exam three 2

Hip and Pelvis Muscles

• Gluteus Maximus
  • Originates from the posterior iliac crest, sacrum, and coccyx.
  • Inserts on the gluteal tuberosity of the femur and the IT band.
  • Responsible for hip extension and external rotation.
    • Upper fibers contribute to abduction.
    • Lower fibers contribute to adduction.
• Gluteus Medius
  • Originates from the outer surface of the ilium.
  • Inserts on the lateral surface of the greater trochanter.
  • Responsible for hip abduction.
    • Anterior fibers contribute to internal rotation.
    • Posterior fibers contribute to external rotation.
• Piriformis
  • Originates from the anterior surface of the sacrum.
  • Inserts on the greater trochanter of the femur.
  • Responsible for external rotation of the extended hip and abduction of the flexed hip.
• Psoas Major and Minor
  • Originates from the T12-L5 vertebral bodies and transverse processes for the major, and T12 & L1 vertebrae for the minor.
  • Inserts on the lesser trochanter of the femur for the major, and the pectineal line for the minor.
  • Responsible for hip flexion and trunk flexion when the femur is fixed.

Knee and Thigh Muscles

• Rectus Femoris
  • Originates from the anterior inferior iliac spine (AIIS).
  • Inserts on the tibial tuberosity via the patellar tendon.
  • Responsible for knee extension and hip flexion.
• Vastus Medialis
  • Originates from the linea aspera (medial lip).
  • Inserts on the tibial tuberosity via the patellar tendon.
  • Responsible for knee extension.
• Vastus Intermedius
  • Originates from the anterior and lateral surface of the femur.
  • Inserts on the tibial tuberosity via the patellar tendon.
  • Responsible for knee extension.
• Sartorius
  • Originates from the anterior superior iliac spine (ASIS).
  • Inserts on the medial tibia (pes anserinus).
  • Responsible for hip flexion, abduction, external rotation, and knee flexion.
• Gracilis
  • Originates from the inferior pubic ramus.
  • Inserts on the medial surface of the tibia (pes anserinus).
  • Responsible for hip adduction, knee flexion, and internal rotation of the knee.
• Semimembranosus
  • Originates from the ischial tuberosity.
  • Inserts on the posterior medial tibial condyle.
  • Responsible for hip extension, knee flexion, and internal rotation of the knee.
• Biceps Femoris
  • Originates from:
    • Long head: Ischial tuberosity
    • Short head: Linea aspera
  • Inserts on the head of the fibula.
  • Responsible for knee flexion and external rotation; the long head also contributes to hip extension.

Hip and Pelvis - Joint Movements

• Hip joint movements:
  • Flexion
  • Extension
  • Abduction
  • Adduction
  • Internal rotation
  • External rotation
• Pelvic tilt/rotation:
  • Anterior tilt (hip flexion)
  • Posterior tilt (hip extension)
  • Lateral tilt (hip abduction/adduction)
  • Rotation (internal/external rotation)
• Pelvic rotations influence hip movement and alignment but are not hip movements themselves.

Ankle and Foot Muscles

• Gastrocnemius
  • Originates from the posterior surfaces of the medial and lateral femoral condyles.
  • Inserts on the posterior surface of the calcaneus via the Achilles tendon.
  • Responsible for plantar flexion of the ankle and assists with knee flexion.
• Soleus
  • Originates from the posterior surface of the proximal tibia and fibula.
  • Inserts on the posterior calcaneus via the Achilles tendon.
  • Responsible for plantar flexion of the ankle.
• Tibialis Anterior
  • Originates from the lateral condyle and upper lateral surface of the tibia.
  • Inserts on the medial cuneiform and base of the first metatarsal.
  • Responsible for dorsiflexion and inversion of the foot.

Foot and Ankle - Injuries

• Commonly injured ligaments during ankle sprains caused by excessive inversion:
  • Anterior talofibular ligament (ATFL)
  • Calcaneofibular ligament (CFL)

Trunk and Spine Muscles

• Rectus Abdominis
  • Trunk flexion, posterior pelvic tilt
• External Oblique
  • Trunk flexion, lateral flexion (same side), rotation (opposite side)
• Internal Oblique
  • Trunk flexion, lateral flexion (same side), rotation (same side)
• Transverse Abdominis
  • Compresses abdominal cavity, stabilizes lumbar spine
• Erector Spinae (Iliocostalis, Longissimus, Spinalis)
  • Trunk extension, lateral flexion
• Quadratus Lumborum
  • Lateral flexion of the trunk, lumbar extension, pelvic elevation

Trunk and Spine - Vertebrae

• Segments of the spinal column and the number of vertebrae in each:
  • Cervical - 7
  • Thoracic - 12
  • Lumbar - 5
  • Sacral - 5 (fused)
  • Coccygeal - 4 (fused)
• The vertebral body is the load-bearing part of the vertebrae.
• Transverse (sides) and spinous (back) processes come off the vertebrae, serving as attachment sites for muscles and ligaments, increasing leverage for movement and stability.
• Facet joints are small joints between vertebrae that guide and restrict movement, particularly resisting excessive rotation and shear forces.
• The spine should have four curves in normal vertical alignment: cervical lordosis, thoracic kyphosis, lumbar lordosis, and sacral kyphosis.
  • Lordosis: Excessive inward curve (lumbar or cervical)
  • Kyphosis: Excessive outward curve (thoracic)
  • Scoliosis: Abnormal lateral curve of the spine

Intervertebral Discs

• Intervertebral discs absorb shock, allow spinal flexibility, and distribute loads during movement.
• The discs are composed of the annulus fibrosus (outer ring) and nucleus pulposus (gel-like center).
• Disc herniation occurs when the nucleus pulposus pushes through a tear in the annulus fibrosus, potentially pressing on nerves.
• Compression is the most common form of loading on the discs.