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Vertebral Column and bony thorax. Vertebral Column and bony thorax. Formed from 34-56 bones in the different adult animals Extends from skull to pelvis Transmits weight of trunk to the lower limbs Surrounds and protects the spinal cord. Vertebral Column. 1- Cervical Vertebrae
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Vertebral Column and bony thorax • Formed from 34-56 bones in the different adult animals • Extends from skull to pelvis • Transmits weight of trunk to the lower limbs • Surrounds and protects the spinal cord
Vertebral Column 1- Cervical Vertebrae 2- Thoracic Vertebrae 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 Vertebrae • Seven cervical vertebrae (C1 – C7) – smallest and lightest vertebrae • C3 – C7 are typical cervical vertebrae • Body is small, wider side to side • Spinous processes - short and bifid (except C7) • Vertebral foramen - large and triangular • Transverse processes- contain transverse foramina
Atlas – C1 • Lacks a body and spinous process • No intervertebral disc between C1 and C2 • Supports the skull • Cranial articular facets receive the occipital condyles (Atlanto-occipital Joint)
The Axis - C2 • 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 • Spinous process- long, sharp, projects caudally • The spine of 11th vertebrae is perpendicular (anticlinal). • 12th and 13th process project cranially • Vertebral Foramen - circular • Each side of the body bears demifacets for articulation with ribs
Lumbar Vertebrae (L1 – L5) • Body– large, kidney shaped • Transverse processes are thin and tapered • Spinous processes are short, thick, blunt, and point caudally
Sacrum (S1 – S3) • Formed from 3 fused vertebrae
Coccyx (Caudal): • Is the "tailbone" • Small, triangular bone • Formed from 15-20 vertebrae • Offers only slight support to pelvic organs
Intervertebral Discs • Cushion-like pads between vertebrae • Nucleus pulposus – gives the disc its elasticity and compressibility • Annulus fibrosis – strong outer ring of fibrocartilage which surrounds the nucleus pulposus and limits its expansion
Bony Thorax • Forms the framework of the chest • Components of the bony thorax • Thoracic vertebrae – dorsally • Ribs – laterally • Sternum and costal cartilage – ventrally • Functions • Protects thoracic organs • Supports shoulder girdle and upper limbs • Provides attachment sites for muscles
Sternum • Composed form eight unpaired segments, the sternbrae. • Joined by intersternebral cartilages • Manubrium – 1st sternbra • Xiphoid process – last sternbra
Ribs • 13 pairs, form the sides of the thoracic cage • All ribs attach to vertebral column dorsally • True ribs - superior nine pairs of ribs which attach directly to sternum by costal cartilage • False ribs – remaining 3 pairs of ribs which attach indirectly to the sternum • Float ribs-rib#13
- Structure • Shaft –bulk of the rib • Head – dorsally most end • Neck – constricted portion of head beyond head • Tubercle – articulates with transverse process of the thoracic vertebrae