Advanced Human Anatomy: Lower Limbs

• The information provided is about advanced human anatomy, focusing on the lower limbs, hip, foot, and related structures.

Lower Limbs

• The lower limb supports the body's weight, transferring support to the axial skeleton via the hip and sacroiliac joints.
• Hip and knee joints lock to provide stability, balance and conserve muscles' energy for prolonged standing.
• The lower limb consists of the gluteal region (buttocks and lateral hip), thigh, leg, and foot.

Veins and Cutaneous Nerves

• Superficial veins drain blood towards the heart, communicating with deep veins parallel to the arteries of the lower limb.
• Lower limb veins include femoral, great saphenous, and small saphenous veins.
• Nerves are terminal sensory branches of major lower limb nerves.
• The nerves arise from the lumbar (L1-L4) and sacral (L4-S4) plexuses.
• The gluteal region has superior, middle, and inferior cluneal nerves.
• The thigh includes posterior, lateral, anterior, and medial cutaneous nerves.
• The leg has lateral sural, superficial fibular, saphenous, and sural cutaneous nerves.

Hip

• The pelvis comprises the right and left coxal (hip) bones, sacrum, and coccyx.
• The proximal femur (thigh bone) articulates with the pelvis at the acetabulum.
• Other features of the pelvic girdle include its stabilizing lumbosacral and sacroiliac joints.

Hip Joints

• The hip joint is a classic ball-and-socket synovial joint.
• Sacroiliac ligaments include posterior, anterior, and interosseous ligaments.

Arteries of the Hip Joint

• Arteries include the medial circumflex femoral, lateral circumflex femoral, acetabular branch, and gluteal branches (superior and inferior).

Nerve Plexuses

• The sacral and coccygeal plexus are part of the nerve plexuses.
• The lumbar plexus, femoral nerve, and obturator nerve are also components of the nerve plexuses.

Gluteal Region

• Superficial muscles include the three gluteal muscles and the tensor fasciae latae laterally.
• The gluteus maximus extends the hip, stabilizes, and rotates it laterally (externally).
• The gluteus medius and minimus abduct and medially (internally) rotate the thigh.
• The tensor fasciae latae abducts, medially (internally) rotates and stabilizes the extended knee.
• Deep muscles include lateral rotators.

Anterior Compartment (Thigh)

• The muscles include the quadriceps and are primarily knee extensors.
• The Sartorius and rectus femoris secondarily lex the thigh at the hip.
• They are innervated by the femoral nerve and supplied by the femoral artery and its deep branch.
• The psoas major and iliacus (iliopsoas muscle) act as flexors of the thigh at the hip joint.

Medial Compartment (Thigh)

• The muscles primarily adduct the thigh at the hip and can secondarily lex and/or rotate the thigh.
• Muscles are largely innervated by the obturator nerve and supplied by the obturator and the deep femoral arteries.
• The pectineus muscle is largely innervated by the femoral nerve and by a branch of the obturator nerve.
• The adductor magnus receives innervation from the tibial portion of the sciatic nerve.

Posterior Compartment (Thigh)

• Muscles are largely flexors of the leg at the knee and extensors of the thigh at the hip.
• The posterior compartment muscles do not include the the short head of biceps femoris muscle.
• They are known as the hamstrings, rotate the knee and are attached proximally to the ischial.
• These are innervated by the tibial division of the sciatic nerve
• They are supplied by the femoral and deep femoral arteries.

The Femoral and Obturator Arteries

• The femoral artery supplies the tissues of the thigh, descending into the adductor canal.
• The obturator artery also supplies the superomedial thigh.

Pelvic Fractures

• Pelvic fractures impact the pelvis and sacrum, categorized as stable or unstable.
• Stable fractures involve one side of the pelvic ring.
• Unstable fractures involve two portions of the pelvic ring or ligamentous disruption.

Intracapsular Femoral Neck Fracture

• Type I: impaction of the superior femoral neck (incomplete).
• Type II: nondisplaced (complete fracture).
• Type III: partial displacement between femoral head and neck.
• Type IV: complete displacement between femoral head and neck.

The Foot

• The bones of the foot are arranged to form the longitudinal and transverse arches.
• Supporting structures include tibialis anterior/posterior, fibularis longus muscles, and specific ligaments.
• Specific ligaments include the plantar calcaneonavicular (spring) ligament, plantar calcaneocuboid (short plantar) ligament, & long plantar ligament.

Synovial Sheaths and Retinacula

• Synovial sheaths offer protection and lubrication for muscle tendons passing from the leg to the foot.
• Retinacula are fibrous bands tethering tendons at the ankle.
• Flexor retinaculum spans from medial malleolus to calcaneus (tethers plantarflexor tendons).
• Extensor retinaculum has superior and inferior bands tethering dorsiflexor tendons.
• Fibular retinacula consists of superior and inferior bands tethering fibularis tendons of the lateral compartment.

Dorsum of the Foot

• Dorsal foot has two intrinsic muscles.
• The muscles are the extensor digitorum brevis and extensor hallucis brevis muscles function to extend the toes.
• The muscles are innervated by the deep fibular nerve.
• The anterior tibial artery, via its dorsalis pedis branch, provides blood supply.
• The dorsal venous arc drains to the great and or small saphenous veins.

Sole of the Foot

• The sole is protected by the plantar aponeurosis.
• Beneath the aponeurosis, intrinsic muscles are arranged into four layers: the lumbrical and interosseus muscles.
• The medial or lateral plantar nerves innervate the sole.
• The medial and lateral plantar arteries supply blood derived from the posterior tibial artery.