Anatomy of the ribs. There are 12 ribs on each side. All 12 connect posteriorly with the vertebrae of the spine. Ribs 1–7 connect anteriorly directly to the sternum, while ribs 8–10 attach to the superior costal cartilages. Ribs 11 and 12 are floating ribs with no anterior attachment. The intercostal vein, artery, and nerve run in the costal groove, which is located along the inferior border of each rib.

Anterior chest wall

• Pectoralis major muscle: The origin is the anterior surface of the medial half of the clavicle and the anterior surface of the sternum. It inserts into the upper humerus. The blood supply is the pectoral branch of the thoracoacromial trunk.

• Pectoralis minor muscle: The origin of the muscle is on the third through fifth ribs near their cartilages. It inserts into the coracoid process of the scapula.

Lateral chest wall

• Serratus anterior muscle: The origin is the lateral part of the first 8–9 ribs. It inserts into the medial aspect of the scapula.

Posterior chest wall

• Latissimus dorsi muscle: The origin is the spinous processes of the lower thoracic spine and posterior iliac crest. It inserts into the upper portion of the humerus.

• Trapezius muscle: The origin of the trapezius muscle is large, from the occipital bone down through the spinous processes of T12. It inserts on the lateral third of the clavicle and the scapula.

• Erector spinae muscle: The origin is the spinous processes of T9–T12 vertebrae and the medial slope of the iliac crest.

• Access to fractures underlying the scapula is obtained through the “auscultatory triangle” between the superior edge of the latissimus dorsi, the lateral border of the trapezius, and the inferomedial border of scapula.

Deep partial thickness and full thickness circumferential or near circumferential burns of the neck, chest, abdomen, or extremities can cause serious local or systemic complications and need surgical release of the burn eschar to relieve obstruction or high pressures and restore perfusion.

• Circumferential burns of the neck can cause airway obstruction.

• Circumferential burns of the chest can cause respiratory compromise with increased peak inspiratory pressures, hypoxia, and hypercapnia.

• Circumferential burns of the abdomen can cause intra- abdominal hypertension and abdominal compartment syndrome.

• Circumferential burns of the extremities can cause muscle compartment syndrome.

Deep partial or full thickness circumferential extremity burns require prophylactic escharotomy.

Near circumferential extremity burns require frequent neurovascular checks to assess for need of escharotomy. Worsening neurovascular exam or pressure measurement >30 mmHg should prompt urgent escharotomy of the affected extremity.

In severe burns requiring massive fluid resuscitation, abdominal or extremity compartment syndromes may develop independent of circumferential burns. It is important that these high-risk patients are monitored closely and decompressive laparotomy or extremity fasciotomies are performed timely in the appropriate cases.

Electrical burns or burns associated with crush injuries may require fasciotomies, in addition to escharotomies, to restore adequate perfusion.

The right common carotid artery originates from the innominate (brachiocephalic) artery. The external landmark is the right sternoclavicular joint. The left common carotid artery originates directly from the aortic arch in the superior mediastinum.

The carotid sheath contains the common and internal carotid arteries, the internal jugular vein, and the vagus nerve. The internal jugular vein lies lateral and superficial to the common carotid artery and vagus nerve. The vagus nerve lies posteriorly, between the artery and the vein. On occasion the vagus nerve may be located anterior to the vessels.

The carotid sheath and its contents are covered superficially by the platysma, anterior margin of the sternocleidomastoid muscle, and the omohyoid muscle. Deep to the vessels are the longus colli and longus capitis muscles. Medial to the carotid sheath is the esophagus and trachea.

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

The facial vein crosses the carotid sheath superficially to enter the internal jugular vein at the level of the carotid bifurcation.

The external carotid artery lies medial to the internal carotid artery for the majority of their course. The first branch of the external carotid artery is the superior thyroid artery located near the carotid bifurcation.

The internal carotid artery does not have any extracranial branches.

At the level of the angle of the mandible, the internal and external carotid arteries are crossed superficially by the hypoglossal nerve (Cranial Nerve XII) and the posterior belly of the digastric muscle. The glossopharyngeal nerve (Cranial Nerve IX) passes in front of the internal carotid artery, above the hypoglossal nerve.

The external carotid arteries terminate in the parotid gland, where they divide into the superficial temporal and maxillary arteries.

At the level of the skull base, the internal carotid arteries cross deep and medial to the external carotid arteries to enter the carotid canal behind the styloid process.

The diaphragm consists of a peripheral muscular segment and central aponeurotic segment. It is attached to the lower sternum, the lower six ribs, and the lumbar spine. During expiration it reaches the level of the nipples. The central tendon of the diaphragm is fused to the base of the pericardium.

It has three major openings, which include the aortic foramen – which allows passage of the aorta, the azygos vein, and the thoracic duct – the esophageal foramen for the esophagus, and the vagus nerves, and finally the vena cava foramen, which contains the inferior vena cava (Figure 19.1).

The arterial supply stems from the phrenic arteries that are direct branches off of the aorta as it exits the hiatus, while the venous drainage is directly into the inferior vena cava.

The diaphragm is innervated by the phrenic nerve, which originates from the C3–C5 nerve roots, courses over the anterior scalene muscle, continues into the mediastinum along the pericardium, and terminates in the diaphragm.

Negative pressure wound therapy (NPWT) provides a closed, moist environment with a regulated level of negative pressure to the wound bed, stimulating perfusion and granulation tissue formation, reduction of local edema, removal of infected fluid, and wound volume contraction.

NPWT can be used in a variety of wounds, including large traumatic wounds, fasciotomy sites, skin grafted wounds or burns, necrotizing soft tissue infections, infected orthopedic hardware or joints, and wounds with exposed or infected bone or tendon.

The recommended optimal negative pressure is 125 mmHg.

Veraflo therapy is a specialized wound dressing that combines negative pressure therapy with automated intermittent wound irrigation. The system instills irrigation fluid into the wound, allows soaking of the wound for determined period of time (usually 10–20 minutes), followed by negative pressure for a defined period of time (usually 3–4 hours). The settings and instillation volume can be customized as needed.

The principles of soft tissue wound management differ significantly based on whether or not infection is present.

• For noninfected soft tissue defects, such as large traumatic wounds, operative management is guided by debridement of dead or ischemic tissues and wound approximation, where possible. Negative pressure therapy may be applied as an adjunct to stimulate granulation tissue formation and wound shrinkage.

• For infected wounds, operative management is guided by debridement of all infected and necrotic tissue. Systemic antibiotics are often necessary for invasive infections. NPWT with intermittent irrigation (VAC Veraflo System) may be locally applied to enhance wound granulation and closure and decrease bacterial burden as well as frequency of debridements.

Appropriate surgical debridement and wound hemostasis are imperative prior to application of NPWT.

NPWT reduces the number of surgical debridements, is more comfortable than the traditional dressings, shortens the time to wound closure and hospital stay, and lowers costs.

The arm is divided into two muscle compartments:

• The anterior compartment, which contains the biceps, the brachialis, and coracobrachialis, all innervated by the musculocutaneous nerve.

• The posterior compartment, which contains the triceps, which is innervated by the radial nerve.

The forearm is divided into three muscle compartments:

• The anterior or flexor compartment, which contains the muscles responsible for wrist flexion and pronation of the forearm. These muscles are innervated by the median and ulnar nerves and receive blood supply mainly from the ulnar artery.

• The posterior or extensor compartment, which contains the muscles responsible for wrist extension. They are innervated by the radial nerve and the blood supply is provided mainly by the radial artery.

• The mobile wad is a group of three muscles on the radial aspect of the forearm that act as flexors at the elbow joint. These muscles are often grouped together with the dorsal compartment. The blood supply is provided by the radial artery and the innervation by branches of the radial nerve.

The hand includes ten separate osteofascial compartments:

• The transverse carpal ligament, over the carpal tunnel, is a strong and broad ligament. The tunnel contains the median nerve and the finger flexor tendons.

The inferior vena cava (IVC) is formed by the confluence of the common iliac veins, just anterior to the L5 vertebral body, and posterior to the right common iliac artery. As it courses superiorly towards the diaphragm, it lies to the right of the lumbar and thoracic vertebral bodies. It enters the thorax at T8, where the right crus of the diaphragm separates the IVC and aorta. In most individuals, there is a small segment of suprahepatic IVC, about 1 cm in length, between the liver and diaphragm, which is amenable to cross clamping.

The IVC receives four or five pairs of lumbar veins, the right gonadal vein, the renal veins, the right adrenal vein, the hepatic veins, and the phrenic veins. It is of practical importance to remember that all lumbar veins are below the renal veins and that between the renal veins and the hepatic veins, besides the right adrenal vein, there are no other venous branches. The left lumbar veins pass behind the abdominal aorta.

The confluence of the renal veins with the IVC lies posterior to the duodenum and the head of the pancreas.

The retrohepatic IVC is about 8–10 cm in length and is adhered to the posterior liver, helping to anchor the liver in place. In this liver “tunnel,” several accessory veins from the caudate lobe and right lobe drain directly into the IVC.

There are three major hepatic veins which drain the liver into the IVC. The extrahepatic portion of these veins is short, measuring about 0.5–1.5 cm in length. The right hepatic vein is the largest. In about 70% of individuals, the middle vein drains into the left hepatic vein to enter the IVC as a single vein.

The thoracic IVC is almost entirely in the pericardium.

The pericardium envelops the heart and attaches to the roots of the great vessels. This includes the ascending aorta, pulmonary artery, pulmonary veins, the last 2–4 cm of superior vena cava, and inferior vena cava.

The phrenic nerves descend on the lateral surfaces of the pericardium.

Acute accumulation of as little as 200 mL of fluid in the pericardial sac may result in fatal cardiac tamponade.

The right atrium is paper thin, approximately 2 mm. The left atrium is slightly thicker at approximately 3 mm.

The right ventricle is approximately 4 mm thick and the left ventricular wall thickness is approximately 12 mm.

The two main coronary arteries, left main and right coronary arteries, originate at the root of the aorta, as it exits the left ventricle. The left main coronary artery divides into the left anterior descending artery (LAD) and the circumflex artery, and provides blood supply to the left heart. The right coronary artery divides into the right posterior descending and acute marginal arteries, supplying blood to the right heart, as well as the sinoatrial and atrioventricular nodes responsible for regulating cardiac rhythm.

Intracranial pressure (ICP) can be measured by a monitor placed into one of the lateral ventricles; in the subarachnoid, subdural, or epidural spaces; or in the brain parenchyma.

ICP monitors should be placed in a patient’s nondominant hemisphere (e.g. right hemisphere in a right-handed person).

Kocher’s point is the external skin landmark most commonly used for insertion; at this point, the catheter trajectory to the frontal horn of the lateral ventricle avoids bridging veins, the superior sagittal sinus, and the motor strip. Kocher’s point is located 2 cm anterior to the coronal suture at the mid-pupillary line (2–3 cm lateral to midline). The coronal suture is approximately 11–12 cm from the base of the nose.

Alternative sites for placement include Keen’s point, which is located 2.5 cm posterior and superior to the top of the ear (posterior-parietal), a Frazier burr hole (occipital-parietal), and Dandy’s point (occipital).

Damage Control (DC) initially referred to surgical techniques used in the operating room. This concept has now been expanded to include damage control resuscitation, which includes permissive hypotension, early empiric blood component therapy, and the prevention and treatment of hypothermia and acidosis.

DC techniques can be applied to most anatomical areas and structures, including the neck, chest, abdomen, vessels, and fractures.

DC surgery is an abbreviated procedure with the goal of rapidly controlling bleeding and contamination so that the initial procedure can be terminated, decreasing surgical stress and allowing a focus on resuscitation. This should be considered in patients with progressive physiologic exhaustion, who are at risk of irreversible shock and death. After physiologic resuscitation, the patient is returned to the operating room for definitive reconstruction and eventual definitive closure of the involved cavity.

The standard indications for DC include:

• Patients in “extremis,” with coagulopathy, hypothermia <35°C, acidosis (base deficit >15 mmol/L), elevated lactate, prolonged hypotension on pressors.

• Bleeding from difficult to control injuries (complex liver injuries, retroperitoneum, mediastinum, neck, and complex vascular).

• In suboptimal environments, such as the rural or battlefield setting or with inexperienced surgeons without the adequate skillset to definitively manage the injury.

For maximum benefit, damage control should be considered early, before the patient reaches the “in extremis” condition! Consider the nature of the injury, the physiologic condition of the patient, comorbid conditions, the available resources, and the experience of the surgeon. The timing of DC surgery is critical in determining the outcome.

The pancreas lies transversely in the retroperitoneum, at the L1–L2 vertebral level, between the duodenum and the hilum of the spleen.

The head of the pancreas lies over the inferior vena cava (IVC), right renal hilum, and the left renal vein at its junction with the IVC.

The uncinate process extends to the left and wraps from around the superior mesenteric vessels. It is in close proximity to the inferior pancreaticoduodenal artery.

The neck of the pancreas lies over the superior mesenteric vessels and the proximal portal vein. The space between the neck and the superior mesenteric vessels is avascular and allows blunt dissection without bleeding. The area to either side of the midline is vascular and should be avoided.

The body of the pancreas lies over the suprarenal aorta and the left renal vessels. It is intimately related to the splenic artery and vein.

The major pancreatic duct (Wirsung) traverses the entire length of the pancreas and drains into the ampulla of Vater, approximately 8 cm below the pylorus. The lesser duct of Santorini branches off the superior aspect of the major duct, at the level of the neck of the pancreas, and drains separately into the duodenum, approximately 2–3 cm proximal to the ampulla of Vater.

The pancreas receives its blood supply from both the celiac artery and the superior mesenteric artery.

• The head of the pancreas and the proximal part of the duodenum receive their blood supply from the anterior and posterior pancreaticoduodenal arcades. These arcades lie on the surface of the pancreas, close to the duodenal loop. Any attempts to separate the two organs results in ischemia of the duodenum.

• The body and tail of the pancreas receive their blood supply mainly from the splenic artery. The splenic artery originates from the celiac artery and courses to the left along the superior border of the pancreas. It follows a tortuous route, with parts of it looping above and below the superior border of the pancreas. It gives numerous small and short branches to the body and tail of the pancreas.

• The splenic vein courses from left to right, superiorly and posteriorly to the upper border of the pancreas, inferiorly to the splenic artery. It is not tortuous like the artery. It joins the superior mesenteric vein, at a right angle, behind the neck of the pancreas, to form the portal vein. The inferior mesenteric vein crosses behind the body of the pancreas and drains into the splenic vein.

The portal vein is formed by the junction of the superior mesenteric and splenic veins, in front of the inferior vena cava and behind the neck of the pancreas.

The common bile duct (CBD) courses posterior to the first part of the duodenum, in front of the portal vein, continues behind the head of the pancreas, often partially covered by pancreatic tissue, and drains into the ampulla of Vater, in the second part of the duodenum.

Severe bleeding in complex pelvic fractures usually originates from branches of the internal iliac artery, presacral venous plexus, fractured bones, and soft tissues. Major iliac vascular injuries are encountered in about 10% of patients with severe pelvic fracture.

The abdominal aorta bifurcates into the two common iliac arteries at the L4-L5 level. The iliac veins are located posterior and to the right of the common iliac arteries. The ureter crosses over the bifurcation of the common iliac artery as it branches into the external and internal iliac arteries.

The internal iliac artery is about 4 cm long. At the level of the greater sciatic foramen, it divides into the anterior and posterior trunks. It supplies numerous splanchnic and muscular branches and terminates as the internal pudendal artery, which is a potential source of hemorrhage in anterior ring disruptions. Hemorrhage following pelvic fracture can occur from any branch.

The most commonly injured internal iliac artery branches (in decreasing order of frequency) are the superior gluteal, internal pudendal, and obturator arteries.

• The superior gluteal artery is the largest branch of the internal iliac artery. It exits the pelvis through the greater sciatic foramen above the piriformis muscle. It provides blood supply to gluteus medius and minimus muscles.

• The internal pudendal artery passes through the greater sciatic foramen, courses around the sciatic spine, and enters the perineum through the lesser sciatic foramen.

• The obturator artery courses along the lateral pelvic wall and exits the pelvis through the obturator canal. In 30% of cases, the obturator artery is perfused from both internal and external iliac arteries, making angioembolization more complicated.

The trachea divides into the right and left main bronchi at the level of the sternal angle (T4 level). The right bronchus is wider, shorter, and more vertical compared to the left. The right bronchus divides into three lobar bronchi, supplying the right upper, middle, and lower lung lobes respectively. The left bronchus divides into two lobar bronchi, supplying the left upper and lower lobes.

The lung has a unique dual blood supply. The pulmonary artery trunk originates from the right ventricle and gives the right and left pulmonary arteries. The right pulmonary artery passes posterior to the aorta and superior vena cava. The left pulmonary artery courses anterior to the left mainstem bronchus. The pulmonary arteries supply deoxygenated blood from the systemic circulation directly to alveoli where gas exchange occurs. These vessels are large in diameter, but supply blood in a low pressure system.

The bronchial arteries arise directly from the thoracic aorta. These vessels are smaller in diameter, and supply the trachea, bronchial tree, and visceral pleura.

The venous drainage of the lungs occurs from the pulmonary veins. They originate at the level of the alveoli. There are two pulmonary veins on the right and two on the left. These four veins join at or near their junction with the left atrium usually within the pericardium. These veins carry oxygenated blood back to the heart for distribution to the systemic circulation.

The lung is covered superiorly, anteriorly, and posteriorly by pleura. At its inferior border the investing layers come into contact forming the inferior pulmonary ligament that connects the lower lobe of the lung, from the inferior pulmonary vein to the mediastinum and the medial part of the diaphragm. It serves to retain the lower lung lobe in position.

The uterus, adnexa, superior bladder, and upper rectum are peritonealized. These structures attach to the pelvis and to one another via a variety of peritoneal reflections and vascular and fibrous ligaments and pedicles.

• Pelvic organs:

  • Reproductive organs: uterus, fallopian tubes, ovaries

  • Rectum: separated from the uterus by the posterior cul-de-sac, or Pouch of Douglas

  • Urinary system:

    • Bladder: shares a common peritoneal lining with the lower uterine segment and cervix

    • Ureters: Common sites for injury during gynecologic procedures:

      • Near the pelvic brim when the ovarian vessels are divided for oophorectomy

      • Along the peritoneum during retroperitoneal pelvic dissection

      • At the cardinal ligament during transection of the uterine arteries, where the ureter crosses under the uterine vasculature (“water under the bridge”)

      • At the lateral angles of the vaginal cuff closure

• Vascular pedicles:

  • Ovarian vessels: branch from the aorta (right ovarian vein drains to IVC and left ovarian vein to the left renal vein) and supply the adnexa

  • Uterine vessels: branch medially from internal iliac vessels and course toward then along the uterus

  • Parametrial/vaginal vessels: branches of the internal iliac arteries that course through the parametria

• Ligaments and peritoneal reflections:

  • Utero-ovarian ligament: connects ovaries to uterus

  • Mesosalpinx: peritoneal reflection that suspends the fallopian tube and contains mesosalpingeal vessels

  • Round ligament: extends from the bilateral uterine cornua and courses through the deep inguinal ring

  • Broad ligament: peritoneal reflection attaching the uterus to the round ligament, adnexa, and sidewall

  • Cardinal ligament: the connection between the lower uterine segment/cervix and pelvic sidewall

  • Uterosacral ligament: connects the base of the cervix to the sacrum