Anatomy

Superficial Back muscles

Trapezius muscle

• Action
  • Scapular elevation, retraction, depression.
• Innervation
  • Spinal accessory nerve (CN XI)

Rhomboid major and minor muscles

• Action→ Scapular retraction
• Innervation → Dorsal scapular nerve

Teres major muscle

• Action → Adduction, extension and internal rotation of the humerus
• Innervation → lower subscapular nerve

Latissimus dorsi muscle

• Action → Adduction, extension and internal rotation of the humerus
• Innervation→ thoracodorsal nerve

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Random information from RX Q-bank (not that important)

• Pain with forced expiration, twisting and lateral bending → indicates rotation injury to serratus posterior inferior muscle (intermediate back muscle). </aside>

Vertebral Anatomy

Components

• The vertebral bodies form the anterior, weight-bearing portion of the vertebral column.
• The posterior portion of the vertebral column contains the midline spinous process, the transverse processes, and the articulating processes of the facet joints.
• The posterior vertebral arch connects the anterior and posterior portions of the vertebral column and consists of the pedicle, the intervening pars interarticularis, and the lamina.
• The posterior vertebral arch and the posterior portion of the vertebral body form the triangularly shaped spinal canal.

                       **Anatomy of the vertebra**

• Other picture

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Clinical correlation

• Laminectomy → removal of the lamina (yellow colored area). </aside>

                  **Vertebral ligaments**

• Other picture

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Anatomical relations

• Spinal cord is bordered anteriorly by posterior longitudinal ligament and posteriorly by ligamentum flavum. </aside>

Back pain

Differential diagnosis of back pain

Neoplastic cord compression

Etiology

• Most commonly results from local extension of vertebral metastases into the
  • Most commonly→ Epidural space
  • Rarely→ Intramedullary
• Malignancies with a propensity for bony metastasis include Prostate, Breast, Kidney, Thyroid, and Lung (mnemonic: Pb KTL, or "lead kettle").

Presentation

• Epidural metastasis
  • Severe back pain (often worse at night).
  • Motor weakness and/or sensory deficits.
  • Urinary and fecal retention or incontinence are common late-stage findings.
• Intramedullary
  • Usually associated with lung cancer
  • Brown-Sequard syndrome (ie, ipsilateral hemiplegia, contralateral sensory loss)

Diagnosis

• MRI is diagnostic.

Spondylolisthesis

Definition

• Anterior slippage of a vertebral body over the subjacent vertebra

Etiology

• Bilateral spondylolysis (ie, pars interarticularis fracture).

Pathogenesis

• Repetitive hyperextension and rotation movements (e.g., in gymnastics, swimming, weight lifting)→ stresses the facet joints and posterior vertebral arch→ spondylolysis with subsequent spondylolisthesis.

• Other picture

Pott disease

Pathophysiology