Anatomy Lecture 14 The Lower Appendicular Musculature

Front 1

Muscles acting on the hip and femur (anterior)

Back 1

Iliacus and psoas major are the two principal anterior muscles. They insert jointly on the lesser trochanter of the femur as the iliopsoas. Both function in flexing the hip joint on the thigh, the iliacus is innervated by the femoral nerve while the psoas major recieves segmental innervation from the lumbar plexus.

Front 2

Lateral muscles of the hip

Back 2

tensor fascia lata. This muscle is embedded in a thickening of the fascia lata of the thigh-the iliotibial band. The tensor fascia lata contracts to tighten the iliotibial band and assist in bracing the knee when you raise the opposite foot in walking.

Front 3

Posterior muscles of the hip

Back 3

Gluteal muscles: gluteus maximus, gluteus medius, gluteus minimus. The maximus is a major hip extensor and is innervated by the inferior gluteal nerve. The medius and minimus are abductors and medially rotate the femur and are both innervated by the superior gluteal nerve.

Front 4

The five lateral rotators of the posterior muscles of the hip.

Back 4

Piriformis, superior gemellus, obturator internus, inferior gemellus, quadratus femoris. These muscles rotate the femur laterally and oppose medial rotation by the gluteus medius and minimus. They re all innervated segmentally by the sacral plexus.

Front 5

Posterior compartment of the thigh

Back 5

Semitendinosus, semimembranosus, biceps femoris (long and short heads). All these muscles are innervated by the sciatic nerve.

Front 6

Medial compartment of the thigh

Back 6

Adduction of the hip. These muscles are innervated by the obturator nerve. Muscles are adductor longus, adductor brevis (under the longus), adductor magnus (also extends hip), gracilis, pectineus.

Front 7

Anterior compartment of the thigh

Back 7

Extension of the leg. Muscles include: sartorius. components of the quadriceps femoris include the rectus femoris, vastus lateralis, vastus medialis, vastus intermedius. These four members share a common tendon-the quadricpes tendon. It has the patella embedded in it and subsequently attaches to the tibial tuberosity as the patellar ligament.

Front 8

Compartments of the leg

Back 8

Superficial Posterior compartment contains the gastrocnemius and the soleus. The Deep Posterior Compartment contains the flexor hallucis longus, flexor digitorum longus and the tibialis posterior. The lateral compartment contains the fibularius longus and the fibularis brevis. The anterior compartment contains the tibialis anterior, extensor hallucis longus, and extensor digitorum longus.

Front 9

Anterior compartment of the leg

Back 9

These muscles dorsiflex the ankle to keep your toes scraping the ground as you walk. These muscles include: tibialis anterior, extensor digitorum longus, extensor hallucis longus, and fibularis tertius. These muscles are all innervated by the deep fibular nerve.