203: Living Anatomy of the Lower limb

Gluteal Region

• The gluteus medius muscle contracts during mid-stance to prevent pelvic drop when the opposite foot is off the ground.
• The gluteus medius muscle can be palpated immediately superior to the greater trochanter.
• The gluteus medius muscle, along with gluteus minimus, abducts the thigh.

Hip Joint

• The hip joint is a ball and socket joint that can perform a wide range of movements.
• The movements that can be performed at the hip joint include flexion, extension, abduction, adduction, circumduction, medial (internal) rotation, and lateral (external) rotation.

Hamstring Muscles

• The hamstring muscles can be palpated during an isometric contraction of the muscle group, such as flexing the knee against resistance.
• Injury to the biceps femoris muscle may result in weakness of flexion and lateral rotation of the knee.

Popliteal Fossa

• The borders of the popliteal fossa are formed by the tendons of the semimembranosus and semitendinosus muscles (upper medial border), the tendon of the biceps femoris muscle (upper lateral border), and the two heads of the gastrocnemius muscle (inferior borders).
• The popliteal artery can be palpated using both hands cuffed around the knee.

Knee Joint

• The knee joint is a complex hinge joint that can perform flexion and extension.
• The femoral condyles can be palpated when the knee is flexed, and are located either side of the patella.
• The shape of the femoral condyles provides a stable base for the locking mechanism of the knee.
• The patella would track laterally during locomotion if the vastus medialis muscle is injured.

Ankle and Foot

• The ankle (talocrural) joint is formed between the tibia, fibula, and talus.
• The movements that can be performed at the talocrural joint include dorsiflexion and plantarflexion of the foot.
• The tibialis anterior muscle can be palpated while dorsiflexing the foot.
• Following a tear of the tibialis anterior muscle, the movements of dorsiflexion and inversion of the foot would be weakened.
• Eversion and inversion of the foot occur at the subtalar joint.
• The tendons of the tibialis anterior, extensor hallucis longus, and extensor digitorum longus muscles can be palpated between the lateral and medial malleoli.
• The pulse of the dorsalis pedis artery can be located on the dorsum of the foot, with the extensor hallucis longus tendon lying medial to the artery.

Gastrocnemius Muscle and Achilles Tendon

• The gastrocnemius muscle can be palpated while standing on tiptoes.
• The Achilles tendon (tendocalcaneus) can be traced from the gastrocnemius muscle toward its insertion on the calcaneus.
• The soleus and plantaris muscles also insert into the Achilles tendon.

Tarsal Tunnel and Posterior Tibial Artery

• The tarsal tunnel is located between the calcaneus and the medial malleolus.
• The pulse of the posterior tibial artery can be located within the tarsal tunnel.
• The posterior tibial artery is important for assessing peripheral circulation.

Tibial Nerve and Tarsal Tunnel

• The tibial nerve passes through the tarsal tunnel.
• If the tibial nerve is injured at the tarsal tunnel, sensation would be altered on the plantar surface of the foot.

Fibularis Longus Muscle

• The fibularis longus muscle can be palpated on the lateral side of the leg.
• A simple bedside test to assess the function of the fibularis longus muscle is to ask the patient to evert their foot against resistance.