thoracic, lumbar , sacrum & coccyx vertebrae

ANATOMY MUSKULOSKELETAL

AXIAL SKELETONTHORACIC, LUMBAR, SACRUM AND

COCCYX

BY : HERMIZAN BIN HALIHANAFIAH

HERMIZAN BIN HALIHANAFIAH 2

Thoracic Vertebrae• T1-T12

• Larger and stronger than cervical vertebrae.

• Spinous process of T1 and T2 are long, laterally

flattened, and directed inferiorly.

• In contrast, the spinous process of T11 and T12 are

shorter, broader and directed more posteriorly.

• Compare to cervical vertebrae, thoracic vertebrae also

have longer and larger transverse process.


Thoracic Vertebrae


Cont…• Articulate with the ribs.

• Articulating surface of the vertebrae are called facets

and demifacets.

• Except for T11 and T12, the transverse process have

facets for articulating with the tubercles of the ribs.

• The bodies of the thoracic vertebrae also have facets

and demifacets for articulation with the head of the

ribs.

• The articulation between the thoracic vertebra and the

ribs called vertebrocostal joint.


Cont…

• T1 has a superior facet and inferior demifacets for

head of ribs.

• T2-T8 have superior and inferior demifacets for head

of ribs.

• T9 has a superior demifacets

• T10-T12 have superior facet.

• Movements of the thoracic vertebrae are limited by

thin intervetebral disc and by attachment of the ribs

to the sternum.


Vertebrocostal Joint


Typical Thoracic Vertebrae

• Larger body than cervical but smaller than lumbar.

• Spinous processes pointed and angled downward.

• Superior articular facets face posteriorly permitting

some relation between adjacent vertebrae.

• Rib attachment – costal facets on vertebral body and

at ends of transverse processes for articulation ribs.


Lumbar Vertebrae• Largest and strongest in the vertebral column because the

amount of body weight supported by the vertebrae increase

towards the inferior end of the backbone.

• Their processes are short and thick.

• The superior articular process directed medially instead of

superiorly and the inferior articular facets directed laterally

instead of inferiorly.

• Spinous process are thick and broad and project posteriorly –

attachment of the large back muscles.


Lumbar Vertebrae


Large BodySuperior articular facets facing medially

Inferior articular facets facing

laterally

Spinous process thick, broad, project posteriorly


Copyright 2009, John Wiley & Sons, Inc.

Vertebral Column


Sacrum• Triangular bone

• Formed by the union of 5 sacral vertebrae

• Indicated as a S1-S5.

• The fusion of the sacral vertebrae begins ages 16-18

and its usually completed by age 30.

• The sacrum serves as a strong foundation for the

pelvic girdle.

• It is positioned at the posterior portion of the pelvic

cavity medial to the hip bone.


Cont….

• Female sacrum are shorter, wider and more curved

between S2 and S3 than a male sacrum.

• The concave anterior side of the sacrum faces the

pelvic cavity.

• Its smooth and contains four transverse lines

(ridges) that mark the joining of the sacral vertebral

bodies.

• At the end of these lines are four pairs of anterior

sacral foramina.


Cont…

• The lateral portion of the superior surface

contains a smooth surface called the sacral ala,

which is formed by the fused transverse

processes of the 1st sacral vertebrae.

• The convex, posterior surface of the sacrum

contains a median sacral crest and lateral sacral

crest.


Cont…

• Median sacral crest is the fused of the spinous

processes of the upper sacral vertebrae.

• Lateral sacral crest is the fused transverse processes

of the sacral vertebrae.

• 4 pairs of posterior sacral foramina communicate with

the anterior sacral foramina through which nerves and

blood vessels pass.

• The sacral canal is a continuation of the vertebral

canal.


Cont…

• The laminae of the 5th sacral vertebrae, and sometimes the

4th sacral vertebrae fails to meet.

• This leaves an inferior entrance to the vertebral canal called

the sacral hiatus.

• On the either side of the sacral hiatus are the sacral cornua,

the inferior articular processes of the fifth sacral vertebrae.

• The narrow inferior portion of the sacrum is called apex.

• The broad superior portion of the sacrum is called base.


Cont…

• The anteriorly projecting border of the base called sacral

promontory.

• On both of the lateral surface, the sacrum has a large

auricular surface that articulates with the illium of each of

hipbone to form sacroilliac joint.

• Posterior to the auricular surface is a roughened surface

called sacral tuberosity, contain depression for the

attachment of the ligamants.

• The sacral tuberosity is the another surface of the sacrum

that formed sacroilliac joint with the hipbones.


Sacroilliac Joint


Cont…

• The superior articular surface of the sacrum

articulate with the 5th lumbar vertebrae .

• The base of the sacrum articulates with the

body of the 5th lumbar vertebrae, to form the

lumbosacral joint.


Coccyx• Triangular

• Formed by the fusion of usually four coccygeal

vertebrae.

• Indicated as a Co1-Co4

• The coccygeal vertebrae fused when a person is

between 20-30 years of age.

• The dorsal surface of the body of coccyx contain 2

long coccygeal cornua that are connected by

ligaments to the sacral cornua.


• Coccygeal cornua are the pedicles and superior

articular process of the 1st coccygeal vertebrae.

• On the lateral surface of the coccyx are a series of

transverse processes, the first pair being the largest.

• The coccyx articulates with the apex of the sacrum.

• In females, the coccyx points inferiorly and males

points anteriorly.

Coccyx


Normal Curves of the Vertebrae

• Normal curves – 4 slight bends of vertebral column.

• Cervical and lumbar curves are convex (bulging out)

• Thoracic and sacral curves and concave (cupping in).

• The curves of the vertebral column increase its strength, help

in maintain balance in the upright position, absorb shocks

during walking, and help protect vertebrae from fracture.


• Fetus only has a single anteriorly concave curve.

• The thoracic and sacral curves are called primary curvature because they form earlier during fatal development.

• The cervical and lumbar curves are known as secondary curves because they begin to form later, several month after birth.

• All curves are fully developed by age 10.

Normal Curves of the Vertebrae


Primary Curvature of Newborn


Cont…

• Various condition may exaggerate the

normal curves, resulting abnormal curves.

• 3 such abnormal curves called:

1. Kyphosis

2. Lordosis

3. Scoliosis


KYPHOSIS

• Kyphosis is a curving of the spine that causes a bowing of the back, such that the apex of the angle points backwards leading to a hunchback or slouching posture.


• Caused by muscular

imbalance, vertebral

fractures, congenital,

nutritional.

KYPHOSIS


KYPHOSIS


LORDOSIS• Inward curvature of a portion

of the vertebral column

• Two segments of the vertebral column, namely cervical and lumbar, are normally lordotic, that is, they are set in a curve that has its convexity anteriorly (the front) and concavity posteriorly (behind), in the context of human anatomy


• Mainly because of the difference of thickness between the anterior and posterior part of the intervertebral disc

• Common causes of excessive lordosis including tight low back muscles, excessive visceral fat, and pregnancy.

LORDOSIS (cont..)


LORDOSIS


SCOLIOSIS

• Scoliosis is a medical condition in which a person's spine is curved from side to side, and may also be rotated.

• Congenital or idiopathic


SCOLIOSIS


Scoliosis


Superficial Muscles of Back

• Trapezius

• Latisimus dorsi

• Levator scapulae

• Rhomboid major

• Rhomboid minor


Intermediate Muscles of Back

• Serratus posterior

superior


inferior


• Serratus posterior superior

– O – ligamentum nuchae,

spinous process of C7-T3

– I – upper borders of 2nd –

5th ribs

– A – Elevate the ribs,

assist in inspiration




inferior

– O – Vertebra T11- L3

– I – Inferior border of 9th- 12th

ribs

– A – depress the lower ribs,

aids in expiration



• Can divide into 4 groups:

1. Splenius

2. Erector spinae

3. Transversospinalis

4. Segmental

Deep Muscles of Back


Splenius Group (referred to previous lesson slide)

• Bandages like

• Important to move the head and neck region.

• Superiorly (head) – splenius capitis

• Inferiorly (neck) – splenius cervicis– Origin – spine of T3-T6– Insertion – transverse process C1-C4– Action – same with splenius capitis– Nerve cervical spinal nerve


• Erector spinae group.

– 3 columns muscles

– From sacrum to the ribs

– Extends vertebral column

– Consists

- illiocostalis (lateral)

- Longissimus( intermediate)

- spinalis (medial)



Iliocostalis (lateral fiber)• Consists 3 fibers:

1. Iliocostalis cervicis

2. Iliocostalis thoracis

3. Illiocostalis lumborum

• Origin – Ribs 1-6, ribs 7-12

and Iliac crest of pelvic

• Insertion – transverse process

of C4-C6, Ribs 1-6, ribs 7-12


Iliocostalis

• Action

• Acting together, muscles of each

region extend and maintaining

erect posture of vertebral

column.

• Acting singly, laterally flex and

rotation vertebral column of their

respective region at the same

side of contracting muscles.


• Consists 3 fibers:

1. Longissimus capitis

2. Longissimus cervicis

3. Longissimus thoracis

• Origin – Articular process of C4-C7 and transverse process of T1-T4, transverse process of T4-T5, Transverse process of lumbar vertebra.

Longissimus (Intermediate Fiber)


• Insertion – mastoid process of temporal, transverse process of C2-C6, transverse process of all thoracic and upper lumbar vertebra and 9th and 10th ribs.

• Action – Longissimus capitis (together extend head, singly rotate head), Longissimus cervicis and thoracis (extends vertebral column)

Longissimus



1. Spinalis capitis

2. Spinalis cervicis

3. Spinalis thoracis

• Origin – arises with semispinalis capitis, ligamentum nuchae and spinous process of C7 , spinous processes of T10-L2

Spinalis (medial)


• Insertion – between superior

and inferior nuchal line of

occipital bone, spinous process

of axis , spinous process of

superior thoracic vertebra (T3-

T4).

• Action – acting together

extends vertebral column

Spinalis (medial)


Transversospinales Muscles

• Semispinalis

• Multifidus

• Rotatores


• Semispinalis group

– Vertebra to vertebra

– Important for extends neck

• Consists:

– Semispinalis capitis

– Semipinalis cervicis

– Semispinalis thoracis

Semispinalis Group


• Origin – Articular process C4-C6

and transverse process C7-T7,

transverse process of T1-T5,

Transverse process of T6-T10.

• Insertion – occipital bone.

Spinous process of C1-C5 and

spinous process of C6-T4

• Action – extends neck, extends

vertebral column

Semispinalis Group


• Origin – sacrum, ilium,

transverse process of

lumbar, thoracis and C4-C7

• Insertion – spinous process

of a more superior vertebra.

• Action – extends vertebral

column (both), lateral flex

vertebral column (singly)

Multifidus


Rotatores

• Origin – transverse process

of all vertebra

• Insertion – spinous process

of vertebra superior to the

one of origin.

• Action – together weakly

extends vertebral column


Segmental


1. Interspinales

2. Intertransversarii



1.Interspinales

2.Intertransversarii

Segmental


Interspinales • Origin – superior surface

of all spinous process• Insertion – inferior

surface of spinous process of vertebra superior to the one of origin

• Action – weakly extends vertebral column (together)


• Origin – transverse

process of all vertebra

• Insertion – transverse

process of vertebra

superior to the one origin

• Action – extends vertebral

column (together)

Intertransverseraii


• Quadratus lomborum– O - iliac crest and

iliolumbar ligament– I - Last rib and transverse

processes of lumbar vertebrae

– A - Alone, lateral flexion of vertebral column; Together, depression of thoracic rib cage


thoracic, lumbar , sacrum & coccyx vertebrae

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