Gross Anatomy of the Back Flashcards
What are the major bones of the back?
scapula
clavicle
humerus
rib(s)
hip
vertebral colum
What is the main function of the vertebral column
transmit weight of trunk to lower limbs
What does the vertebral column do?
surrounds and protects the spinal cord
How many bones and why type does the vertebral column contain?
26 irregular bones
What are the cervical vertebrae and how many do are there?
vertebrae of the neck, 7 of them (C1 is at the base of the skull)
What are the thoracic vertebrae and how many are there?
vertebrae of the thoracic cage, 12 of them (T1 is just below C7)
What are the lumbar vertebrae and how many are there?
vertebrae of the lower back, 5 of them (L1 is just below T12)
What is the sacrum?
bone inferior to the lumbar vertebrae
What is the coccyx?
terminus of the vertebral column
What are the different categories of vertebrae?
cervical
thoracic
lumbar
sacrum
coccyx
What happens to the vertebrae as we go down the spine?
they get larger to support our weight
What is the purpose of the curvature of the vertebral column?
increase the resilience and flexibility of the spine
has a natural curve to transmit out weight evenly
What two parts of the vertebral column are posteriorly concave curvatures?
cervical and lumbar
What to parts of the vertebral column are posteriorly convex curvatures?
thoracic and sacral
What are 3 abnormal spine curvatures?
scoliosis
kyphosis
lordosis
What is scoliosis?
abnormal lateral curve
What problem might arise due to scoliosis?
compromization of respiratory function
What is kyphosis?
hunchback
What is lordosis?
swayback
What is the general structure of vertebrae?
body or centrum
vertebral arch
vertebral foramina
intervertebral formaine
seven processes
What is the body of vertebrae?
anterior weight bearing region
What is the vertebral arch?
composed of pedicles and laminae that, along with centrum, enclose vertebral foramen
What is the vertebral foramina?
together make up vertebral canal for spinal cord
What is the intervertebral foramina?
lateral openings between adjacent vertebrae for spinal nerves
What are the seven processes of the vertebra and how many are there of each?
spinous process
transverse processes (2)
superior articular processes (2)
Interior articular processes (2)
What is the projection of the spinous process?
projects posteriorly
What is the projection of the transverse processes?
project laterally
How do the superior articular processes protrude?
superiorly inferiorly
How do the inferior articular processes protrude?
inferiorly
What is Pars Interarticularis?
segment of bone in between the superior and inferior articular facets
small bony arch in the back of the spine between the facet joints
scottie dog appearance on oblique radiographs
What happens if there is a defect in the Pars Interarticularis?
leads to spondylolysis
Where is a common area where fractures occur, typically in the lumbar region?
Pars Interarticularis
“define” C1-C-7
smallest, lightest vertebrae
What are the features of C3-C7 vertebrae?
oval body
spinous processes are bifid (expect C7)
Large, triangular vertebral foramen
Transverse foramen in each transverse process
What are C3-C7 classified as?
typical vertebrae
What does bifid mean?
looks like it has feet
What is the transverse foramen?
opening in transverse process, only seen in cervical vertebrae
What is another name for C1?
Atlas
What is another name for C2?
axis
What are the unique features of atlas (C1)?
no body or spinous process
consists of anterior and posterior arches and 2 lateral masses
superior surfaces of lateral masses articulate with the occipital condyles
What are the unique features of axis (C2)?
dens (odontoid process) projects superiorly into the anterior arch of the atlas
dens (not seen in other vertebra) is a pivot for the rotation of the atlas
What is the dens/odontoid process?
developmentally though to be the detached body of C1
What are characteristics of the thoracic vertebrae?
All 12 articulate with ribs at facets (not typically seen in C or L) and demifacets
long spinous process
location of articular facets allows rotation of this area of spine
Where might an extra facet be seen and what does this mean?
C7 and that person would have a 13th rib which can be symptomatic
How would you describe lumbar vertebrae?
short, thick pedicles and laminae
flat hatchet-shaped spinous processes
What prevents the lumbar vertebrae from rotating?
orientation of the articular facets locks lumbar vertebrae together to prevent rotation
How many vertebrae make up the sacrum?
5 fused vertebrae
S1-S5
What does the sacrum form?
the posterior wall of the pelvis
What does the sacrum articulate with?
L5 superiorly and with articular surfaces of the hip bones laterally
What is another term for the coccyx?
tailbone
How many vertebrae make up the coccyx?
3-5 fused vertebrae
What does the coccyx articular with?
superiorly with the sacrum
What is the sacral promontory?
upper margin of first sacral process
What is the ligamentum flavum?
connects laminae of adjacent vertebrae
this is where spinal anesthetic is injected
Where are the anterior and posterior longitudinal ligaments found?
from the neck to the sacrum
What are short ligaments?
connect each vertebra to those above and below
What are intervertebral discs?
cushionlike pads composed of two parts
nucleus pulposus
anulus fibrosus
What is the nucleus pulposus intervertebral disc?
inner gelatinous nucleus that gives the disc its elasticity and compressibility
What is the anulus fibrosus intervertebral disc?
outer collar composed of collagen and fibrocartilage
What is a disorder of the vertebral column?
ankylosing spondylitis
What is ankylosing spondylitis?
mobility of vertebral column is compromised - can result in fusing of vertebrae
What happens in spinal stenosis?
the vertebral foramen becomes narrowed
What is spondylolysis?
refers to the separation of the pars interarticularis
fracture WITHOUT displacement of the bone
What is spondylolisthesis?
refers to anterior slippage of one vertebra over another (in the front of the spine)
fracture WITH displacement of the bones
What is a dermatome?
area of skin innervated by the cutaneous branches of a single spinal nerve
All but which spinal nerve participate in dermatomes?
C1
Why do most dermatomes overlap?
so destruction of a single spinal nerve will not cause complete numbness
if we have an injury or cut, we don’t lose sensation
How many pairs of spinal nerves do we have?
31 pairs
What is the purpose of roots in regards to spinal nerves?
each spinal nerve connects to the spinal cord via 2 roots
What are ventral roots in regards to spinal nerves?
contain motor (efferent) fibers from the ventral horn motor neurons
fibers innervated skeletal muscles
What are dorsal roots in regards to spinal nerves?
contain sensory (afferent) fibers from sensory neurons in the dorsal root ganglia
conduct impulses from peripheral receptors
motor=?
efferent
sensory=?
afferent
How do dorsal and ventral roots interact?
they unite to form spinal nerves which then emerge from the vertebral column via the intervertebral foramina
What happens with disc prolapse?
whole spinal nerve is compromised
What is rami in regards to spinal nerves?
each spinal nerve branches into mixed rami
dorsal ramus
larger ventral ramus
meningeal branch
What does rami communicate?
communicates (automatic pathways) join to the ventral rami in the thoracic region
What ventral rami form interlacing nerve networks called plexuses?
cervical
brachial
lumbar
sacral
NOT T2-T12
What is a plexus?
interlacing nerve networks
What and how is the back innervated?
it is innervated by dorsal rami via several branches
What do the ventral rami of T2-T12 as intercostal nerves supply?
supply muscles of the ribs, anterolateral thorax, and abdominal wall
What is deep fascia?
it includes collagen and tissue and it it thicker on the back
What is thoracolumbar fascia and what does it do?
deep fascia
covers deep muscles of the back
attaches medially to spine of vertebrae
inferiorly to ilium
provides attachments to muscles
What are the 3 muscle groups of the back?
superficial layer
intermediate layer
deep layer
What is the origin of almost all 3 muscle groups?
vertebrae
What is the function of the superficial layer of the back muscles?
move upper extremity (arm)
What is the function of the intermediate layer of the back muscles?
respiratory muscles (insert to rib)
What is the function of the deep layer of the back muscles?
move trunk and back
What is the trapezius supplied by?
11th cranial nerve
How many cranial nerves do we have?
12
What muscle helps us to shrug our shoulders?
levator scapulae
What is the triangle of auscultation?
best place to pick up breath sounds
triangular area medial to the scapula
overlies the 6th intercostal space
What are the boundaries of the triangle of auscultation?
interior - latissimus dorsi
medial - trapezius
lateral - medial border of scapula
What is the inferior lumbar (petit) triangle?
an area not covered by muscle
What are the boundaries of the inferior lumbar (petit) triangle?
inferior - iliac crest
posterior - latissimus dorsi
anterior - external abdominal oblique
What is the clinical importance of the inferior lumbar (petit) triangle?
herniations occasionally occur
What muscles are included in the intermediate group of muscles in the back?
lavatores costarum
serratus posterior superior
serratus posterior inferior
What are the muscles of the superficial group of muscle in the back?
trapezius
latissimus dorsi
levator scapulae
rhomboid minor
rhomboid major
What does the serratus posterior superior do?
attaches to ribs to help in inspiration
deep to rhomboid
What does the serratus posterior inferior do?
pulls thoracic cage down helping in expiration
deep to latissimus dorsi
What are the 3 subdivisions of the deep group of muscles of the back?
splenius
erector spinae
spinotransverse (transversospinal)
What are the 3 muscles of the erector spinae from lateral to medial?
iliocostalis
longissiums
spinalis
What is the sub-occipital triangle?
pair of muscular triangles, situated on each side of the mid line in the suboccipital region
What are the 3 muscles of the sub-occipital triangle?
obliquus capitis superior
obliquus capitis inferior
rectus capitis posterior major
What parts are included in the sub-occipital triangle?
3rd part of vertebral artery, C1 (suboccipital nerve), plexus of vein
