GAS Lower extrem

What are the four regions of the lower extremity?

Gluteal, thigh, leg, and foot.

What are the boundaries of the thigh?

From inferior to the hip/inguinal ligament to the knee joint.

What are the boundaries of the leg?

Between the knee and ankle joints.

What part of the lower extremity is not covered in this course?

The foot, distal to the ankle.

What three bones fuse to form the pelvic/coxal bone?

Ilium, ischium, and pubis.

What is the longest bone in the body?

Femur.

What type of bone is the patella?

Sesamoid bone.

What is the main weight-bearing bone of the leg?

Tibia.

What is the function of the fibula?

It is non-weight-bearing and supports the tibia and ankle laterally.

What are major pelvic bone landmarks?

Iliac fossa, wing/ala, obturator foramen, ischial tuberosity, greater/lesser sciatic notches, ischial spine, pubic tubercle, superior/inferior pubic rami, and acetabulum.

What are the major functions of the lower limb?

Support the trunk and locomotion through coordinated action of the lower-limb joints.

Which compartment primarily flexes the hip?

Anterior thigh.

Which compartments primarily extend the hip?

Gluteal and posterior thigh.

Which compartment primarily adducts the thigh?

Medial thigh.

Which compartment primarily abducts the thigh?

Gluteal compartment.

Which compartments primarily medially rotate the hip?

Medial and anterior thigh compartments.

Which compartment primarily laterally rotates the hip?

Gluteal compartment.

Which compartments flex the knee?

Posterior thigh and posterior leg.

Which compartment extends the knee?

Anterior thigh.

Which compartment dorsiflexes the ankle?

Anterior leg.

Which compartment plantarflexes the ankle?

Posterior leg.

Where do inversion and eversion occur?

At the talocalcaneal/subtalar joint.

What is the lumbar plexus?

A plexus from L1–L4 providing motor and cutaneous innervation to the lower limb.

What two major nerves are listed from the lumbar plexus?

Femoral (L2–L4) and obturator (L2–L4).

What forms the sacral plexus?

The lumbosacral trunk plus S1–S3.

What are major nerves of the sacral plexus?

Sciatic, superior gluteal, inferior gluteal, nerve to quadratus femoris, and nerve to obturator internus.

What happens to part of L4 and L5?

They continue as the lumbosacral trunk and join S1–S3 to form the sacral plexus.

When does the external iliac artery become the femoral artery?

After passing under the inguinal ligament.

What does the femoral artery supply?

The anterior thigh; it travels anteromedially and passes through the adductor canal.

What artery supplies the posterior thigh?

Deep/profunda femoral artery via perforating branches.

When does the femoral artery become the popliteal artery?

After passing through the adductor hiatus.

What does the popliteal artery supply?

The knee via genicular arteries, then divides into anterior and posterior tibial arteries.

What does the anterior tibial artery supply?

Anterior leg and dorsum of foot; it continues as dorsalis pedis.

What does the posterior tibial artery supply?

Posterior leg and plantar foot; it gives off fibular arteries to the lateral leg.

What can a weak or asymmetric lower-limb pulse suggest?

Peripheral artery disease or arterial obstruction.

What is the most superficial gluteal muscle?

Gluteus maximus.

What is the primary action of gluteus maximus?

Powerful hip extension; also lateral rotation, abduction, and hip/knee stabilization.

What nerve innervates gluteus maximus?

Inferior gluteal nerve (L5, S1, S2).

What arteries supply gluteus maximus?

Superior and inferior gluteal arteries.

What is the primary action of gluteus medius?

Thigh abduction and pelvic stabilization during gait; anterior fibers medially rotate.

What is the prime abductor of the thigh?

Gluteus medius.

What nerve innervates gluteus medius and minimus?

Superior gluteal nerve (L4, L5, S1).

What does tensor fasciae latae do?

Assists abduction and medial rotation, stabilizes the extended knee via the IT tract, and stabilizes the femoral head.

What nerve innervates tensor fasciae latae?

Superior gluteal nerve.

What is the key landmark role of piriformis?

It divides the greater sciatic notch/foramen into structures exiting superior versus inferior to it.

Which deep gluteal muscles laterally rotate and abduct the femur?

Piriformis, obturator internus, superior gemellus, and inferior gemellus; quadratus femoris laterally rotates.

What nerve innervates piriformis?

S1–S2.

What nerve innervates obturator internus and superior gemellus?

Nerve to obturator internus.

What nerve innervates inferior gemellus and quadratus femoris?

Nerve to quadratus femoris.

What is the IT band/tract?

A lateral thickening of fascia lata receiving insertions from tensor fasciae latae and gluteus maximus.

Which gluteal nerve exits superior to piriformis?

Superior gluteal nerve—the exception.

Which major nerves exit inferior to piriformis?

Sciatic, inferior gluteal, nerve to quadratus femoris, nerve to obturator internus, and posterior cutaneous nerve of thigh.

What is sciatica?

Compression of the sciatic nerve, often from a herniated disc or bony overgrowth, causing leg pain/numbness and sometimes weakness.

What is the major arterial supply to the gluteal region?

Internal iliac artery.

Which gluteal artery and nerve exit superior to piriformis?

Superior gluteal artery and nerve.

Which gluteal artery and nerve exit inferior to piriformis?

Inferior gluteal artery and nerve.

What is the motor function of the pudendal nerve?

Perineal muscles, external urethral sphincter, external anal sphincter, and levator ani.

What is the sensory territory of the pudendal nerve?

Penis/clitoris and most perineal skin.

What are the three thigh compartments?

Anterior, medial, and posterior.

What is the general function of the anterior thigh compartment?

Hip flexion and knee extension.

What is the general function of the medial thigh compartment?

Thigh adduction and pelvic/postural stabilization.

What is the general function of the posterior thigh compartment?

Hip extension, knee flexion, and hip/knee stabilization.

What nerve innervates the anterior thigh compartment?

Femoral nerve.

What artery supplies the anterior thigh compartment?

Femoral artery.

What nerve innervates the medial thigh compartment?

Obturator nerve.

What artery supplies the medial thigh compartment?

Obturator artery.

What nerve innervates the posterior thigh compartment?

Sciatic nerve via tibial and common fibular divisions.

What artery supplies the posterior thigh compartment?

Perforating branches of the deep femoral artery.

What is the pectineus innervation exception?

Pectineus has dual innervation from femoral and obturator nerves.

What is the short-head biceps femoris innervation exception?

It is innervated by the common fibular division; the rest of the posterior thigh is supplied by the tibial division.

What muscles are in the anterior thigh?

Iliacus, pectineus, sartorius, and quadriceps femoris: rectus femoris, vastus medialis, vastus intermedius, vastus lateralis.

What are the motor and sensory functions of the femoral nerve?

Motor: anterior thigh for knee extension and hip flexion. Sensory: anteromedial thigh and medial leg via saphenous nerve.

What muscles are in the medial thigh?

Obturator externus, pectineus, adductor longus, adductor brevis, adductor magnus, and gracilis.

What are the motor and sensory functions of the obturator nerve?

Motor: medial thigh/adduction. Sensory: medial thigh skin.

What muscles are in the posterior thigh?

Semimembranosus, semitendinosus, long and short heads of biceps femoris, and hamstring part of adductor magnus.

What are the two divisions of the sciatic nerve?

Tibial and common fibular/peroneal divisions.

Which posterior thigh muscle is supplied by the common fibular division?

Short head of biceps femoris.

Which posterior thigh muscles are supplied by the tibial division?

All other posterior thigh muscles listed.

What are the terminal branches of the common fibular nerve?

Superficial fibular and deep fibular nerves.

What are the key knee ligaments?

Patellar ligament, MCL/TCL, LCL, ACL, and PCL.

What distinguishes MCL from LCL?

MCL is flattened, attaches to medial meniscus, and blends with the capsule; LCL is cord-like and does not attach to menisci or blend with capsule.

What does the ACL resist?

Anterior dislocation of the tibia.

What does the PCL resist?

Posterior dislocation of the tibia.

What artery supplies the knee joint?

Popliteal artery through genicular branches.

What are the four major genicular arteries?

Superior lateral, superior medial, inferior lateral, and inferior medial genicular arteries.

What are the superficial posterior leg muscles?

Gastrocnemius, soleus, and plantaris.

What do the superficial posterior leg muscles attach to distally?

They blend into the calcaneal/Achilles tendon.

What nerve innervates the superficial posterior leg compartment?

Tibial nerve.

What artery supplies the superficial posterior leg compartment?

Posterior tibial artery.

What are the functions of the superficial posterior leg compartment?

Knee flexion/rotation, plantarflexion and inversion, and toe flexion.

What is the Achilles/calcaneal tendon?

The thickest tendon in the body; it attaches plantaris, gastrocnemius, and soleus to the calcaneus.

Which muscle is NOT attached to the Achilles tendon?

Popliteus.

What are the deep posterior leg muscles?

Flexor digitorum longus, tibialis posterior, flexor hallucis longus, and popliteus.

What nerve innervates the deep posterior leg compartment?

Tibial nerve.

What artery supplies the deep posterior leg compartment?

Posterior tibial artery.

What are the functions of the deep posterior leg compartment?

Plantarflexion/inversion, knee flexion/rotation, and toe flexion.

What does popliteus do?

Stabilizes the knee and 'unlocks' it by laterally rotating the femur on a fixed tibia.

What is the function of the lateral leg compartment?

Plantarflexion and eversion.

What muscles are in the lateral leg compartment?

Fibularis/peroneus longus and brevis.

What nerve innervates the lateral leg compartment?

Superficial fibular nerve.