Muscles of Back Flashcards
Origin, Insertion, Innervation, Action
Splenius Capitis
O: Nuchal Ligament, Spinous process of C6-C7
I: Mastoid Process, Lateral third of superior nuchal line
Innervation: Posterior Rami of spinal nerves
A: bilateral - extend head/neck, unilateral - ipsilateral rotation of head and lateral flexion of neck
Splenius Cervicis
O: Nuchal Ligament, Spinous process of C6-C7
I: Transverse processes of upper cervical vertebrae
Innervation: Posterior Rami of spinal nerves
A: bilateral - extend head/neck, unilateral - ipsilateral rotation of head and lateral flexion of neck
Erector Spinae Group
Iliocostalis, Longissimus, Spinalis
Iliocostalis
O: Common tendon from iliac crest, sacrum and lumbar vertebrae, surrounding thoracolumbar fascia
I: Angles of lower ribs and cervical transverse processes
Innervation: Posterior rami of spinal nerves
A: bilateral - extend back, unilateral - laterally flex vertebral column
Longissimus
O: Common tendon from iliac crest, sacrum and lumbar vertebrae, surrounding thoracolumbar fascia
I: Ribs, transverse processes of thoracic and certical vertebrae, mastoid process
Innervation: Posterior rami of spinal nerves
A: bilateral - extend back and head, unilateral - lateral flexion of vertebral column
Spinalis
O: Common tendon from iliac crest and sacrum, spinous processes
I: Spinous processes of sacrum/lumbar vertebrae to those of higher vertebrae (usually thoracic, sometimes cervical
Innervation: Posterior rami of spinal nerves
A: bilateral - extend back, unilateral - lateral flexion of vertebral column
Semispinalis
O: Transverse processes of lower cervical and most thoracic vertebrae
I: Spinous processes of vertebrae 4-6 levels superior, superior nuchal line (S. capitis only)
Innervation: Posterior rami of spinal nerves
A: Stabilize vertebral column, Bilateral - extension of vertebral column, unilateral: contralateral rotation and ipsilateral flexion
Multifidus
O: Common tendon of erector spinae from iliac crest and sacrum, transverse processes
I: Spinous processes of vertebrae 2-4 levels superior
Innervation: Posterior rami of spinal nerves
A: Stabilize vertebral column, bilateral - extension of vertebral column, unilateral: contralateral rotation and ipsilateral flexion
rotatores
O: Transverse processes (mostly thoracic)
I: Spinous processes of vertebrae 1-2 levels superior
Innervation: Posterior rami of vertebrae 1-2 levels superior
A: Stabilize vertebral column, bilateral - extension of vertebral column, unilateral: contralateral rotation and ipsilateral flexion
rectus capitis posterior major
O: Spinous process of C2
I: Lateral inferior nuchal line
Innervation: suboccipital nerve (posterior ramus of C1)
A: Postural, assist in rotation and extension of head
rectus capitis posterior minor
O: posterior tubercle of C1
I: medial inferior nuchal line
Innervation: suboccipital nerve (posterior ramus of C1)
A: Postural, assist in rotation and extension of head
Obliquus capitis superior
O: transverse process of C1
I: above lateral inferior nuchal line
Innervation: suboccipital nerve (posterior ramus of C1)
A: Postural, assist in rotation and extension of head
Obliquus capitis inferior
O: spinous process of C2
I: transverse process of C1
Innervation: suboccipital nerve (posterior ramus of C1)
A: Postural, assist in rotation and extension of head
Trapezius
O: superior nuchal line, external occipital protuberance, nuchal ligament, spinous processes of C7-T12
I: Lateral third of clavicle, acromion, spine of scapula
Innervation: Spinal accessory nerve, C3-4 anterior rami for proprioception
A: elevate, retract, depress scapula. glenoid-up rotation of scapula
Latissimus Dorsi
O: lower thoracic spinous processes, thoracolumbar fascia, iliac crest
I: intertubercular sulcus of humerus
Innervation: thoracodorsal nerve
A: Adduct, medially rotate and extend arm
