Letulle method

REMOVAL OF ORGANS
After the initial examination of organs and cavities, abdominal contents are removed. Carotid arteries are identified and examined. Scissors or scalpel is used to transect laryngeal pharynx above the level of epiglottis through thyro-hyoid membrane. Esophagus is transected as well. Larynx is reflected inferiorly and carotids are cut. The tongue is removed by cutting posterior of ramii of hyoid bone and through the neck, oral cavity is reached and tongue is grasped. Tip of the tongue is flipped posteriorly into the neck and anterior attachments are cut free. Pleural and connective tissue is freed from any adhesions. Right and left leaves of diaphragm are cut along their lateral and posterior surfaces and the cut is extended through psoas muscle excluding vertebral column.

For pelvic region, bladder and prostrate are separated from pelvic wall by retracting them with non-operating hand. Rectum is separated from coccyx by extending the plane of dissection posteriorly and transected at the level of proximal urethra. Rectum is cut less than 2 cm above the anorectal junction. Pelvic organ is now reflected upwards and outwards exposing the iliac vessels bilaterally. Connective tissue attachments are now removed and organ block is removed.

Neck is lifted and thoracic organs are reflected detaching the posterior attachments and adhesions if any. Inferior and upwards traction is applied, cutting any attachments like diaphragmatic and abdominal wall.

EXAMINATION OF BODY CAVITIES
Following removal of thoracic and abdominal mass, body cavities and walls are inspected once again. Testes are removed by entering the scrotal sac from inguinal canal which is previously enlarged by blunt dissection. Pushing and lifting the tested and spermatic cord upwards towards pelvic brim and the testes cut free.

SEPARATION OF INDIVIDUAL ORGANS
Once the organs are removed, they are placed on a dissecting board. The most posterior structure, Aorta, is identified and arch of the aorta lifted and transected with scissors and lumen cut longitudinally until the bifurcation of abdominal aorta. Any atheromatous plaques or aneurysms encountered must be recorded. Then Aorta is stripped off from its attachment.

Esophagus is opened next along its posterior aspect and examined to seek for any fistulas, variceal bleeding points or mucosal and sub mucosal variances. On exposing the bed of adrenals below hemi-diaphragm, glands are palpated to identify adrenals. Supra-renal fat above superior pole of kidneys is dissected away. The adrenals are then removed carefully and weighed. Right adrenal is pyramidal in shape and left is semi-lunar. Neck and thoracic organs are now separated from abdominal block by cutting between inferior aspect of pericardium and superior surface of diaphragm.

Neck and Thoracic Organs Examination
The lungs are transected at the level of carina of both bronchii, near the hilum. Each lung is weighed and the surface inspected. Pulmonary parenchyma is palpated to look for any mass or areas of consolidation as seen in cases of chronic lung diseases like pneumonia, tuberculosis, etc.

Many doctors examine the lungs fresh although fixation can be done. The method of McCulloch and Rutty is best for examination of fresh lungs. For slicing lungs, a sharp long knife is essential. After slicing the lungs longitudinally, lung parenchyma is examined for consolidation and scarring. Large airways and blood vessels are examined for presence of thrombi or emboli.

Heart
After careful removal of pericardium, the surface of the heart is examined, with the coronaries cut in cross sections at 2-3mm intervals. Heart is sliced at 1cm interval in short axis at the apex and continued until the inferior margin of atrio-ventricular groove. The remaining portions of atrium and ventricular chambers are opened. Presence of any artificial valves should be recorded. Heart is weighed after removal of vessels and postmortem clots.

EXAMINATION OF ABDOMINAL ORGANS

Stomach and Intestines
Anterior aspect of the organ block is exposed to dissect diaphragm away from esophagus and liver. Omental fat is removed from greater curvature of stomach and using an Enterotome, the stomach is opened along its greater curvature from pylorus to cardiac sphincter. The cut is continued through duodenum to expose ampulla of Vater and duodenal mucosa. It is advisable to leave the head of the pancreas intact.

Pancreas
Fat surrounding the pancreas should be excised and the pancreas weighed. Serial transverse sections are made along it long axis to examine pancreatic parenchyma. Several cut sections are made through head of pancreas allowing examination of pancreatic parenchyma and Wirsung and Santorini ducts.

Liver and biliary tree
On rotating the liver posteriorly, the inferior surface can be accessed. Mild compression on gall bladder will extrude bile from ampulla. Through the common bile duct, with a help of fine scissors, an opening can be made into the hepatic duct, cystic duct and gallbladder. Another way is to open the gall bladder and extend incision through the duct. Any calculi retrieved should be collected for biochemical analysis.

Removal of adherent diaphragm and lesser omentum can assist in visualization of liver surface. It must be weighed before dissection. It can be cut in parasagittal, coronal and horizontal planes to examine the underlying consistency and fatty changes.

Spleen
The spleen is removed at its hilum, its capsular surface examined, and weighed. Many examiners make multiple slices of the spleen along its short axis. Another method is to make sections along the long axis of the spleen either parallel or perpendicular to the plane of hilum. With any method, sufficient sections should be made to be able to inspect the parenchyma fully. Note whether the follicles are visible, and examine the condition of connective tissue trabeculae.

EXAMINATION OF THE GENITOURINARY ORGANS
The ureters are identified by inspecting them running along each side of midline through fat and fascia. Average luminal circumference is measured and opened along its long axis to look for any abnormality until bladder is reached.

Kidneys are removed by blunt dissection around renal capsule and perinephric fat. The kidneys are weighed after removing adherent perinephric fat. A longitudinal section is then cut along the lateral plane of both kidneys, which exposes pelvis, calyces and cortico-medullary junction. Calculi if present, should be collected. The capsule is stripped and the surface examined for any cysts or lesions.

Examination of Testis
Right testes can be differentiated from left by viewing the lateral aspects of both. Any attached spermatic cord is detached by cutting through it. Testes are weighed and cut along the sagittal plane to examine the parenchyma. 

Examination of female genitor-urinary tract
In females, the procedure is slightly different, owing to anatomical variation in both sexes. Rectum is opened through posterior midline and removed from pelvic region. Scissors are introduced into urethra and opened along its long axis until bladder is reached. Bladder is separated from its attachments. Fallopian tubes and ovaries are examined and dimension of ovaries measured. Fallopian tubes are opened longitudinally and serial cross sections are made. Ovaries are cut lengthwise exposing parenchyma for inspection. Proximal vaginal canal is opened along its lateral surfaces and the epithelial surface examined. Cervix is examined and width of Os measured. Uterus is opened along its lateral aspect to measure dimension of cavity and thickness of endometrium.

Examination of male and female genitalia
Genitalia are not always removed as a part of routine examination. In special circumstances like sexual assault or extensive trauma in this region, extensive dissection may be required. Abdominal incision is extended to the base of penis. Mid portion of pubic arch is removed with help of saw and entire genital block is removed along with bladder, prostrate and rectum.

In females, the abdominal incision is extended up to labia majora. Pubic arch is removed with saw and elliptical incision id made around external genitalia and anus and the block containing vagina, uterus, bladder and rectum is removed in a single block for examination.