Back and Spine
Lordosis secondary curves (lumbar and cervical), bending backwards i.e. the concavity is posterior
Kyphosis primary curves (sacral and thoracic), bending forwards, i.e. the concavity is anterior
Scoliosis curve laterally i.e. S instead of I
Only the cervical vertebrae have transverse foramen (foramina transversium)
Only the thoracic vertebrae have articular facets for the ribs
The spinal nerves C1-C8 exit above their respective vertebrae, T1-S4 exit below their respective vertebrae
T7 is the most frequently fractured vertebra in the spine (because it is the deepest point in the spines lordosis)
As one ages one loses H2O from the discs. Young discs are 88% H2O. less water = less height
There are 7 Cervical vertebrae, 12 Thoracic vertebrae, and 5 Lumbar vertebrae arranged on top of the Sacrum, 5 fused vertebrae that attach to the pelvis. The Coccyx, 4 fused vertebrae lie caudal to the sacrum.
Pedicle (Latin for "little feet") the 2 posterior projections form the body that attach the 4 articular processes, the spinous process, the 2 transverse processes, and the lamina to the vertebral body.
Lamina two broad plates of bone that for the roof of the vertebra foramen when they unite in the median plane.
Spinous Process the process that projects out dorsally from the lamina.
Vertebra prominens C7, because its spinous process can be palpated when the head is tilted forward.
Transverse process the processes that project laterally from the vertebral arch
Atlas the 1st cervical vertebra
Axis the 2nd cervical vertebra, the Dens (Odontoid Process) arises from the axis and projects up to articulate the atlas
Foramen Transversarum distinct for the cervical vertebrae, allows for passage of the vertebral arteries
Sacral promontory an important OB landmark, the projecting anterior edge of the body of S1
Centrum the ossification center for the central mass of the vertebral body
Annular epiphyses 2 of the 5 secondary centers of ossification, one forms superiorly, the other inferiorly, to the centrum
Zygapophyseal facet articular processes that arise from the junction of the pedicles and lamina. The superior articular facet projects superiorly, the inferior articular facet projects inferiorly.
Intervertebral foramen formed by pedicles from a superior and an inferior vertebrae. Spinal nerves exit through these.
Costal facet articulations for the ribs, on thoracic vertebrae
Vertebral canal the collection of vertebral foramen in which the spinal cord (wrapped in meninges) travels
intervertebral discs the fibrous annulus fibrosis surrounds the more cartilaginous nucleus pulposis
zygapophyseal the synovial joint between the inferior articular facets of the superior vertebra and the superior articular facets of the inferior vertebra. These are surrounded by fibrous capsules that are looser in the cervical region.
craniovertebral the atlanto-occipital and atlanto-axial joints, Synovial only, have no intervetebral discs and no facet joints
atlanto-occipital the joint between the skull and the 1st cervical vertebra (the altas). Allows nodding of the head.
atlanto-axial between the 1st and 2nd vertebrae. Allows rotation of the head. Excess prevented by the alar ligaments.
flexion touching your toes
extension bending backwards
rotation "doing the twist"
lateral flexion bending to the side to touch your toes
There are 3 groups of muscles on the back
Intrinsic back muscles: have 3 layers
Superficial layer of deep back muscles
splenius (Greek, bandage)
- Superficial (trapezius, latissimis dorsi) concerned with limb movemen
- Intermediate (serratus anterior) concerned with respiration
- Deep "intrinsic back muscles" concerned with movement of the vertebral column
- All muscles posterior to the transverse process get innervation from the dorsal rami.
splenius cervicis (neck) posterior tubercles of C1-C4
Þ laterally flex and rotate head to the same side, togetherÞ extend head and neck
Innervation: dorsal rami of inferior cervical nerves
Intermediate layer of deep back muscles
erector spinae (3 vertical columns of muscle) "I love sushi" from lateral to medial
- Origin: inferior ½ of the ligamentum nuchae and the spinous process of T1-T6
- Insertion: Sp. Capitus (head) lateral aspect of mastoid process and lateral 1/3rd of the superior nuchal line of the occipital bone.
Deep layer of the deep back muscles Next 3 are known as the Transversospinal muscle because their fibers run for the transverse to the spinous processes
- (1) iliocostalis (lateral column)
- (2) longissimus (intermediate column)
- (3) spinalis (medial column)
- Origin: a broad tendon attached to the posterior iliac crest, posterior sacrum, sacral and lumbar spinous processes.
- Iliocostalis (3 parts)
- 1st iliocostalis lumborum attached to inferior 6 ribs
- 2nd iliocostalis thoracis attached to all ribs
- 3rd iliocostalis cervicis attached to superior 6 ribs and posterior tubercles of C4-C6
- Longissimus (3 parts)
- 1st longissimus thoracis the tips of the transverse processes of all thoracic vertebrae and into the tubercels of the inferior 9 ribs.
- 2nd longissimus cervicis extends from the superior thoracic transverse processes to the cervical transverse processes
- 3rd longissimus capitus attaches to the mastoid process of the temporal bone
- Spinalis (3 parts)
- 1st spinalis thoracis
- 2nd sp cervicus
- 3rd sp. Capitus
- Action: bilaterally, extends head and part of vertebral column. Unilaterally, laterally flexes head or vertebral column.
- Innervation: dorsal rami of spinal nerves
levator costarum 12 muscles in the thoracic region
- Semispinalis (3 parts, thoracis, cervicis, and capitus)
- Origin: transverse processes from ~T10 and up
- Insertion: spinous processes of superior vertebrae
- Action: bilaterally, extend thoracic and cervical regions, Unilaterally, rotate these regions towards the opposite side
- Innervation: the dorsal rami of the cervical nerves
- Multifidus divided into many bundles, covers the laminae of S4 to C2, fibers pass superiomedially from the vertebral arches to the spinous processes spanning 1 to 3 vertebrae
- Actions unilaterally, flexes the trunk laterally and rotates towards the opposite side, bilaterally, extend the trunk and stabilize the vertebral column.
- Innervation: dorsal rami of the cervical spinal nerves
- Rotatores short muscles that run the length or the vertebral column
- Origin transverse process of one vertebrae
- Insertion the spinous process of the vertebrae immediately superior
- Actions rotate the superior vertebra to the opposite side and stabilization
- Innervation the dorsal rami of the spinal nerves
- Interspinales small muscles that unite the spinous processes of consecutive vertebrae
- Action lateral flexion of superior vertebra, bilaterally extend the vertebral column
- Innervation dorsal rami of the cervical spinal nerves
- Intertransversarii small muscles that unite the transverse processes of consecutive vertebrae. Similar action to interspinales
- Innervation from the ventral rami of cervical spinal nerves
- Origin the transverse process of thoracic vertebra
- Insertion the rib immediately below
- Action aid in respiration (by raising ribs during inspiration)
- Innervation lateral division of the dorsal rami of the spinal nerves.
Spinal cord travels down through the spinal canal, usually ends at L1-L2 giving rise to the Cauda equina (L4 in kids)
Meninges protective membranes that cover the spinal cord (out to in Dura mater, Arachinoid mater, Pia mater)
cervical enlargement extends form C4-T1, where the ventral rami of the brachial plexus leave the spinal cord.
lumbar enlargement T11-L1, the swelling of the spinal cord where lumbar and sacral plexi nerves leave.
dorsal root entering the cord contain afferent or sensory fibers from sensory nerve endings
ventral root leaving the cord contain efferent or motor fibers which are distributed to muscles and glands
dura mater (Latin; hard mother) tough outermost membranous covering of the spinal cord
arachnoid mater (greek; spider) delicate filamentous avascular intermediate covering of the spinal cord
subarachnoid space between the arachnoid mater and pia mater, contains CSF
spinal ganglion dorsal root ganglia, where the cell bodies of the axons making up the dorsal root are.
extradural space space between the ligamentous walls of the spinal canal and the dura mater, contains fat and loose CT.
filum terminale a slender fibrous strand that descends with the cauda equina, leaves the inferior end of the dural sac and passes through the sacral hiatus to insert into the dorsum of the coccyx. A remnant of spinal cord from the tail.
cauda equina the bundle of nerve rootlets in the subarachnoid space caudal to the termination of the spinal cord
conus medularis the inferior end of the spinal cord tapers abruptly into the conus medularis
anterior longitudinal ligament strong fibrous band that covers and connects the anterior aspects of the bodies of the vertebrae and intervertebral discs. Extends from the sacrum to C1 (atlas)
posterior longitudinal ligament narrower/weaker than the anterior long ligament. Runs on the posterior aspect of the vertebral bodies within the vertebral canal. Runs from C2 to the sacrum and prevents protrusion of the intervertebral discs.
ligamentum flavum (yellow ligaments), attach the lamina of adjacent vertebrae, attach to the anterior surface of the inferior borders of the superior vertebras laminae and attach to the posterior surface of the inferior vertebras laminae.
basivertebral vein drains the vertebra, exits through a foramen on the posterior surface of the vertebral body
cruciate ligament a cross at the base of the skull, made from the transverse ligament of the atlas (from one tubercle of the atlass lateral mass to the other) and the superior and inferior bands that connect the occipital bone to the axis
spondylolysis if the L5 vertebra has two parts (either congenital or acquired) and the posterior stays in the normal relation with the sacral arch while the anterior is still in its place in the vertebral column. 5% incidence.
spondylolisthesis a spondylolysis where the anterior part moves anteriorly (anterior displacement of the vertebra from the vertebral column), this can put pressure on the spinal nerves and cause back pain.
spina bifida failure of fusion of the laminae of the vertebral arch, may be herniation of the meninges or spinal cord.
disc herniation a protrusion of the nucleus pulposa (usually posteriolaterally), that may compress an adjacent spinal nerve root and cause symptoms (typically low back and leg pain)
rheumatoid arthritis can destroy the transverse ligament of the atlas, making a person prone to injury via the dens being set free and driven into the cervical region of the spinal cord causing quadriplegia or death.
lumbago acute mid and low back pain that radiates down the posterolateral aspect of the thigh often caused by a disc protrusion at L5/S1.
Sciatica pain resulting from irritation of the sciatic nerve