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Femoral Region and Hernias: Anatomy

A femoral hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias is an uncommon type of groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias in which intra-abdominal contents herniate under the inguinal ligament and through the femoral ring into the femoral canal. More common in adults than in children, femoral hernias usually present with swelling Swelling Inflammation that protrudes into the femoral triangle (inferiorly to the inguinal ligament and medial to the femoral vein). Although uncommon, femoral hernias are frequently associated with complications, secondary to the small size of the canal, leading to hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias incarceration Incarceration Inguinal Canal: Anatomy and Hernias and/or strangulation Strangulation Inguinal Canal: Anatomy and Hernias.

Last updated: 9 Mar, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Anatomy

Femoral ring

The femoral ring is the proximal or abdominal/pelvic opening of the femoral canal. 

Boundaries:

  • Anterior: inguinal ligament
  • Posterior: pectineal ligament and muscle
  • Medial: lacunar ligament
  • Lateral: medial border of the femoral vein
Femoral ring

Boundaries of the femoral ring and canal in relation to the femoral vessels and nerve

Image by Lecturio.

Femoral canal

The femoral canal is a cylindrical space, making up the medial compartment enclosed within the femoral sheath.

  • Same boundaries as the femoral ring
  • Extends 1–2 cm into the thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy
  • Contains loose areolar tissue, lymphatic vessels Lymphatic Vessels Tubular vessels that are involved in the transport of lymph and lymphocytes. Lymphatic Drainage System: Anatomy, and lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy
  • The femoral sheath is a fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis that encloses the contents of the femoral triangle (except the femoral nerve), each within its own compartment.
Femoral canal

Closeup of the femoral triangle featuring the location of the femoral canal in relation to the neighboring structures of the inner thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy

Image by Lecturio.

Femoral triangle

The femoral triangle is located on the medial aspect of the anterior thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy.

  • Boundaries: 
    • Lateral: sartorius Sartorius Thigh: Anatomy muscle
    • Medial: adductor longus Adductor longus Thigh: Anatomy muscle
    • Superior (base): inguinal ligament
    • Apex: continuous with the adductor canal
    • Floor: pectineus Pectineus Thigh: Anatomy and adductor brevis Adductor brevis Thigh: Anatomy medially, and iliopsoas laterally
    • Roof: fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis lata, superficial fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis, and skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions
      • Fascia lata overlies the femoral triangle; the saphenous opening here allows entrance of lymphatic vessels Lymphatic Vessels Tubular vessels that are involved in the transport of lymph and lymphocytes. Lymphatic Drainage System: Anatomy and the greater saphenous vein; the femoral hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias protrudes through this opening

Femoral hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias

The femoral hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias is the protrusion of intra-abdominal contents under the inguinal ligament, through the femoral ring, and into the femoral canal, producing a “bulge” or swelling Swelling Inflammation in the femoral triangle.

Femoral hernia

Closeup of the femoral triangle featuring the location of a femoral hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias

Image by Lecturio.

Mnemonics

To remember the borders of the femoral triangle—SAIL:

  • S: Sartorius muscle
  • A: Adductor longus muscle
  • IL: Inguinal Ligament

To remember the contents of the femoral triangle (from lateral to medial)—NAVEL:

Epidemiology and Etiology

Epidemiology

  • More common in women, with a female-to-male ratio of 3:1
  • Represents < 5% of all hernias

Etiology

  • Any condition that increases intra-abdominal pressure and enlarges/weakens the ligamentous structures of the pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy (e.g., the femoral ring)
  • Risk factors:
    • Increased intra-abdominal pressure
      • Obesity Obesity Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Obesity
      • Constipation Constipation Constipation is common and may be due to a variety of causes. Constipation is generally defined as bowel movement frequency < 3 times per week. Patients who are constipated often strain to pass hard stools. The condition is classified as primary (also known as idiopathic or functional constipation) or secondary, and as acute or chronic. Constipation
      • Chronic cough 
      • Recurrent, regular Regular Insulin, or violent vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia (e.g., eating disorder)
      • Prostatic hypertrophy Hypertrophy General increase in bulk of a part or organ due to cell enlargement and accumulation of fluids and secretions, not due to tumor formation, nor to an increase in the number of cells (hyperplasia). Cellular Adaptation (causes straining during micturition)
    • Enlarged/weakened femoral ring
      • Female gender Gender Gender Dysphoria (wider pelvis Pelvis The pelvis consists of the bony pelvic girdle, the muscular and ligamentous pelvic floor, and the pelvic cavity, which contains viscera, vessels, and multiple nerves and muscles. The pelvic girdle, composed of 2 “hip” bones and the sacrum, is a ring-like bony structure of the axial skeleton that links the vertebral column with the lower extremities. Pelvis: Anatomy)
      • Advanced age
      • Multiparity
      • Previous surgical repair of inguinal hernias Inguinal Hernias An abdominal hernia with an external bulge in the groin region. It can be classified by the location of herniation. Indirect inguinal hernias occur through the internal inguinal ring. Direct inguinal hernias occur through defects in the abdominal wall (transversalis fascia) in Hesselbach’s triangle. The former type is commonly seen in children and young adults; the latter in adults. Inguinal Canal: Anatomy and Hernias

Clinical Presentation

  • Globular, subcutaneous swelling Swelling Inflammation or “bulge” in the groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination that may or may not be tender
  • Located inferior to the inguinal ligament and medial to the femoral vein
  • Swelling or “bulge” enlarges with Valsalva maneuvers

Types of femoral hernias

Depending on the location and contents of the protrusion, several subtypes of femoral hernias have been described:

  • Serafini’s hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: The hernial sac lies behind the femoral vessels.
  • Velpeau’s hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias (or prevascular): The hernial sac lies in front of the femoral vessels, which can lead to this type being mistaken for a femoral aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms.
  • Laugier’s hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: The hernial sac transverses the lacunar ligament or the pectineal ligament of Cooper.
  • Hesselbach’s hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: The neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess of the sac lies lateral to the femoral vessels.
  • Cloquet’s hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: The hernial sac descends deep to the femoral vessels through the pectineal fascia Fascia Layers of connective tissue of variable thickness. The superficial fascia is found immediately below the skin; the deep fascia invests muscles, nerves, and other organs. Cellulitis.
  • De Garengeot’s hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias: The hernial contents include the vermiform appendix Appendix A worm-like blind tube extension from the cecum. Colon, Cecum, and Appendix: Anatomy, which often leads to incarceration Incarceration Inguinal Canal: Anatomy and Hernias of the hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias and requires an appendectomy Appendectomy Appendectomy is an invasive surgical procedure performed with the goal of resecting and extracting the vermiform appendix through either an open or a laparoscopic approach. The most common indication is acute appendicitis. Appendectomy as part of the surgical repair.
Subtypes of femoral hernias

Types of femoral hernias

Image by Lecturio.

Complications

  • Incarceration: Hernia becomes irreducible.
  • Strangulation Strangulation Inguinal Canal: Anatomy and Hernias: Constriction by femoral ring partially or completely obstructs the blood supply to the herniated part of the bowel, leading to ischemic necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage. Clinical manifestations of strangulation:
    • Cardinal signs of inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation ( erythema Erythema Redness of the skin produced by congestion of the capillaries. This condition may result from a variety of disease processes. Chalazion, swelling Swelling Inflammation, pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, warm to touch)
    • Nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics, vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia, and severe abdominal pain Abdominal Pain Acute Abdomen
    • Signs of mechanical bowel obstruction Bowel obstruction Any impairment, arrest, or reversal of the normal flow of intestinal contents toward the anal canal. Ascaris/Ascariasis (colicky abdominal pain Abdominal Pain Acute Abdomen, nausea, bilious or fecal vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia, constipation, abdominal distension)
    • Signs of peritonitis Peritonitis Inflammation of the peritoneum lining the abdominal cavity as the result of infectious, autoimmune, or chemical processes. Primary peritonitis is due to infection of the peritoneal cavity via hematogenous or lymphatic spread and without intra-abdominal source. Secondary peritonitis arises from the abdominal cavity itself through rupture or abscess of intra-abdominal organs. Penetrating Abdominal Injury, followed by paralytic ileus Ileus A condition caused by the lack of intestinal peristalsis or intestinal motility without any mechanical obstruction. This interference of the flow of intestinal contents often leads to intestinal obstruction. Ileus may be classified into postoperative, inflammatory, metabolic, neurogenic, and drug-induced. Small Bowel Obstruction (due to intestinal perforation Intestinal perforation Perforated viscus or GI perforation represents a condition in which the integrity of the GI wall is lost with subsequent leakage of enteric contents into the peritoneal cavity, resulting in peritonitis. The causes of perforated viscus include trauma, bowel ischemia, infections, or ulcerative conditions, all of which ultimately lead to a full-thickness disruption of the intestinal wall. Perforated Viscus)

Diagnosis and Management

Diagnosis

  • Mainly a clinical diagnosis
  • If palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination is difficult (e.g., obesity), diagnosis can be confirmed by an ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI) of the groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination area, which will show signs of small bowel obstruction Bowel obstruction Any impairment, arrest, or reversal of the normal flow of intestinal contents toward the anal canal. Ascaris/Ascariasis.

Differential diagnoses

  • Inguinal hernia Inguinal hernia An abdominal hernia with an external bulge in the groin region. It can be classified by the location of herniation. Indirect inguinal hernias occur through the internal inguinal ring. Direct inguinal hernias occur through defects in the abdominal wall (transversalis fascia) in hesselbach’s triangle. The former type is commonly seen in children and young adults; the latter in adults. Inguinal Canal: Anatomy and Hernias
  • Swollen femoral lymph Lymph The interstitial fluid that is in the lymphatic system. Secondary Lymphatic Organs node
  • Aneurysm of the femoral artery
  • Dilation of the saphenous vein
  • Abscess of the psoas muscle Psoas muscle A powerful flexor of the thigh at the hip joint (psoas major) and a weak flexor of the trunk and lumbar spinal column (psoas minor). Psoas is derived from the greek ‘psoa. Pyelonephritis and Perinephric Abscess

Management

  • Due to the high risk of complications because of the small size of the canal/ring, all femoral hernias should be surgically repaired.
  • Non-complicated hernias: early elective surgical repair with mesh hernioplasty 
  • Complicated hernias: herniorrhaphy within 4 hours of the onset of symptoms in order to prevent bowel ischemia Bowel ischemia Mesenteric ischemia is a rare, life-threatening condition caused by inadequate blood flow through the mesenteric vessels, which results in ischemia and necrosis of the intestinal wall. Mesenteric ischemia can be either acute or chronic. Mesenteric Ischemia and necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage

Clinical Relevance

Femoral vascular access: The femoral artery and vein are easily accessed within the femoral triangle for interventional procedures. 

The following conditions are included in the differential diagnoses of femoral hernias:

  • Inguinal hernias: a protrusion of intra-abdominal contents through the deep inguinal ring Deep inguinal ring Inguinal Canal: Anatomy and Hernias, producing an indirect inguinal hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias, or through a weakness in the posterior wall of the inguinal canal Inguinal canal The tunnel in the lower anterior abdominal wall through which the spermatic cord, in the male; round ligament, in the female; nerves; and vessels pass. Its internal end is at the deep inguinal ring and its external end is at the superficial inguinal ring. Inguinal Canal: Anatomy and Hernias, producing a direct inguinal hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias. Presents with similar clinical manifestations as the femoral hernia Hernia Protrusion of tissue, structure, or part of an organ through the bone, muscular tissue, or the membrane by which it is normally contained. Hernia may involve tissues such as the abdominal wall or the respiratory diaphragm. Hernias may be internal, external, congenital, or acquired. Abdominal Hernias; however, inguinal hernias Inguinal Hernias An abdominal hernia with an external bulge in the groin region. It can be classified by the location of herniation. Indirect inguinal hernias occur through the internal inguinal ring. Direct inguinal hernias occur through defects in the abdominal wall (transversalis fascia) in Hesselbach’s triangle. The former type is commonly seen in children and young adults; the latter in adults. Inguinal Canal: Anatomy and Hernias are located above the inguinal ligament. In some cases, the 2 types may be indistinguishable during physical examination. 
  • Aneurysm of the femoral artery: an arterial dilation caused by weakness of the wall of the femoral artery, located in the medial aspect of the thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy. Aneurysm of the femoral artery is the 2nd-most common peripheral aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms. May present as painless, pulsatile swelling Swelling Inflammation with a palpable thrill and a continuous murmur at the mid-inguinal point. Femoral aneurysms can rupture, which may cause life-threatening, uncontrollable bleeding. 

References

  1. Drake, R.L., Vogl, A.W., & Mitchell, A.W.M. (2014). Gray’s Anatomy for Students (3rd ed.). Philadelphia, PA:  Churchill Livingstone.
  2. Goethals, A., Azmat, C.E., & Adams, C.T. (2020). Femoral Hernia. NCBI/StatPearls Publishing LLC. https://www.ncbi.nlm.nih.gov/books/NBK535449/

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