STRUCTURE OF THE HUMAN BODY

Vertebral Levels 2011 - 2012 Landmarks and internal structures found at various vertebral levels.

Vertebral Landmark Internal Significance Level • Bifurcation of common carotid artery. C3 Hyoid

Superior border of thyroid C4 cartilage • Larynx ends; begins • ends; begins • Inferior thyroid A crosses posterior to carotid sheath. • Middle cervical sympathetic ganglion C6 Cricoid cartilage behind inf. thyroid a. • Inferior laryngeal nerve enters the larynx. • Vertebral a. enters the transverse. Foramen of C 6.

• Thoracic duct reaches its greatest height C7 prominens • Isthmus of thyroid gland

Sternoclavicular joint (it is a • Highest point of apex of lung. T1 finger's breadth below the bismuth of the thyroid gland T1-2 Superior angle of the T2 Jugular notch T3 Base of • Division between superior and inferior • Ascending ends T4 (of Louis) • Arch of aorta begins & ends. • Trachea ends; primary bronchi begin

• Heart T5-9 Body of T7 Inferior angle of scapula • Inferior vena cava passes through T8 diaphragm

T9 Xiphisternal junction • Costal slips of diaphragm T9-L3

• Esophagus through diaphragm T10

• Aorta through diaphragm • Thoracic duct through diaphragm T12 • Azygos V. through diaphragm

• Pyloris of immediately above and to the right of the midline. • Duodenojejunal flexure to the left of midline and immediately below it Tran pyloric plane: Found at the • on a line with it L1 midpoint between the jugular • Origin of Superior Mesenteric artery notch and the pubic • Hilum of kidneys: left is above and right is below. • Celiac a. originates just above and renal arteries originate just below this line.

• Thoracic duct begins L2 • Azygos and hemiazygos begin

• Aorta bifurcates into common iliac arteries L4/L5 Iliac crest • Inferior vena cava formed from common iliac veins

• End of dural sac Posterior superior iliac spine S2 • Middle of sacroiliac joint (dimple)

• Pelvic colon ends and begins; important landmark in surgery of recto S3 Posterior inferior iliac spine sigmoid carcinoma