Topic Overview

Back

Introduction

• Constitutes posterior aspect of trunk extending from neck to gluteal region.

• Functions:

  • Supports body weight.

  • Protects spinal cord and roots.

  • Provides attachment for muscles controlling movements of head, neck, and limbs.

• Main components:

  • Vertebral column.

  • Spinal cord and meninges.

  • Muscles of back (superficial, intermediate, deep).

  • Associated vessels, nerves, and joints.

Surface Landmarks

1. Vertebral Column

• C7 (vertebra prominens) → prominent spinous process felt at base of neck.

• Scapula

  • Root of spine → opposite T3 vertebra.

  • Inferior angle → opposite T7 vertebra.

• Iliac crest → highest point corresponds to L4 vertebra (line joining both crests = intercristal line).

• Posterior superior iliac spine (PSIS) → marked by a dimple in skin at level of S2 vertebra.

2. Other Bony Landmarks

• Occipital protuberance at back of skull → attachment for ligamentum nuchae.

• Sacral hiatus → palpable at lower end of sacrum, landmark for caudal epidural anesthesia.

3. Muscular Landmarks

• Trapezius → upper back, forms posterior boundary of posterior triangle of neck.

• Latissimus dorsi → lower back, forms posterior axillary fold.

• Erector spinae → prominent vertical muscle mass felt beside lumbar spine in muscular individuals.