Mod 2 - Back Flashcards
Vertebral column
forms the basic structure of
the trunk.
It consists of 33-34 vertebrae and intervertebral
disks.
There are 7 cervical, 12 thoracic, 5 lumbar, 5 sacral
and 4-5 coccygeal vertebrae in human.
Intervertebral disks (fibrocartilage)
between the
vertebrae, absorb shock, assure no friction
between the bones and facilitate the movements
of the vertebral column.
2 types of ossifications for bone creation
Enchondral ossification
Intremembrane ossification
Primary Curvatures
Born with thoracic and sacral curvatures
Secondary Curvatures
3 months for cervical
Standing up around 9-10 months – 2nd secondary curvature appears in lumbar
Spinal cord is in the
vertebral foramen
The spinal cord becomes condensed
down the spine
The spinal cord terminates down the spine not through
the whole spine
What is the lower level of the spinal cord where it terminates?
Adult - L1
Newborn - L3
Extension of the duramatter is
S2
spinal cord goes from
C1 to L1 where it ends
Cauda equina contains the
terminal filum
The pinkish part of the cord(sub arachnoid space) contains
the CSF(cerebral spinal fluid)
8th day of life the
Bilaminar disk is formed
Notochord formed by day 18 gives the signal to form
the neural groove – forms nervous system
Neural tube forms the brain AND the spinal cord
Day 24 – cranial neuropore should close
Day 26 – caudal neuropore should close
If the cranial neuropore does not close then
the baby is born without a head – Anencephaly
If the caudal neuropore does not close then
Spina Bifida – hole on back
Meningocele, myelomeningoole, or spina bifida occulta(course hair at site of problem but less severe)
The nucleus pulposus is the remnant of the
notochord
Exoderm forms
the nervous system and skin
Endoderm forms
internal structures like lungs
Mesoderm forms
bones and vertebrae
Denticulate ligament in the
pia matter at end of spinal cord
Dorsal ramus(to muscles and skin of back)
Ventral ramus(skin of front)
The dorsal root is purely sensory
The ventral root is purely motor
The DRG is at the level of(not in) vertebral foramen and exit at
the intervertebral foramen
Between arachnoid matter and pia matter is the
subarachnoid space with the CSF
Epidural space(between vertebral body and cord) holds
fatty tissue
7cervical vertebrae AND 8 cervical nerves(shifts at T1 note pattern below)
go for bigger number the C1 nerve comes out between C1 and occipital bone C2 nerve is between C1 and C2 etc nerve then vertebrae C3 and C4 = 4th nerve
C7 and T1 = 8th cervical nerve T1 and T2 = T1 nerve go for smaller number
C1 = Atlas
no spinous process
anterior and posterior arches and tubercles
C2 = Axis
Dens utilized the transverse ligament of atlas to secure the odontoid process
figure 2-16
Cruciate ligament
hangman fracture can kill
ligament snaps and the brain stem can be impacted or disrupted
Characteristics of cervical vertebrae
A- transverse foramen.
B- bifid spinous process. C- small vertebral body.
D- large and triangular vertebral canal
Contents of the transverse foramen
vertebral artery
vertebral artery
pass through the transverse
foramen of the 6 upper Cervical Vertebrae.
They enter the skull through the
Foramen Magnum
Atlas (1st cervical V., C1)
Has:
- no spinous process
- no body, small anterior arch - a larger posterior arch. -
- Anterior tubercle
- Posterior tubercle
- Large vertebral foramen
- 2 lateral masses.
Each mass has a superior and an inferior articular facet.
- Atlanto-occipital joint (between atlas and occipital bone).
Axis (2nd cervical V., C2)
Has an Odontoid process (dens) with an anterior articular facet to articulate with
atlas, and a posterior articular facet for transverse ligament of atlas.
Hangman Fracture
in the arch of axis pushes the dens posteriorly
and compresses the brain stem, leading to death.
*Fracture of the dens is a typical fracture of C2.
Atlanto-occipital articulation (upper head joint):
Between superior articular facet of Atlas and Occipital condyles
Atlanto-Axial articulation (lower head joint):
Consists of median and lateral atlanto-axial articulations.
Clinical tips:
*cervical rib: when the costal element is
preserved independently. Usually bilateral,
if one sided, usually on the left side
*The presence of a cervical rib may cause
a triad of disorders:
A- Ischemic muscle pain due to compression
of the subclavian artery.
B- pain in the ulnar side of the forearm & hand.
C- palpable mass over the clavicle.
Thoracic Vertebrae:
There are 12 thoracic vertebrae in human.
Important characteristics:
Have 2 articular facets on their
lateral side (one on the body and the other
on the transverse process).
Spinous process is long and slopes posteroinferiorly.
Costo-vertebral joints:
The head of each rib articulates with 2 adjacent
vertebrae and the disk between them
Costo-transverse joints: between the tubercle
of the rib and the transverse process of it’s own
vertebra
Lumbar vertebrae:
There are 5 lumbar vertebrae in human.
Characteristics:
Large body, kidney shape.
Long transverse process.
Relatively small vertebral foramen.
*Lumbar puncture:
Is done at L3-L5 region.
The intercrestal line (iliac crests) is at the
level of L4 approximately (safe region).
Joints of the vertebral column:
Zygapophysial joints
Uncovertebral joints
Zygapophysial joints
These are the small vertebral joints between
the articular processes.
Uncovertebral joints
Between cervical vertebrae. They develop
by age and may become pathologic and
permit disk herniation especially in C5 region.
Unscenic processes can create uncovertebral joint(not everyone gets them)
more often in boys
a sudden movement can rupture the disk in C6-C7 which could cause significant damage to entire spinal cord
Intervertebral disks
Fibrocartilage tissue.
They consist of an outer tense part, the
Anulus Fibrosus and a soft jelly-like nucleus
called the Nucleus Pulposus (remnant of the
Notochord, embryonic tissue).
Intervertebral disks Function
Acts as a shock absorber, is compressible and
permits slight degree of movement of the
vertebrae over each other.
They build up approximately 20% of the length
of the vertebral column (taller in the mornings).
Intervertebral Disk Herniation
Mostly posterolaterally where the Anulus
Fibrosus is thinner
Ligaments of the vertebral column:
Many, among them,
- Anterior longitudinal lig
- Post. Longitudinal lig
- Ligamentum flavum , yellowish in color
due to Elastic fibers, facilitates movements
Intertransverse ligs
Interspinous lig
Supraspinal lig.
L4 nerve goes out sharply(almost 90 degree angle) so a herniation in L4-5 then
L5 gets damage because L5 is actually a bit closer to the disk
L5 and S1 nerve roots are most commonly damaged because
thicker than most other nerves
intervertebral foramen they exit are narrower than others
typically causes sciatica
Vertebral artery moves up to transverse foramen of C6
find origin on vertebral artery
Origin
Basilar artery at top of cerival then to brain
C1 sub occipital nerve from sub occipital triangle
C2 greater occipital nerve
Sacrum:
Consists of 5 sacral vertebrae and the
intervertebral disks that lie between them.
It has a concave anterior surface and a
convex dorsal surface.
Females: sacrum is wider, shorter,
more concave.
Males: sacrum is longer and less wide.
*Sacral hiatus, Sacral horns (cornua)
*Epidural anesthesia is given through sacral
hiatus to block the pelvic nerves.
Coccyx:
Four vertebrae (rudimentary).
Cornua or horns of coccyx facing
sacrum.
Injury to coccygeal vertebrae:
Falling on buttocks, specially in females,
Painful delivery.
Coccydyna: pain in coccyx
Abnormal fusion and
defects of the vertebrae:
Sacralization of L5
Lumbarization of S1
Spina Bifida:
Failure of vertebral arches to form or fuse.
Usually In lumbar or sacral vertebrae
Leading to meningocele (just meninges bulge
out of the vertebral canal) or
meningomyelocele (meninges plus
spinal cord bulge out).
Spina bifida Occulta:
*Folic acid substitution in conception and
during pregnancy decreases the risk of
spina bifida.
Extrinsic muscles of the back:
Superficial layer: consists of the trapezius and latissimus dorsi.
Superficial layer: These lie deeper than trapezius and latissimus dorsi.
They include the Levator scapulae, rhomboid minor and major,
the serratus posterior superior and inferior belong to the intermediate extrinsic
back muscles however are discussed here with the superficial intrinsic back muscles
Intrinsic muscles of the back:
Superficial intrinsic back muscles: Splenius cervicis and capitis
The two splenii rotate and extend the head and neck.
Contraction of each splenius rotates the head to the side of contraction.
Bilateral contraction extends cervical spine and the head.
They are innervated by dorsal rami.
Intermediate intrinsic back muscles:
Consists of lateral group muscles including the Iliocostalis lumborum, thoracis,
cervicis; and Longissimus thoracis, cervicis, capitis.
and medial group, the Spinalis thoracis and cervicis and capitis (might be missing).
Deep intrinsic back muscles:
Semispinalis thoracis, cervicis and capitis,
Multifidus, Rotators, Interspinales, Intertransversarii and Levatores costarum
Trapezius M: has 3 parts
- Descending part
- Transverse part
- Ascending part
Descending part:
Origin: from external occipital protuberance,
superior nuchal line, and Ligamentum nuchae
Insertion: lateral third of the clavicle
Transverse part: from C7-T3 spinous process
Inserted to: clavicle and scapula (acromion)
Ascending part: from T3-T12 spinous process
Insertion: spine of the scapula
Trapezius M Action and Inntervation
*Action: elevation, retraction and rotation
of scapula.
Helps in adduction and slight elevation of arm
**Innervation: spinal root of Accessory nerve
(CNXI) and C3-C4 (propioception and pain).
Rhomboid Minor and Major
Rhomboid Minor:
Origin: spinous process of C6 and C7.
Insertion: medial margin of scapula.
Rhomboid Major: caudal to Rh. minor
Origin: spinous process of T1-T4
Insertion: medial margin of scapula
*Action of both muscles: press the scapula
to the thoracic wall, retraction of scapula medially.
Nerve supply: dorsal scapular nerve (C4-C5)
Levator Scapulae
Origin: transverse process of C1-C4
Insertion: superior angle of scapula
Action: elevates the scapula
Innervation: dorsal scapular nerve (C4-C5)
Latissimus dorsi M: (coughing M)
Origin: vertebral part T7-T12 spinous process thoracolumbar part (from fascia) iliac part (from iliac crest) costal part: 10-12th rib inferior angle of scapula
Insertion: crest of the lesser tubercle
of humerus.
*Action:
Adduction and lowering the arm, medial
rotation and extension of the arm (humerus).
Raises the body toward the arm when climbing.
*Innervation:
Thoracodorsal N. (C6, C7, C8).
Serratus post. Inferior
Innervation: intercostal nerves (T9-T12).
may function as accessory
muscles of
respiration (in COPD).
Serratus post. Superior
Function: rib elevation
may function as accessory
muscles of
respiration (in COPD).
Muscles of the back are divided into two groups:
the extrinsic and intrinsic muscles,
separated by the superficial layer of thoracolumbar fascia:
Extrinsic muscle of the back include
the trapezius, latissimus dorsi. Levator scapulae,
rhomboid minor and major. These are also related to the upper limb and therefore, are
also discussed there.
Serratus posterior superior and inferior, belong to the intermediate
extrinsic back muscles.
Intrinsic muscles of the back are grouped into
superficial, intermediate, and deep layers
Intrinsic muscles
Superficial layer
Splenius muscles (capitis and cervicis).
The splenius muscles and several smaller muscles (including the deep muscles forming
the suboccipital triangle) on the back of the neck are discussed in the back muscles but
they also belong to the superficial and deep muscles of the head and neck.
Intrinsic muscles
Intermediate intrinsic back muscles
Iliocostalis, Longissimus dorsi, and Spinalis are
in this group. They are also called the erector spinae muscles.
Intrinsic muscles
Deep intrinsic back muscles
These are divided into two groups, the transversospinal
and deep segmental muscles.
Transversospinalis muscles: Semispinalis, Multifidus, and Rotators.
Deep segmental back muscles: Interspinales, Intertransversarii, and
Levatores costarium
Vertebrobasilar syndrome
head tilted up pinches basilar artery to head and individual passes out
looking up for long periods
Intrinsic muscles of the back
Superficial intrinsic back muscles:
Splenius cervicis and capitis:
The two splenii rotate and extend the head and neck.
Contraction of each splenius rotates the head to the side of contraction.
Bilateral contraction extends cervical spine and the head.
They are innervated by dorsal rami.
Intrinsic muscles of the back
Intermediate intrinsic back muscles:
Consists of lateral group muscles including the Iliocostalis lumborum, thoracis, cervicis;
and Longissimus thoracis, cervicis, capitis.
and medial group, the Spinalis thoracis and cervicis and capitis (might be missing).
Intrinsic muscles of the back
Deep intrinsic back muscles:
Semispinalis thoracis, cervicis and capitis,
Multifidus, Rotators, Interspinales, Intertransversarii and Levatores costarum
Intrinsic muscles of the back
(erector Spinae)
Lateral (superficial) group
**Lateral group:
Iliocostalis, lumborum, thoracis, cervicis
Longissimus thoracis, cervicis, capitis
Splenius crvicis and capitis
*Innervation: all by primary spinal dorsal rami
*Action: for erect posture of the body and
the two splenii rotate the head.
Extensors when both sides contract and flexion
when one side contracts.
Intrinsic muscles of the back
(erector Spinae)
Medial deep group.
Interspinales Muscles
Intertransverse muscle cervicis
and lumbar.
Spinalis Thoracis and Cervicis and
perhaps capitis as well.
Rotator brevis and longus thoracis
Multifidus
Semispinalis cervicis and capitis
All innervated by various primary dorsal rami.
Action: Extensors when both sides contract
and flexion when one side contracts.
Some stabilize and some rotate the
vertebral column.
Suboccipital triangle Parts
Rectus capitis post. Major
Oblique capitis superior
Oblique capitis inferior
Suboccipital triangle
Rectus capitis post. Major
Oblique capitis superior
Oblique capitis inferior
**Content:
A- 3rd part of vertebral artery,
B- Suboccipital nerve (C1) innervating
all 3 muscles
C- Suboccipital plexus of veins
Action: turning the head backward or
laterally.
**Vertebrobasilar syndrome
Sensory innervation of the region:
Greater occipital nerve (C2)
