- Created by Kirsten Schaeffer - Spring 2006

Study Sheet 01 - The Back Typical vertebrae are found in these regions (3): cervical, thoracic, lumbar Atypical vertebrae are found in these regions (2): sacrum, coccyx

Unique characteristic of cervical spinous processes: they are bifid (have a cleft)

Why is the atlas's vertebral foramen so wide? to accommodate the medulla What is the odontoid projection on the axis? the dens (used to be the body of the atlas)

Location of the carotid tubercle: C6; anterior tubercle of the transverse process - the common carotid artery lies against it

Significance of the carotid tubercle: the common carotid artery can become compressed against it

Definition of foramen transversarium: hole in the transverse processes of the cervical vertebrae; transmits the vertebral artery and vein, sympathetic nerve fibers

C7 AKA: vertebra prominens C7 spinous process: bifid or not? not bifid First cervical spinal nerve exits between: C1 and occipital bone

How do the cervical spinal nerves generally exit the vertebral column (relative to the vertebrae)?

through the intervertebral foramen above the same-named vertebra, except for C8 (exits between C7 and T1)

Aortic impression is found on these thoracic vertebrae: T5-T8, on the left side of the vertebral body

Function of the mammillary process in the lumbar vertebrae:

gives muscle attachment for the multifidus and medial intertransverse muscles

Contents of the sacral canal (3): lower part of cauda equina, lower part of filum terminale, distal end of dural sac

Translation of cauda equina: horse's tail The dural sac is the termination of this meninx (yes, that's the crazy singular form of meninges): dura mater

These travel through the anterior and posterior sacral foramina, respectively (2): ventral and dorsal rami of the sacral spinal nerves

Anesthesia injected into sacral foramina is called: caudal epidural anesthesia

Location of the coccyx: at the anus

Relation of the coccyx to the sacrum: the coccyx may or may not be fused with the sacrum

During childbirth, what can happen to the sacrococcygeal joint? it can move posteriorly

Coccygeal ligament AKA: external terminal filum

Function of the coccygeal ligament: anchors the inferior end of the spinal cord and the spinal meninges

- Created by Kirsten Schaeffer - Spring 2006

Study Sheet 01 - The Back

Functions of the intervertebral disc (3): shock absorption, weight bearing, permits movement between two vertebrae (acts as a semi-fluid ball-bearing)

Vertebral column comprises how much of a person's height? 2/5

Outer portion of intervertebral disc called: annulus fibrosus Inner portion of intervertebral disc called: nucleus pulposus

Nucleus pulposus made up of: 70-80% water, collagen and elastin fibers, mucoid material

If the nucleus pulposus' water content decreases, this can happen:

height of vertebral column decreases (i.e. shrinkage during old age)

Superiorly, the anterior longitudinal ligament communicates with (1): anterior atlanto-occipital membrane

Superiorly, the posterior longitudinal ligament is continuous with this membrane:

tectorial membrane

Ligamentum nuchae is in this vertebral region: cervical region

Ligamentum nuchae is attached to this bony landmark of the skull: external occipital protuberance

These back muscles make up the superficial group (2): trapezius muscle, latissimus dorsi muscle

These back muscles make up the deep group (6):

serratus posterior superior muscle, serratus posterior inferior muscle, splenius muscle (capitis and cervicis), three parts of erector spinae muscle: spinalis muscle, longissimus muscle, iliocostalis muscle

Serratus posterior superior muscle:

Origin: nuchal ligament, spinous processes of C7 to T3 vertebrae

Insertion: superior borders of 2nd to 4th ribs Innervation: 2nd to 5th intercostal nerves Action: elevate ribs Serratus posterior inferior muscle: Origin: spinous processes of T11 to L2 vertebrae Insertion: inferior borders of 8th to 12th ribs near their angles Innervation: anterior rami of T9 to T12 thoracic spinal nerves Action: depress ribs Splenius muscle:

Origin: arises from nuchal ligament and spinous processes of C7-T3 or T4 vertebrae

Insertion:

splenius capitus: fibers run superolaterally to mastoid process of temporal bone and lateral third of superior nuchal line of occipital bone; splenius cervicis: tubercles of transverse processes of C1-C3 or C4 vertebrae

Innervation: posterior rami of spinal nerves

Action: acting alone: laterally flex neck and rotate head to side of active muscles; acting together: extend head and neck

- Created by Kirsten Schaeffer - Spring 2006

Study Sheet 01 - The Back

Common origin of all erector spinae muscles:

arises by a broad tendon from posterior part of iliac crest, posterior surface of sacrum, sacroiliac ligaments, sacral and inferior lumbar spinous processes, and supraspinous ligament

Insertion of spinalis muscle: thoracis, cervicis, capitis; fibers run superiorly to spinous processes in the upper thoracic region and to cranium

Insertion of longissimus muscle: thoracis, cervicis, capitis; fibers run superiorly to ribs between tubercles and angles to transverse processes in thoracic and cervical regions, and to mastoid process of temporal bone

Insertion of iliocostalis muscle: lumborum, thoracis, cervicis; fibers run superiorly to angles of lower ribs and cervical transverse processes

Common innervation of all erector spinae muscles:

posterior rami of spinal nerves (which spinal nerves depends on which region of the spine the muscle in question is located)

Common action of all erector spinae muscles:

acting bilaterally: extend vertebral column and head; acting unilaterally: laterally flex vertebral column

Intercostal nerves in the thoracic region made up of (1): ventral rami (not plexuses)

Transversospinalis muscle group made up of (6):

semispinalis muscle, multifidus muscles, rotatores muscles, interspinalis muscles, intertransversarii muscles, levatores costarum muscles

Semispinalis muscle:

Origin: arises from transverse processes of C4-T12 vertebrae (capitis: transverse processes of the upper thoracic vertebrae)

Insertion: thoracis, cervicis, capitis; fibers run superomedially to occipital bone and spinous processes in thoracic and cervical regions, spanning 4-6 segments

Innervation: posterior rami of spinal nerves

Action: extends head and thoracic and cervical regions of vertebral column and rotates them contralaterally

Multifidus muscle:

Origin:

arises from posterior sacrum, posterior superior iliac spine of ilium, aponeurosis of erector spinae, sacroiliac ligaments, mammillary processes of lumbar vertebrae, transverse processes of T1-T3, articular processes of C4-C7

Insertion: thickest in lumbar region; fibers pass obliquely superomedially to entire length of spinous processes of vertebrae, located 2-4 segments superior to origin

Innervation: posterior rami of spinal nerves Action: stabilizes vertebrae during local movements of vertebral column Rotatores muscle:

Origin: arises from transverse processes of vertebrae; best developed in thoracic region

Insertion: fibers pass superomedially to attach to junction of lamina and transverse process or spinous process of vertebra immediately (brevis) or 2 segments (longus) superior to vertebra of origin

Innervation: posterior rami of spinal nerves

Action: stabilize vertebrae and assist with local extension and rotatory movements of vertebral column

- Created by Kirsten Schaeffer - Spring 2006

Levatores costarum muscles: Origin: tips of transverse processes of C7 and T1-T11 vertebrae Insertion: pass inferolaterally and insert on rib between tubercle and angle Innervation: posterior rami of C8-T11 spinal nerves Action: elevate ribs, assisting respiration

- Created by Kirsten Schaeffer - Spring 2006

Study Sheet 01 - The Back

Suboccipital muscle group made up of (4): rectus capitis posterior major muscle, rectus capitis posterior minor muscle, obliquus capitis inferior muscle, obliquus capitis superior muscle

Common action of all suboccipital muscles:

postural: extends head on vertebra C1 and rotates it on vertebrae C1 and C2

Common innervation of all suboccipital muscles: suboccipital nerve (C1) = dorsal ramus of C1

Rectus capitis posterior major muscle: Origin: spinous process of vertebra C2 Insertion: lateral part of inferior nuchal line of occipital bone Rectus capitis posterior minor muscle: Origin: posterior tubercle of posterior arch of vertebra C1 Insertion: medial part of inferior nuchal line of occipital bone Obliquus capitis superior muscle: Origin: transverse process of vertebra C1 Insertion: occipital bone between superior and inferior nuchal lines Obliquus capitis inferior muscle: Origin: spinous process of vertebra C2* Insertion: transverse process of vertebra C1 What is the cerebellomedullary cistern and what does it contain?

it is the enlarged part of the subarachnoid space; it contains CSF

How is a cisternal puncture performed?

for children: the needle is inserted through the posterior atlanto-occipital membrane into the cerebromedullary cistern; for adults: the lumbar cistern is used most frequently

Boundaries of the suboccipital triangle (3): rectus capitis posterior major muscle, obliquus capitis inferior muscle, obliquus capitis superior muscle

Roof of the suboccipital triangle (1): semispinalis capitis Floor of the suboccipital triangle (1): posterior atlanto-occipital membrane

Contents of the suboccipital triangle (4): occipital artery, vertebral artery, greater occipital nerve, suboccipital nerve

Source of the occipital artery: external carotid artery Source of the vertebral artery: subclavian artery Dorsal rami of spinal nerves contain what types of fibers (3)? motor, sensory, sympathetic fibers

Dorsal rami of C1 AKA: suboccipital nerve Dorsal rami of C2 AKA: greater occipital nerve Dorsal rami of C3 AKA: 3rd occipital nerve

- Created by Kirsten Schaeffer - Spring 2006

Study Sheet 01 - The Back Blood supply to the vertebrae in the neck by (2): vertebral arteries, ascending cervical arteries

Blood supply to the vertebrae in the thorax by (1): posterior intercostal arteries

Blood supply to the vertebrae in the abdomen by (2): subcostal arteries, lumbar arteries

Blood supply to the vertebrae in the pelvis by (3):

iliolumbar arteries, lateral sacral arteries, median sacral arteries

Does the vertebral venous plexus have valves? What is the consequence? no; blood can flow in either direction

The vertebral venous plexus drains these groups of structures (3): back muscles, vertebrae, spinal cord

The vertebral venous plexus has connections with these structures (3): cranial dural sinuses, pelvic veins, azygos vein

Clinical significances of spread of disease via the vertebral venous plexus (2):

prostate cancer can spread to the spinal cord and can result in paralysis; provides a route by which pelvic inflammatory diseases (like sepsis) can spread to other regions

Vertebral venous plexus is made up of (2): anterior and posterior spinal veins