Venous cutdown is a surgical procedure when venous access is difficult, and other procedures like the Seldinger technique, ultrasound-guided venous access, and intraosseous vascular access have failed.

The vein of choice for venous cutdown is the long/great saphenous vein. It is part of the superficial venous collecting system of the lower extremity. It is the preferred vein as the long saphenous vein has anatomic consistency and is superficially located at the ankle anterior to the medial malleolus. It is also the most commonly used conduit for cardiovascular bypass operations.

Origin- in the foot at the confluence of the dorsal vein of the first digit and the dorsal venous arch of the foot
Route- runs ANTERIOR to the medial malleolus and travels up in the medial leg and upper thigh.
Termination: in the femoral vein within the femoral triangle

Regarding the other options:
The short saphenous vein passes posterior to the lateral malleolus.
The dorsalis pedis vein accompanies the dorsalis pedis artery on the anterior foot.
The posterior tibial vein is part of the deep venous system accompanying the posterior tibial artery. There is no significant sural vein (there is a sural nerve), but the sural veins accompany the sural arteries and drain to the popliteal vein.

The adrenal medulla comprises chromaffin cells (pheochromocytes), which are functionally equivalent to postganglionic sympathetic neurons. They synthesize, store and release the catecholamines noradrenaline (norepinephrine) and adrenaline (epinephrine) into the venous sinusoids.
The majority of the chromaffin cells synthesize adrenaline.

The prostate is separated from the rectum by the Denonvilliers fascia (rectoprostatic fascia).

Waldeyers fascia functions to separate the rectum and the sacrum.

The superficial inguinal ring is an opening in the aponeurosis of the external oblique muscle, just above and lateral to the pubic crest.

The superficial ring resembles a triangle more than a ring with the base lying on the pubic crest and its apex pointing towards the anterior superior iliac spine. The sides of the triangle are crura of the opening in the external oblique aponeurosis. The lateral crura of the triangle is attached to the pubic tubercle. The medial crura of the triangle is attached to the pubic crest.

The external oblique aponeurosis forms the anterior wall of the inguinal canal and also the lateral edge of the superficial inguinal ring. The rectus abdominis lies posteromedially, and the transversalis posterior to this.

The inguinal canal is a passage in the lower anterior abdominal wall just above the inguinal ligament. It transmits the following structures:
1. genital branch of genitofemoral nerve
2. ilioinguinal nerve
3. spermatic cord (males only)
4. round ligament of the uterus (females only)

The ilioinguinal is a direct branch of the first lumbar nerve. The ilioinguinal nerve enters the inguinal canal via the abdominal musculature (and not through the deep (internal) inguinal ring) and exits through the superficial (or external) inguinal ring.

The openings for the other nerves in the answer options are:
Sciatic nerve – exits the pelvis via the greater sciatic foramen
Obturator nerve – descends into pelvis via the obturator foramen
Femoral nerve – descends from the abdomen through the pelvis behind the inguinal canal

The Iliohypogastric nerve also arises from the first lumbar root with the ilioinguinal nerve but pierces the transversus abdominis muscle posteriorly, just above the iliac crest, and continues anteriorly between the transversus abdominis and the internal abdominal oblique muscles.

The tenth cranial nerve (vagus nerve) has both sensory and motor divisions.

It emerges from the anterolateral surface of the medulla in a groove between the olive and the inferior cerebellar peduncle as a series of 8-10 rootlets . It leaves the skull through the middle compartment of the jugular foramen and descends within the carotid sheath between the internal carotid artery and internal jugular vein. The right vagus crosses in front of the first part of the subclavian artery. It gives off the right recurrent laryngeal nerve at this point.

The left recurrent laryngeal nerve passes around the ligamentum arteriosum.

The external laryngeal nerve supplies the cricothyroid muscle while the recurrent laryngeal nerve supplies the other laryngeal muscles.

The cranial part of the accessory nerve supplies all the muscles of the palate, via the pharyngeal plexus and the pharyngeal branch of the vagus nerve, except the tensor veli palatini which is supplied by the mandibular branch of the trigeminal nerve.

The Sternothyroid, Sternohyoid, and Omohyoid muscles are supplied by the ansa cervicalis while the thyrohyoid muscle is supplied by the hypoglossal nerve.

The AV node has an intrinsic firing rate of 40-60 beats per minute which is clinically significant in cases of damage to the conducting pathways as patients continue to have a ventricular rate of 40-60. Patients who have an AV node supplied by the right coronary are said to be right dominant. The remaining 10% are left dominant and supplied by the left circumflex.

The right coronary artery supplies the right atrium, right ventricle, interatrial septum, and the inferior posterior third of the interventricular septum. It also supplies the atrioventricular node + sinoatrial node in most patients. The posterior descending artery supplies the posterior third of the interventricular septum.

The heart receives blood supply from coronary arteries. The right and left coronary arteries branch off the aorta and supply oxygenated blood to all heart muscle parts.

The left main coronary artery branches into:
1. Circumflex artery – supplies the left atrium, side, and back of the left ventricle. The left marginal artery arises from the left circumflex artery. It travels along the obtuse margin of the heart.
The left marginal artery, a branch of the circumflex artery, supplies the left ventricle.
2. Left Anterior Descending (LAD) artery – supplies the front and bottom of the left ventricle and front of the interventricular septum

The right coronary artery branches into:
1. Right marginal artery
2. Posterior descending artery

The inferior vena cava is formed by the union of the right and left common iliac veins. This occurs at the L5 vertebral level. The IVC courses along the right anterolateral side of the vertebral column and ascends through the central tendon of the diaphragm at the T8 vertebral level.

The taeniae coli are the three outer muscular bands of the cecum, ascending colon, transverse colon, and descending colon.

The taeniae coli converge at the base of the appendix in the cecum where they form a complete longitudinal layer. In the ascending and descending colon, the bands are located anteriorly, posteromedially, and posterolateral.

The ascending cervical artery lies media the phrenic nerve on scalenus anterior and can easily be mistaken for the phrenic nerve at operation.

The phrenic nerve passes across scalenus anterior and medius inferiorly.

The subclavian artery is separated from the vein by the scalenus anterior.

The brachiocephalic vein is formed at the medial border of scalenus anterior by the subclavian vein and the internal jugular vein.

Emerging from the lateral border of scalenus anterior are the trunks of the brachial plexus .

The external iliac artery is the larger of the two branches of the common iliac artery. It forms the main blood supply to the lower limbs. The common iliac bifurcates into the internal and external iliac artery anterior to the sacroiliac joint.

The external iliac artery courses on the medial border of the psoas major muscles and exits the pelvic girdle posterior to the inguinal ligament. Here, midway between the anterior superior iliac spine and the pubic symphysis, the external iliac artery becomes the femoral artery and descends along the anteromedial part of the thigh in the femoral triangle.

The pectineus forms the posterior border of the femoral canal.
The femoral vein forms the lateral border of the femoral canal.
The medial border of the adductor longus muscle forms the medial wall of the femoral triangle.
The medial border of the sartorius muscle forms the lateral wall of the femoral triangle.

At the ankle joint, midway between the malleoli, the anterior tibial artery changes names, becoming the dorsalis pedis artery (dorsal artery of the foot).

The dorsalis pedis artery is palpated against the underlying tarsals, immediately lateral to the tendon of extensor hallucis longus, from the midpoint between the malleoli to the proximal end of the first intermetatarsal space.

The popliteal artery forms the anterior tibial artery.
The tibioperoneal trunk is a branch of the popliteal artery.
The peroneal artery (also known as the fibular artery) supplies the lateral compartment of the leg.
The external iliac artery is formed from the common iliac artery at the level of the pelvis.

The duodenojejunal flexure is the point where the duodenum becomes the jejunum.

The ligament of Treitz, which arises from the right crus of diaphragm, provides suspension for support.

Between the ileum and the caecum is the ligament of Treves.

The superior mesenteric artery branches from the abdominal aorta just 1-2 cm below the origin of the celiac trunk. It lies posterior to the body of the pancreas and splenic vein and is separated from the aorta by the left renal vein. It passes forwards and inferiorly, anterior to the uncinate process of the pancreas and the third part of the duodenum, to enter the root of the small bowel mesentery and supply the midgut.

The important landmarks of vessels arising from the abdominal aorta at different levels of vertebrae are:

T10 – oesophageal opening in the diaphragm

T12 – Coeliac trunk, aortic hiatus in the diaphragm

L1 – Left renal artery

L2 – Testicular or ovarian arteries

L3 – Inferior mesenteric artery

L4 – Bifurcation of the abdominal aorta

Foramen ovale, ductus arteriosus (DA) and ductus venosus (DV) are the three important cardiac shunts in-utero.

At birth the umbilical vessels constrict in response to stretch as they are clamped. Blood flow through the ductus venosus (DV) decreases but the DV closes passively in 3-10 days.

As the pulmonary circulation is established, there is a drastic fall in pulmonary vascular resistance and an increased pulmonary blood flow. This increases flow and pressure in the Left Atrium that exceeds that of the right atrium. The difference in pressure usually leads to the IMMEDIATE closure of the foramen ovale.

The DA is functionally closed within the first 36-hours of birth in a healthy full-term newborn. Subsequent endothelial and fibroblast proliferation leads to permanent anatomical closure within 2 – 3 weeks.

Oxygenated blood from the placenta passes via the umbilical vein to the liver. Blood also bypasses the liver via the ductus venosus into the inferior vena cava (IVC). The Crista dividens is a tissue flap situated at the junction of the IVC and the right atrium (RA). This flap directs the oxygen-rich blood, along the posterior aspect of the IVC, through the foramen ovale into the left atrium (LA).

The Eustachian valve also known as the valve of The IVC is a remnant of the crista dividens.

Specific knowledge of the anatomical relationship is required to address this examination question.

The first rib is small and thick and contains a single facet that articulates at the costovertebral joint. It consist of a head, neck and shaft but a discrete angle is deficit. Along the side the shaft is indented with a groove for the subclavian artery and the lower brachial plexus trunk. Front to the scalene tubercle is a space for the subclavian vein.

The first rib has the scalenus front muscle joined to the scalene tubercle, isolating the subclavian vein (anteriorly) from the subclavian artery (posteriorly). This anatomical relationship is of major significance with respect to subclavian vein cannulation.

The 1st rib has the following relationships:

superior: lower trunk of the brachial plexus, subclavian vessels, clavicle.

inferior: intercostal vessels and nerves

posterior and inferior: pleura

anterior: sympathetic trunk (over neck)

superior intercostal artery, ventral T1 nerve root

The mitral valve is the valve between the left atrium and left ventricle. It opens when the heart is in diastole (relaxation) which allows blood to flow from the left atrium to the left ventricle. In systole (contraction), the mitral valve closes to prevent the backflow of blood from the left ventricle to the left atrium.

The mitral valve is located posterior to the sternum at the level of the 4th costal cartilage. It is best auscultated over the cardiac apex, where its closure marks the first heart sound.

The mitral valve anatomy is composed of five main structures:
1. Left atrial wall – the myocardium of the left atrial wall extends over the posterior leaflet of the mitral valve. (left atrial enlargement is one of the causes for mitral regurgitation)
2. Mitral annulus – a fibrous ring that connects with the anterior and posterior leaflets. It functions as a sphincter that contracts and reduces the surface area of the valve during systole (Annular dilatation can also lead to mitral regurgitation)
3. Mitral valve leaflets (cusps) – The mitral valve is the only valve in the heart with two cusps or leaflets. One anterior and one posterior.
i. The anterior leaflet is located posterior to the aortic root and is also anchored to the aortic root.
ii. The posterior leaflet is located posterior to the two commissural areas.
4. Chordae tendinae – The chordae tendinae connects both the cusps to the papillary muscles.
5. Papillary muscles – These muscles and their cords support the mitral valve, allowing the cusps to resist the pressure developed during contractions (pumping) of the left ventricle

The anterior and posterior cusps are attached to the chordae tendinae which itself is attached to the left ventricle via papillary muscle.

A peripherally inserted central catheter (PICC) line is a long, thin tube inserted into the vein of a patient’s arm to gain access to the large central veins near the heart. PICC line is indicated for parenteral nutrition or to deliver medications. They can be used for medium-term venous access, defined as anywhere between several weeks to 6 months.

The veins of choice for PICC are:
1. Basilic
2. Brachial
3. Cephalic
4. Medial cubital vein

The vein of choice is the right basilic vein as it has a large circumference and is located superficially. It has the most straight route to the final destination of PICC (SVC or Right atrium). It courses through the axillary vein, then the subclavian, and finally settles into the SVC. It also has the least number of valves and a shallow angle of insertion when compared to the other veins.

The basilic vein drains the medial end of the dorsal arch of the upper limb, passes along the medial aspect of the forearm, and pierces the deep fascia at the elbow. The basilic vein joins the venae comitantes of the brachial artery to form the axillary vein at the elbow.
The posterior circumflex humeral vein is encountered before the axillary vein. However, a PICC line is unlikely to enter this structure because of its entry angle into the basilic vein.

The cephalic vein is a superficial vein that runs through the forearm and the arm, before draining into the axillary vein where it terminates.

The small and large intestinal walls are composed of the following common layers:
1. Mucosa
2. Submucosa
3. Muscularis Externa
4. Adventitia

Intestinal villi are highly vascular projections of the mucosal surface that cover the entire small intestinal mucosa. They increase the lumen’s surface area, which aids in absorption and digestion, the primary functions of the small intestine. Villi are large and most abundant in the duodenum and jejunum.

In both the small and large intestines, the muscularis mucosae are found within the mucosa. The myenteric nerve plexus is found innervating the muscularis externa. The mucosa is lined with columnar epithelial cells, and goblet cells may be present to secrete mucins.

The costal elements of the seventh cervical vertebrae form projections known as cervical ribs, which are present in approximately 0.5% – 1 % individuals.

A cervical rib commonly comprises of a head, neck and tubercle. The body of the rib varies from person to person. It extends into the posterior triangle of the neck, where it is either free anteriorly, or attached to the first rib / sternum.

Patients with a cervical rib mostly are asymptomatic and it is usually diagnosed as an incidental finding on chest x-ray. However, in some cases, the subclavian artery and the lower trunk of the brachial plexus are compressed where they pass over the cervical rib. This leads to a condition known as ”neurovascular compression syndrome,” in which these neurovascular structures are compressed between the cervical rib and scalenus anterior.

The most common cause of neurogenic symptoms in approximately 80% of the patients with cervical rib is neck trauma.

In most cases, the tingling, numbness and impaired circulation to the upper limb appears only after puberty. This is because the neck elongates, and the shoulders droop slightly.

The deep inguinal ring is the entrance of the inguinal canal. It is an opening in the transversalis fascia around 1 cm above the inguinal ligament. Therefore, the superolateral wall is made by the transervalis fascia.

The inferior epigastric vessels run medially to the deep inguinal ring forming its inferomedial border.

The inguinal canal extends obliquely from the deep inguinal ring to the superficial inguinal ring.
An indirect inguinal hernia arises through the deep inguinal ring lateral to the inferior epigastric vessels.

The patient likely suffers from pulmonary embolism due to her history of frequent international travels. A filter is placed in the inferior vena cava to decrease the risk of future episodes of pulmonary embolism. The IVC filter is a small, wiry device that can catch blood clots and stop them from going into the heart and lungs. Your IVC is a major vessel that brings deoxygenated blood from the lower body to the heart, from where it is pumped into the lungs.

The filter is placed via a thin catheter inserted into the femoral vein in the groin. The catheter is gently moved up into your IVC, and a filter is introduced.

The IVC is a retroperitoneal organ.

The porta hepatis is a fissure in the inferior surface of the liver. All the neurovascular structures that enter and leave the porta hepatis are:
1. hepatic portal vein
2. hepatic artery
3. hepatic ducts
4. hepatic nerve plexus (It contains the sympathetic branch to the liver and gallbladder and the parasympathetic, hepatic branch of the vagus nerve.)

These structures supply and drain the liver. Only the hepatic vein is not part of the porta hepatis.
The porta hepatis is also surrounded by lymph nodes, that may enlarge to produce obstructive jaundice.
These structures divide immediately after or within the porta hepatis to supply the functional left and right lobes of the liver.

The cystic duct lies outside the porta hepatis and is an important landmark in laparoscopic cholecystectomy.

The coeliac axis refers to one of the splanchnic arteries located within the abdomen.

It arises from the aorta almost horizontally at the level of the T12 vertebrae

The inguinal triangle of Hesselbach’s is an important clinical landmark on the posterior wall of the inguinal canal. It has the following relations:
Inferiorly – medial third of the inguinal ligament
Medially – lower lateral border of the rectus abdominis
Laterally – inferior epigastric vessels

Direct inguinal hernia is when the bowel bulges directly through the abdominal wall. These hernias usually protrude through Hesselbach’s triangle

The deep inguinal ring lies approximately 1.5-2cm above the midpoint of the inguinal ligament, the halfway point between the anterior superior iliac spine and the pubic tubercle, next to the epigastric vessels.

It is an important point in determining the nature of an inguinal hernia (direct or indirect). The patient is asked to cough after the hernia is reduced, with pressure applied to the deep inguinal ring. The hernia reappearing indicates it is direct, moving through the posterior wall of the inguinal canal.

Inferior and lateral to the pubic tubercle is the normal anatomical position of the neck of a femoral hernia.

Superior and medial to the pubic tubercle is the site of the superficial inguinal ring, and the normal anatomical position of the neck of an inguinal hernia.

The mid-inguinal point is located halways between the pubic symphysis and the anterior superior iliac spine. It is the surface marking for taking the femoral pulse.

The inferior mesenteric artery originates 3-4 cm above the bifurcation of the abdominal aorta. The left colic artery branches off the inferior mesenteric artery, arising close to its origin from the abdominal aorta. Other branches of IMA include the three sigmoid arteries that supply the sigmoid colon.

The left colic artery branches off from IMA to supply the distal 1/3 of the transverse colon and the descending colon. It moves upwards posterior to the left colic mesentery and then travels anteriorly to the psoas major muscle, left ureter, and left internal spermatic vessels, before dividing into ascending and descending branches.

The pectinate muscles (musculi pectinati) are parallel muscular ridges that extend anterolaterally on the right atrial walls. The most prominent pectinate muscle, which forms the bridge of the sulcus terminalis internally, is the taenia sagittalis (second crest or septum spurium).

In the left atrium, the pectinate muscles are confined to the inner surface of its atrial appendage. They tend to be fewer and smaller than in the right atrium. This is due to the embryological origin of the auricles, which are the true atria.

Pectinate muscles of the atria are different from the trabeculae carneae, which are found on the inner walls of both ventricles.

The interior of the right atrium has five distinct features:
1. Sinus venarum – smooth, thin-walled posterior part of the right atrium where the SVC, IVC, and coronary sinus open
2. Musculi pectinati – a rough anterior wall of pectinate muscles
3. Tricuspid valve orifice – the opening through which the right atrium empties blood into the right ventricle
4. Crista terminalis – separates the rough (musculi pectinati) from the smooth (sinus venarum) internally
5. Fossa ovalis – a thumbprint size depression in the interatrial septum, which is a remnant of the oval foramen and its valve in the foetus

The left gastric artery is the smallest branch that originates from the coeliac trunk—the coeliac trunk branches of the abdominal aorta at the vertebral level of T12.

The left gastric artery runs along the superior portion of the lesser curvature of the stomach. A peptic ulcer that is serious enough to erode through the stomach mucosa into a branch of the left gastric artery can cause massive blood loss in the stomach, leading to hematemesis. The patient also takes Naproxen, a non-steroidal anti-inflammatory drug that is a common cause for peptic ulcers in otherwise healthy patients.

The left gastric artery is responsible for 85% of upper GI bleeds. In cases refractory to initial treatment, angiography is sometimes needed to embolise the vessel at its origin and stop bleeding. During an angiogram, the radiologist will enter the aorta via the femoral artery, ascend to the level of the 12th vertebrae and then enter the left gastric artery via the coeliac trunk.

The important landmarks of vessels arising from the abdominal aorta at different levels of vertebrae are:

T12 – Coeliac trunk

L1 – Left renal artery

L2 – Testicular or ovarian arteries

L3 – Inferior mesenteric artery

L4 – Bifurcation of the abdominal aorta