Place the tourniquet around the limb and weave the strap through the buckle. Alternatively, in tourniquets that come preassembled, they can be slipped over the limb. If possible, clothing should be removed prior to placement. If this is not possible, avoid placing tourniquet over bulky clothing or pockets.

Traffic collisions, followed by falls, are by far the most common cause of severe blunt abdominal trauma. Solid organs, usually the spleen and liver, are the most commonly injured organs. Hollow viscus perforations are fairly uncommon (about 3% of blunt abdominal trauma), and they are often associated with seat-belts or high-speed deceleration injuries.

• The liver is tethered by the following ligaments:

  • The falciform ligament attaches the liver anteriorly to the diaphragm and the anterior abdominal wall above the umbilicus.

  • The coronary ligaments extend laterally to attach the liver to the diaphragm. Beginning at the suprahepatic inferior vena cava (IVC), the lateral extensions of the coronary ligaments form the triangular ligaments (right and left), which are also attached to the diaphragm.

• The anatomical division of the liver into the eight classic Couinaud segments has no practical application in traumatic liver resection, where the resection planes are nonanatomical and are dictated by the extent of injury. However, the external anatomical landmarks may be useful in planning operative maneuvers.

  • The plane between the center of the gallbladder and IVC runs along the middle hepatic vein, and serves as the line of division between the right and left lobes.

  • The left lobe is divided by the falciform ligament into the medial and lateral segments.

  • Dissection along the falciform ligament should be performed carefully, so as to avoid injury to the portal venous supply to the medial segment of the left lobe inferiorly and the hepatic veins superiorly.

• The retrohepatic IVC is approximately 8–10 cm long and is partially embedded into the liver parenchyma. In some cases, the IVC is completely encircled by the liver, further complicating exposure and repair.

• There are three major hepatic veins (right, middle, and left), as well as multiple accessory veins. The first 1–2 cm of the major hepatic veins are extra-hepatic, with the remaining 8–10 cm intra-hepatic. In approximately 70% of patients, the middle hepatic vein joins the left hepatic vein before entering the IVC.

• The common hepatic artery originates from the celiac artery. It is responsible for approximately 30% of the hepatic blood flow, but supplies 50% of the hepatic oxygenation. It branches into the left and right hepatic arteries at the liver hilum in the majority of patients. In a common anatomical variant, the right hepatic artery may arise from the superior mesenteric artery. Less frequently, the entire arterial supply may arise from the superior mesenteric artery. Alternatively, the left hepatic artery may arise from the left gastric artery in 15–20% of patients.

• The portal vein provides approximately 70% of hepatic blood flow, and 50% of the hepatic oxygenation. It is formed by the confluence of the superior mesenteric vein and the splenic vein behind the head of the pancreas. The portal vein divides into right and left extrahepatic branches at the level of the liver parenchyma.

• The porta hepatis contains the hepatic artery (medial), common bile duct (lateral), and portal vein (posterior, between the common bile duct and the hepatic artery).

• The right hepatic duct is easier to expose after removal of the gallbladder.

• The left hepatic duct, the left hepatic artery, and the left portal vein branch enter the undersurface of the liver near the falciform ligament.

• For trauma purposes the neck is divided into three distinct anatomical zones.

  • Zone 1: from the sternal notch to the cricoid cartilage.

  • Zone 2: from the cricoid cartilage to the angle of the mandible.

  • Zone 3: from the angle of the mandible to the base of the skull.

• Knowing the contents of each zone is important when considering possible injuries.

  • Zone 1: the major vessels of the upper mediastinum, the lung apices, esophagus, trachea, thoracic duct, and thyroid gland.

  • Zone 2: the carotid sheath and contents, vertebral arteries, esophagus, trachea, pharynx, and the recurrent laryngeal nerve.

  • Zone 3: distal carotid and vertebral arteries, distal jugular veins.

• At the level of the superior border of the thyroid cartilage the common carotid artery bifurcates into the internal and external carotid arteries.

• At the level of the angle of the mandible, the internal and external carotid arteries are crossed superficially by the hypoglossal nerve and the posterior belly of the digastric muscle.

• The external landmark of the pharyngoesophageal and laryngotracheal junctions is the cricoid cartilage. On esophagoscopy, this is located 15 cm from the upper incisor teeth.

• The cricothyroid membrane is four fingerbreadths above the sternal notch.

• The cervical esophagus extends from the cricopharyngeus muscle into the chest to become the thoracic esophagus.

• The external landmark of the pharyngoesophageal junction is the cricoid cartilage. On esophagoscopy, this is at 15 cm from the upper incisors.

• The esophagus lacks a serosal layer and consists of an outer longitudinal and inner circular muscle layer.

• The cervical esophagus is approximately 5–7 cm long and lies posterior to the cricoid cartilage and trachea and anterior to the longus colli muscles and vertebral bodies. It is flanked by the thyroid gland and carotid sheath on either side.

• Blood supply is primarily from the inferior thyroid artery, although significant collateral circulation exists.

• The recurrent laryngeal nerves lie on either side of the esophagus in the tracheoesophageal groove.