Iliopectineal arch
Arcus iliopectineus
The iliopectineal arch is a thickened band of iliac fascia under the inguinal ligament that divides the space into muscular and vascular compartments.
At a glance
- English
- Iliopectineal arch
- Latin (TA2)
- Arcus iliopectineus
- System
- Connective tissue
- Region
- Lower limb
- Side
- Paired, left and right
About the iliopectineal arch
The iliopectineal arch is a strong fibrous band at the front of the hip, beneath the inguinal ligament. It is a thickened part of the iliac fascia, the sheet covering iliopsoas, and it runs from the back of the inguinal ligament down and inwards to the iliopubic eminence on the hip bone. Though it is filed with the hip muscles, it is really a fascial partition rather than a muscle.
The gap between the inguinal ligament in front and the hip bone behind is large, and the arch splits it into two compartments. The lateral one, the muscular lacuna, carries iliopsoas, the femoral nerve and usually the lateral femoral cutaneous nerve into the thigh. The medial one, the vascular lacuna, carries the femoral artery and vein, the femoral branch of the genitofemoral nerve and, at its innermost part, the femoral canal with its lymph vessels and a lymph node.
This division explains why the femoral nerve lies outside the femoral sheath, while the femoral artery and vein lie inside it. In the groin the order from lateral to medial is nerve, artery, vein, then the empty space of the femoral canal, and the arch separates the nerve from the vessels. Beyond the ligament, the arch blends with the fascia over iliopsoas and pectineus.
The arch has clinical weight. Infections tracking down within the psoas sheath, such as a psoas abscess, stay in the muscular compartment and point in the upper thigh lateral to the femoral vessels. A femoral hernia, by contrast, pushes through the vascular compartment at the femoral canal, medial to the vein. Surgeons repairing hernias and doing groin approaches to the hip use the arch as a landmark between nerve and vessels.
Function and supply
- Begins at
- Back of the inguinal ligament, as a thickening of the iliac fascia.
- Ends at
- Iliopubic eminence of the hip bone.
- Function
- Divides the space beneath the inguinal ligament into the lateral muscular lacuna and the medial vascular lacuna.
Anthromica
See the iliopectineal arch where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
