The document provides anatomical information about the back, including: 1) It describes the anatomical planes and commonly used anatomical terms for location. 2) It identifies the typical structures of a vertebra including the vertebral body, pedicles, lamina, and processes. 3) It lists the muscles of the back in three layers - superficial, intermediate, and deep layers - and identifies key muscles in each layer.

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4. ANATOMICAL PLANES MEDIAN PLANE Imaginary vertical plane passing longitudinally through the body from front to back, dividing it into right and left halves. SAGITTAL PLANES Imaginary vertical plane passing through the body parallel to the median plane. CORONAL PLANES (Frontal) Imaginary vertical plane passing through the body at right angles to the median plane, dividing the body into anterior and posterior portions. HORIZONTAL PLANES (Transverse) Imaginary planes passing through the body at right angles to both the median and coronal planes (parallel to the horizon).

5. COMMONLY USED TERMS OF RELATIONSHIP AND COMPARISON ANTERIOR (VENTRAL) Nearer to the front POSTERIOR (DORSAL) Nearer to the back MEDIAL Nearer to the median plane LATERAL Farther from the median plane SUPERIOR (CRANIAL) Nearer to the head INFERIOR (CAUDAL) Nearer to the feet PROXIMAL Nearer to the trunk or point of origin DISTAL Farther from the trunk or point of origin SUPERFICIAL Nearer to or on the surface DEEP Farther from the surface CENTRAL Nearer to the center PERIPHERAL Farther away from the center

6. Sacral Hiatus 7 Cervical 12 Thoracic 5 Lumbar 5 Sacral 4-5 Coccygeal Sacral Cornu Sacral Cornu VERTEBRAL COLUMN

7. * Vertebral Canal Contains spinal cord Pedicle Lamina Spinous Process Transverse Process Intervertebral Foramen Body * TYPICAL VERTEBRA

8. Spinous Process Anterior Longitudinal Ligament Posterior Longitudinal Ligament Supraspinous Ligament Body VERTEBRAL LIGAMENTS Ligamentum Flavum Lamina

9. Vertebral Spinous Process Vertebral Body Intervertebral Disc Supraspinous Ligament Anterior Longitudinal Ligament Ligamentum Flavum Intervertebral Foramen VERTEBRAL LIGAMENTS

11. Pia Mater Dorsal Root of Spinal Nerve Dorsal Rootlets of Spinal Nerve Dura Arachnoid Sleeve Ventral Root of Spinal Nerve MENINGES OF SPINAL CORD 3 Meningeal Layers Dura Mater Arachnoid Subarachnoid Space Pia Mater Subarachnoid Space Dura Arachnoid Sleeve

12. Conus Medullaris L2 Cauda Equina Internal Filum Terminal Termination of Dural Sac S4 External Filum Terminal Spinal Cord Covered with Pia Mater Iliac Crest L4 SPINAL CORD

13. 8 Cervical Spinal Nerves 12 Thoracic Spinal Nerves 5 Lumbar Spinal Nerves 5 Sacral Spinal Nerves Cauda Equina End of Dura Arachnoid Sleeve Dura Arachnoid Sleeve DISC HERNIATION C8 T9 L4 S1 T9 L4 Subarachnoid Space 1 Coccygeal Spinal Nerve

14. Subclavian Artery Vertebral Artery Posterior intercostal Arteries Lumbar Arteries Lateral Sacral Artery Segmental Arteries (Radicular) Posterior Spinal Arteries Anterior Spinal Artery ANTERIOR VIEW POSTERIOR VIEW Intervertebral Artery

15. External Venous Plexus External Venous Plexus Internal Venous Plexus Intervertebral Vein CONTRIBUTIONS TO BATSON’S PLEXUS OF VEINS

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17. 1 – Trapezius CN XI Test: shoulder shrug 2 - Latissimus Dorsi Thoracodorsal Nerve Test: arm extension * Thoracolumbar Fascia SUPERFICIAL BACK MUSCLES – SUPERFICIAL LAYER * 1 2

18. * Thoracolumbar Fascia SUPERFICIAL BACK MUSCLES – INTERMEDIATE LAYER 1 – Levator Scapulae 2 – Rhomboid Minor 3 – Rhomboid Major Dorsal scapular n. (C5) Elevate and retract scapula * 1 2 3

19. SUPERFICIAL BACK MUSCLES – DEEP LAYER 1 – Serratus Posterior Superior 2 – Serratus Posterior Inferior ventral rami of thoracic and lumbar spinal nerves 1 2

20. Lumbar Triangle Site of potential herniations 1 – External Abdominal Oblique 2 – Quadratus Lumborum (floor) 3 – Latissimus Dorsi (reflected) 4 – Iliac Crest Triangle of Auscultation 1 – Trapezius *Inferior angle of the scapula 2 – Latissimus TRIANGLES OF THE BACK * * Upper Lobe of Lung Lower Lobe of Lung Oblique Fissure 1 1 2 3 2 1

21. DEEP BACK MUSCLES 1 – Semispinalis 2 – Splenius Suboccipital Triangle Contents Vertebral a & v 1 2 1 2 3 Erector Spinae Muscles 1 – Spinalis 2 – Longissimus 3 – Iliocostalis Function extension of the vertebral column & head Lateral rotation of the vertebral column & head Dorsal rami of spinal nerves

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