L-Spine anatomy 1/25

What forms the central axis of the skeleton?

Vertebral column

Where is the vertebral column located?

Centered in the midsagittal plane of the posterior trunk

What are the main functions of the vertebral column?

Protects the spinal cord, supports the trunk and skull, and provides muscle attachments

What type of bones make up the vertebral column?

Small, irregular bones called vertebrae

How many vertebrae are present in early life?

33 vertebrae

How many true (movable) vertebrae are there?

24 vetebrae

Which vertebrae are considered false (fixed)?

Sacral and coccygeal vertebrae

What happens to the sacral vertebrae?

They fuse to form the sacrum

What happens to the coccygeal vertebrae?

They fuse to form the coccyx

What are the five regions of the vertebral column?

Cervical, thoracic, lumbar, sacral, and coccygeal

Which vertebrae are located in the neck region?

Cervical vertebrae

Which vertebrae are located in the thoracic region?

Thoracic vertebrae

Which vertebrae are located in the lower back?

Lumbar vetebrae

Which vertebrae fuse to form the sacrum?

Sacral vertebrae

Which vertebrae fuse to form the coccyx?

Coccygeal vertebrae

What type of curvature is the cervical spine?

Lordotic

What type of curvature is the thoracic spine?

Kyphotic

What type of curvature is the lumbar spine?

Lordotic

What type of curvature is the pelvic spine?

Kyphotic

What is kyphosis?

Increased kyphotic curvature of the thoracic spine

What are the two main parts of a vertebra?

Vertebral body and vertebral arch

Which part of a vertebra is anterior?

Vertebral body

Which part of a vertebra is posterior?

Vertebral arch

What space is formed by the vertebral body and arch?

Vertebral foramen

What is formed by the articulation of vertebral foramina?

Vertebral canal

What structures form the vertebral arch?

Two pedicles and two laminae

What are pedicles?

Projections extending posteriorly from the vertebral body

What do vertebral notches form?

Intervertebral foramina

What are laminae?

Thin plates projecting posteriorly and medially from pedicles

What projects posteriorly and inferiorly from the laminae?

Spinous process

What projects laterally from the junction of pedicles and laminae?

Transverse processes

How many articular processes does a typical vertebra have?

Four

What are the two types of articular processes?

Two superior and two inferior

What do articular processes form?

Zygapophyseal (facet) joints

What are zygapophyseal joints also called?

Interarticular facet joints

What is spina bifida?

Congenital failure of the laminae to fuse

How many lumbar vertebrae are there?

five

Where is the lumbar spine located?

Posterior abdominal region

How do lumbar transverse processes compare to thoracic?

Smaller than thoracic transverse processes

What is the pars interarticularis?

Portion of the lamina between the articular processes

What radiographic sign represents the pars interarticularis?

Scottie dog sign

What joints are demonstrated on posterior oblique lumbar spine images?

Downside zygapophyseal joints

What joints are demonstrated on anterior oblique lumbar spine images?

Upside zygapophyseal joints

What does an LPO lumbar spine demonstrate?

Left (downside) zygapophyseal joints

What is the sacrum formed from?

Fusion of five sacral vertebrae

What is the shape of the sacrum?

Curved and triangular

Where is the sacrum located?

Between the iliac bones

What joints are formed between the sacrum and ilium?

Sacroiliac (SI) joints

What is the sacral promontory?

Anterior projecting margin of S1

What is the sacral canal?

Continuation of the vertebral canal

What is the coccyx formed from?

Fusion of three to five rudimentary vertebrae

How does the coccyx curve?

Inferiorly and anteriorly from the sacrum

What separates vertebral bodies?

Intervertebral disks

What is the function of intervertebral disks?

Act as cushions

What is the annulus fibrosus?

Outer fibrocartilaginous portion of the disk

What is the nucleus pulposus?

Central soft portion of the disk

What type of joints are intervertebral joints?

Cartilaginous, slightly movable

What type of joints are zygapophyseal joints?

Synovial (diarthrodial) gliding joints

At what angle are L1–L4 facet joints oriented?

45 degrees from the coronal plane

At what angle are L5–S1 facet joints oriented?

60 degrees from the coronal plane

What is a herniated nucleus pulposus (HNP)?

Protrusion of the nucleus pulposus through the annulus fibrosus

What is another term for HNP?

Slipped disk

What commonly causes HNP?

Improper body mechanics or injury

Where do most HNPs occur?

L4–L5 and L5–S1

Why is HNP painful?

Compression of the spinal cord or nerve roots

What is spondylolysis?

Congenital defect or fracture of the pars interarticularis

Which projection best demonstrates spondylolysis?

Oblique lumbar spine

Why are athletes with unilateral spondylolysis at risk?

Increased stress fracture risk of the opposite pars

What is spondylolisthesis?

Forward displacement of one vertebral body over another

Which projection best demonstrates spondylolisthesis?

Lateral lumbar spine

Where does spondylolisthesis most commonly occur?

L5–S1 and L4–L5

What is osteoarthritis (DJD) of the spine?

Degeneration from wear and tear

What are common radiographic signs of DJD?

Lipping and bone spurring