Vertebrae & inter-vertebral discs By D. Safa Ahmed Akram Rheumatologist Parts of the vertebra The typical vertebra is composed of: • Body • Vertebral arch: 1. 2 pedicles 2. 2 transverse proscesses 3. 2 laminae 4. 2 facet joints 5. Spinous proscess The disc *Composed of a jelly-like material called the nucleus pulposis si hcihw , gnidnuorrus fo reyal a yb dednuorrus rbfio-cartilage called the annulus fibrosis. Functions *Separates the vertebrae *Act as a cushion *Facilitate spine movements The vertebral column (spine) is composed of: • Cervical spine (lordotic). • Thoracic spine (kyphotic). • Lumbar spine (lordotic). • Sacrum (kyphotic). • Coccyx • Composed of 7 vertebrae , seperated by an intervertebral disc. • The first vertebrae is called Atlas and the second is called the Axis . otiator daeh rof elbisnopser tinu a mrof htob yehTn • The 3rd-6th vertebrae are typical vertebrae which are responsible for flexion-extension & lateral bending movements of the head and neck. • The 1st, 2nd and 7th cervical vertebrae are atypical, while from C2-C6 are considered typical. C3-C6: • The body is smaller than the thoracic vertebrae. • The vertebral arch is larger. • Have 1 vertebral foramen and 2 transverse foramens. • The vertebral foramen of the cervical spine is the largest. • Each transverse process contain a transverse foramen through which the vertebral artery, vein and nerve pass. • Spinous processes are bifid (split into 2 parts). C1 (Atlas): • Is shaped as a ring • Lacks a body and a spinous process. • Has superior and inferior articular facets. • The superior articular facet articulates with the occipital bone of the skull to form the atlanto-occipital joint (yes movement). • The inferior articular facet articulates with the axis to form the atlanto-axial joint. • Its vertebral foramen is divided into 2 foramens by the transverse ligament (posterior foramen for the spinal cord and anterior foramen for the dens of the axis). C2 (Axis): • Has a body • Has a process that project upwards called the dens or the odontoid process that articulate with the atlas (pivot joint) that produce the no movement. C7 : • Its body is larger. • Has one large spinous process (not bifid) that can be felt at the base of the neck. • Its vertebral foramen is smaller than the other cervical vertebrae. • T1-T12. • Larger and stronger and have longer and larger transverse processes than the cervical vertebrae but their body is smaller than the lumbar vertebrae. • They articulate with the ribs forming the costo-vertebral joints. • The movement of the thoracic spine is limited by the articulation with the ribs and by a thin intervertebral disc. • L1-L5. • Largest and strongest of the vertebrae because of the weight that they support. • Their spinous process are short and thick. • Movement of the lumbar spine include: flexion, extension and lateral flexion and rotation. • S1-S5. • It is a triangular bone formed by the union of these 5 sacral vertebrae. • It provides strong support to the pelvic girdle. • In the female the sacrum is shorter, wider and more curved than in the male. • Contains 4 transverse lines (ridges). • Contains 4 pairs of anterior sacral foramens. • The sacrum articulates with the ilium and form the sacro-iliac joints on each side. • The sacrum articulates with the 5th lumbar vertebra to form the lumbosacral joint. • Co1-Co4. • 4 coccygeal vertebrae fused to form the triangular coccyx. • It articulate with the sacrum at the sacro-coccygeal joint. • In the females the coccyx points inferiorly while in the male it points anteriorly. .