BACK ANATOMY

Vasculature of vertebral column

-Arteries -Periosteal branches: supply the periosteum -Equatorial branches: supply central core -Nutrient branches: supply bone marrow -Veins -Internal anterior and posterior vertebral venous plexuses -External anterior and posterior vertebral venous plexuses

Ligamenta flava:

broad, pale yellow band of elastic tissue joining the laminae of adjacent vertebrae. Form posterior wall of vertebral canal. Limit flexion and separation of vertebral laminae, protecting IV disks

IV disks:

cartilaginous joints, connecting articulating surfaces of adjacent vertebral bodies

Anterior atlanto-axial membrane:

extends from anterior arches of Atlas to anterior arches of Axis. Merges with anterior longitudinal ligament in the center

Anterior atlanto-occipital membrane:

extends from anterior arches of Atlas to anterior margin of FM. Merges with anterior longitudinal ligament in the center

Posterior atlanto-axial membrane:

extends from posterior arches of Atlas to posterior arches of Axis. It's a superior continuation of Ligamenta flava, but less elastic fibers

Posterior atlanto-occipital membrane:

extends from posterior arches of Atlas to posterior margin of FM. Perforated to allow passage for the vertebral artery

Laminae:

flat plates continuous with pedicles that join posteriorly in the midline

Cause of spina bifida:

folic acid deficiency

Vertebral foramen

formed by vertebral arch and posterior surface of vertebral body. The succession of vertebral foramina forms the vertebral canal

Superior and inferior longitudinal bands:

from transverse ligament to occipital bone superiorly and to body of C2 inferiorly

Median sacral crest:

fused rudimentary spinous processes of sacral vertebrae

semispinalis capitis

goes to the head through the spine, one on R & L

spinalis thoracis

goes to the thoracic vertebrae

Apex:

inferior end that articulates with coccyx

Sacral hiatus:

inverted U-shape, resulting from lack of laminae and spinous processes of S5 vertebra. Clinical relevance: provides access to the sacral epidural space for administration of anesthetics (caudal nerve block)

Vertebral movement

is reduced to the superior 24 vertebrae. The 5 sacral vertebrae are fused, and the 4 coccygeal vertebrae usually fuse after age 30, limiting movement of these vertebrae

Vertebra L5:

largest of the moveable vertebrae

Spinous process location

median and posterior

Multifidus:

middle layer

Sacral cornua:

represents inferior articular process of S5 vertebra. Helps in the anatomical location of the sacral hiatus

Ala:

represents the fused transverse processes of sacral vertebrae

Interspinous ligaments:

weak ligaments joining adjacent spinous processes. Inconsequential in the cervical region

Pedicles:

short, cylindrical projecting posteriorly from body

Posterior longitudinal ligament:

weaker, narrower band than ALL. Runs within vertebral canal along posterior aspect of vertebral bodies. Extens from body of C2 to sacrum. Limits flexion

Zygapophysial joints:

synovial joint between superior and inferior articular facets of adjacent vertebrae. Allows gliding movements.

Atlanto-occipital joint:

synovial joint, with thin, loose capsule between superior articular facets of the Atlas and the condyles of the occipital bone. Flexion & extension (e.g. nodding). Anatomical equivalent of zygapophysial joint

Lateral atlanto-axial joints(2):

synovial, gliding joint, with thin, loose capsule between inferior articular facets of the Atlas (C1) and the superior articular facets of the Axis (C2). Anatomical equivalent of zygapophysial joint

how many processes could one vertebrae have?

up to 7 -spinous process -2 transverse processes -4 articular processes (superior & 2 inferior)

Base of sacrum:

superior surface of S1 vertebra

Alar ligaments:

extend superolaterally from each side of dens to lateral margin of FM. Check ligaments, prevent excessive rotation of the joints

Vertebral arch is located

posterior to vertebral body

Articular processes:

project from the junction of pedicles and laminae. Each bears an articular surface (or facet)

Transverse processes:

project postero-laterally from the junction of pedicles and laminae

Craniovertebral joints

-Atlanto-occipital joint -Ligaments -Anterior atlanto-occipital membrane: -Posterior atlanto-occipital membrane: -These two membranes are strong sheets of connective tissue that extend laterally towards the atlanto-occipital joint, and help prevent excessive movement of atlanto-occipital joint -Atlanto-axial joints: 1) Lateral atlanto-axial joints(2): -Ligaments: -Anterior atlanto-axial membrane: -Posterior atlanto-axial membrane: 2) Median atlanto-axial joint (1) -Ligaments -Tectorial membrane: -Cruciate ligament -Transverse ligament of atlas: -Superior and inferior longitudinal bands: -Alar ligaments: extend superolaterally from each side of dens to lateral margin of FM. Check ligaments, prevent excessive rotation of the joints

C3 - C7 (typical vertebrae)

-Body -Transverse process -Transverse foramina: vertebral artery goes through C3 - C6, but no C7 -Anterior tubercle: muscle attachment -Posterior tubercle: muscle attachment -Pedicles -Lamina -Superior articulate facet: more transverse plane to allow more articulation, gliding movement -Inferior articulate facet: more transverse plane to allow more articulation, gliding movement -Vertebral foramen: triangular and large, contains large portion of spinal cord -Uncus of body: raised lateral margins of the superior surface of cervical vertebrae C3 - C7 -Spinous process: bifurcated in whites, but not as common in blacks or females. C7 (vertebra prominens): defines the inferior limit of the neck posteriorly.

Characteristics of C1

-Carries the cranium -No body -Anterior arch -Anterior tubercle -Articular facet for dens: on posterior surface of the anterior arch -Lateral masses: bear the weight of cranium -Transverse process: project laterally, and are relatively flat -Transverse foramen: passage for vertebral arteries and accompanying veins -Superior articular facet: articulates with occipital condyle -2 Inferior articular facet: articulates with axis (C2) -Tubercle for transverse ligament of Atlas: the ligament helps to hold the dens of C2 in place -Posterior arch -Posterior tubercle --Groove for vertebral artery: allows passage for vertebral artery into cranium

division of the different types of vertebrae

-Cervical (7) -Thoracic (12) -Lumbar (5) -Sacrum (5) -Coccyx (4)

Limitations to the mobility of the vertebral column

-Compressibility and elasticity of the IV discs -Shape and orientation of the zygapophysial joints -Resistance of back muscles and ligaments -Attachment to thoracic cage -Bulk of surrounding tissue

Primary curvatures

-Develop during the fetal period, related to fetal (flexed) position -kyphosis

Secondary curvatures

-Develop from extension from the fetal position -Begin to develop during late fetal period, and truly become obvious in infancy -Called lordosis (pl. lordoses) and are concave posteriorly -Cervical lordosis -Lumbar lordosis: is more pronounced in women than males

Characteristics of thoracic vertebrae

-General features --Have bodies --Vertebral arches --Seven processes for muscular and articular connections -Typical features --Costal facets (bilateral demifacets): articulate with head of ribs, usually occur in superior and inferior pairs --Transverse costal facets: articulate with tubercles of ribs --Spinous processes: long and sloped inferiorly

Joints of vertebral bodies

-IV disks -Ligaments (support) -Anterior longitudinal ligament (ALL): -Posterior longitudinal ligament:

Intrinsic back muscles

-Innervation: posterior rami of spinal nerves -Function: posture and movement of vertebral column. All are extensors (meaning, backward bending when both sides contract together) acting on the axial skeleton -Enclosed in deep fascia running the length of the medial aspect of the back. Separates intrinsic back (move skeleton) muscles from extrinsic back (limb) muscles -Thoracolumbar fascia: is the thoracic and lumbar parts of the deep fascia surrounding the intrinsic back muscles -Groups of intrinsic back muscles -Superficial layer -Intermediate layer -Deep layer

Characteristics of sacral vertebrae (Sacrum)

-Location: 5 fused sacral vertebrae in the adult between the hip bones -Forms the roof and posterosuperior wall of the pelvic cavity -Function: provides strength and stability to the pelvis, and transmits the weight of the body to the pelvic girdle -Characteristic features --Sacral canal --Anterior and posterior sacral foramina --Median sacral crest --Base of sacrum --Sacral promontory --Ala --Apex --Sacral hiatus --Sacral cornua

Characteristics of lumbar vertebrae

-Location: lower back, between thorax and sacrum -Characteristics of lumbar vertebrae -General features ---Have bodies ---Vertebral arches ---Seven processes for muscular and articular connections -Typical features --Massive bodies --Transverse process -----Accessory process --Superior articular process -----Mamillary processes --Vertebra L5

Vertebral Function

-Protect spinal cord and spinal nerves -Supports the weight of the body superior to the pelvis -Involved in posture and locomotion

why do the cervical vertebrae have the greatest range and variety of movement of all vertebral regions?

-Relative thickness of discs compared to the vertebral bodies -Nearly horizontal orientation of facets -Small amount of surrounding body mass

Movements of cervical portion of vertebral column

-Rotation -Lateral bending -Flexion -Extension

parts of the back

-Skin and subcutaneous tissue -Muscles: superficial (axioappendicular) and deep (intrinsic back muscles) -Vertebral column -Ribs (medial to the angle of ribs) -Spinal cord and meninges -Segmental nerves and vessels

Characteristics of C2

-Strongest of cervical vertebrae -Atlas (C1) carries the cranium and rotates on the Axis (C2) -Body -Dens: projects superiorly from the body, and articulates with the posterior surface of the anterior arch of the Atlas, forming a synovial joint. Embryologically, the dens represent the remnant of the body of the Atlas. ---Anterior articular facet: articulates with posterior surface of anterior arch of Atlas (C1) ---Posterior articular facet: where the dens is supported by transverse ligament of atlas -Pedicles -Lateral masses -Superior articular facet: where the atlas (C1) rotates -Inferior articular facet: articulates with C3 -Transverse process: extends latero-inferior -Transverse foramen: passage for vertebral arteries and accompanying veins -Laminae -Spinous process: bifurcated in whites, but not as common in blacks or females

Extrinsic back muscles

-Superficial (trapezius, latissimus dorsi, levator scapulae, and rhomboids) -Posterior axioappendicular muscles controlling UL movements -Supplied by anterior rami nerves -Intermediate (serratus posterior) -Participate in respiration, but most likely in proprioception -Supplied by anterior rami nerves

Intrinsic back muscle layers

-Superficial layer -Splenius muscles (cervicis and capitis) -Location: lateral posterior portion of neck -Function: Cover and hold (like a bandage) deep neck muscles in place -Innervation: posterior rami -Intermediate layer -Erector spinae muscles -Location: along each side of the vertebral column between spinous processes and angle of ribs -Function: main extensors of the vertebral column -Innervation: posterior rami -Columns -Iliocostalis: lateral column -Longissimus: intermediate column -Spinalis: medial column -Deep layer -Transversospinales muscle group -Location: deep to erector spinae -Function: extensors of the vertebral column -Innervation: posterior rami

Joints of vertebral arches

-Zygapophysial joints -Ligaments (accessory ligaments supporting the vertebral arches) -Ligamenta flava: -Interspinous ligaments: -Nuchal ligament:

vertebrae typically contain

-body -vertebral arch --pedicles --laminae -vertebral foramen -vertebral notches -lateral masses -processes --spinous process --transverse processes --articular processes

deep layer of back muscle

-semispinalis capitis -spinalis cervicis -spinalis thoracis -multifidus -rotatores -cervical interspinal cervical intertransverse -levatores costorum -lumbar interspinales -lumbar intertransversarii

what can remove folic acid from our systems?

Alcohol

vertebrae typically contain how many vertebral notches?

2

Vertebrae typically have contain how many pedicles and laminae?

2 Pedicles 2 Laminae

vertebral length

72 - 75 cm long in the adult, and ~ ¼ is formed by the IV discs

Secondary curvature

C&L

which of the 33 vertebrae are abnormal?

C1, C2, C7

Which set of vertebrae has the greatest range and variety of movement of all vertebral regions

Cervical vertebrae

Movements of vertebral column

Flexion - extension Lateral flexion - lateral extension Rotation

Joints of thoracic wall

Intervertebral joints -IV disks -Ligaments (support) -Anterior longitudinal ligament -Posterior longitudinal ligament -Zygapophysial joints: -Ligaments (accessory ligaments supporting the vertebral arches) -Ligamenta flava -Interspinous ligaments -Supraspinous ligament: connects tips of spinous processes from C7 to sacrum; merge superiorly with the nuchal ligament

Characteristics of coccygeal vertebrae (Coccyx)

Location: usually 4 fused coccygeal vertebrae Remnant of the skeleton of the embryonic tail-like caudal eminence Does NOT participate in body weight bearing Characteristic features Coccygeal cornua: rudimentary articular process of Co 1 vertebra that articulate with the sacral cornua

Innervation of vertebral column

Recurrent meningeal branches of spinal nerves -Only branches that arise from the spinal nerve before it divides into anterior and posterior rami -Runs back through the intervertebral foramina after the spinal nerve has emerged -Supply -Periosteum -Ligamenta flava -IV discs -Posterior longitudinal ligament -Spinal dura mater -Blood vessels in the vertebral canal

Primary curvature

S&T

Back muscles

Support and move the vertebral column Divided into extrinsic and intrinsic back muscles

REMEMBER SPINA BIFIDA

VERTEBRAL COLUMN IS EXPOSED

Massive bodies:

account for much of the thickness of the lower trunk in the median plane

Curvatures of vertebral column provide

additional flexibility to that of the IV discs

Sacral promontory:

anterior projection of the edge of the body of S1 vertebra

what is the C1 known as?

atlas

What is C2 known as?

axis

Vertebrae size:

become larger from cervical to sacrum and then become smaller from sacrum to coccyx. The initial increase in size is due to increased body weight bearing, which is transferred from cervical -> thoracic -> lumbar -> sacrum -> pelvis -> legs

where are the cervical vertebrae located?

between cranium and thoracic vertebrae

the more superfical the back muscle, the more _______ it is

broad

Supraspinous ligament:

connects tips of spinous processes from C7 to sacrum; merge superiorly with the nuchal ligament

Sacral canal:

continuation of the vertebral canal in the sacrum

Vertebral column extends from?

cranium to apex of coccyx

shape & characteristics of vertebral body

cylindrical, anterior part that supports body weight

Rotatores:

deep layer

kyphosis

excessive outward curvature of the spine, causing hunching of the back.

Anterior and posterior sacral foramina:

exit for the anterior and posterior rami of spinal nerves

does the C1 have pedicles?

no, it doesn't have a body

Lumbosacral angle:

occurs at the junction of the long axis of the lumbar and sacral region

Accessory process:

on posterior surface of the base of the transverse processes and provides attachment for the intertransversarii muscles

Mamillary processes:

on posterior surface of the superior articular process and provide attachments for the multifidus and intertransversarii muscles

spinalis cervicis

only on cervical vertebrae

Median atlanto-axial joint (1):

pivot joint between dens of C2 and anterior arch of C1

Back comprises of:

posterior aspect of the trunk, between neck and buttocks

Transverse ligament of atlas:

strong band extending between tubercles on lateral masses of C1

Anterior longitudinal ligament (ALL):

strong, broad fibrous band covering and connecting the anterolateral aspects of vertebral bodies and IV disks. Extends from anterior aspect of FM to pelvic surface of sacrum. Limits extension (only ligament that limits extension)

Nuchal ligament:

strong, broad, and thickened fibroelastic tissue. Extends from occipital protuberance and posterior border of FM to spinous processes of cervical vertebrae. Muscle attachment (Found only in the neck)

Semispinalis:

superficial layer

Vertebral notches:

superior and inferior to each pedicle. Superior and inferior notches of adjacent vertebrae form the intervertebral foramina (exit for spinal nerves and accompanying vessels)

Tectorial membrane:

superior continuation of posterior longitudinal ligament, starting at the body of Axis (C2) until anterior aspect of FM