Human Anatomy - Kotsan I. Y. 2009

Anatomy of the Trunk Skeleton
Development of the Trunk Skeleton

The source of Development of the human Axial Skeleton is the sclerotome, which consists of A large number of mesenchymal Cells. At approximately the end of the first month of embryonic development, these cells proliferate, elongate in various directions, fuse together, and form a membranous Connective Tissue from which the vertebrae begin to form. At the end of the second and beginning of the third month of development, the connective tissue transforms into Cartilage, which, starting from the end of the third month, is replaced by Bone tissue.

Ossification of the vertebrae typically begins from three centers (nuclei) of ossification: one in the body and two in the arch. The ossification centers in the arch fuse During the first year of life, and the arch fuses with the vertebral body at 3–4 years of age.

The First and Second cervical vertebrae differ in their development from other vertebrae. The atlas has one ossification center in each of the future lateral masses, from which bone tissue grows into the posterior arch. In the anterior arch, an ossification center appears only during the first year of life. Part of the body of the first vertebra, still in the cartilaginous stage, separates from it and joins the body of the second vertebra, transforming into the dens (odontoid process). The latter has an independent ossification center and fuses with the bony body of the second vertebra at 3–5 years of the child's life.

The sacral vertebrae develop, like all others, from three main ossification centers. In the upper three sacral vertebrae, at 6–7 months of intrauterine life, additional ossification centers appear, through which the lateral PARTS OF THE sacrum (rudiments of sacral Ribs) develop. At 17–25 years of age, the sacral vertebrae fuse into a single bone. In the coccygeal vertebrae, which are vestigial, a single ossification center arises at various times (ranging from 1 year to 20 years of age).

The ribs originate in the mesenchymal Cells of the ventral processes of the sclerotomes, which are gradually replaced by membranous connective tissue. At the beginning of the second month of embryonic development, alongside The formation of the vertebrae, short cartilaginous strips appear in this connective tissue, extending laterally and then ventrally until the entire rib transforms into hyaline cartilage.

The replacement of the rib cartilage with bone tissue begins at the end of the second month of development, when ossification centers appear at the site of the future angles of the ribs. From these centers, bone tissue spreads in both directions, gradually replacing the entire body of the rib. In the HEAD of the rib, an ossification center appears at 15–20 years of age and fuses with the rib bone at 18–25 years. In the ten upper ribs, an ossification center also appears in the tubercle of the rib at 15–20 years of age.

Simultaneously with the onset of rib development near the body's midline, two cartilaginous strips arise at the site of the future Sternum. These strips connect with the sternal ends of the ribs and transform into the cartilaginous precursor of the sternum. At approximately 4–6 months of fetal development, one or two ossification centers appear in the manubrium of the sternum. At 7–8 months, ossification centers appear in the upper part of the sternum, in the middle part just before birth, and in the lower part during the first year of life. Separate parts of the sternal body fuse into a single bony body at 15–20 years of age. The xiphoid process begins to ossify at 6–20 years and fuses with the body of the sternum after 30 years. The manubrium fuses with the body last, or may not fuse at all (in which case a synchondrosis remains at the junction of the manubrium and the body of the sternum).

Key Latin terms

Vertebral Column (spine) — collumna vertebralis

Vertebra — vertebra

Vertebral body — corpus vertebrae

Vertebral arch — arcus vertebrae

Pedicle of the vertebral arch — pedunculus arcus vertebrae

Lamina of the vertebral arch — lamina arcus vertebrae

Vertebral foramen — foramen vertebrale

Inferior vertebral notch — incisura vertebralis inferior

Superior vertebral notch — incisura vertebralis superior

Spinous process — processus spinosus

Transverse process — processus transversus

Articular process — processus articularis

Articular surface — facies articularis

Vertebral canal — canalis vertebralis

Intervertebral foramen — foramen intervertebralis

Cervical vertebrae — vertebrae cervicales

Groove for spinal nerve — sulcus nervus spinalis

Anterior tubercle — tuberculum anterius

Posterior tubercle — tuberculum posterius

Costal process — processus costalis

Costotransverse process — processus costotransversarium

Transverse foramen — foramen transversum

Atlas — atlas

Anterior arch of atlas — arcus anterior atlantis

Anterior tubercle — tuberculum anterius

Fovea for odontoid process — fovea dentis

Posterior arch of atlas — arcus posterior atlantis

Posterior tubercle — tuberculum posterius

Sulcus for vertebral artery — sulcus arteria vertebralis

Lateral mass of atlas — massa lateralis atlantis

Superior articular surface — facies articularis superior

Inferior articular surface — facies articularis inferior

Axis — axis

Body of axis — corpus axis

Dens of axis — dens axis

Apex of dens — apex dentis

Anterior articular surface — facies articularis anterior

Posterior articular surface — facies articularis posterior

Carotid tubercle — tuberculum caroticum

Vertebra prominens — vertebra prominens

Thoracic vertebrae — vertebrae thoracicae

Costal facets — fovea costales

Costal facet of the transverse process — fovea costalis processus transversi

Lumbar vertebrae — vertebrae lumbales

Mamillary process — processus mamillaris

Accessory process — processus accessorius

Sacral vertebrae — vertebrae sacrales

Sacrum — os sacrum

Base of the sacrum — basis ossis sacri

Apex of the sacrum — apex ossis sacri

Promontory — promontorium

Pelvic surface — facies pelvica

Posterior (dorsal) surface — facies dorsalis

Median sacral crest — crista sacralis mediana

Lateral sacral crest — crista sacralis lateralis

Intermediate sacral crest — crista sacralis intermedia

Lateral part — pars lateralis

Auricular surface — facies auricularis

Sacral tuberosity — tuberositas sacralis

Anterior sacral foramina — foramina sacralia anteriora

Posterior sacral foramina — foramina sacralia posteriora

Transverse ridges — lineae transversae

Sacral canal — canalis sacralis

Sacral hiatus — hiatus sacralis

Sacral cornu — cornu sacrale

Coccygeal vertebrae — vertebrae coccygeae

Coccyx — os coccygis

Coccyx — coccyx

Coccygeal horn — cornu coccygeum

Intervertebral symphysis — symphysis intervertebralis

Intervertebral disc — discus intervertebralis

Nucleus pulposus — nucleus pulposus

Fibrous ring — anulus fibrosus

Anterior longitudinal ligament — lig. longitudinale anterius

Posterior longitudinal ligament — lig. longitudinale posterius

Yellow ligaments — ligg. flava

Zygapophysial joints — articulationes zygapophysiales

Intertransverse ligaments — ligg. intertransversaria

Interspinous ligaments — ligg. interspinalia

Supraspinous ligament — lig. supraspinale

Nuchal ligament — lig. nuchae

Atlanto-occipital joint — articulatio atlantooccipitalis

Median atlanto-axial joint — articulatio atlantoaxialis mediana

Lateral atlanto-axial joint — articulatio atlantoaxialis lateralis

Alar ligaments — ligg. alaria

Cruciform ligament of atlas — lig. cruciforme atlantis

Transverse ligament of atlas — lig. transversum atlantis

Longitudinal bands — fasciculi longitudinales

Lumbosacral joint — articulatio lumbosacralis

Iliolumbar ligament — lig. iliolumbale

Sacrococcygeal joint — articulatio sacrococcygea

Anterior sacrococcygeal ligament — lig. sacrococcygeum anterius

Deep posterior sacrococcygeal ligament — lig. sacrococcygeum posterius profundum

Superficial posterior sacrococcygeal ligament — lig. sacrococcygeum posterius superficiale

Lateral sacrococcygeal ligament — lig. sacrococcygeum laterale

Lordosis — lordosis

Kyphosis — kyphosis

Scoliosis — scoliosis

Thoracic cage — Thorax

True ribs — costae verae

False ribs — costae spuriae

Floating ribs — costae fluitantes

Rib — costa

Rib bone — os costalis

Costal cartilage — cartilago costalis

Body of the rib — corpus costae

Anterior end — extremitas anterior

Posterior end — extremitas posterior

Superior border — margo superior

Inferior border — margo inferior

External surface — facies externa

Internal surface — facies interna

Costal groove — sulcus costae

Head of the rib — caput costae

Articular surface of the rib head — facies articularis capitis costae

Crest of the rib head — crista capitis costae

Neck of the rib — collum costae

Crest of the neck of the rib — crista colli costae

Rib tubercle — tuberculum costae

Articular facet of the rib tubercle — facies articularis tuberculi costae

Angle of the rib — angulus costae

First rib — costa prima

Superior surface — facies superior

Inferior surface — facies inferior

External border — margo externus

Internal border — margo internus

Tubercle of the anterior scalene Muscle — tuberculum musculi scaleni anterioris

Groove for the subclavian vein — sulcus venae subclaviae

Groove for the Subclavian Artery — sulcus arteriae subclaviae

Second rib — costa secunda

Tuberosity for the serratus anterior muscle — tuberositas musculi

serrati anterioris

Sternum — sternum

Body of the sternum — corpus sterni

Manubrium of the sternum — manubrium sterni

Xiphoid process — processus xiphoideus

Clavicular notch — incisura clavicularis

Jugular notch — incisura jugularis

Costal notch — incisura costalis Sternal angle — angulus sterni

Sternocostal joints — articulationes sternocostales

Radiate sternocostal ligaments — ligg. sternocostalia radiata

Sternocostal synchondrosis of the first rib — synchondrosis sternocostalis costae primae

Interchondral joints — articulationes interchondrales

Costal arch — arcus costalis

Costovertebral joints — articulationes costovertebrales

Joint of head of rib — articulatio capitis costae

Costotransverse joint — articulatio costotransversaria

Intra-articular ligament of head of rib — lig. capitis costae intraarticulare

Radiate ligament of head of rib — lig. capitis costae radiatum

Superior costotransverse ligament — lig. costotransversarium superius

Lateral costotransverse ligament — lig. costotransversarium laterale

Costotransverse ligament — lig. costotransversarium

Superior thoracic aperture — apertura thoracis superior

Inferior thoracic aperture — apertura thoracis posterior

Infrasternal angle — angulus infrasternalis.