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