Back-AnatomyZone

• 7 Cervical
• 12 Thoracic
• 5 Lumbar
• Sacrum (5 fused)
• Coccyx (3-5 fused)

• Shock absorbers between vertebrae
• Outer: annulus fibrosus (fibrous)
• Inner: nucleus pulposus (jelly like)

nucleus pulposus herniates out through annulus fibrosus and presses on spinal nerves or cord, in lumbar region can cause sciatica

Where Spinal nerves emerge

1st cervical spinal nerve emerges superior to C1 between C1 and the skull

Level of: Angle of Louis, Bifurcation of trachea, and beginning/end of aortic arch

• At birth only 1 curve (thoracic, C-shaped)
• Develop cervical and lumbar curves (secondary curvatures)
• Pelvic curve begins between L5-S1
• Convex curves: Cervical and Lumbar
• Concave curve: Thoracic

• Atlas: C1, nodding of head, no vertebral body
• Axis: C2, turning of head

• Condylar, synovial
• Flexion and Extension of head, slight lateral motion

rotation, limited flexion/rotation due to ribcage

significant flexion and extension, lateral flexion, tiny amount of rotation

• Body (anterior part)
• Neural arch (posterior part)
• 2 pedicles on superior part of neural archLaminae
• Transverse processes
• Superior articular facets
• Inferior articular facets
• Spinous process

spinal cord

• Transverse foramen in transverse processes
• Allow for passage of vertebral artery

• Articulates with heads of ribs at superior and inferior facets
• Facet on transverse process articulates with tubercle of ribs

• Superficial, responsible for movements at shoulder and upper limbs
• All extrinsic muscles receive sensory info from ventral (anterior) rami of spinal nerves because they insert into the upper limbs
• Trapezius
• Latissimus Dorsi
• Rhomboid Major
• Rhomboid minor
• Levator scapulae

• O: External occipital protuberance, ligamentum nuchae; spinous processes of C7-T12
• I: spine of scapula; posterior surface of lateral ⅓ of clavicle and acromion of scapula
• A: Elevates and depresses scapula; also retracts scapula
• N: Innervated by Spinal Accessory nerve (XI); Sensory info from ventral rami of C3 and C4

• O: Spinous process of T7-L5; inferior angle of scapula; inferior 3-4 ribs; iliac crest; thoracolumbar fascia
• I: humerus in between insertion of pectoralis major and teres major“ Lady between two majors”
• A: Adducts the arm, extends arm, and internally rotates humerus
• N: C6, C7, and C8

• Deep to trapezius
• O: Spinous processes of T2 to T5
• I: medial border of scapula inferior to insertion of rhomboid minor
• N: C4-C5
• A: Retracts scapula and rotates it to depress glenoid cavity; also fixes scapula to thoracic wall

• O: C7 and T1; nuchal ligaments
• I: medial border of scapula superior to rhomboid major insertion
• N: C4-C5
• A: Retracts and rotates scapula; fixes scapula to thoracic wall

• O: Transverse process of C1
• I: Superior angle of scapula and medial border
• N: C4-C5
• A: Elevates scapula

• Attach to ribs; involved in respiratory function
• Serratus posterior superior
• Serratus posterior inferior

• Attached to ribs and spinous processes
• Elevate ribs

• Attached to ribs and spinous processes
• Depress ribs

• Move spine, neck, and head; innervated by posterior rami
• Splenius capitis
• Splenius cervicis
• Erector spinae muscles
• Transversospinalis muscles

• O: Spinous processes of cervical vertebrae
• I: Skull
• A: If both, extends neck, draws head back; if contract individually, turns head

• Largest group in back
• Primary extensors of vertebral column and head
• 3 Muscles:Iliocostalis (most lateral), Longissimus, Spinalis (Most medial)

• Transverse to spinous processes
• Semispinalis (most superficial)
• Multifidus
• Rotares (most deep)

• Vertical arteries
• Segmental arteries

• 1 anterior spinal artery and 2 posterior spinal arteries
• Vertebral artery comes off subclavian artery on each side
• Rise up and pass through transverse foramen of cervical vertebrae
• Through foramen magnum and anastomose to form basilar artery and anterior spinal artery

Anterior spinal artery runs down entire spinal cord along ventral median fissure

• Come off as 2 branches of vertebral artery
• Run length of spinal cord along posterolateral aspects of spinal cord

• Feed into spinal cord at different levels
• Come through intervertebral foramina along with spinal nerve roots
• Come off of different arteries depending on level
• Split into posterior radicular and anterior radicular arteries along spinal cord

• Vertebral artery
• Deep cervical artery

Posterior intercostal arteries

Lumbar arteries

At some levels, these arteries come off segmental arteries and directly join the anterior and posterior spinal arteries

• Anterolateral spinal veins
• Posterolateral spinal veins
• Anterior spinal vein
• Posterior spinal vein
• Radicular veins

Sit anterolaterally to dorsal and ventral nerve roots; run down length of spinal cord

Sit postterolaterally to dorsal and ventral nerve roots;  run down length of spinal cord

Anterior and posterior spinal veins run down length of spinal cord

• Drain blood from longitudinal spinal veins into internal vertebral venous plexus which sits in extradural space
• Internal vertebral venous plexus drains into external vertebral venous plexus which drain into systemic veins (ascending lumbar vein and azygos veins)