Exact Location of the Deep Inguinal Ring
The deep inguinal ring is located approximately one-third of the distance from the mid-inguinal point to the midpoint of the inguinal ligament, which is about 9.6 mm medial to the midpoint of the inguinal ligament and 4.5 mm lateral to the mid-inguinal point. 1
Anatomical Landmarks and Measurements
The deep inguinal ring can be precisely located using the following anatomical landmarks:
- Mid-inguinal point (MIP): The midpoint of a line drawn from the anterior superior iliac spine (ASIS) to the pubic symphysis
- Midpoint of inguinal ligament (MPIL): The midpoint of a line drawn from the ASIS to the pubic tubercle
Precise Measurements
Research studies have provided specific measurements to locate the deep inguinal ring:
- Located at approximately 41% of the way along the inguinal ligament from the pubic tubercle toward the ASIS 2
- Found at approximately 51% of the way along a line from the pubic symphysis to the ASIS 2
- The mean distance from the ASIS to the deep inguinal ring is approximately 62 mm in cadaveric studies 3
Relationship to Vascular Structures
Contrary to traditional teaching, the deep inguinal ring is positioned:
- Medial or superior to the femoral artery, never lateral 4
- The mean distances from the ASIS to the deep ring and femoral artery are 8.8 cm and 7.7 cm, respectively 4
Clinical Significance
Understanding the exact location of the deep inguinal ring is important for:
- Differentiating between direct and indirect inguinal hernias
- Performing accurate inguinal hernia repairs
- Properly identifying anatomical landmarks during laparoscopic procedures 5
Important Considerations
- The position of the deep inguinal ring remains relatively constant regardless of age, gender, race, BMI, or pelvic habitus 1
- In the inguinal lymphatic anatomy, the deep inguinal ring serves as an important landmark when identifying the inguinofemoral nodal basin 6
- For surgical procedures involving the inguinal region, precise identification of the deep ring is essential to avoid complications and ensure proper repair 5
Common Misconceptions
- Traditional teaching often incorrectly places the deep inguinal ring at the midpoint of the inguinal ligament
- The deep ring is often mistakenly described as being lateral to the femoral artery, when it is actually medial or superior to it 4
- Pre-operative estimates of the position of the deep ring are frequently inaccurate, which can lead to difficulties in distinguishing direct from indirect hernias clinically 2
The most accurate surface marking for the deep inguinal ring is a point just lateral to the mid-inguinal point, approximately one-third of the distance from the mid-inguinal point to the midpoint of the inguinal ligament 1.