Page 499 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

Musculoskeletal, skin, and connective tissue ` anatomy and physiology Musculoskeletal, skin, and connective tissue ` anatomy and physiology section iii 455

Ankle sprains Anterior TaloFibular ligament—most common
ankle sprain overall, classified as a low ankle Fibula Anterior inferior
tibiofibular ligament
sprain. Due to overinversion/supination of foot. Posterior inferior Tibia Anterior talofibular
Anterior inferior tibiofibular ligament—most tibiofibular ligament ligament
common high ankle sprain. Posterior talofibular Navicular
Cuneiform bones
Always Tears First. ligament Talus

Calcaneus Cuboid
Calcaneofibular
ligament
Tarsals Metatarsals Phalanges

Signs of lumbosacral Paresthesia and weakness related to specific lumbosacral spinal nerves. Intervertebral disc (nucleus
radiculopathy pulposus) herniates posterolaterally through annulus fibrosus (outer ring) into central canal due to
thin posterior longitudinal ligament and thicker anterior longitudinal ligament along midline of
vertebral bodies. Nerve affected is usually below the level of herniation.

Disc level
herniation L3-L4 L4-L5 L5-S1
Nerve root L4 pedicle (cut)
L4 L5 S1
L4 body
L4 nerve root
L4-L5 disc
protrusion
L5 body
Dermatome L5 nerve root
L5-S1 disc
protrusion

S1 nerve root

S2 nerve
Weakness of knee extension Weakness of dorsiflexion Weakness of plantar flexion
Clinical patellar reflex Di€culty in heel walking Di€culty in toe walking root
↓
findings Achilles reflex
↓

Neurovascular pairing Nerves and arteries are frequently named together by the bones/regions with which they are
associated. The following are exceptions to this naming convention.
loCation nERVE aRtERy
Axilla/lateral thorax Long thoracic Lateral thoracic
Surgical neck of humerus Axillary Posterior circumflex
Midshaft of humerus Radial Deep brachial
Distal humerus/cubital fossa Median Brachial
Popliteal fossa Tibial Popliteal
Posterior to medial malleolus Tibial Posterior tibial

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