Anatomy Lecture 3: Vertebral Column and Back Muscles

vertebral arch

part of the vertebra formed by 2 pedicles and 2 lamina

vertebral foramen

a hole formed by the vertebral arch and posterior body

intervertebral foramen

a hole formed by the superior and inferior notches of adjacent vertebrae

spinous process

the most posterior projection of the vertebra for muscle/ligament attachment

transverse processes

the lateral projections of the vertebra for muscle/ligament attachment

articular processes

the superior and inferior projections of the vertebra used to form joints with adjacent vertebra

transverse foramen

holes in the cervical vertebra for the vertebral artery

cervical vertebrae

do horizontal articulation for flexion, extension, lateral bending, and rotation

thoracic vertebrae

do frontal articulation with each other for rotation

lumbar vertebrae

do saggital articulation for flexion, extension, and lateral bending

odontoid process

dens

sacral hiatus

where the 4th and 5th sacral vertebra have no laminae and spinous process

Venous system of the vertebral column

Has two external venous plexuses (one on the anterior and one on the posterior vertebra) and one internal venous plexus in the vertebral foramen; are valveless and allows for bidirectional flow

primary spinal curvature

curvature formed in the fetal period to create an anterior concave with the thoracic and sacral portions

secondary spinal curvature

curvature formed postnatally to allow for lifting the head and walking with the cervical and lumbar portions

intervertebral discs

shock absorbers between adjacent vertebra that fuse with bone and are highly viscous; they make up 20-25% of the vertebral column’s length and are composed of anulus fibrosus and nucleus pulposus

anulus fibrosus

a ring of fibrocartilage in IV discs that is thicker anteriorly

nucleus pulposus

A portion of IV discs that is 85% water at birth (dehydrates with age) and changes shape with movement, slightly posteriorly located and surrounded by anulus fibrosus

anterior longitudinal ligament

ligament on the anterior of the vertebra body to limit hyperextension

posterior longitudinal ligament

ligament on the posterior of the vertebra body to limit hyperflexion

ligamentum flavum

ligament between successive laminae in the vertebral foramen; slightly yellow in color

interspinous ligament

ligament between successive spinal processes

supraspinous ligament

vertical ligament that lines the posterior ends of all spinal processes; has thicker area called the nuchal ligament

nuchal ligament

a thicker specialization of the supraspinous ligament along the cervical region

transverse ligament of the atlas

ligament that prevents the dens of C2 from pushing into the spinal cord at C1 and allows for rotation

kyphosis

a condition of increased thoracic curvature, typically from osteoporosis

lordosis

a condition of increased lumbar curvature, typically from abdominal weight, weak muscles, &/or pregnancy

scoliosis

a condition of abnormal curvature and rotation of the spine

spina bifida occulta

A condition a spine split with a vertebral arch defect at around L5/S1 that has no clinical effects except a tuft of hair

spina bifida cystica with meningocele

A condition a spine split with a vertebral arch defect at around L5/S1 that includes a split of the meninges without spinal cord displacement that has no severe neurological effects

spina bifida cystica with meningomyelocele

A condition a spine split with a vertebral arch defect at around L5/S1 that includes a split of the meninges and spinal cord/nerve root displacement that has severe neurological effects

spina bifida myeloschisis

A condition a spine split with a vertebral arch defect at around L5/S1 that includes a split of the meninges and spinal cord (spinal cord is exposed) that has severe neurological effects

fractures

a break of bone that is most common in vertical vertebrae followed by T11 and T12

Whiplash injury

An injury where severe hyperextension of the neck can damage/tear the anterior longitudinal ligament

rupture of the transverse ligament of the atlas

An injury where the ligament holding the dens in place ruptures and the dens can push into the spinal cord; need open-mouth view of x-ray to see

herniated disc

a protrusion of the nucleus pulpous through the anulus fibrosus typically posteriorly or posterolaterally that can compress the spinal cord or nerve roots of spinal nerves in cauda equina; can be localized (only effects spinal nerves of the vertebra inferior of the disc)

extrinsic muscle division

A muscle division where the muscle’s origin is outside the interest area (which is the back here= attach between spine and scapula/upper limb/ribs); has innervation segmentally by the anterior rami (except trapezius) and includes the superficial and intermediate muscle layers

intrinsic muscle division

A muscle division where the muscle’s origin/insertion/action is inside the interest area which is the back here= attach within back and some ribs); has innervation by the posterior rami and includes the deep muscle layers

acromion

part of the posterior scapula that articulates with the clavicle

supraspinous fossa

part of the posterior scapula that is above the scapular spine

infraspinous fossa

part of the posterior scapula that is below the scapular spine

subscapular fossa

the depression of the anterior scapula

coracoid process

an attachment area of the anterior scapula

glenoid fossa

a depression of the scapula for articulation with the head of the humerus

greater tubercle

the large bump on the superior portion of the humerus

lesser tubercle

the smaller bump on the superior portion of the humerus

intertubercular sulcus

the groove of the humerus between the greater and lesser tubercles

deltoid tuberosity

the bump on the humerus body that the deltoid muscle attaches to

radial groove

a depression in the humerus body that protects the radial nerve

trapezius

a layer 1 superficial back muscle that elevates, depresses, retracts/protracts, and superiorly rotates the scapula

CN XI and anterior rami C3-C4

trapezius nerve

transverse cervical artery

trapezius artery

latissimus dorsi

a layer 1 superficial back muscle that adducts, extends, and medially rotates the arm

thoracodorsal nerve (C6-C8)

latissimus dorsi nerve

thoracodorsal artery

latissimus dorsi artery

levator scapulae

a layer 2 superficial back muscle that elevates the scapula

dorsal scapular nerve (C5) and anterior rami (C3-C4)

levator scapulae nerve

rhomboid major/minor

layer 2 superficial back muscles that retract, elevate, and inferiorly rotate scapula

dorsal scapular nerve (C5)

rhomboid major/minor nerve

dorsal scapular artery

levator scapulae and rhomboid major/minor artery

serratus posterior superior

an intermediate back muscle that elevates ribs during inhalation

serratus posterior inferior

an intermediate back muscle that depressed ribs during exhalation

segments of anterior rami

serratus posterior superior and inferior nerve

erector spinae muscles

deep back muscles that function to maintain posture and give dynamic spine control

Iliocostalis, longissimus, spinalis

erector spinae muscles that bilaterally extend vertebral column and head and unilaterally do lateral bending

posterior rami

erector spinae muscles, splenius, and transversospinalis group nerves

splenius

a deep back muscle made of the cervicis and capitis that bilaterally extends the head and unilaterally rotates and laterally bends the head (ipsilateral movements)

transversospinalis group

deep back muscles that origin in the transverse processes and insert on spinous processes

semispinalis

a transversospinalis group deep back muscle that extends and rotates the head and neck; the muscle fibers span over 5 vertebral levels

multifidus

a transversospinalis group deep back muscle that stabilizes the vertebral column and the muscle fibers span over 3 vertebral levels

rotatores

a transversospinalis group deep back muscle that stabilizes the vertebral column and the muscle fiber span 1 vertebral level

vertebra prominens

C7, the bony part you can feel on the base of your neck

lateral mass

thick portions of C1 (and lesser in C2) that act as weight-bearers of the head due to the lack of body in C1; sit under the superior articular facets

triangle of auscultation

an ideal place to listen to lung sounds because of fewer structures blocking the lungs; formed by the latissimus dorsi, trapezius and medial border of the scapula