Anatomy Inguinal Region 2024 - PDF

INGUINAL REGION/GROIN Dr Viktoriia Yerokhina, Lecturer in Medical Sciences [email protected] ANAT.23 - Ant. Abdominal Wall LEARNING OUTCOMES ANAT.23.10 - Describe the anatomy of the superficial and deep inguinal rings. ANAT.23.11 -...

INGUINAL REGION/GROIN Dr Viktoriia Yerokhina, Lecturer in Medical Sciences [email protected] ANAT.23 - Ant. Abdominal Wall LEARNING OUTCOMES ANAT.23.10 - Describe the anatomy of the superficial and deep inguinal rings. ANAT.23.11 - Describe the process of testicular descent into the scrotal sac. ANAT.23.12 - Describe the structure and contents of the spermatic cord. ANAT.23.13 - Describe the boundaries of the inguinal triangle (of Hesselbach) and its clinical significance. ANAT.23.14 - Compare and contrast the anatomy of a direct and an indirect inguinal hernia. ANAT.23.15 - Describe the fate of the processes vaginalis and its contribution to an indirect inguinal hernia. ANAT.23.16 - Explain the advantage of performing vertical surgical incisions on the midline. ANAT.23.17 - Compare and contrast the location of an epigastric versus an umbilical hernia. ANAT.23.18 - Describe the cremasteric reflex arc following stimulation of the anterior scrotal sac. ANAT.23.19 - Explain why a blow to the testis is felt around the umbilicus. ANAT.23.20 - Explain why the initial pain of appendicitis is felt around the umbilicus. ANAT.23.21 - List the dermatomes which overlie the xiphoid process, umbilicus and pubis. ANAT.27 - Inguinal Region ANAT.27.01 - Describe the inguinal ligament and its attachment sites. ANAT.27.02 - Describe the anatomy of the superficial and deep inguinal rings. ANAT.27.03 - Describe the process of testicular descent into the scrotal sac. ANAT.27.04 - Describe the structure and contents of the spermatic cord. ANAT.27.05 - Describe boundaries of the inguinal triangle (of Hesselbach) and its clinical significance. ANAT.27.06 - Compare and contrast the anatomy of a direct and an indirect inguinal hernia. ANAT.27.07 - Describe the fate of the processus vaginalis and its contribution to an indirect inguinal hernia. ANAT.27.08 - Define a varicocele. ANAT.27.09 - Describe the cremasteric reflex arc following stimulation of the anterior scrotal sac. ANAT.27.10 - Explain why the blow to the testis is felt around the umbilicus.  INGUINAL REGION/GROIN Groin (inguinal region) is the area of junction between the anterior abdominal wall and the thigh. It extends between the anterior superior iliac spine and the pubic tubercle. Clinically the inguinal region includes area along and around the inguinal ligament.  INGUINAL REGION/GROIN Importance: anatomically: region where structures exit from and enter into the abdominal cavity; clinically: pathways of exit and entry are potential sites of herniation (inguinal, femoral). Inguinal hernias account for 75% of all hernias of the body. Key structures: inguinal ligament, inguinal canal, and femoral canal. INGUINAL REGION/GROIN  INGUINAL LIGAMENT A strengthened caudal margin of the aponeurosis of the external oblique. It is stretched between the superior anterior iliac spine and pubic tubercle. *Inguinal ligament is not a real ligament but rather a thickening of the aponeurosis of the external oblique.  EXTENSIONS/EXPANSIONS OF THE INGUINAL LIGAMENT Lacunar ligament (Gimbernat’s Ligament) Pectineal ligament (Ligament of Cooper) Reflected part of inguinal ligament Ilioinguinal ligament  INGUINAL CANAL An oblique intermuscular passage about 4 cm long lying above the medial half of the inguinal ligament. Passes through the anterior abdominal wall in the region of the groin. It is directed downward, forward, and medially.  INGUINAL CANAL – CANALIS INGUINALIS Extends from deep inguinal ring (an oval opening in the fascia transversalis) to the superficial inguinal ring (triangular gap in the external oblique aponeurosis). Allows communication between the subperitoneal space and the subcutaneous tissue of the groin. During development, the testes descend through the inguinal canal to reach their definitive position in the scrotum.  CONTENT OF INGUINAL CANAL In males: spermatic cord In females: round ligament of the uterus + Both sexes: Ilioinguinal nerve Genital branch of genitofemoral nerve  BOUNDARIES OF INGUINAL CANAL 1. Inguinal canal 1.1 Deep inguinal ring (anulus inguinalis profundus) – entrance 1.2 Superficial inguinal ring (anulus inguinalis superficialis) – exit BOUNDARIES OF INGUINAL CANAL  WALLS OF INGUINAL CANAL 2. Ventrally: aponeurosis of the external oblique 3. Dorsally: transversalis fascia – covers the gap between the fused inferior margins of internal oblique and transversus abdominis and the inguinal ligament 4. Cranially: inferior margins of internal oblique and transversus abdominis (their aponeusorises fuse medially to form the inguinal falx, or conjoint tendon, which runs along the lateral margin of the rectus abdominis and inserts on the pecten pubis) 5. Caudally: inguinal ligament of Poupart  CRYPTORCHIDISM Failure of one or both testicles to descend to their natural position in the scrotum Descent of the testes: complete by week 33 Undescended testes are often located in the inguinal canal. Epidemiology: most common congenital anomaly of the genitourinary tract Etiology: unknown, possibly multifactorial Risk factors Prematurity Low birth weight Variants Inguinal testis: testicle is located between the external and internal inguinal ring, preventing adequate mobilization (90% of cases) Intra-abdominal testis: testicle is located proximal to the internal inguinal ring Ascending testes Testicular retraction into the scrotal pouch is possible However, the testes immediately retract into the groin after manipulation.  LAYERS OF THE INGUINAL CANAL From outside to inside: 1. Superficial inguinal ring (anulus inguinalis superficialis) – aperture in the aponeurosis of the external oblique; the end of the inguinal canal and is superior to the pubic tubercle 1.1 Medial crus – medial fibrous margin of the ring 1.2 Lateral crus – lateral fibrous margin 1.3 Intercrural fibers – fibers strengthening the aponeurosis on the craniolateral margin of the ring  LAYERS OF THE INGUINAL CANAL 2. Space under the inguinal falx 2.1 Inguinal falx / conjoint tendon of Henle – the caudal fused margin of the internal oblique and transversus abdominis 2.2 Interfoveolar ligament of Hesselbach – passes ventral to the inferior epigastric vessels 3. Deep inguinal ring – formed by the transveralis fascia, as it extends into the inguinal canal as the internal spermatic fascia – bound laterally by the interfoveolar ligament and inferior epigastric vessel  SPERMATIC CORD - FUNICULUS SPERMATICUS A collection of structures that pass through the inguinal canal to and from the testis. It begins at the deep inguinal ring lateral to the inferior epigastric artery and ends at the testis. Venous pampiniform plexus lowers the temperature inside the spermatic cord, which is necessary for the proper maturation of spermatozoa. Layers of the abdominal wall continue over the spermatic cord and the scrotum, forming their coverings. SPERMATIC CORD - FUNICULUS SPERMATICUS  CONTENT OF SPERMATIC CORD 1. Ductus deferens, in the posterior part. 2. Three arteries: a) Testicular artery, from abdominal aorta. b) Cremasteric artery, from inferior epigastric artery. c) Artery to ductus deferens, from inferior vesical artery. 3. Veins - pampiniform venous plexus. 4. Lymphatics from testis 5. Nerves, genital branch of genitofemoral nerve and sympathetic fibers. 6. Remains of processus vaginalis -– a remnant of the peritoneal fold.  CONTENT OF SPERMATIC CORD Transverse section of the spermatic cord showing its covering content CONTENT OF SPERMATIC CORD - LYMPHATICS  COVERINGS OF SPERMATIC CORD From within outward: 1. Internal spermatic fascia, derived from fascia transversalis. 2. Cremasteric fascia consisting of loops of skeletal muscle fibres derived from internal oblique muscle, united by areolar tissue. 3. External spermatic fascia, derived from aponeurosis of external oblique muscle. A 35-year-old man is admitted to the hospital with an indirect inguinal hernia. During an open hernioplasty (in contrast to a laparoscopic procedure), the spermatic cord and the internal abdominal oblique muscles are identified. Which component of the spermatic cord is derived from the internal abdominal oblique muscle? A. External spermatic fascia B. Cremaster muscle C. Tunica vaginalis D. Internal spermatic fascia E. Dartos fascia COVERINGS OF SPERMATIC CORD  VARICOCELE Abnormal enlargement and tortuosity of the pampiniform plexus in the scrotum due to proximal obstruction of the spermatic vein Epidemiology Most common cause of scrotal enlargement in men Found in 15% of healthy men Etiology Idiopathic/primary The cause of primary varicocele is not fully understood. Left testicle is most commonly affected (85% of cases) The longer course of the left spermatic vein and its insertion at a 90° angle into the left renal vein predisposes to slower drainage and increased hydrostatic pressure. Left renal vein passes between the aorta and superior mesenteric artery → ↑ susceptibility of the renal vein to compression (nutcracker phenomenon) → ↑ intravascular pressure in the left spermatic vein → varicocele formation Symptomatic/secondary Caused by a mass in the retroperitoneal space obstructing venous drainage into IVC (right- sided varicocele) or left renal vein (left-sided varicocele) or a thrombotic event (e.g., pampiniform plexus obstruction in renal cell carcinoma) Persist in the supine position due to a physical obstruction to blood flow within the spermatic vein.  VARICOCELE Soft bands/strands are palpable in the upper pole of the affected scrotum The appearance of a “bag of worms” on the radiograph is characteristic of a varicosity of the pampiniform venous plexus.  CREMASTERIC REFLEX Reflex is elicited by stroking the medial, inner part of the thigh. A normal response is contraction of the cremaster muscle that pulls up the testis on the same side of the body. Cremasteric reflex may be absent with testicular torsion, upper and lower motor neuron disorders, as well as a spine injury of L1-L2. It can also occur if the ilioinguinal nerve has accidentally been cut during a hernia repair.  INTERNAL SURFACE OF THE ANTERIOR ABDOMINAL WALL The internal surface of the anterior abdominal wall is lined by parietal peritoneum and is decorated by five folds and six depressions.  FOLDS OF INTERNAL SURFACE OF THE ANTERIOR ABDOMINAL WALL 1. Median umbilical fold (plica umbilicalis mediana) – an unpaired fold formed by the median umbilical ligament (a remnant of the urachus) 2. Medial umbilical fold (plica umbilicalis medialis) – a paired fold formed by the medial umbilical ligament 3. Lateral umbilical fold (plica umbilicalis lateralis) – a paired fold formed by the inferior epigastric vessels.  DEPRESSIONS OF INTERNAL SURFACE OF THE ANTERIOR ABDOMINAL WALL 4. Supravesical fossa (fossa supravesicalis) – between the median and medial umbilical folds 5. Medial inguinal fossa / inguinal triangle of Hesselbach (fossa inguinalis medialis / trigonum inguinale) – between the medial and lateral umbilical folds 6. Lateral inguinal fossa / deep inguinal ring (fossa inguinalis lateralis / anulus inguinalis profundus) – laterally to the lateral umbilical fold.  INGUINAL TRIANGLE (HESSELBACH’S TRIANGLE) Situated deep to the posterior wall of the inguinal canal  seen on the inner aspect of the lower part of the anterior abdominal wall. Medial: lower 5 cm of the lateral border of the rectus abdominis muscle Lateral: inferior epigastric artery Inferior: medial half of the inguinal ligament. Floor of the triangle is covered by the peritoneum, extraperitoneal tissue, fascia transversalis.  COMMON SITES OF HERNIA In the areas where the abdominal wall is thinner it is possible for the abdominal structures to go through (prolapse). Hernia is an outpouching of the parietal peritoneum through a preformed or secondarily established opening. A hernia defect is a canal or ring between the abdominal wall and the hernial sac, formed by the parietal peritoneum and pathological CT. Hernia can contain the intestines, omentum and other abdominal organs.  INGUINAL HERNIA 1.1 Direct – pass directly through the medial inguinal fossa and the superficial inguinal ring – it is possible to feel the pulse of the inferior epigastric artery – acquired (develop aft er birth) – may enter the scrotum in men (scrotal hernia) 1.2 Indirect – pass through the lateral inguinal fossa – deep inguinal ring and the superficial inguinal ring – it is not possible to feel the pulse on the inferior epigastric artery – can be congenital or acquired – in men, it can pass through the inguinal canal into the scrotum (scrotal hernia) Indirect inguinal hernia is the most common of the two types of inguinal hernias and is much more common in men than in women.  INGUINAL HERNIA Indirect inguinal hernia protrudes lateral to the inferior epigastric vessels through the deep inguinal ring Direct inguinal hernia protrudes medial to the inferior epigastric vessels through a defect in the posterior wall of the inguinal canal. A 79-year-old man is brought to the emergency department because of a 1-hour history of severe groin pain, nausea, and vomiting. He reports that he has had a groin swelling that worsens with standing, coughing, and straining for the past 3 months, but he has not sought medical attention for it. Examination shows a nonreducible bulging mass of the left groin that is severely tender to palpation; the overlying skin is erythematous. Abdominal ultrasound shows protrusion of abdominal contents through a defect medial to the inferior epigastric vessels. Which of the following is the most likely site of protrusion of the patient's groin mass? A. Inguinal triangle B. Linea alba C. Rectus abdominis muscle D. Deep inguinal ring E. Inferior lumbar triangle A 45-year-old man was admitted to the hospital with groin pain and a palpable mass just superior to the inguinal ligament. The patient was diagnosed with a hernia and a surgical repair was performed. During the operation the surgeon found a loop of intestine passing through the deep inguinal ring. Which type of hernia was this? A. Direct inguinal B. Umbilical C. Femoral D. Lumbar E. Indirect inguinal INGUINAL HERNIA  INGUINAL HERNIA Uncomplicated inguinal hernia: an inguinal hernia that is completely reducible and not associated with signs of bowel obstruction or strangulation Complicated inguinal hernia: an inguinal hernia that is either irreducible (incarcerated) or associated with mechanical bowel obstruction and/or strangulation Occult inguinal hernia: an inguinal hernia that is not identifiable on physical examination. A 54-year-old man is admitted to the hospital with severe back pain. Radiographic examination suggests carcinoma of the left kidney blocking the drainage of the testicular vein. Which of the following conditions will be most likely associated with these signs? A. Varicocele B. Rectocele C. Cystocele D. Hydrocele E. Hypospadias A 45-year-old man is admitted to the hospital with a massive hernia that passes through the inguinal triangle (of Hesselbach). Which of the following structures is used as a landmark to distinguish a direct inguinal hernia from an indirect inguinal hernia? A. Inferior epigastric vessels B. Femoral canal C. Inguinal ligament D. Rectus abdominis muscle (lateral border) E. Pectineal ligament  SUBINGUINAL SPACE (PELVIFEMORAL SPACE) Space between the inguinal ligament and the hip bone is called pelvifemoral/subinguinal space. Muscles (psoas major and iliacus) and neurovascular structures of posterior abdominal wall/pelvis pass into the femoral region of the thigh through this space. This space is divided by the ilioinguinal ligament/arch into two parts: a) Large lateral part called lacuna musculorum. b) Small medial part called lacuna vasculorum. SUBINGUINAL SPACE (PELVIFEMORAL SPACE)  SUBINGUINAL SPACE (PELVIFEMORAL SPACE) Iliacus and psoas muscles, and femoral and lateral cutaneous nerves of thigh pass through the lacuna musculorum behind the fascia iliaca. External iliac vessels in abdomen become femoral vessels as they pass through the medial part of the subinguinal space—the lacuna vasculorum. IMPORTANT ABDOMINAL AND INGUINAL INCISION SITES AND POTENTIAL INDICATIONS The choice of incision site depends on the indication for and urgency of surgery.  MCQ FOR SELF-CONTROL https://forms.gle/4QEeD1yUP3FzfUVq5 REFERENCES