Clinical Anatomy of the Lower Limb Flashcards
Gross structure of the bony pelvis?
Ilium, ischium, pubic bone and sacrum
These are held by strong ligaments:
• Sacrotuberous
• Sacrospinous
• Sacroiliac
Clinical significance of the pelvic vasculature?
Many arteries and veins, meaning that there is potential for bleeding to occur, with a pelvic fracture; there is also a large potential space that can be filled before clotting occurs
Pelvic nerves?
Pudendal nerves and pelvic splanchnic nerve are important for bladder and bowel control; with pelvic fractures, a PR exam must be done
Sciatic nerve supplies the lower limb and every muscle below the knee; it is sensitive to injury in the greater sciatic notch
Contents of the pelvis?
Urethra, rectum and bladder can be injured with pelvic trauma
Describe the capsule of the hip joint
Inserts into the ring anastamosis at the base of the neck
Clinical importance of the blood supply of the hip joint?
Retinacular arteries are susceptible to damage in intracapsular hip fractures
Superior head is supplied by small end arteries and these are susceptible to blockage with, e.g: fat, thrombus, N gas (decompression sickness); can lead to AVASCULAR NECROSIS OF THE FEMORAL HEAD
Main abductors of the hip? Clinical importance?
Gluteus medius (mainly) and minimus; these tilt the pelvis (towards the stance leg) when standing on one leg (single stance phase of gait)
Damage can cause +ve Trendellenburg gait (pelvis tilts away from stance leg)
Function of the gluteus maximus?
Extension and external rotation
Categories of hip joint muscles?
Flexors, adductors and short external rotators
Also, rectus femoris and hamstrings act as secondary flexors/extensors
Injuries of the anterior muscles of the thigh?
Quadriceps femoris can have:
• Muscle tears
• Quadriceps OR patellar tendon rupture (must test SLR)
Nerve supply to the quadriceps femoris?
Femoral nerve
Injuries of the posterior muscles of the thigh?
Hamstrings can have:
• Muscle tears
• Common hamstring origin avulsion (more serious)
Why can the semitendinosus be used as a tendon graft for, e.g: ACL reconstruction?
Semimembranosus and biceps femoris are the most powerful hamstrings
Nerve supply to hamstrings?
Sciatic nerve (tibial and common fibular nerves)
Clinical importance of the nerve supply to the adductors of the thigh?
Supplied by the OBTURATOR nerve, which can refer pain from the hip to the knee (must do hip exam in someone with knee pain and must check internal rotation)
Function of the adductor hiatus?
Transmits:
• Femoral artery and vein from Hunter’s (subsartorial) canal into the popliteal fossa
• Saphenous nerve (supplied sensation to the medial calf and shin)
Types of cartilage in the knee?
Hyaline cartilage (covers bones)
Fibrocartilaginous menisci (act as shock absorbers between the convex femoral condyles and relatively flat plateau)
Describe meniscal tears
Medial meniscus is fixed whereas the lateral meniscus is mobile
MM tears are more common (9:1)
Ligaments of the knee and their functions?
MCL - resists valgus stress
ACL - resists internal rotation and anterior translation of the tibia
PCL - resists posterior translation of the tibia OR anterior translation of the tibia, e.g: descending stairs
LCL - resists valgus stress and helps to resists external rotation (with PCL and posterolateral corner)
Anatomical and mechanical axes of the lower limb?
Average tibiofemoral angle (anatomic axis) is 6 degrees which causes the centres of the hip, knee and ankle (mechanical axis) to align perfectly
This allows symmetric distribution of loaf between the medial and lateral compartments
Consequences of varum/valgum deformity of the knees?
Increased load on the knee predisposes to medial or lateral, respectively, compartment OA
Function of the knee bursae?
Reduce friction but may become inflamed (bursitis), part. in people who kneel a lot, e.g: carpenters:
• Suprapatellar and infrapatellar
• Prepatellar
• Patellar, sartorius, gracilis, semitendinosus tendons
• Pes anserine
• Shin bone
Compartments of the leg and the nerve supply?
Anterior - deep peroneal/fibular nerve
Lateral - superficial peroneal/fibular nerve
Superficial and deep posterior - tibial nerve
Describe compartment syndrome
Swelling results in pressure, which occludes venous drainage and leads to secondary ischaemia
Emergency fasciotomy to relieve pressure
Injuries of the ankle?
Ligament sprains are common and usually stable; for instability, 2 out of 3 lateral ligaments must be incompetent
Sometimes, the ankle joint can become unstable with a mixture of fracture and ligament rupture
What to look for on X-ray, for instability?
Talar shift
What is tarsal coalition?
Abnormal connection between the tarsal bones
Movements of the foot?
Composite movements inv. the ankle and subtalar joints and the midfoot, allowing pronation and supination
Eversion/inversion
Dorsiflexion/plantarflexion
Abduction/adduction
What individual movements does pronation of the foot consist of?
- Eversion
- Abduction
- Dorsiflexion
What individual movements does supination of the foot consist of?
- Inversion
- Adduction
- Plantar flexion
Maintenance of the medical arch of the foot?
Tibialis posterior and plantar fascia but the tibialis posterior tendon and plantar fascia can degenerate (microtears, tendonitis and pain)
Also, the tibialis posterior can elongate leading to painful flat foot (pes planus) and hindfoot valgus
Describe creation of claw and hammer toe deformities
Imbalance of the flexor and extensor tendons
