Lecture 11 - The Spine & Axial Skeleton Flashcards
How may vertebrae are in the body
- > 7 Cervical
- > 12 Thoracic
- > 5 Lumbar
- > 5 Sacral
- > 1 Coccyx
landmarks of a typical vertebra
- Body (black)
- Intervertebral disc (black)
- Vertebral arche (black)
- > pedicles
- > laminae - Faucets (blue)
- > sup and inf - Processes (green)
- > spinous and transverse - Pars (yellow)
- > interarticularis - Inf and Superior notches (purple)
- Intervertebral foramen (brown)
general characteristics of cervical, lumbar, and thoracic verts
atlanto-occipital joint
- > articulation between atlas and the occipital bone of the skull
- > it is a pair of joints; synovial with condyloid subclass
movement of atlanto-occipical joint
Flex/Extend
- > 10-15 deg
slight lateral motion
atlantoaxial joint
- > articulation of the atlas (C1) and the axis (C2)
- > it is a synovial joint but has a pivot subtype
movements of atlantoaxial joint
rotation of the head
- > 50 degrees
Flex/extend
- > 10 degrees
unconvertebral joint
- > aka Luschka’s joint
- > articulations between vertebral body C3-C7 and the uncinate process
- > its a synovial and cartilagenous joint
movement of unconvertebral joint
- > flexion and extension
- > some rotation
what are the special joint on the thoracic vertebrae and what do they do
Costovertebral joint
- > articulation between the head of the rib and the body of the thoracic vert
Costotranserve joint
- > articulation between the tubercle of the rib with the transverse process of the thoracic vert
type and function of special costovertebral and costotransverse joints
- > both are synovial plane joints
- > allow a small degree of gliding to move the ribs superiorly and posteriorly, to increase the volume of the ribcage
what is the zygapophyseal (facet) joint and how much can it move
- > articulation between the inferior articulating facet of the superior vertebrae to the superior articulating facet of the inferior vertebrae
- > synovial joint
- > guide and limits movement of the segments of the spinal column
*prevents hyper-extension, hyperflexion, and herniation of intervertebral discs
intervertebral joints
articulation between adjacent vertebral bodies
- > cartilaginous joint
- > can perform minimal/slight movements
lumbrosacral joint
- > articulation between L5 and the first segement of the sacrum S1 (L5-S1)
- > cartilaginous-symphysis joint
- > can perform slight movements
sacroiliac joint
- > articulation between the coxal bone and the sacrum
- > its a synovial (plane) joint in children and cartilaginous in adults
- > can perform very slight movements
ROM of the spine
Flexion
- > 40-60 degrees
Extension
- > 20-25 deg
Lat flexion
- > 15-20 deg
Rotation
- > 3-18 deg
intervertebral discs
- > AKA intervertebral cartilage
- > cartilaginous joints
- > each disc consists of an outer annulus fibrosus (several layers of fibrocartilage) and an inner nucleus pulposes (loose fibres suspended in a mucoprotein gel)
- > it is a shock absorber
what is a herniated disc how does it happen
- > it occurs when a portion of the nuclus pushes through a crack in the annulus
- > can happen with age or it can slip out of place while you are twisting, turning, or lifting an object
describe the curves of the vertebral column at birth and when you’re older
you’re born with a kyphotic c-shaped spine
and you have an S shaped spine when you’re older
- > 20-40 deg in the t-spine
- > 30-50 in the L-spine
classify the different vert section into lordotic or kyphotic curves, when do they develop
Cervical
- > lordotic, development occurs when an infant lifts their head
Thoracic
- > kyphotic, occurs during fetal development
Lumbar
- > lordotic
- > devel occurs when infant learns to walk
Pelvic (sacral)
- > kyphotic, develops during fetal development
ligaments of the spine
- Cruciate ligament
- interspinous ligament
- ligamentum flava
- Ant & Post logitudinal ligament
- Supraspinous ligament
characteristics of cruciate ligament of the spine
- > shaped like cross
- > transverse ligament (on atlas) is the strongest part of cruciate ligament
- > vertical fibres attach to occipital bone and to body of axis
- > its function is to hold dens in place agains atlas
characteristics of interspinous ligament
- > connects adjacent posterior spines
- > large angle of obliquity
- > its function is to limit flexion and it helps facet joints stay in contact
characteristics of ligamentum flava
- > connects laminae of vert
- > 80% elastin, 20% collagen
- > its function is to limit flexion; its highly elastic capacity (from elastin) prevents buckling into the spinal canal during extension
characteristics of Ant/Posterior longitudinal ligaments
- > ribbon like ligaments
- > attach at vertebral bodies and annulus
- > the function of ant. lig. is to resist excessive extension; post is to resist excessive flexion
characteristics supraspinous ligament
- > connects tips of spinous processes
- > its function is to resist excessive flexion
muscles of the erector spinae group
- > spinalis
- > longissimus
- > illiocostalis
functions and location of the erector spinae muscle group
Spinalis
- > most medial group
- > extends vertebral column
Longissimus
- > middle group
- > extends and laterally flexes vertebral column
Illiocostalis
- > most lateral group
- > extends and laterally flexes vertebral column
thoracic portion of the erector spinae
Illiocostalis and longissimus
- > 75% slow twitch fibres
- > greatest mechanical advantage for extension
- > line of action is parallel to spine
- > main function together is extension
lumbar portion of erector spinae
Illiocostalis and longissimus
- > 50/50 slow-fast twitch fibre composition
- > line of action is oblique (posterior-caudal)
- > their main function is to creat posterior shear forces against anterior shear forces during flexion
when is the oblique line of the lumbar portion of the erector spinae muscles lost
during flexion cause by posterior hip rotation
quadratus lumborum
muscle of the abdominal wall
- > it is activated during flexion lateral flexion/extension
- > hardly changes in length during spine movements, which tells us its a stabilizer
