Intrinsic Back Muscles Flashcards
Where does the multifidus originate from?
- Posterior sacrum
- Posterior iliac spine of ilium
- aponeurosis of erector spine
- sacro-iliac ligaments
- mammillary processes
- transverse processes of T1-T3
- articular processes of C4-C7
What intrinsic muscles make up the superficial muscles?
Splenius capitis( inserts at head)
Splenius cervicis (inserts at neck)
What are the general innervations for the Intrinsic back muscles?
Posterior rami of the spinal nerves
What are the muscles of the suboccipital triangle innervated by?
Posterior ramus of C1
SUBOCCIPITAL NERVE
What is the origin and insertion of the obilquus capitis superior muscles of the suboccipital triangle?
Origin: Transverse process of Atlas
Insertion: Occipital bone between superior and inferior nuchal lines
Does the multifidus attach to the spinous process of every vertebrae?
Yes it does so obliquely superomedially
What is the origin and insertion of the Rectus capitis posterior major?
Origin: Spinous process of vertebra C2
Insertion: Lateral part of inferior nuchal line of occipital bone
What muscles make up the suboccipital triangle?
- Rectus capitis posterior minor
- Rectus capitis posterior major
- Obliquus capitis inferior
- Obliquus capitis superior
What vertebrae does suboccipital triangle include?
Posterior aspect of C1 and C2 vertebrae
What is the action of semispinalis?
To extend cervical and thoracic vertebrae
To rotate the cervical and thoracic vertebral column contralaterally
What muscles are especially important in providing stability for your spine and slight rotation if they contract?
Multifidus and Rotatores are very small muscles located deep in the back.
Multifidus is located between the transverse process and spinous processes of all vertebrae. (2-4 segments or vertebrae)
Rotatores are located between the transverse processes and spinous processes. (1-2 vertebrae)
What is the role of the multifidus?
Stabilizes the vertrebrae during local movement
They extend the complete spine as long as they are innervated by the dorsal rami (C3–S3).
What is the suboccipital triangle deep to?
- Superior part of posterior cervical region
- sternocleidomastoid
- splenius
- semispinalis muscles
What intrinsic muscles make up the Deep Major muscles?
Transversospinalis
- Rotatores
- Mulitfidus
- Semispinalis
What is the common origin attachment point for the erector spinae muscles?
A broad tendon that attaches inferiorly to the
- posterior part of iliac crest
- posterior aspect of sacrum
- sacro-iliac ligaments
- sacral and inferior lumbar processes
What is the splenius deep to?
Immediately deep to the serratus posterior superior
Extrinsic
- Rhomboid major and minor
- Trapezius
What is the origin and insertion of the obliquus capitis inferior
Origin: posterior tubercle of posterior arch of axis
Insertion: transverse process of atlas
What is distal attachment for splenius cervicis?
Tubercles of transverse processes of C1-C3 or C4 vertebrae
What is the distal attachment for the spinalis?
fibers run superiorly to the spinous processes of the upper thoracic region to the cranium
What are the erector spinae muscles known for?
They are chief extensors of the vertebral column
What are the contents of the suboccipital triangle?
Vertebral artery
Suboccipital nerve
What intrinsic muscles make up the Erector spinae?
Spinalis (medial most)
Longissimus
Illiocostalis (lateral most)
(SLI)
What is the greater occipital nerve?
C2
What is at the roof of the suboccipital triangle?
Semispinalis capitis
What is the distal attachment of the splenius capitis?
Fibers run superolaterally to the mastoid process of temporal bone and lateral third of superior nuchal line of occipital bone
Where does the iliocostalis lumberum end?
At the lower 6 or 7th angle of ribs
Why is the transversospinalis muscle group called this?
- They originate from transverse processes of vertebrae and insert at spinous processes of superior vertebrae.
- They occupy the gutter between the transverse and spinous processes
- The laminae between them and the ligaments link them together
What are the semispinalis innervated by and what is the action?
Posterior rami of spinal nerves
Extends the head, neck, and thoracic vertebrae (Bilateral)
Rotates them contralaterally (Unilateral)
What is the splenius muscle group innervated by?
Posterior rami of spinal nerves
What is the distal attachment of the semispinalis?
Superomedial to occipital bone
Spinous processes of thoracic and cervical regions spanning 4-6 segments
What is the only erector muscle with a lumborum portion?
Iliocostalis
Iliocostalis has cervicis, thoracis, lumberum
All the others only have thoracis, cervicis, capitis
What is the distal attachment for Longissimus?
Fibers run superiorly to ribs between tubercles and angles to transverse processes in thoracic and cervical regions and to mastoid process of temporal bone
What is the multifidus?
It is the middle layer between the semipinalis and rotatores
Short, triangular muscular bundles
Why are intrinsic muscles regarded as being true muscles?
All of their attachments are on the back of the body
These muscles perform movements on the back and vertebral column
What is the origin of the rectus capitis posterior minor?
Origin: Posterior tubercle of posterior arch of Atlas
Insertion: Medial part of inferior nuchal line of occipital bone
What is the proximal attachment of semispinalis?
Transverse processes of C4 to T2 vertebrae
What innervates the erector spinae muscles?
Posterior rami of the spinal nerves
Where is the multifidus thickest?
What muscles make up the boundaries of the suboccipital triangles?
Supermedial : rectus capitis posterior major
Superlateral: obliquus capitis superior
Inferolateral: obliquus capitis inferior
Are the erector spinae deep or intermediate intrinsic muscles of the back?
Intermediate
Deep to the splenius but superficial to the deep muscles of back
What is the proximal attachment of splenius muscle?
Nuchal ligament
spinous processes of C7- T6 vertebrae
Where does the semispinalis muscles originate from?
The transverse processes of T7-12 (Thoracis to cervicis)
Transverse processes of T6-C3 (Capitis)
What is the action of the splenius?
Together: draw head and neck backward, extending neck
Individually: rotate head to side of active muscle (turn face to same side) (ipsilateral)
How is each column (spinalis, longissimus, iliocostalis) divided?
They are divided regionally into three parts according to the superior or distal attachments.
Example
Spinalis capitis (head)
Spinalis cervicis (spinous process of cervical vertebrae)
Spinalis thoracis (spinous process of thoracic vertebrae)
What is the triangle of auscalation?
This is a triangle in the lumbar region used to listen to sounds made by the thoracic region, particularly the lungs.
latissimus dorsi inferiorly
trapezius muscle superiorly
rhomboid major
What is at the floor of the suboccipital triangle ?
Posterior atlanto-occipital membrane
Posterior arch of atlas
What is the distal attachment for the iliocostalis?
Fibers run superiorly to angles of lower ribs and cervical transverse processes
Where are the rotatores best developed?
Thoracic region
What muscle is superficial to the splenius muscles of the neck?
The origin of the Descending trapezius fiber
What fascia is the erector muscle deep to?
Thoracolumbar fascia
