yoga anatomy mod 2€¦ · of the neck • origin - lower 1/2 of ligmentum nuchae and the spinous...

Module 2

The Human Spine

Anatomy &Physiology

Introduction to the

Vertebral Column

Bones - vertebrae

• Vertebrae

• 33 total

• 5 sections

• From superior to inferior:

• Cervical - 7 vertebrae

• Thoracic - 12 vertebrae

• Lumbar - 5 vertebrae

• Sacrum - 5 vertebrae

• Fused in the adult

• Coccyx - 3-5 vertebrae

• Fused in the adult

Bones - vertebrae

• Nomenclature

• The vertebrae are named for their region, using the first letter of the region and

numbered from top down

• Examples:

• C1, T8, L4

• First cervical, eighth thoracic, and fourth lumbar

• Special nomenclature

• C1 is also known as the atlas

• In Greek mythology, Atlas was the primordial Titan who supported the heavens

• In anatomy, Atlas is the vertebra that supports the head

• C2 is also known as the axis

• It forms the pivot upon which the atlas rotates

Bones - curves

• Primary & Secondary Curves

• Kyphosis - posterior convexity

• Primary curve

• Thoracic & Sacral

• Lordosis - anterior convexity

• Secondary curve

• Cervical & Lumbar

Bones - General Vertebral Anatomy• Vertebral Size

• Increase size from the cervical to lumbar region and decrease in size from sacral to coccygeal region.

• Typical Vertebra

• 2 major parts

• Vertebral Body

• Anterior

• Cylindrically shaped

• Vertebral Arch

• Posterior

• Irregularly shaped

• 3 non-articular processes

• 2 transverse

• 1 spinous

• 4 articular processes

• Facets

• 2 superior & 2 inferior

Bones - vertebrae• Vertebral foramen or canal

• Hole formed between the vertebral body and arch that allows for the passages of the spinal

cord

• Intervertebral foramen

• Hole formed between two adjacent vertebra, superior and inferior vertebral notch, that allows

for the passage of the spinal nerve

Joints - Articulations• 2 main types

• Intervertebral Joints

• Between the vertebral bodies and interposed discs

• Cartilaginous joints of the symphysis type

• Facet Joints

• Between the superior and inferior articulating facets

• Diarthrodial or synovial joints

• Synovial joints are also present where the vertebral column articulates with the ribs, with the skull, and with the pelvis

Connective Tissue

• Intervertebral Disc (IVD)

• 23 total

• Makes up about 20%-33% of the length of the

vertebral column

• Increase in size from the cervical to lumbar region

• 3 mm - cervical

• 9 mm - lumbar

• Greatest IVD to vertebral body ratio occurs in

the cervical and lumbar region and therefore

allows for the greatest ROM

• 2 main parts

• Nucleus pulposus

• Annulus fibrosis

• Nutrition

• Imbibition

Connective Tissue

• Vertebral end plates

• Thin layers of cartilage that cover the

superior and inferior surfaces of the

vertebral bodies

• Ligaments

• 6 main ligaments

• Anterior longitudinal ligament

• Posterior longitudinal ligament

• Ligamentum flavum

• Supraspinal ligament - becomes the

ligmentum nuchae in the cervical

region

• Interspinal ligament

• Inter transverse ligament

Nerves• Spinal cord

• Located within the spinal canal

• Cylindrical shaped with a tapered end, the conus medullaris

• Cauda equina

• The bundle of nerves occupying the spinal canal below the conus medullaris

• Protected by the vertebra, spinal ligaments, CSF, and the meninges

• Meninges

• A collection of 3 membranes that surround and protect the spinal cord

• Dura

• Arachnoid

• Pia

• Spinal nerves

• 31 pairs that exit the spinal canal via the intervertebral foramen

Nerves

• The spinal nerves have two

divisions

• Anterior root

• Ventral nerve root

• Motor function

• Posterior root

• Dorsal nerve root

• Sensory function

Muscles - superficial layer

• Splenius capitus - a broad,

strap like muscle in the back

of the neck

• Origin - lower 1/2 of

ligmentum nuchae and the

spinous processes of C6-T4

• Insertion - mastoid process

and occipital bone

• Action - extend, rotate, and

laterally flex the head

Muscles - superficial layer

• Splenius cervicis

• Origin - spinous processes of

T3-T6

• Insertion - posterior transverse

processes of C1-C3

• Action

• Bilaterally: extenders head

and neck

• Unilaterally: lateral flexion

and rotation to same side

Muscles

• Erector spinae group

• A series of longitudinal muscles

that run the length of the spine

• Can be divided into 3 groups

from lateral to medial

• Iliocostalis

• Longissimus

• Spinalis

I Love Spine

Muscles - intermediate layer

• Iliocostalis - spans 3 regions: lumborum,

dorsi, cervicis

• Origin - broad tendon from posterior

iliac crest, posterior sacrum,sacral

and lumbar spinous processes, and

supra spinous ligament

• Insertion - angles of the lower ribs

and cervical transverse processes

• Action

• Bilaterally: extends the vertebral

column and head,

• Unilaterally: side bends the

vertebral column


• Longissimus - spans 3 regions: thoracis,

cervicis, capitis

• Origin - broad tendon from posterior

iliac crest, posterior sacrum, sacral and

lumbar processes, and supraspinous

ligament

• Insertion - ribs, transverse processes of

cervical and thoracic vertebra, mastoid

process

• Action

• Bilaterally: extend the vertebral

column and head

• Unilaterally: side bends vertebral

column


• Spinalis - spans 3 regions: dorsi,

cervicis, capitis

• Origin - spinous processes of the

lumbar, thoracic, and cervical

regions

• Insertion - spinous processes of

upper thoracic and mid cervical

regions, and the skull

• Action

• Bilaterally: extends the vertebral

column and head

• Unilaterally: side bends the

vertebral column

Muscles - deep layer

• Semispinalis - a

transversospinalis muscle

• Semispinalis capitis

• Origin - transverse

processes C7-T6

• Insertion - between inferior

and superior nucheal line

of occipital bone

• Action: extends the head


• Semispinalis cervicis


processes of T1-T6

• Insertion - spinous

processes of C2-C5

• Action - extends the

cervical spine


• Semispinalis dorsi


processes of T6-T10

• Insertion - spinous

processes C6-T4

• Action - extends vertebral

column


• Multifidus - small muscles that

span the entire spine, from the

sacrum to axis

• The muscle spans three joint

segments.

• Origin - sacrum, PSIS, and

transverse processes

• Insertion - spinous processes

• Action - functions primarily as

a spinal stabilizer


• Levator costarum


processes of C7-T12

• Insertion - superior

surface of the ribs

immediately inferior to the

proceeding vertebra

• Action - assists in

elevation of the thoracic

rib cage

Kinesiology

• Intervertebral joints

• Extremely limited movement

• Translation

• 3 - side to side, superior and inferior, anterior to posterior

• Rotation

• 3 - side to side, vertical axis, anterior to posterior

• Kinetic chain

• The compound effects of these small amounts of translation and rotation at a series of vertebrae produce a large ROM for the column as a whole.

• Flexion and extension

• Lateral Flexion

• Rotation

Kinesiology

• Coupled motion

• Coupling - consistent association of one motion about an axis with

another motion around a different axis.

• Coupled motion varies from region to region and is dependent upon

several factors

• Spinal posture and curves

• Orientation of the articulating facets

• Fluidity, elasticity, and thickness of the IVD

• Extensibility of the muscles, ligaments, and joint capsules

Cervical Spine

Bones• 7 cervical vertebra

• C1-C7

• Typical Cervical Vertebrae

• Body

• Small

• Uncinate processes C3-C7

• Arches

• Superior facets

• Face superior, posterior, and medial

• Inferior facets

• Face inferior, anterior, and lateral

• Transverse processes

• Transverse foremen

• Contains the vertebral artery, vein, and

venous plexus

• Spinous process

• Short, slender, and bifid

Bones

• Atypical Cervical Vertebra

• Atlantoaxial complex

• C1 - Atlas

• No vertebral body

• No IVD between C1 & occiput

• No spinous process

• Ring shaped

• 5 articulating facets

• 2 superior that are slightly concave to

articulate with the slightly convex

occipital condyles

• 2 inferior that are slightly convex

• 1 located on the interior surface of the

anterior arch that articulates with the

dens of C2

Bones

• Atypical cervical vertebra

• Atlantoaxial complex

• C2 - Axis

• Odontoid process or

dens

• No IVD between C1 &

C2

Joints

• Atlanta-occipital joint

• Plane synovial joint

• Composed of the 2 concave superior zygapophyseal facets of the

atlas that articulate with the 2 convex occipital condyles of the skull

• Atlanto-axial joint

• 3 separate joints

• 1 Atlanto-Odontoid joint

• Synovial pivot joint in which the dens of the axis rotates in an

osteoligmentous ring

• 2 lateral joints between the superior zygapophyseal facets of the

axis and the inferior zygapophyseal facets of the atlas

Connective Tissue

• Ligaments

• Cruciform ligament

• Transverse band

• Longitudinal band

• Alar ligaments

• Apical ligament of the

dens

Connective Tissue

• Ligamentum nuchae - a

fibrous membrane that

represents the extension of

the supraspinous ligament in

the neck

Nerves• Spinal nerves

• 8 pairs of cervical spinal nerves

• Brachial plexus

• Formed by 5 cervical nerve roots

• Combine into 3 trunks

• Divide into 6 divisions

• Combine into 3 cords

• Divide into 5 branches or peripheral

nerves

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Muscles

• Sternocleidomastoid (SCM)

• Origin - sternum, medial portion

of the clavicle

• Insertion - mastoid process

• Action

• Bilaterally: flexes neck, raises

sternum

• Unilaterally: tilts head

towards side of contraction

and rotates head away from

side of contraction

Muscles

• Scalenes


processes of C2-C7

• Insertion - first and second

ribs

• Action - elevate ribs and

laterally flex head

Muscles

• Platysma

• A thin sheet like muscle that

covers the anterior cervical

region

• Action - tenses the neck and

depresses the lower lip and

angles of the mouth

Muscles

• Levator scapulae

• Origin - Transverse

processes of C1-C4

• Insertion - superior medial

border of the scapula

• Action - elevates scapula

when spine is fixed.

Laterally flexes head when

shoulder is fixed

Kinesiology

• The cervical spine is designed for a relatively large amount of mobility

• The neck moves about 600 times an hour whether we are awake or asleep

• Cervical ROM

• Flexion and extension

• Lateral Flexion

• Rotation

• Atlanto-occipital joint

• Permits primarily a nodding motion of the head

• Flexion and extension in the saggital plane around a coronal axis

• Atlanto-axial joint

• Rotation, lateral flexion, Flexion and extension

• 55%-58% of the total cervical rotation occurs at the Atlanto-axial joint

Thoracic Spine

Bones

• 12 thoracic vertebra

• T1 - T12

• The majority of the thoracic

vertebra adhere to the basic

structural design of all vertebrae

except for some minor variations

• T1 & T12 are transitional

vertebrae and therefore

possess characteristics of the

cervical and lumbar

vertebrae, respectively

Bones

• Typical thoracic vertebrae

• Body

• Equal transverse and anteroposterior diameters

• Demifacets for articulating with heads of ribs are located on the posterolateral corners

• Arches

• Transverse processes have thickened ends that support oval facets for articulating with the heads of ribs

• Spinous processes vary by groups of 4

• First four point posteriorly

• Second four point almost inferior

• Third four point more distally and horizontally

Joints

• Facet joints

• Superior facets face posteriorly, in an almost

vertical plane

• Inferior facets face anterior

• Costovertebral and costotransverse joints

• Demifacets and oval facets articulate with the

ribs

Nerves

• 12 thoracic nerves

• Intercostal nerves

• Anterior divisions of the

thoracic spinal nerves T1-

T11

• Subcostal nerve

• T12 lies below the last rib

Kinesiology

• Law of side bending and rotation in the

thoracic spine

• Side bending and rotation occur to the

opposite side, except when the movements

are begun in flexion; then they occur to the

same side

• This is an example of coupled motion

Lumbar Spine

Bones

• 5 vertebra

• L1 - L5

• The first four lumbar vertebrae are similar in

structure. The fifth vertebra has structural

adaptations for articulation with the sacrum.

• Typical lumbar vertebrae

• Body

• Massive, kidney shaped

• Arches

• Facets

• Superior facet are vertical and concave

and face medial and posteriorly

• Inferior facets are vertical and convex

and face lateral and posteriorly

Bones

• The fifth lumbar vertebra is a transitional vertebra that differs from the rest of the lumbar vertebrae in that it has a wedge shaped body. The IVD between L5 & S1 is also wedged shaped. This wedged shape helps form the lumbosacral angle.

• The inferior facets of L5 face anteriorly to articulate with the posterior facing superior facets of S1

Nerves

• Lumbar plexus

• L1-L4 nerve roots

• And sometimes T12 nerve root

• Controls the muscles of the anterior

thigh and medial leg with cutaneous

innervation to the same area

• Sacral plexus

• L4-S3 nerve roots

• These nerve roots join together to form

the sciatic nerve

• Sciatic nerve is the largest and longest

nerve in the body

• Supplies the muscles of the

posterior leg

Kinesiology

• The orientation of the facet joints from L1-L4 limits lateral flexion and rotation; however, the orientation highly favors flexion and extension.

• Law of side bending and rotation in the lumbar spine

• Side bending and rotation occur to the same side, except when movements are begun in flexion; then they occur to the opposite side

The Sacrum

Bones

• The sacrum is created by the

fusion of five vertebrae

• Base

• Superior part

• 2 oval superior facets that

articulate with L5

• Apex

• Distal end

• Articulates with the coccyx

Joints

• Sacroiliac joint

• Consist of the Articulations between the left and right articular surfaces

of the sacrum and the left and right iliac bones

• The articulating surfaces of the sacrum are auric ulnar (c) shaped and

covered with hyaline cartilage

• The articulating surfaces of the ilia are also c-shaped and the type of

cartilage coving the surface continues to be a matter of debate

• The structure and function of the SI joints change significantly from

birth through adulthood

• At birth, the surfaces are smooth and move freely

• After puberty, the joint surfaces develop ridges and grooves that

begin to limit movement. At this point, the SI joints begin to serve

more of a weight-bearing, and stability role

Connective Tissue

• Three ligaments that support the SI joint

• Anterior sacroiliac ligament

• Connects the anterior sacrum to the medial ilium

• Posterior sacroiliac ligament

• One part runs from the dorsum of the sacrum to the tuberosity of the ilium; the other part runs obliquely from the third tubercle of the posterior sacrum to the posterior superior iliac spine (PSIS)

• Interosseous sacroiliac ligament

• Connects the tuberosity of the sacrum and the ilium

• Ligaments that connect the sacrum and the ischium

• Sacrotuberous ligament

• Connects the sacrum to the tuberosity of the ischium

• Sacrospinous ligament

• Connects the lateral sacrum and the coccyx to the ischium

Kinesiology

• Nutation is the commonly used term to refer to movement of the sacral promontory of the sacrum anteriorly and inferiorly while the coccyx moves posteriorly in the relationship to the ilium

• Counternutation refers to the opposite movement in which the anterior tip of the sacral promontory moves posteriorly and superiority while the coccyx moves anterior in relationship to the ilium

• Nutation and counternutation are passive movements but they must accompany extension and flexion for them to be normal, healthy, and complete

• Active spinal extension ( back bend) - the sacrum passively nutates

• Active spinal flexion ( forward bend) - the sacrum passively counternutates

The end

• Pathologies and injuries will be covered

during module 8

• Muscles not covered in this module will be

covered during modules 3,4,5

• The rib cage will be covered in module 4

along with cranial anatomy ( time permitting)

yoga anatomy mod 2€¦ · of the neck • origin - lower 1/2 of ligmentum nuchae and the spinous...

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