Vertebral Column and Vertebral Column and bony thoraxbony thorax

Vertebral Column and bony thoraxVertebral Column and bony thorax

•Formed from 34-56 bones in the different Formed from 34-56 bones in the different adult animals adult animals

•Extends from skull to pelvis Extends from skull to pelvis

•Transmits weight of trunk to the lower Transmits weight of trunk to the lower limbs limbs

•Surrounds and protects the spinal cordSurrounds and protects the spinal cord

Vertebral ColumnVertebral Column

1- Cervical Vertebrae1- Cervical Vertebrae

2- Thoracic V2- Thoracic Vertebrae

3- 3- Lumbar Vertebrae

4- Sacrum

5- Coccyx (Caudal)

Typical Vertebrae:Consists of:

1- Body (1)

2- A vertebral arch - right and left Pedicles and Lamiae

3- Transverse process (7)

4- Spinous process (9)

5- Articular process (5)

Cervical VertebraeCervical Vertebrae

Seven cervical vertebrae (CSeven cervical vertebrae (C11 – C – C77) – ) – smallest and lightest vertebrae smallest and lightest vertebrae

•CC33 – C – C77 are typical cervical vertebrae are typical cervical vertebrae

•Body is small, wider side to side Body is small, wider side to side

•Spinous processes - short and bifid (except Spinous processes - short and bifid (except CC77) )

•Vertebral foramen - large and triangular Vertebral foramen - large and triangular

•Transverse processes- contain transverse Transverse processes- contain transverse foraminaforamina

Atlas – CAtlas – C11

•Lacks a body and spinous process Lacks a body and spinous process

•No intervertebral disc between C1 and C2 No intervertebral disc between C1 and C2

•Supports the skull Supports the skull

–Cranial articular facets receive the Cranial articular facets receive the occipital condyles (Atlanto-occipital Joint)occipital condyles (Atlanto-occipital Joint)

The Axis - CThe Axis - C22

-The most prominent feature is ridge like spinous process

- Cranially the body project peg like eminence (the dens)

Vertebrae (T1 – T13)

All articulate with ribs All articulate with ribs •Spinous process- long, sharp, projects Spinous process- long, sharp, projects caudally caudally •The spine of 11The spine of 11thth vertebrae is perpendicular vertebrae is perpendicular (anticlinal).(anticlinal).•1212thth and 13 and 13th th process project cranially process project cranially •Vertebral Foramen - circular Vertebral Foramen - circular •Each side of the body bears demifacets for Each side of the body bears demifacets for articulation with ribs articulation with ribs

Lumbar Vertebrae (L1 – L5)

Body– large, kidney shaped Body– large, kidney shaped •Transverse processes are thin and Transverse processes are thin and tapered tapered •Spinous processes are short, thick, blunt, Spinous processes are short, thick, blunt, and point caudally and point caudally

Sacrum (S1 – S3)

•Formed from 3 fused vertebrae Formed from 3 fused vertebrae

Coccyx (Caudal):

•Is the "tailbone" Is the "tailbone"

•Small, triangular bone Small, triangular bone

•Formed from 15-20 vertebrae Formed from 15-20 vertebrae

•Offers only slight support to pelvic organsOffers only slight support to pelvic organs

Intervertebral DiscsIntervertebral Discs

•Cushion-like pads between vertebrae Cushion-like pads between vertebrae

•Nucleus pulposus – gives the disc its Nucleus pulposus – gives the disc its elasticity and compressibility elasticity and compressibility

•Annulus fibrosis – strong outer ring of Annulus fibrosis – strong outer ring of fibrocartilage which surrounds the nucleus fibrocartilage which surrounds the nucleus pulposus and limits its expansionpulposus and limits its expansion

Bony Thorax

Forms the framework of the chest Forms the framework of the chest •Components of the bony thorax Components of the bony thorax

•Thoracic vertebrae – dorsally Thoracic vertebrae – dorsally

•Ribs – laterally Ribs – laterally

•Sternum and costal cartilage – ventrally Sternum and costal cartilage – ventrally

•Functions Functions •Protects thoracic organs Protects thoracic organs

•Supports shoulder girdle and upper limbs Supports shoulder girdle and upper limbs

•Provides attachment sites for musclesProvides attachment sites for muscles

Sternum

•Composed form eight unpaired segments, Composed form eight unpaired segments, the sternbrae.the sternbrae.

• Joined by intersternebral cartilagesJoined by intersternebral cartilages

–Manubrium – 1Manubrium – 1stst sternbra sternbra

–Xiphoid process – last sternbraXiphoid process – last sternbra

Ribs

•13 pairs, form the sides of the thoracic 13 pairs, form the sides of the thoracic cage cage

•All ribs attach to vertebral column All ribs attach to vertebral column dorsally dorsally

•True ribs - superior nine pairs of ribs True ribs - superior nine pairs of ribs which attach directly to sternum by costal which attach directly to sternum by costal cartilage cartilage

•False ribs – remaining 3 pairs of ribs False ribs – remaining 3 pairs of ribs which attach indirectly to the sternumwhich attach indirectly to the sternum

•Float ribs-rib#13Float ribs-rib#13

- Structure- Structure

•Shaft –bulk of the rib Shaft –bulk of the rib

•Head – dorsally most end Head – dorsally most end

•Neck – constricted portion of head Neck – constricted portion of head beyond head beyond head

•Tubercle – articulates with transverse Tubercle – articulates with transverse process of the thoracic vertebraeprocess of the thoracic vertebrae