Femoral Region and Hernias

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 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
• Contains loose areolar tissue, lymphatic vessels, and lymph nodes
• The femoral sheath is a fascia that encloses the contents of the femoral triangle (except the femoral nerve), each within its own compartment.

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.

• Boundaries: 
  • Lateral: sartorius muscle
  • Medial: adductor longus muscle
  • Superior (base): inguinal ligament
  • Apex: continuous with the adductor canal
  • Floor: pectineus and adductor brevis medially, and iliopsoas laterally
  • Roof: fascia lata, superficial fascia, 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. Structure and Function of the Skin
    • Fascia lata overlies the femoral triangle; the saphenous opening here allows entrance of lymphatic vessels and the greater saphenous vein; the femoral hernia protrudes through this opening

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Femoral hernia

The femoral hernia 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 in the femoral triangle.

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:

• N: femoral Nerve
• A: femoral Artery
• V: femoral Vein
• E: Empty space (femoral canal)
• L: deep inguinal Lymph nodes

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 (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, or violent vomiting (e.g., eating disorder)
    • Prostatic hypertrophy (causes straining during micturition)
  • Enlarged/weakened femoral ring
    • Female gender (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)
    • Advanced age
    • Multiparity
    • Previous surgical repair of inguinal hernias

Clinical Presentation

• Globular, subcutaneous swelling or “bulge” in the groin 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

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Types of femoral hernias

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

• Serafini’s hernia: The hernial sac lies behind the femoral vessels.
• Velpeau’s hernia (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. Extremity and Visceral Aneurysms.
• Laugier’s hernia: The hernial sac transverses the lacunar ligament or the pectineal ligament of Cooper.
• Hesselbach’s hernia: The neck of the sac lies lateral to the femoral vessels.
• Cloquet’s hernia: The hernial sac descends deep to the femoral vessels through the pectineal fascia.
• De Garengeot’s hernia: The hernial contents include the vermiform appendix, which often leads to incarceration of the hernia 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.

Complications

• Incarceration: Hernia becomes irreducible.
• Strangulation: Constriction by femoral ring partially or completely obstructs the blood supply to the herniated part of the bowel, leading to ischemic necrosis. 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, swelling, pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain, warm to touch)
  • Nausea, vomiting, and severe abdominal pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain
  • Signs of mechanical bowel obstruction (colicky abdominal pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain, nausea, bilious or fecal vomiting, constipation, abdominal distension)
  • Signs of peritonitis, followed by paralytic ileus (due to intestinal perforation)

Diagnosis and Management

Diagnosis

• Mainly a clinical diagnosis
• If palpation is difficult (e.g., obesity), diagnosis can be confirmed by an ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI) of the groin area, which will show signs of small bowel obstruction Small Bowel Obstruction Small bowel obstruction (SBO) is an interruption of the flow of the intraluminal contents through the small intestine, and is classified as mechanical (due to physical blockage) or functional (due to disruption of normal motility). The most common cause of SBO in the Western countries is post-surgical adhesions. Small bowel obstruction typically presents with nausea, vomiting, abdominal pain, distention, constipation, and/or obstipation. Small Bowel Obstruction.

Differential diagnoses

• Inguinal hernia
• Swollen femoral lymph node
• Aneurysm of the femoral artery
• Dilation of the saphenous vein
• Abscess of the psoas muscle

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 and necrosis

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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, producing an indirect inguinal hernia, or through a weakness in the posterior wall of the inguinal canal Inguinal canal The inguinal region, or the groin, is located in the RLQ and LLQ of the anterior abdominal wall, bordered by the thigh inferiorly, the pubis medially, and the iliac crest superolaterally. The inguinal canal is a tubular structure that runs in a straight line from the anterior superior iliac spine to the pubic tubercle. Inguinal Canal and Hernias, producing a direct inguinal hernia. Presents with similar clinical manifestations as the femoral hernia; however, inguinal 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. 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. Extremity and Visceral Aneurysms. May present as painless, pulsatile swelling with a palpable thrill and a continuous murmur at the mid-inguinal point. Femoral aneurysms can rupture, which may cause life-threatening, uncontrollable bleeding.