Anatomy of Spine for Medical Coder

The spine (vertebral column) consists of 33 vertebrae, divided into 5 regions.

It contain 26 bones.

1.Cervical (C1 to C7) : C1 is said to be Atlas, C2 is said to be Axis

2.Thoracic (T1 to T12)

3.Lumbar (L1 to L5)

4.Sacral (S1 to S5)

5.Coccyx (4 Fused)

Internal Structure of Each Vertebra

Each vertebra has:

• Vertebral body (anterior)

• Spinous process

• Transverse processes

• Pedicles

• Lamina

Vertebra is the structural bony part of spine, it is the weight bearing structure. Two vertebra are seperated to each other through spinal disc.

Spinous process is the body projection of the spine at the back.

Transverse Process is the side bony projection of the spine at the right and left side.

Pedicle is a short, thick, strong bony bridge that connects the vertebral body (front) to the posterior part of the vertebra.

Lamina is a thin, flat, plate-like bony structure that forms part of the posterior vertebral arch of a vertebra. Lamina forms the posterior wall (roof) of the spinal canal

Intervertebral Disc Anatomy

Between vertebrae (except C1–C2)

Two parts:

• Annulus fibrosus (outer ring)

• Nucleus pulposus (inner gel)

Procedure performed in following region of Spine

Vertebra :

Corpectomy = removal of vertebral body

Vertebroplasty / Kyphoplasty done inside vertebral body

Pedicle

Screw is placed in pedicle , known as pedicle screw fixation.

Intervertebral disc

• Discectomy

• Disc replacement

• Microdiscectomy

Lamina

• Laminectomy = removal of lamina

• Laminotomy = partial removal

What is Segment and Intervertebral Space ?

A vertebral segment refers to one complete vertebra.

An intervertebral space is the space between two adjacent vertebrae.

Intervertebral Foramen vs Vertebral Foramen

The vertebral foramen is the central hole within a single vertebra.

When stacked together, these form the Spinal canal

The intervertebral foramen is the opening between two adjacent vertebrae through which the spinal nerve exits.

Expalanation of Articular Process , Articular Facet and Facet Joint

The articular process is a bony projection that extends from the posterior part of a vertebra and helps connect one vertebra to another.

The smooth surface present on this projection is called the articular facet.

Each vertebra has four articular processes—two superior articular processes that project upward and two inferior articular processes that project downward.

The superior articular processes of one vertebra articulate (join) with the inferior articular processes of the vertebra above it, and the inferior processes articulate with the vertebra below. These articulations form the facet joints, also known as zygapophyseal joints.

These joints are located on the posterior (back) side of the spine and are synovial joints that allow controlled movement such as bending and twisting while providing stability to the vertebral column.

What is lateral recess ?

Definition:The lateral recess (also called the subarticular zone) is a narrow space inside the spinal canal, just before the nerve root exits the spine.

Location:

• Between the central spinal canal and the intervertebral foramen

• Found at each vertebral level, within the vertebra

What is end plate ?

The vertebral end plate is a thin layer of tissue that separates each vertebral body from the intervertebral disc.

It acts as the interface between bone and disc.

Disease of Spine

1️⃣ Degenerative Disc Disease (DDD)

Degenerative disc disease is a condition in which the intervertebral discs gradually lose hydration and elasticity due to aging or wear and tear. As the disc degenerates, it loses height and shock-absorbing ability, which can lead to back pain, stiffness, and sometimes nerve compression. It commonly affects the cervical and lumbar spine and may lead to disc

herniation or spinal stenosis.

2️⃣ Disc Herniation

A disc herniation occurs when the inner gel-like nucleus pulposus protrudes through a tear in the outer annulus fibrosus. This can compress nearby spinal nerves, causing symptoms such as radiating pain (sciatica), numbness, tingling, or weakness in the arms or legs. Lumbar disc herniation commonly affects L4–L5 or L5–S1 levels.

3️⃣ Spinal Stenosis

Spinal stenosis is the narrowing of the spinal canal or intervertebral foramina, which compresses the spinal cord or nerve roots. It is usually caused by degenerative changes, thickened ligaments, or bone spurs. Patients may experience back pain, leg pain while walking (neurogenic claudication), or weakness.

4️⃣ Spondylosis

Spondylosis refers to degenerative changes in the spine, including disc degeneration, bone spur formation (osteophytes), and facet joint arthritis. It is commonly age-related and may occur in the cervical, thoracic, or lumbar spine. It may or may not cause symptoms.

5️⃣ Spondylolisthesis

Spondylolisthesis is a condition in which one vertebra slips forward over the vertebra below it. It may result from degeneration, trauma, congenital defects, or stress fractures. This condition can cause back pain, nerve compression, and instability of the spine.

6️⃣ Scoliosis

Scoliosis is an abnormal lateral curvature of the spine. Instead of being straight, the spine curves sideways in an “S” or “C” shape. It may be congenital, idiopathic (unknown cause), or neuromuscular in origin. Severe cases can affect posture and lung function.

7️⃣ Kyphosis

Kyphosis is an excessive outward curvature of the thoracic spine, leading to a rounded or hunched back appearance. It may result from osteoporosis, vertebral fractures, developmental disorders, or degenerative changes.

8️⃣ Compression Fracture

A compression fracture occurs when a vertebral body collapses, often due to osteoporosis, trauma, or cancer. It commonly affects the thoracic or lumbar spine and causes sudden back pain and reduced height.

9️⃣ Facet Arthropathy

Facet arthropathy is degeneration or arthritis of the facet joints located at the posterior part of the spine. It causes localized back pain and stiffness and may contribute to spinal stenosis or nerve compression.

🔟 Ankylosing Spondylitis

Ankylosing spondylitis is a chronic inflammatory disease that primarily affects the spine and sacroiliac joints. It causes pain, stiffness, and progressive fusion of vertebrae, leading to reduced spinal mobility.