Back Anatomy Overview

Back Anatomy

• The back is a complex structure composed of several parts, including bones, muscles, ligaments, and nerves.

Bones of the Back

• Vertebrae: The spinal column consists of individual vertebrae

  • Cervical vertebrae (C1-C7): Located in the neck region
    • C1 (Atlas): Supports the skull.
    • C2 (Axis): Allows head rotation.
  • Thoracic vertebrae (T1-T12): Located in the upper back, corresponding to the ribs.
  • Lumbar vertebrae (L1-L5): Located in the lower back
    • L1-L5): Larger size to support more weight
  • Sacrum (S1-S5): Fused vertebrae forming the base of the spine.
  • Coccyx: The tailbone, the most inferior part.

• Clavicle: Collarbone.

• Scapula: Shoulder blade.

• Ribs: Connected to the thoracic vertebrae, forming the rib cage.

Shoulder and Thorax

• The scapula, clavicle, ribs, and sternum make up the shoulder and thorax region.
• The glenoid fossa is the part that forms the shoulder joint.

Vertebral Anatomy

• Vertebral body: The anterior, weight-bearing portion of each vertebra.
• Pedicle: Connects the body to the vertebral arch.
• Lamina: Forms the posterior portion of the vertebral arch.
• Superior articular process: Joints with the vertebra above.
• Inferior articular process: Joints with the vertebra below.
• Transverse Process: Projects on each side of the vertebra.
• Spinous Process: Projects posteriorly from the vertebral arch.
• Vertebral Foramen: Canal where the spinal cord passes.

Intervertebral Discs

• Located between vertebrae, these act as shock absorbers.

Ligaments of the Vertebral Column

• These connect vertebrae and support the column.
• Anterior longitudinal ligament: Connects the anterior surface of adjacent vertebral bodies.
• Posterior longitudinal ligament: Connects the posterior surface of adjacent vertebral bodies.
• Ligamentum flavum: Located between lamina of adjacent vertebrae.
• Supraspinous ligament: Runs along the spinous processes.

Spinal Cord

• The spinal cord extends from the brain stem to the lumbar region and contains nerves.
• Conus medullaris: The tapered end of the spinal cord
• Cauda equina: Collection of nerve roots extending below the conus medullaris.
• The ending of the dura mater (protective covering) occurs at the level of the S2 vertebrae

Spinal Nerves

• Branch from the spinal cord and innervate muscles and provide sensation.
• Spinal nerves have a dorsal root (sensory) and a ventral root (motor).

Posterior (Dorsal) Rami

• Innervate intrinsic back muscles and skin of the back.

Muscles of the Back

• Extrinsic back muscles: These originate from the rib cage or the clavicle, and move the upper limb.
  • Trapezius Muscle
  • Latissimus Dorsi Muscle
  • Levator Scapulae Muscle
  • Rhomboid muscles (major and minor)
  • Serratus Posterior (superior and inferior)
• Intrinsic back muscles: These originate from and insert on vertebrae and ribs. They move the trunk.
  • Erector spinae and its subdivisions (iliocostalis, longissimus, spinalis)
  • Subcategories of intrinsic muscles, including Semispinalis, Rotatores, Interspinales, Intertransversarii, and Levatores costarum.

Deep Intrinsic Muscles

• Multifidus muscle is a deep, intrinsic muscle.

Motions of the Back

• Back muscles can extend, flex, rotate, and laterally flex parts of the body, including the head, neck, and spine.

Skin Innervation of the Back

• Nerves supply sensation and motor function to the skin of the back.

Explore the intricate anatomy of the back, focusing on the various bones, muscles, and joints that make up this complex structure. Understand the roles of vertebrae, the shoulder, and thorax, and their importance in supporting the human body. This quiz tests your knowledge of the key components involved in back anatomy.