Surface Markings of the Abdominal Wall Quiz

Study Notes

Surface Markings of the Abdominal Wall

Abdominal wall is divided into four quadrants by vertical and horizontal imaginary lines intersecting at the umbilicus.
Costal margin represents the lower edge of the thorax, formed by the 7th-10th ribs.
Infrasternal angle is created by the 7th-10th costal cartilages meeting the xiphoid process.
Iliac crest serves as the superior border of the ilium, marking the superiolateral margin of the greater pelvis.
Inguinal ligament spans from the anterior superior iliac spine to the pubic tubercle.
Linea alba runs from the xiphoid process to the pubic symphysis, dividing the rectus abdominis muscle.
Umbilicus is central in the abdominal wall's surface landmarks.
Linea semilunaris is a curved line on either side of the rectus abdominis, extending from the 9th rib to the pubic tubercle.

Anatomical Planes and Regions

Nine regions of the abdominal wall are defined by four planes, including the transpyloric plane.
Transpyloric plane lies midway between the jugular notch and the upper border of the pubic symphysis, intersecting the 9th costal cartilages, and passing through the pylorus at the lower border of L1.
The subcostal line can be substituted with the transpyloric plane for clinical reference.

Inguinal Canal

The inguinal canal is an oblique passage located in the lower part of the anterior abdominal wall, running parallel and above the inguinal ligament.
It measures approximately 4 cm in length and serves different functions in males and females.
In males, the inguinal canal facilitates the passage of structures to and from the testis, while in females, it allows the round ligament of the uterus to extend from the uterus to the labium majus.

Gubernaculum and Descent of the Testis

Gubernaculum aids in the descent of the gonads during the prenatal period, pulling both future testis and future ovary down towards the labioscrotal swelling.
In males, the testis travels a longer distance to reach the scrotum; in females, the gubernaculum shortens, becoming the round ligament of the uterus in the labia majora.

Inguinal Ligament Structures

The inguinal ligament connects the anterior superior iliac spine to the pubic tubercle and originates from the external oblique aponeurosis, which is folded back.
Its lower border adheres to the deep fascia of the thigh, forming the superior border of the femoral triangle and the inferior border of Hesselbach’s triangle.
The lacunar ligament extends from the medial end of the inguinal ligament and is continuous with the pectineal ligament, which thickens the periosteum of the pubis's pectineal line.

Hernias and Clinical Implications

The lacunar ligament defines the boundary of the femoral canal, which may be incised during surgical release of a femoral hernia.
Indirect hernias can develop in the inguinal canal due to anatomical weaknesses and pressures.

Description

Test your knowledge on the surface markings and landmarks of the abdominal wall, including the highest point of the iliac crest, tubercle of the iliac bone, and anterior superior iliac spine. Learn about the divisions of the abdominal wall into four quadrants and key landmarks like the costal margin, infrasternal angle, and iliac crest.