spinal exam 2

true ribs

ribs 1-7, connect directly to sternum

false ribs

ribs 8-10 connect indirectly to sternum, ribs 11-12 don’t connect to sternum and are known as floating ribs

typical ribs

ribs 3-9, morphologically similar, well defined vertebral end with head, neck, and tubercle, elongated body, sternal end

atypical ribs

ribs 1, 2, 10, 11, 12, morphologically different from each other

3 regions of ribs

vertebral end (head, neck, tubercle), corpus/body (costal angle, costal groove), sternal end (costal cartilage)

atypical rib 1

head- single articular surface, neck- lacks well-defined crest, tubercle- articular and non-articular surface, body- flattened, costal angle and groove absent, scalene tubercle present (attachment site for anterior scalene, serratus anterior, middle scalene), groove for subclavian artery/first thoracic nerve, groove for subclavian vein

sternal end of atypical ribs 1, 2, 10, 11, 12 are

continuous with costal cartilage

atypical rib 2

head- superior articular surface (joints with T1), inferior articular surface (joints with T2), tubercle- articular surface, non-articular surface, neck- well-defined crest, attachment site for superior costatransverse ligament of T1 and inferior costotransverse ligament of T2 transverse process, body- elevated along superior border (tuberosity for serratus anterior)

atypical rib 2 is the only atypical rib without

a singular articular surface on the head

costovertebral joints

costocentral and costotransverse joints

costocentral joints

synovial plane diarthrosis arthrodial joints, articular surface(inferior/superior) on head of rib articulating with costal facet/demifacet of thoracic vertebral body

costotransverse joints

synovial plane diarthrosis arthrodial joints, articular surface on tubercle of rib articulating with transverse costal facet on transverse process of thoracic vertebrae

articular surfaces are separated by

interarticular crest on head of rib

interarticular crest

articulates with IVD between vertebral bodies, attachment site for interarticular ligament

atypical rib 10

head- single articular surface, neck- well-developed crest, tubercle- articular surface (joints with TP of T10), non-articular surface (attachment site for lateral costotransverse ligament)

T/F occasionally the tubercle of atypical rib 10 only consists of non-articular surface

T

body of atypical rib 10

bent posteriorly for 2-3 inches (curves anteriorly to sternum), external surface is roughened, attachment site of iliocostalis muscle and thoracolumbar fascia, costal angle and costal groove present

costal angle

posterior surface of rib at location of directional change

costal groove

present on inferior margin of inferior surface of rib, groove for intercostal artery, vein, nerve

atypical rib 11

head- single articular surface (T11), neck- lacks well-defined crest, tubercle- may be absent or consists of only non-articular surface(no costovertebral joint but still articulates with T10), body- slight costal angle, shallow costal groove, sternal end is somewhat pointed

atypical rib 12

head- single articular surface (T12), neck- lacks well-defined crest, tubercle- absent, body- costal angle and groove absent

which rib body is shortest and most rudimentary?

rib 12

stabilizing ligaments of rib 12

superior costotransverse ligament of T11, Lumbocostal ligament from L1

vertebrosternal ribs

articulate with vertebra proximally and sternum distally, ribs 1-7

vertebrochondral ribs

articulate with vertebra proximally and costal cartilage distally, ribs 8-10

vertebral ribs

articulate with vertebra proximally with no stabilizing tissue at distal end (floating ribs), ribs 11-12

ribs develop from

sclerotomes

costal processes elongate in

thoracic region

anterior ends of ribs fuse with

lateral plate mesoderm (sternum)

sternal bars fuse and undergo

endochondral ossification (manubrium → sternal body → xiphoid process}

ossification within sternal bars

covert to bone

regional differences between vertebrae and ribs due to

expression of Hox gene family

chondrification of mesenchyme results in

2 lateral plates in sternal region that migrate and fuse at midline to form a cartilaginous template for sternum

sternabrae

centers of ossification appear along vertical axis within cartilaginous template

ossification of sternum

numbers of ossification centers and time of their appearance varies but they later follow a typical pattern and timing of ossification

primary ossification centers of sternum

9 total- 3 in manubrium (appear in manubrium sterni 5th fetal month), 6 in corpus sterni (single center in sternabrae 1-2 \~5th fetal month, bilateral centers in sternabrae 3/4 \~5/6th fetal months), arise caudally to cranially

secondary ossification center of sternum

may be xiphoid process during/after 3rd year of life, or not exist bc xiphoid process stay cartilaginous

primary ossification center

the first place where bone formation begins in the axle of a bone or in the body of an irregular bone

secondary ossification center

area of ossification that appears after the primary center of ossification at the end/edges of bone

synchondroses between sternabrae undergo

synostosis in a caudal to cranial direction, begins at puberty-25

manubrosternal joint

cartilaginous (amphiarthrosis) symphysis joint between manubrium, corpus sterni, and xiphoid process, tend to remain unchanged

ribs primary ossification center

1, in region that becomes body of rib

ribs secondary ossification centers

occur in regions that become head, articular and non-articular surfaces of tubercle, specific locations vary among ribs

ossification centers of typical ribs 3-9

4 total; 1 primary- in body of rib, appears late in 2nd fetal month; 3 secondary- in head, articular, and non-articular surfaces of tubercle, arise during puberty

ossification centers of atypical rib 1

3 total; 1 primary- in body, arises late in 2nd fetal month; 2 secondary- in head and tubercle, arise during puberty

ossification centers of atypical rib 2

4 total; 1 primary- in body, arises late in 2nd fetal month; 3 secondary- in head, articular, and non-articular surface of tubercle, arise during puberty

ossification centers of atypical rib 10

3 total; 1 primary- in body, arises end of 2nd fetal month; 2 secondary- in head and tubercle, arise after puberty

ossification centers of atypical ribs 11-12

1 in body, appears late in 2nd fetal month

thoracic region vertebrae

12 rib bearing vertebrae (+/-1), typical upper=T2-T4, typical lower=T5-T8, atypical=T1, T9-12

typical thoracic vertebrae

vertebral body- heart shaped/triangular, posterior height 1-2mm greater than anterior height; vertebral foramen- oval/circular compared to cervical region, corresponds to size of spinal cord; spinous process- long, slanting posteriorly and inferiorly in 40 degree angle

laminal of typical thoracics

slope inferiorly and posteriorly, overlap laminae from segment below (“shingling” that limits ROM for stability of ribs)

posterior border of spinal canal along length of thoracic region

lamina and ligamentum flavum

each transverse process terminates in a

transverse tubercle that supports the transverse costal facet

intertransverse ligament

attaches to transverse process of thoracic vertebra above and below

T2-T6 transverse costal facets

concave, face superior and lateral

T7-T8 transverse costal facets

flat, face superior and lateral

pars interarticularis

region between superior and inferior articular processes (lamina) along same side of vertebra, homologous with articular pillars of cervicals

T/F the width between the left/right superior articular processes is less than the left/right inferior articular processes in T2-T4

F- it’s greater

aortic impression

left side of vertebral bodies and epiphyseal rims of T5-T8 become flattened compared to right side, due to pressure from aorta impacting the secondary ossification centers

the width between left/right superior articular process is greater than the width between left/right inferior articular processes in T5-T8

F- they are equal

spinous process angle of T2-T4 vs T5-T8

40 degrees vs 60 degrees

4 costocentral joints on vertebral body of typical thoracic

left/right superior costal demifacets, left/right inferior costal demifacets

3 ligaments associated with each costocentral joint

capsular ligament, stellate/radiate ligament, interatricular ligament

costocentral capsular ligament

synovial plane (diarthrosis arthrodial) joint, stabilizes costocentral joint, collagen fibers from capsular igament extend into thoracic IVF giving small contribution to anterior boundary of IVF

costocentral radiate/stellate ligament

3 regions within- upper band, middle band, lower band; superficial to costocentral joint and constocentral capsular ligament, connects head of rib with vertebral bodies and IVD

costocentral interarticular ligament

connects to interarticular crest on head of ribs with associated IVD

structures attaching to typical thoracic vertebral bodies

anterior longitudinal ligament (ALL), posteroe longitudinal ligament (PLL), costocentral capsular ligaments, costocentral radiate ligaments, longus colli (T2-T3 only)

costotransverse joint

synovial plane (diarthrosis arthrodial) joint, articular surface of rib tubercle articulates with the transverse costal facet of the thoracic transverse process at same level

capsular costotransverse ligament

surrounds articular surface of tubercle of rib, attaches to transverse costal facet, 3 supporting ligaments- superior/inferior/lateral costotransverse

what kind of joint are the costotransverse ligaments?

fibrous (amphiarthrosis) syndesmosis

superior costotransverse ligament

attaches the lower border of transverse process to neck of rib below- T3 transverse process to neck of rib 4

lateral costotransverse ligament

attaches nonarticular surface of rib tubercle to transverse tubercle at same level- T3 transverse process attaches to rib 3

inferior costotransverse ligament

attaches anterior border of transverse process to back of neck of rib at same level- T3 transverse process attaches to rib 3

ligament attachments to typical thoracic transverse process

intertransverse, capsular costotransverse, superior/inferior/lateral costotransverse ligament

ligaments attachments to typical thoracic spinous process

interspinous ligament, supraspinous ligament

10 synovial joint surfaces present on typical thoracics

2 superior costal demifacets, 2 inferior costal demifacets, 2 transverse costal facets, 2 superior articular facets, 2 inferior articular facets

muscle attachments to typical thoracic spinous process

trap, lat dorsi, rhomboid major, serratus posterior superior, splenius cervicis/capitis, spinalis thoracis/cervicis/capitis, semispinalis thoracis, multifidus, rotator longus/brevis, interspinalis

muscle attachments to typical thoracic transverse process

longissimus thoracis/cervicis/capitis, semispinalis thoracis/cervicis/capitis, multifidus, rotator longus/brevis, intertransversarii

typical thoracic joint surfaces

10 synovial, 8 fibrous syndesmosis, 2 cartilaginous symphysis

8 fibrous syndesmosis joints of typical thoracics

4 costocentral radiate ligaments, 2 ALL, 2 PLL

atypical T1

complete superior costal facet present and inferior demifacet present, superior surface is cup-shaped like cervicals with uncinate processes, inferior surface is flattened like thoracics and lacks anterior/posterior lips and lateral grooves, spinous process nearly horizontal, defined spinous tubercle

exceptions to muscle and ligament attachments to spinous process of T1

lattisimus dorsi and splenius cervicis absent, rhomboid minor instead of major; ligaments are typical

exceptions to muscle and ligament attachments to transverse process of T1

semispinalis thoracis absent, levator costorum brevis present; ligaments are typical

14 joint surfaces of T1 vertebral body

4 costocentral (synovial plane) joints- L/R superior costal facet, L/R inferior costal demi-facets; 8 fibrous syndesmosis joints- 2 ALL, 2 PLL, 4 costocentral radiate ligaments; 2 cartilaginous symphysis joints

10 synovial joints on atypicals T1 & T9

4 zygapophyseal- superior/inferior articular process/facets, 4 costocentral- L/R superior costal facets, L/R inferior costal demifacets, 2 costotransverse- L/R transverse costal facets

atypical T9

body- large superior costal demifacet for rib 9, 10th rib may articulate with only IVD between T9/T10 when inferior costal demifacet on T9 is absent; arch- spinous process starts to shorten and become horizontal

exceptions to muscle and ligament attachments to transverse process of T9

semispinalis thoracis, levator costorum longus present; ligaments are typical

exceptions to muscle and ligament attachments to spinous process of T9 and T10

spinalis thoracic/cervicis/capitis, semispinalis thoracis absent; ligaments are typical

semispinalis will be absent at all spinous processes below what?

T6

T9 vertebral body joint surfaces

4 synovial joints- 4 costocentral; 8 fibrous syndesmosis joints- 2 ALL, 2 PLL, 4 costocentral radiate ligaments; 2 cartilaginous symphysis joints

atypical T10

costotransverse joint may be present or absent for rib 10- costotransverse radiate ligaments directly correlated, para-articular process

para-articular process

results from ossification at ligamentum flavum attachment sites, may be present at any level but most common at T10

exceptions to muscle and ligament attachments to transverse process at T10

levator costorum longus present; ligaments are typical

exceptions to muscle and ligament attachments to transverse process at T11

muscles are typical; only intertransverse ligament present

exceptions to muscle and ligament attachments to spinous process at T11 and T12

semispinalis thoracis absent; ligaments are typical

10 vertebral body joint surfaces at T10

2 synovial (costocentral) joints- L/R superior costal facets; 6 fibrous syndesmosis- 2 ALL, 2 PLL, 2 costocentral radiate ligaments; 2 cartilaginous symphysis joints

8 synovial joints of T10

4 zygapophyseal- superior/inferior L/R articular processes; 2 costocentral- L/R superior costal facet; 2 costotransverse- L/R transverse costal facet

atypical T11

resembles lumbar bodies, kidney-shaped outline, costal facet below superior epiphyseal rim close to pedicle, short & thick transverse process, costotransverse joint absent, spinous process short, thick, becoming rectangular

6 synovial joints of T11

4 zygapophyseal- superior/inferior L/R articular process/facets; 2 costocentral- L/R superior costal facet

atypical T12

kidney-shaped body, flat superior articular facet, convex inferior articular facet, short/broad/horizontal spinous process, prone to injuries from stress, superior costal facet lies on pedicle, 3 tubercles in place of a typical transverse process