Lower Limb Muscles Anatomy Quiz

Lower Limb Muscles

• Gluteal Muscles: Composed of gluteus maximus, medius, and minimus, along with tensor fasciae latae. These muscles are crucial for hip extension, abduction, and external rotation.
• Hamstring Muscles: Include biceps femoris, semitendinosus, and semimembranosus. Functioning as knee flexors and hip extensors, they play a vital role in locomotion and posture.
• Quadriceps Muscles: Consist of rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. These muscles are prime knee extensors, essential for activities like walking and running.
• Anterior Compartment Muscles (Thigh): Contain muscles like tibialis anterior, extensor hallucis longus, and extensor digitorum longus. Their roles centre on dorsiflexion and extension of toes, crucial for foot movements.
• Posterior Compartment Muscles (Thigh): Include the semitendinosus, semimembranosus, and biceps femoris. These muscles act as hip extensors and knee flexors.
• Medial Compartment Muscles (Thigh): Comprise adductors longus, brevis, magnus, gracilis, and pectineus. Primarily responsible for adduction of the thigh.

Lower Limb Vascular System

• Femoral Artery: The major artery of the thigh, supplying blood to the lower limb. It branches into the popliteal artery, which is located behind the knee.
• Popliteal Artery: Supplies blood to the knee joint and the muscles of the lower leg. It further branches into the anterior tibial, posterior tibial and peroneal arteries.
• Anterior Tibial Artery: Supplies blood to the anterior compartment of the lower leg, including the muscles responsible for dorsiflexion.
• Posterior Tibial Artery: Supplies blood to the posterior compartment of the lower leg, including the muscles responsible for plantarflexion.
• Peroneal Artery: Supplies blood to the lateral compartment of the lower leg and the foot.
• Veins: Corresponding veins (femoral, popliteal, anterior and posterior tibial, peroneal) accompany the arteries and are responsible for returning deoxygenated blood to the heart. Valves prevent backflow.

Lower Limb Nerves

• Femoral Nerve: Innervates the quadriceps femoris muscle group, providing sensation for the anterior thigh and medial leg.
• Sciatic Nerve: Largest nerve in the body. It splits into the tibial and common fibular (peroneal) nerves. The tibial nerve innervates the hamstrings and posterior leg muscles.
• Common Fibular (Peroneal) Nerve: Divides into superficial and deep branches. The superficial branch supplies sensation and innervates muscles responsible for eversion of the foot. The deep branch controls dorsiflexion and extension of the toes.
• Obturator Nerve: Innervates the medial thigh muscles (adductors).
• Tibial Nerve: Innervates the posterior muscles of the lower leg, including plantarflexors and knee flexors. It also provides sensation to the sole of the foot and the heel.
• Superficial Peroneal Nerve: Innervates muscles that evert the foot.
• Deep Peroneal Nerve: Innervates muscles that dorsiflex the foot and extend the toes.

Muscle Groups and Actions

• Hip Flexors: Psoas major, iliacus, rectus femoris. These muscles facilitate hip flexion.
• Hip Extensors: Gluteus maximus, hamstrings. These muscles extend the hip joint.
• Knee Flexors: Hamstrings (biceps femoris, semitendinosus, semimembranosus), sartorius. These muscles are responsible for bending the knee.
• Knee Extensors: Quads (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius). These muscles straighten the knee.
• Ankle Dorsiflexors: Tibialis anterior, extensor digitorum longus, extensor hallucis longus. These are crucial for raising the foot upward.
• Ankle Plantarflexors: Gastrocnemius, soleus, tibialis posterior. These muscles lower the foot downward.
• Foot Inverters: Tibialis posterior, flexor hallucis longus, flexor digitorium longus. These muscles turn the sole of the foot inward.
• Foot Evertors: Peroneus longus, peroneus brevis. These muscles turn the sole of the foot outward.

Functional Anatomy

• Walking: Involves a complex interplay between multiple muscle groups. The hip flexors, extensors, knee flexors, and extensors, and ankle plantarflexors and dorsiflexors all play a role in creating and maintaining balance.
• Running: Requires even greater force generation than walking.
• Balance: The lower limb's muscles and joints provide essential stability and postural control.
• Stabilization of the lower limb: The muscles are vital for maintaining alignment and stability during activities.

Clinical Significance

• Fractures: Common injuries affecting bones in the lower limb (femur, tibia, fibula, etc.)
• Ligament Injuries: Damage to ligaments surrounding joints (ACL, PCL, MCL, etc.) common in sports.
• Muscle Strains: Tears or overstretching of muscles, often due to overuse or improper technique during exercise.
• Nerve Injuries: Conditions that affect nerves can result in pain, tingling, numbness, and weakness in the lower limb.
• Vascular Disorders: Conditions including peripheral artery disease or deep vein thrombosis can interrupt blood flow and oxygen delivery in the lower limb.
• Arthritis: Inflammation of joints, leading to pain, stiffness, or mobility limitations in the lower limb (hip osteoarthritis, knee OA, etc.).
• Muscle Atrophy: Degeneration of muscle tissue that can result into muscle weakness or loss of function.
• Postural abnormalities: Pelvic or spinal imbalances may cause abnormal alignment leading to lower limb pain and dysfunction.