The femoral sheath (also called the crural sheath) is a funnel-shaped downward extension of abdominal fascia within which the

femoral artery The femoral artery is a large artery in the thigh and the main arterial supply to the thigh and leg. The femoral artery gives off the deep femoral artery or profunda femoris artery and descends along the anteromedial part of the thigh in the fem ...

and

femoral vein In the human body, the femoral vein is a blood vessel that accompanies the femoral artery in the femoral sheath. It begins at the adductor hiatus (an opening in the adductor magnus muscle) as the continuation of the popliteal vein. It ends at th ...

pass between the

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...

and the

thigh In human anatomy, the thigh is the area between the hip (pelvis) and the knee. Anatomically, it is part of the lower limb. The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of bone ...

. The femoral sheath is subdivided by two vertical partitions to form three compartments (medial, intermediate, and lateral); the medial compartment is known as the

femoral canal The femoral canal is the medial (and smallest) compartment of the three compartments of the femoral sheath. It is conical in shape. The femoral canal contains lymphatic vessels, and adipose and loose connective tissue, as well as - sometimes - a ...

and contains

lymphatic vessels The lymphatic vessels (or lymph vessels or lymphatics) are thin-walled vessels (tubes), structured like blood vessels, that carry lymph. As part of the lymphatic system, lymph vessels are complementary to the cardiovascular system. Lymph vessel ...

and a

lymph node A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that inclu ...

, whereas the intermediate canal and the lateral canal accommodate the femoral vein and the femoral artery (respectively). Some neurovascular structures perforate the femoral sheath. Topographically, the femoral sheath is contained within in the

femoral triangle The femoral triangle (or Scarpa's triangle) is an anatomical region of the upper third of the thigh. It is a subfascial space which appears as a triangular depression below the inguinal ligament when the thigh is flexed, abducted and laterally rot ...

Structure

The femoral sheath is funnel-shaped fascial structure, with the wide end directed superior-ward. The femoral sheath is formed by an inferior-ward prolongation - posterior to the

inguinal ligament The inguinal ligament (), also known as Poupart's ligament or groin ligament, is a band running from the pubic tubercle to the anterior superior iliac spine. It forms the base of the inguinal canal through which an indirect inguinal hernia may dev ...

- of abdominal fascia, with

transverse fascia The transversalis fascia (or transverse fascia) is a thin aponeurotic membrane of the abdomen. It lies between the inner surface of the transverse abdominal muscle and the parietal peritoneum. It forms part of the general layer of fascia lining ...

being continued down anterior to the femoral vessels, and

iliac fascia The iliac fascia, or Abernethy's fascia, is a fascia in the region of the ilium of the pelvis. It has the following connections: * ''laterally'', to the whole length of the inner lip of the iliac crest. * ''medially'', to the linea terminalis of ...

posterior to these. The femoral sheath is strengthened anteriorly by the

iliopubic tract The iliopubic tract is a thickened band of fibers curving over the external iliac vessels, at the spot where they become femoral, on the abdominal side of the inguinal ligaments and loosely connected with it. It is apparently a thickening of the t ...

.'''' The narrowed inferior/distal end of the femoral sheath concludes by blending with the

tunica adventitia The tunica externa (New Latin "outer coat"), also known as the tunica adventitia (New Latin "additional coat"), is the outermost tunica (layer) of a blood vessel, surrounding the tunica media. It is mainly composed of collagen and, in arteries, ...

of the femoral vessels about 4 cm inferior to the

.'''' The lateral wall of the sheath is vertical and is perforated by the lumboinguinal nerve; the medial wall is directed/oriented obliquely inferolaterally and is perforated by the

great saphenous vein The great saphenous vein (GSV, alternately "long saphenous vein"; ) is a large, subcutaneous, superficial vein of the leg. It is the longest vein in the body, running along the length of the lower limb, returning blood from the foot, leg and thig ...

, and by

Lymphatic vessel The lymphatic vessels (or lymph vessels or lymphatics) are thin-walled vessels (tubes), structured like blood vessels, that carry lymph. As part of the lymphatic system, lymph vessels are complementary to the cardiovascular system. Lymph vess ...

.'''' The femoral sheath is contained in the

Compartments and contents

The sheath is divided by two vertical partitions which stretch between its anterior and posterior walls:'''' * The (smallest) medial compartment is named the

, and contains some lymphatic vessels and a lymph gland embedded in a small amount of

areolar Loose connective tissue, sometimes called areolar tissue, is a cellular connective tissue with thin and relatively sparse collagen fibers. Its ground substance occupies more volume than the fibers do. It has a viscous to gel-like consistenc ...

tissue. * The intermediate compartment contains the

. * The lateral compartment contains the

Function

The femoral sheath allows for the

and the

to pass between the abdomen and the thigh.

History

The femoral sheath is also known as the crural sheath.

Additional Images

File:Slide8GGGGG.JPG, Femoral sheath

References

External links

Photo and overview at gla.ac.uk
*

Lower limb anatomy {{Portal bar, Anatomy