Back Anatomy

cervical arterial supply

Occipital, vertebral, deep cervical, and ascending intercostal arteries

Cervical vertebra (how to differentiate)

-bifid spinus process -smallest -foramen transversarium

Serratus posterior inferior

Inserts on lower border of ribs 9-12 Depresses the ribs intermediate extrinsic muscle

sacral arterial supply

iliolumbar and lateral sacral arteries

intrinsic deep muscles

transversospinal group

transversospinal group

-Semispinalis, Multifidus, Rotatores -Short fibers, segmental -Very small muscles (interspinales, intertransversarii, levatores costarum) -intrinsic deep muscles

Spinotransverse group

-Splenius capitis and splenius cervicis -Extends, rotates, and laterally flexes head and neck -intermediate intrinsic muscle

Sacrospinalis group

-aka Erector spinae -Iliocostalis, longissimus, spinalis muscles -Extension and control of flexion (head, spine), side bending -Long fibers, covers top to bottom -intermediate intrinsic muscle

internal vertebral venous plexus

-in epidural space b/w dura mater and vertebral canal -4 major veins (2 anterior, 2 posterior) w/ lots of tributaries and communications -tributaries from spinal cord and vertebra -route of early metastasis of lung, breast, and prostate cancer

vertebral venous system

-internal vertebral venous plexus -external vertebral venous plexus -intervertebral vein

Lumbar vertebra (how to differentiate)

-large body -thick, blunt spinous process

denticulate ligaments

-lateral extensions of pia mater -helps hold the spinal cord in position in the subarachnoid space

Thoracic vertebra (how to differentiate)

-long spinous process -costal facets

Functions of the spine

-protects spinal cord and nerves -supports weight of body superior to pelvis -supports head and provides stiff yet flexible axis for the body -supports body posture and allows locomotion

Intermediate extrinsic back muscles

-serratus posterior superior -serratus posterior inferior

Intermediate Intrinsic back muscles

-spinotransverse group -sacrospinalis group

Posterior longitudinal ligament

-very strong -supports posterior vertebra and discs -limits flexion

lumbar arterial supply

subcostal and lumbar arteries

Superficial Extrinsic Back Muscles

-Latissimus Dorsi -Trapezius -Rhomboids (major and minor) -Levator Scapulae

Ligamentum nuchae

-attaches to C2-C6 -triangular shaped median fibrous septum between muscles on two sides of posterior neck to support back of skull -formed by thickened supraspinous ligaments

lymphatic drainage of the back-superficial

-axillary nodes (above iliac crest) -superficial inguinal nodes (below iliac crest)

Ligamentum flavum (yellow ligament)

-connects the laminae of adjacent vertebra -helps straighten vertebral column after flexion

lymph drainage of the back-deep

-deep cervical -posterior mediastinal -lateral aortic -sacral nodes

L4-L5 herniation (from chart)

-pain- above sacroiliac joint,hip, lateral thigh, and leg -numbness- lateral leg, first 3 toes -weakness- dorsiflexion of great toe and foot, difficulty walking on heels; foot drop may occur -atrophy- minor or nonspecific -reflexes-posterior tibial reflex diminished or absent, changes uncommon in knee and ankle jerks

L3-L4 herniation (from chart)

-pain- lower back, hip, posterolateral thigh, anterior leg -numbness- anteromedial thigh and knee -weakness- quadriceps -atrophy- quadriceps -reflexes- knee jerk diminished

L5-S1 herniation (from chart)

-pain- over sacroiliac joint, hip, posterolateral thigh, and leg to heel -numbness-back of calf, lateral heel, foot and toe -weakness- plantar flexion of foot and great toe may be affected, difficulty walking on toes -atrophy- gastrocnemius and soleus -reflexes-ankle jerk diminished or absent

Serratus posterior superior

Inserts on upper border of ribs 2-5 Elevates the ribs intermediate extrinsic muscle

Anterior longitudinal ligament

anterior side of vertebral body; limits extension widens as it descends; maintains joint stability

Thoracic arterial supply

posterior intercostal arteries