Thigh and gluteal

• The lower limbs are divided into gluteal region, hip, thigh, knee, leg, ankle, and foot.
• The gluteal region, also known as the buttock, is the transitional region between the trunk and the lower limbs, largely made up of gluteal muscles and a thick layer of superficial fascia (fat).
• The gluteal region is bounded superiorly by the iliac crest, inferiorly by the Gluteal fold (skin fold), and medially by the intergluteal (natal) cleft.
• The muscles in the gluteal region include both superficial and deep groups.
• The blood vessels in the gluteal region include the superior and inferior gluteal vessels.
• The nerves in the gluteal region include the superior and inferior gluteal nerves, sciatic nerve, pudendal nerve, posterior cutaneous nerve of thigh, nerve to obturator internus, and nerve to quadratus femoris.
• The ligaments in the gluteal region include the sacrotuberous ligament, which connects the sacrum to the ischial tuberosity, and the sacrospinous ligament, which connects the sacrum to the spine of the ischium.
• The great saphenous vein is the longest vein in the body, arising from the medial end of the dorsal venous arch of the foot and passing upward in front of the medial malleolus.
• The foramen in the gluteal region is the Greater Sciatic Foramen, which is formed by the greater sciatic notch of the hip bone and the sacrotuberous and sacrospinous ligaments, providing an exit from the pelvis into the gluteal region.
• The great saphenous vein ascends in company with the saphenous nerve over the medial side of the leg and behind the knee and then on the medial side of the thigh.
• The great saphenous vein passes through the saphenous opening and joins the femoral vein.
• Structures passing through the Greater Sciatic Foramen include the piriformis, sciatic nerve, posterior cutaneous nerve of the thigh, superior and inferior gluteal nerves, nerve to obturator internus, and nerve to quadratus femoris.
• The great saphenous vein is connected to the small saphenous vein by one or two branches.
• Several perforating veins connect the great saphenous vein with the deep veins.
• The lesser sciatic foramen is formed by the lesser sciatic notch of the hip bone and the sacrotuberous and sacrospinous ligaments.
• The lesser sciatic foramen provides an entrance into the perineum from the gluteal region and structures such as the tendon of the obturator internus muscle, nerve to the obturator internus, pudendal nerve, internal pudendal artery and vein pass through it.
• The muscles of the gluteal region are divided into two groups: the superficial group which includes gluteus maximus, gluteus medius, gluteus minimus and tensor fasciae latae, and the deep group which includes piriformis, obturator internus, superior gemellus, inferior gemellus and quadratus femoris, which are lateral rotators of the hip or extensile ligaments of the hip joint.
• Gluteus maximus extends and laterally rotates the thigh, while gluteus medius and minimus abduct and medially rotate the thigh.
• Gluteus maximus is the thickest muscle in the body.
• The sciatic nerve, a branch of the sacral plexus (L4 and 5; S1, 2, and 3), emerges from the pelvis through the lower part of the greater sciatic foramen and is the largest nerve in the body, consisting of tibial and common peroneal nerves.
• The sciatic nerve passes between the superficial and deep group of the muscles.
• The superior and inferior gluteal nerves are branches of the sacral plexus that leave the pelvis through the upper part and lower part of the greater sciatic foramen, respectively, with the inferior gluteal nerve supplying gluteus maximus muscle and the superior gluteal nerve supplying gluteus medius, gluteus minimus and tensor fasciae latae.
• The superior and inferior gluteal arteries are branches from the internal iliac artery and enter the gluteal region through the upper part and lower part of the greater sciatic foramen, respectively.
• The small saphenous vein arises from the lateral end of the dorsal venous arch of the foot.
• The small saphenous vein ascends behind the lateral malleolus in company with the sural nerve.
• The small saphenous vein runs up the middle of the back of the leg.
• The small saphenous vein ends in the popliteal vein.
• Femoral artery is the main arterial supply to the lower limb and enters the thigh under the inguinal ligament, as a continuation of the external iliac artery.
• Femoral artery ends at the opening in the adductor magnus muscle to become the popliteal artery.
• Branches of the femoral artery include the superficial circumflex iliac artery, superficial epigastric artery, superficial external pudendal artery, deep external pudendal artery, and profunda femoris artery.
• Femoral nerve is the largest branch of the lumbar plexus and enters the thigh lateral to the femoral artery.
• About 4 cm below the inguinal ligament, femoral nerve terminates by dividing into anterior and posterior divisions.
• Anterior division of the femoral nerve includes 2 cutaneous branches and 2 muscular branches: sartorius & pectineus.
• Posterior division of the femoral nerve includes 1 cutaneous branch: saphenous nerve and muscular branches: quadriceps muscle.
• The femoral triangle is a triangular depressed area in the upper part of the medial aspect of the thigh just below the inguinal ligament.
• The boundaries of the femoral triangle are superiorly the inguinal ligament, laterally the sartorius muscle, medially the adductor longus muscle, and the floor is the iliopsoas, pectineus, and adductor longus.
• The roof of the femoral triangle is the skin and fasciae of the thigh.
• The contents of the femoral triangle include the femoral nerve and its branches, the femoral artery and its branches, the femoral vein and its tributaries, and the deep inguinal lymph nodes.
• The adductor (subsartorial) canal is an intermuscular cleft on the medial aspect of the middle third of the thigh beneath the sartorius muscle.
• The adductor (subsartorial) canal starts above at the apex of the femoral triangle and ends below at the opening in the adductor magnus (adductor hiatus).