Lower Extremity Anatomy and Pathologies Study Guide

Flashcards covering hip, knee, and ankle pathologies, arthrokinematics, ligaments, pelvic mechanics, and muscle functions.

Osteoarthritis (OA)

Degeneration of articular cartilage causing pain, stiffness, and decreased ROM.

Femoroacetabular Impingement (FAI)

Abnormal contact between the femur and acetabulum, causing pain and limited motion.

Hip Labral Tear

Tear of the acetabular labrum causing pain, clicking, locking, and instability.

Hip Dysplasia

Shallow acetabulum resulting in poor femoral head coverage and instability.

Trochanteric Bursitis

Inflammation of the bursa over the greater trochanter causing lateral hip pain.

Piriformis Syndrome

Compression of the sciatic nerve by the piriformis muscle, causing buttock pain and sciatica-like symptoms.

Hip Joint (Closed-packed)

Full extension, slight abduction, medial rotation.

Hip Joint (Loose-packed)

$30^{\circ}$ flexion, $30^{\circ}$ abduction, slight lateral rotation.

Tibiofemoral Joint (Closed-packed)

Full extension with tibial external rotation.

Tibiofemoral Joint (Loose-packed)

$25^{\circ}$ flexion.

Patellofemoral Joint (Closed-packed)

Full extension.

Talocrural (Ankle) Joint (Closed-packed)

Full dorsiflexion.

Subtalar Joint (Closed-packed)

Supination.

Hip Arthrokinematics (Flexion)

Anterior roll, posterior slide.

Hip Arthrokinematics (Extension)

Posterior roll, anterior slide.

Hip Arthrokinematics (Abduction)

Superior roll, inferior slide.

Hip Arthrokinematics (Adduction)

Inferior roll, superior slide.

Knee Arthrokinematics (OKC)

Concave tibia moving on convex femur; roll and glide occur in the same direction.

Knee Arthrokinematics (CKC)

Convex femur moving on concave tibia; roll and glide occur in opposite directions.

Hip Capsular Pattern

Flexion > Abduction > Internal Rotation.

Knee Capsular Pattern

Flexion more limited than extension.

Ankle Capsular Pattern

Plantarflexion more limited than dorsiflexion.

Nutation

Sacral base moves anterior/inferior and sacral apex moves posterior/superior.

Counter Nutation

Sacral base moves posterior/superior and sacral apex moves anterior/inferior.

Anterior Pelvic Tilt

ASIS moves forward and downward, resulting in increased lumbar lordosis and hip flexion.

Posterior Pelvic Tilt

ASIS moves backward and upward, resulting in a flattened lumbar spine and hip extension.

Coxa Vara

Neck-shaft angle $<120^{\circ}$, resulting in increased stress on the femoral neck and increased hip stability.

Coxa Valga

Neck-shaft angle $>135^{\circ}$, resulting in decreased hip stability and increased risk of dislocation.

Q Angle

Angle formed between ASIS to center of patella and center of patella to tibial tuberosity ($\text{Males } \sim 14^{\circ}$, $\text{Females } \sim 17^{\circ}$).

Iliofemoral Ligament

Also known as the Y ligament of Bigelow; it is the strongest ligament in the body and prevents hyperextension.

Pubofemoral Ligament

Ligament that limits abduction and extension.

Ischiofemoral Ligament

Ligament that limits internal rotation and extension.

Ligamentum Teres

Ligament that carries the blood supply to the femoral head.

Anterior Cruciate Ligament (ACL)

Prevents anterior tibial translation and hyperextension.

Posterior Cruciate Ligament (PCL)

Prevents posterior tibial translation.

Medial Collateral Ligament (MCL)

Resists valgus stress.

Lateral Collateral Ligament (LCL)

Resists varus stress.

Deltoid Ligament

Medial ankle ligament that resists eversion.

Screw-home Mechanism

Automatic rotation during the last $20-30^{\circ}$ of knee extension (tibia rotates externally in OKC, femur rotates internally in CKC) to lock the knee.

Pronation (Ankle)

Triplanar movement consisting of dorsiflexion, eversion, and abduction.

Supination (Ankle)

Triplanar movement consisting of plantarflexion, inversion, and adduction.

Pubococcygeus (PC)

Muscle in the levator ani group that supports pelvic organs and urinary continence.

Puborectalis

Muscle in the levator ani group that maintains the anorectal angle for fecal continence.

Concentric Contraction

Contraction where the muscle shortens and creates the movement.

Eccentric Contraction

Contraction where the muscle lengthens and controls the movement.

Isometric Contraction

Contraction where the muscle contracts with no movement.