Spinal Anatomy Overview

Spinal Anatomy

Regions of the Spine:
- Cervical Spine:
  - Comprises 7 vertebrae (C1-C7).
  - Supports the head and allows for a wide range of motion.
- Thoracic Spine:
  - Contains 12 vertebrae (T1-T12).
  - Attaches to the ribs and provides stability to the chest.
- Lumbar Spine:
  - Made up of 5 vertebrae (L1-L5).
  - Supports the weight of the upper body and allows for flexibility.
- Sacral Spine:
  - Consists of 5 fused vertebrae (S1-S5).
  - Forms the back of the pelvis and connects to the hip bones.
- Coccygeal Spine:
  - Comprises 3-5 fused vertebrae (coccyx).
  - Serves as an attachment site for ligaments and muscles.
Vertebrae Structure:
- Body:
  - The main weight-bearing part of the vertebra.
- Arch:
  - Formed by pedicles and laminae, protecting the spinal cord.
- Processes:
  - Spinous and transverse processes serve as muscle attachment points.
- Intervertebral Discs:
  - Located between vertebrae, providing cushioning and flexibility.
  - Composed of the annulus fibrosus (outer layer) and nucleus pulposus (inner core).
Curvature of the Spine:
- Primary Curves:
  - Thoracic and sacral curves present at birth.
- Secondary Curves:
  - Cervical curve develops as the child holds up their head.
  - Lumbar curve forms with the ability to walk.
Spinal Cord and Nerves:
- Spinal cord runs through the vertebral foramen, protected by the vertebrae.
- Nerve roots emerge from the spinal cord at each vertebral level, forming spinal nerves.
Biomechanics of the Spine:
- Load Distribution:
  - Evenly distributed through vertebral bodies, discs, and ligaments.
- Movement:
  - Flexion, extension, lateral flexion, and rotation facilitated by facet joints.
- Stability:
  - Provided by vertebral ligaments, muscles, and intervertebral discs.
- Elasticity and Resilience:
  - Intervertebral discs allow for shock absorption and flexibility during movement.
Common Conditions:
- Herniated Discs:
  - Occurs when the nucleus pulposus bulges out, potentially pressing on nerves.
- Scoliosis:
  - Lateral curvature of the spine that can affect biomechanics.
- Degenerative Disc Disease:
  - Leads to reduced disc height and loss of cushioning, impacting mobility.

Understanding spinal anatomy is crucial for recognizing its function and the biomechanics involved in movement and load management.

Regions of the Spine

Cervical spine consists of 7 vertebrae (C1-C7), crucial for head support and extensive range of motion.
Thoracic spine contains 12 vertebrae (T1-T12), connects to ribs, enhancing chest stability.
Lumbar spine comprises 5 vertebrae (L1-L5), designed to bear upper body weight and facilitate flexibility.
Sacral spine is formed of 5 fused vertebrae (S1-S5), creates pelvic structure, linking to hip bones.
Coccygeal spine includes 3-5 fused vertebrae (coccyx), serving as attachment point for ligaments and muscles.

Vertebrae Structure

Vertebral body functions as the main weight-bearing component.
The vertebral arch, composed of pedicles and laminae, safeguards the spinal cord.
Spinous and transverse processes on vertebrae act as muscle attachment sites.
Intervertebral discs cushion between vertebrae, enhancing flexibility; they consist of an outer layer (annulus fibrosus) and an inner core (nucleus pulposus).

Curvature of the Spine

Primary curves (thoracic and sacral) are present at birth for structural support.
Secondary curves develop postnatally; the cervical curve emerges as the child raises its head, and the lumbar curve develops with walking ability.

Spinal Cord and Nerves

The spinal cord is housed in the vertebral foramen, shielded by vertebrae.
Nerve roots extend from the spinal cord at each vertebral level, forming the spinal nerves.

Biomechanics of the Spine

Load distribution occurs through vertebral bodies, intervertebral discs, and ligaments, ensuring balance.
Movement includes flexion, extension, lateral flexion, and rotation, enabled by facet joints.
Stability is maintained by vertebral ligaments, muscles, and intervertebral discs, which prevent excessive motion.
Intervertebral discs contribute to elasticity and resilience, allowing shock absorption and flexibility during physical activity.

Common Conditions

Herniated discs arise when the nucleus pulposus protrudes, potentially compressing adjacent nerves.
Scoliosis refers to an abnormal lateral curvature of the spine affecting overall biomechanics.
Degenerative disc disease results in decreased disc height and loss of cushioning, leading to mobility challenges.

Understanding spinal anatomy is fundamental in recognizing the spine's functional dynamics and biomechanics essential for movement and stress management.