Lower Limb
Gluteal region, thigh, knee, leg, ankle, and foot, including the lumbosacral plexus.
31 entriesGluteal region: 4Thigh: 10Knee & popliteal fossa: 8Leg: 6Ankle & foot: 3
Bones (5)
- Bones of the foot HYSeven tarsals, five metatarsals and fourteen phalanges forming the arches of the foot. Fifth metatarsal fractures, calcaneal fractures, stress fractures and plantar fasciitis are the common problems.
- Femur HYThe longest and strongest bone in the body. Femoral neck fractures in older adults, slipped capital femoral epiphysis and avascular necrosis of the head are its high-yield problems.
- Fibula HYSlender lateral bone of the leg that bears little weight but forms the lateral malleolus of the ankle. The common fibular nerve wraps around its neck, where fractures and pressure injure it.
- Patella HYThe largest sesamoid bone, embedded in the quadriceps tendon in front of the knee. It increases the leverage of the quadriceps and is involved in patellofemoral pain, dislocation and fractures.
- Tibia HYThe weight-bearing medial bone of the leg. Its subcutaneous shaft makes open fractures and compartment syndrome common, and the tibial tuberosity is the site of Osgood–Schlatter disease.
Muscles (7)
- Adductor muscles of the thigh Medial compartment muscles — adductor longus, brevis and magnus, gracilis, pectineus and obturator externus — that adduct the hip. They are supplied mostly by the obturator nerve, and adductor strains are the classic "groin pull".
- Gluteus maximus The largest and most superficial gluteal muscle, the main extensor of the hip for rising, climbing and running. Weakness from an inferior gluteal nerve lesion causes a backward-lurching gait.
- Gluteus medius and minimus HYFan-shaped hip abductors that keep the pelvis level when standing on one leg. Weakness or superior gluteal nerve injury produces the Trendelenburg sign; their tendons cause lateral hip pain.
- Hamstrings HYPosterior thigh muscles — biceps femoris, semitendinosus and semimembranosus — that extend the hip and flex the knee. Hamstring strains are common in sprinting sports.
- Piriformis Pear-shaped lateral rotator of the hip and the key landmark of the gluteal region — structures leave the pelvis above or below it. It can irritate the sciatic nerve (piriformis syndrome).
- Quadriceps femoris HYFour-headed extensor of the knee in the anterior thigh, supplied by the femoral nerve. It tests the L4 reflex, and its tendon, patella and patellar ligament form the knee's extensor mechanism.
- Triceps surae and calcaneal tendon HYGastrocnemius and soleus form the calf and insert via the Achilles tendon on the calcaneus to plantarflex the ankle. They carry the S1 ankle reflex; Achilles rupture and tendinopathy are common.
Nerves (5)
- Common fibular nerve HYLateral terminal branch of the sciatic nerve that winds around the fibular neck — the most commonly injured nerve of the lower limb. Injury causes foot drop and numbness of the dorsum of the foot.
- Femoral nerve HYLargest branch of the lumbar plexus (L2–L4), supplying the hip flexors and knee extensors and the skin of the anterior thigh and medial leg. Lesions cause knee buckling and a lost patellar reflex.
- Obturator nerve Lumbar plexus branch (L2–L4) that runs along the lateral pelvic wall through the obturator canal to supply the hip adductors and a patch of medial thigh skin. It is injured in pelvic surgery and childbirth.
- Sciatic nerve HYThe largest nerve in the body (L4–S3), running from the buttock down the back of the thigh and dividing into the tibial and common fibular nerves. It supplies the hamstrings and everything below the knee except a strip of skin on the medial leg.
- Tibial nerve HYLarger terminal branch of the sciatic nerve, running through the popliteal fossa and deep posterior leg to the sole. It supplies the plantarflexors and inverters and the skin of the sole, and is compressed in the tarsal tunnel.
Arteries (2)
- Femoral artery HYContinuation of the external iliac artery below the inguinal ligament and the main artery of the lower limb. Its groin pulse is a key exam site and the usual access for catheterization; the superficial femoral segment is the classic site of claudication-causing atherosclerosis.
- Popliteal artery HYContinuation of the femoral artery through the popliteal fossa, the deepest structure there. It is tethered and easily injured in knee dislocations and is the most common site of peripheral aneurysms.
Veins (2)
- Deep veins of the lower limb HYPaired deep veins that accompany the leg arteries and join to form the popliteal and femoral veins. They carry most venous return, helped by the calf muscle pump, and are where DVT forms.
- Great saphenous vein HYThe longest vein in the body, running superficially from the front of the medial malleolus to the groin. It is the usual source of varicose veins and a common graft for coronary bypass.
Joints (3)
- Ankle joint HYHinge joint in which the talus sits in a mortise formed by the tibia and fibula. Sprains of the lateral ligaments and malleolar fractures are extremely common; the Ottawa rules decide who needs an X-ray.
- Hip joint HYDeep ball-and-socket joint between the femoral head and the acetabulum, built for stability. Osteoarthritis, posterior dislocation, septic arthritis in children and developmental dysplasia are the high-yield topics.
- Knee joint HYThe largest synovial joint — a modified hinge between the femur, tibia and patella, stabilized mainly by ligaments and the menisci. Ligament and meniscal injuries, effusions and osteoarthritis make it one of the most examined joints.
Ligaments (4)
- Collateral ligaments of the knee HYSide ligaments of the knee — the broad MCL, attached to the medial meniscus, resists valgus stress; the cord-like LCL resists varus stress. The MCL is the most commonly injured knee ligament.
- Cruciate ligaments HYCrossed intra-articular ligaments of the knee that prevent the tibia sliding forward (ACL) or backward (PCL) on the femur. ACL tears from non-contact pivoting are among the most common serious sports injuries.
- Lateral ankle ligaments HYThree ligaments from the lateral malleolus — anterior talofibular, calcaneofibular and posterior talofibular — that resist inversion. The ATFL is the most commonly injured ligament in the body.
- Menisci of the knee HYTwo crescent-shaped fibrocartilage pads on the tibial plateau that deepen the articular surfaces, spread load and absorb shock. Tears — traumatic in the young, degenerative in older adults — cause joint-line pain, catching and locking.
Spaces & regions (3)
- Compartments of the leg HYFour tight osteofascial compartments — anterior, lateral, superficial posterior and deep posterior — each with its own muscles, nerve and vessels. Rising pressure after fractures or crush injuries causes compartment syndrome, a surgical emergency.
- Femoral triangle HYTriangular region of the upper anterior thigh containing the femoral nerve, artery, vein and canal. It is the site of the femoral pulse, arterial and venous access, and femoral hernias.
- Popliteal fossa HYDiamond-shaped space behind the knee containing the popliteal vessels, the tibial and common fibular nerves and lymph nodes. Baker cysts, popliteal aneurysms and knee-dislocation vascular injury arise here.