Quick Tips on the Surface Anatomy of Our Body

Our own body is a live specimen for understanding the surface anatomy of human body. Knowledge of surface anatomy may help us to understand the diagnostic terms used by a physician or surgeon. The physical examination parameters of a patient are recorded with reference to certain landmark points which are universally understood. By inspection, palpitation, percussion and auscultations a physician or surgeon studies condition of his/her patient to arrive at a diagnosis. The position of many internal structures and organs is described in relation to various bony points termed as landmark points.

There are some land mark points of surface anatomy of the head; like longitudinal fissure, superior longitudinal sinus, central sucus or fissure of Ronaldo, mastoid processes ete. There are anterior and posterior triangles of neck formed by sternomastoid muscle. In the trunk many of the organs are being described in relation to their surface anatomy. The apex beat of the heart can be heard in the fifth intercostal space, 3¹/₂ inches from the midline. The abdomen is divided into 9 parts by four imaginary lines (two vertical and two horizontal). These 9 parts have been depicted in the figure-1 below:

Figure-1: Abdominal Regions (1: Right Hypochondriac Region, 2: Epigastric Region, 3: Left Hypochondriac Region, 4: Right Lumbar Region, 5: Umbilical Region, 6: Left Lumbar Region, 7: Right Iliac Region, 8: Hypogastric, 9: Left Iliac Region.

The liver occupies parts of the right hypochondriac and epigastric areas, and extends transversely into the left hypochondriac region and also occupies a part of the right lumbar region. The lungs and the heart occupy the thoracic cavity and are well secured there in the protective bony cage. The spleen lies on the left side beneath the ninth, tenth and eleventh ribs. The left kidney lies between the eleventh thoracic to the third lumbar vertebra. The right kidney is slightly lower as its upper pole touches the lower part of the liver.

The rectus abdominus could be felt along each side of the middle line of the abdomen. The umbilicus lies on level with the disc between the third and fourth lumbar vertebrae. The stomach lies in the upper and left aspect of the abdomen, partly behind the lower ribs and cartilages. The fundus of the stomach reaches as high as the fifth left intercostal space. The gall bladder projects slightly from the costal margins at the level of the ninth right costal cartilage. The pancreas lies at the back of the abdominal cavity across the first lumbar vertebra. The aorta passes through the common iliac arteries in front of the fourth lumbar vertebra. The caecum is present on the right side and the commencement of the sigmoid fissure of the colon lie respectively in the right and left iliac fossae.