Main Body: Deep and Superficial Back

vertebral column function

protection of the spinal cord, support of the weight of the body, forms the axis, and plays a role in posture and movement

central canal

formation of the canal which houses the spinal cord- formed by the stacking of vertebral foramina

number of cervical vertebae and spinal nerves

7 vertebrae, 8 spinal nerves

exit of cervical nerves

exit above their respective vertebral body

exit of thoracic through coccygeal nerves 

exits below the corresponding vertebral body 

number of thoracic vertebrae and spinal nerves

T1-T12

number of lumbar vertebrae and spinal nerves

L1-L5

number of sacral vertebrae and spinal nerves

S1-S5

number of coccygeal vertebrae and spinal nerves

Co1-Co3 and C1 (only the one coccygeal spinal nerve)

sacralization 

when L5 is fused to S1, so see only 4 lumbar vertebrae 

lumbarization

when S1 is unfused and have a 6th sacral vertebrae

cervical enlargement

enlargement in the cervical region of the spinal cord that occurs for the plexus of the upper limbs

lumbar enlargement

enlargement of the lumbar plexus for the lumbar plexus

L1/L2

level of the termination of the spinal cord

cauda equina 

the structure that continues after the termination of the spinal cord, is a mass compresses it at the level of L1/L2 then lose everything (motor and sensory) below the belly button 

primary curvature

kyphotic curvature that is present as a fetus

secondary curvature

lordotic curvature that develops as we age and start sitting and using back muscles (from gravity too)

kyphosis

excessive forward flexion of spine

lordosis 

excessive extension of spine 

scoliosis 

in the frontal plane defined by lateral curvature, but also rotatory components are involved 

function of the spinous and transverse processes

muscle attachment and movement

function of the articular processes

restriction of movement

function of the vertebral arch

protection of the spinal cord

vertebral arch elements

2 pedicles and laminae, spinous process, 2 transverse processes, superior and inferior articular processes

atlas 

C1, has no spinous process of body, anterior or posterior arches, atlantooccipital joint: superior articular surface articulates with occipital condyles, yes/nodding motion

axis

C2, strongest cervical vertebrae, atlantoaxial joint, most moveable parts of the spine- has 45 degrees of rotation and the rest of the ROM is compensatory movement from the rest of the spine, dens project up into atlas, “no” movement (rotation)

cervical vertebrae

smallest of 24 moveable vertebrae, bear less weight, C1, C2, C7 atypical, thick body and thin discs, large vertebral foramen, oval transverse foramen for vertebral arteries and veins (except for C7- smallest of non-existent)

uncus of cervical vertebrae

develops where the cervical bodies articulate with each other- isn’t present at birth but develops in 20-30s

thoracic vertebrae

costal facets for articulations with ribs- all except T11 and T12 limits flexion and extension, atypical vertebrae T1 and T12 atypical as inferior ½ has features of lumbar vertebrae, truest are T5-T8, T1 full facet for 1st ribs and demi facet for rib 2, more narrow canal/foramen bc there is no thoracic enlargement 

true ribs

ribs 1-7, direct to sternum via costal cartilage

false ribs

ribs 8-10, connect to inferior extension of 7th costal cartilage

floating ribs

ribs 11 and 12, do not connect to the sternum

atypical ribs

ribs 1, 2, 10 to 12

rib 1 atypical features

1st articular facet and singular vertebrae, scalene tubercle and grooves for subclavian vein and artery

ribs 2 atypical features

tuberosity for serratus anterior

ribs 10-12 atypical features

1 facet and singular vertebrae

ribs 11-12 atypical features

floating and shorter, no neck and tubercle/no costotransverse joints

lumbar vertebrae 

large vertebral bodies with triangular vertebral foramen, long and slender transverse processes (mammillary processes) with short and sturdy spinous processes 

osteoporosis

affects the entire skeleton, but increasingly affects the neck of the femur, the bodies of vertebrae, the metacarpals, and the radius- more subject to fracture (osteoclastic > osteoblastic activity)

laminectomy

surgical excision of one or more spinous processes to access canal and relieve pressure from tumor, herniated disc, bony hypertrophy

pars interarticularis fracture

“scotty dog” fracture, fracture of the pedicle

intervertebral disc functions

allows the spine to be flexible without sacrificing a great deal strength and provide a shock-absorbing effect within the spine and prevent the vertebrae from grinding together

intervertebral disc components 

inner nucleus pulposus, outer annulus, cartilaginous endplates 

nucleus pulposus

gel like structure that sits at inner 1/3 of the intervertebral disc, made of 66-86% water, is a noxious substance that can cause a large inflammatory response if it leaks out

annulus fibrosus

ring shaped disc of fibrous connective tissue

cartilaginous endplates

anchors the discs to adjacent vertebrae

anterior longitudinal ligament

attached to superiorly to base of the skull and extends inferiorly to attach to the sacrum, limits hyperextension, thicker and broader than the posterior and so see less protrusion of discs anteriorly 

posterior longitudinal ligament 

is on the posterior surfaces of the vertebral bodies, limits hyperflexion and supports discs, thinner and less broad, more likely to see disc herniation posteriorly (and somewhat laterally)

tectorial membrane

superior continuation of PLL, extends from axis to anterior floor of foramen magnum, extra support overlaying the C1/C2 joint, dens, transverse lig, alar lig

iliolumbar ligament

tethers and protects flexion and extension, attaches the lumbar transverse processes to the ilium

ligamentum flava

slightly yellow coloration due to high elastin content (80%), located on each side of the vertebrae, pass between the lamina of adjacent vertebrae and helps with returning to neutral from extended position

supraspinous ligament

connects and passes along the tips of the vertebral spinous processes from vertebrae C7 to the sacrum

interspinous ligament

pass between adjacent vertebral spinous processes

nuchal ligament 

strong, broad ligament from the occipital protuberance to the posterior border of the foramen magnum to the spinous processes of the cervical vertebrae, serves as an attachment for muscles 

zygapophyseal joints 

joint between the inferior and superior articular processes, allows for the motion of the spine

atlanto-occipital joint

articulation between the atlas and occiput, allows for nodding motion

atlanto-axial joint

articulation between atlas and axis, allows for rotary motion

cruciate ligament

cross shaped ligament with a superior and inferior longitudinal band and transverse ligament of the atlas, prevents the posterior movement of the dens (so doesn’t press up against the spinal cord) and allows motion to occur below C2

alar ligament

spans from the dens to the base of the foramen magnum, limits rotation and side bend

uncovertebral joint 

articulation of the uncal processes with the superior vertebrae (cervical feature)

ventral rami

branch of the nerve root that travels anterior and supplies motor and sensory to the extremities and anterior trunk

dorsal rami

branch of the nerve root that travels posteriorly and supplies sensation to the back and motor to the intrinsic back muscles

superficial extrinsic axio-appendicular back muscles

latissimus dorsi, trapezius, rhomboids, levator scapulae

intermediate extrinsic back muscles 

serratus posterior superior and inferior 

superficial intrinsic back muscles

spenius capitis and cervicis

intermediate intrinsic back muscles

iliocostalis, longissimus, spinalis

deep intrinsic back muscles

transversospinalis (semispinalis, multifidis, rotatores), and “minor layer” of intertransversarii, interspinalis, levatores costarum

axio-appendicular muscle

attachments to the axial skeleton and the proximal appendicular skeleton of humerus

intrinsic muscles of the back innervation 

dorsal rami of spinal nerves 

intrinsic muscles of the back function

maintain posture and control movements of the vertebral column, enclosed by deep fascia that attaches medially to the nuchal ligament, tips of sp of the vertebrae, and supra-spinous ligament, and the median crest of the sacrum

splenius capitis

PA: nuchal ligament and spinous processes of C7-T6 vertebrae

DA: fibers run superolaterally to the mastoid process to temporal bone and lateral third of superior nuchal line to of occipital bone

Inn: posterior rami of spinal nerves

A: acting alone: laterally flexes and rotates head to side of active muscles, acting with splenius cervicis extends the head and neck

splenius cervicis

PA: nuchal ligament and spinous processes of C7-T6 vertebrae

DA: tubercles of tp fo C1-C3 or C4 vertebrae

Inn: posterior rami of spinal nerves

A: acting alone: laterally flexes and rotates head to side of active muscles, acting with splenius cervicis extends the head and neck

erector spinae muscles

found between the spinous processes centrally and the angles of the ribs laterall, the chief extensors of the vertebral column and are divided into three columns: (from lateral to medial) iliocostalis, longissimus, spinalis

iliocostalis

PA: arises by a broad tendon from the posterior part of the iliacr crest, posterior surface of the sacrum, sacro-iliac ligaments, sacral and inferior lumbar spinous processes, and supraspinous ligament

DA: lumborum, thoaric, cervicis, fibers run superiorly to angles of lower ribs and cervical tp

Inn: posterior rami of spinal nerves

action of erector spinae muscles 

bilaterally: back extension 

unilateral: ipsilateral sidebend 

reverse action: eccentrically controls flexion 

longissimus

PA: arises by a broad tendon from the posterior part of the iliacr crest, posterior surface of the sacrum, sacro-iliac ligaments, sacral and inferior lumbar spinous processes, and supraspinous ligament

DA: thoracis, cervicis, capitis, dibers run superiorly to ribs between tubercles and angles to transverse processes in thoracic and cervical regions and to mastoid process of temporal bone

Inn: posterior rami of spinal nerves

spinalis

PA: arises by a broad tendon from the posterior part of the iliacr crest, posterior surface of the sacrum, sacro-iliac ligaments, sacral and inferior lumbar spinous processes, and supraspinous ligament

DA: thoracis, cervisis, capitis, fibers run superiorly to spinous processes in the upper thoracic region to cranium

Inn: posterior rami of spinal nerves

regional divisions of the erector spinae muscles 

division are split into three parts according to the superior attachments- cervicis, thoracis, lumborum, or capitis

deep layer of the intrinsic muscles of the back

tranversospinalis group- which consists of the semispinalisl multifidis, and rotatores

muscles producing flexion in the cervical intervertebral joints

bilateral action of longus coli, scalene, and SCM

muscles producing extension in the cervical intervertebral joints

• semispinalis cervicis and iliocostalis cervicis

• splenius cervicis and levator scapulae

• splenius capitis

• multifidus

• longissimus capitis

• semispinalis capitis

• trapezius

muscles producing lateral bending in the cervical intervertebral joints

unilateral action of

• iliocostalis cervicis, longissimus capitis and cervicis, splenius capitis and cervicis, intertranversarii and scalenes

muscles producing rotation in the cervical intervertebral joints

unilateral actions of 

• rotatores 

• semispinalis capitis and cervicis 

• multifidus 

• splenius cervicis