iliac crest, and posterior layer of thoracolumbar fascia
I: Angle of 5th (or 6th)-12th ribs, TP of L1-L4, and adjacent thoracolumbar fascia
A:
Bilateral: Spine extension
Unilateral: Lateral flexion of spine (ipsilateral)
In: Lateral branches of posterior rami of spinal n. (C8-L1)
Longissimus capitis
O: TP of C4-T5
I: Mastoid process (posterior margin)
A:
Bilateral: Head and neck extension
Unilateral: Lateral flexion and rotation of head (ipsilateral)
In: Lateral branches of posterior rami of spinal n. (C1-L5)
Longissimus cervicis
O: TP of T1-T5
I: TP of C2-C6
A:
Bilateral: Spine extension
Unilateral: Lateral flexion of spine (ipsilateral)
In: Lateral branches of posterior rami of spinal n. (C1-L5)
Longissimus thoracis
O:
Thoracic part - SP and TP of L1-L5, median sacral crest, posterior surface of sacrum, and posterior iliac crest
Lumbar part - Lumbar intermuscular aponeurosis, medial part of sacropelvic surface of ilium, and posterior sacroiliac ligament
I:
Thoracic part - TP of T1-T12, and angles of 7th-12th ribs
Lumbar part - Accessory and TP of L1-L5
A:
Bilateral: Spine extension
Unilateral: Lateral flexion of spine (ipsilateral)
In: Lateral branches of posterior rami of spinal nn. (C1-L5)
Splenius capitis
O: SP of C7-T3, and nuchal ligament
I: Mastoid process, and lateral superior nuchal line
A:
Bilateral: Head and neck extension
Unilateral: Lateral flexion and rotation of head (ipsilateral)
In: Lateral branches of posterior rami of spinal nn. (C2-C3)
Splenius cervicis
O: SP of T3-T6
I: TP of C1-C3
A:
Bilateral: Neck extension
Unilateral: Lateral flexion and rotation of neck (ipsilateral)
In: Lateral branches of posterior rami of lower cervical spinal nn.
Spinalis cervicis
O: SP of C7-T2, and nuchal ligament
I: SP of C2-C4
A:
Bilateral: Extension of cervical and thoracic spine
Unilateral: Lateral flexion of cervical and thoracic spine (ipsilateral)
In: Posterior rami of spinal nn.
Spinalis thoracic
O: SP of T11-L2
I: SP of T2- T8
A:
Bilateral: Extension of cervical and thoracic spine
Unilateral: Lateral flexion of cervical and thoracic spine (ipsilateral)
In: Posterior rami of spinal nn.
Rotator breves and longi
O and I:
From TP of T1-T12 to SP of the next higher vertebrae (RB) or two levels higher (RL)
A:
Bilateral: extension of thoracic spine
Unilateral: controlateral rotation of the thoracic spine
In: Medial branches of posterior rami of spinal nn.
Multifidus
O:
Cervical part: Superior articular processes of C4-C7
Thoracic part: TP of all thoracic vertebra
Lumbar part: Mammillary processes of lumbar vertebrae
Sacrum part: Posterior aspect of sacrum, PSIS of ilium and posterior sacroiliac ligament
I: Superomedially to SP, two to four levels above origin
A:
Bilateral: Extension of spine
Unilateral: Lateral flexion (ipsilateral) and rotation of spine (contralateral)
In: Medial branches of posterior rami of spinal nn.
Semispinalis capitis
O: Articular processes of C4-C7, and TP of T1-T6
I: Between superior and inferior nuchal lines of occipital bone
A:
Bilateral: Extension of head, cervical and thoracic spine
Unilateral: lateral flexion (ipsilateral) and rotation of head, cervical and thoracic spine (contralateral)
In: Medial branches of posterior rami of spinal nn.
Semispinalis cervicis
O: TP of T1-T6
I: SP of C2-C5
A:
Bilateral: Extension of head, cervical and thoracic spine
Unilateral: lateral flexion (ipsilateral) and rotation of head, cervical and thoracic spine (contralateral)
In: Medial branches of posterior rami of spinal nn.
Semispinalis thoracis
O: TP of T6-T10 (T12)
I: SP of C6-T4
A:
Bilateral: Extension of head, cervical and thoracic spine
Unilateral: lateral flexion (ipsilateral) and rotation of head, cervical and thoracic spine (contralateral)
In: Medial branches of posterior rami of spinal nn.
Serratus posterior superior (quadrilateral muscle)
O: Nuchal ligament, SP of C7-T3
I: Superior border of 2th-5th rib
A: Elevates ribs -> active in inspiration
In: Intercostales n. (2nd-5th)
Serratus posterior inferior
O: SP of T11-L2
I: Inferior border of 9th-12th ribs
A: Depresses ribs -> active in expiration
Prevents narrowing the thoracic aperture
In: Anterior rami of spinal nn. T9-T12
(a.k.a. 9th-11th Intercostal nerves + subcostal nerve)
