Lower Body Musculature Primer CONOR HARRIS CSCS XPS

Lower Body Musculature Primer CONOR HARRIS – CSCS, XPS, CES, CPT

External Obliques Attachments: External surfaces of ribs 5 -12 Linea alba Anterior half of iliac crest Function: Bilateral contraction: Trunk flexion, compresses abdominal viscera, expiration Unilateral contraction: Trunk lateral flexion (ipsilateral), trunk rotation (contralateral)

Internal Obliques Attachments: Inferior borders of ribs 10 -12 Anterior two-thirds of iliac crest Linea alba Function: Bilateral contraction - Trunk flexion, compresses abdominal viscera Unilateral contraction - Trunk lateral flexion (ipsilateral), trunk rotation (ipsilateral) Exhalation

Transverse Abdominis Attachments: Internal surfaces of costal cartilages of ribs 7 -12, Thoracolumbar fascia Anterior two thirds of iliac crest Function: Bilateral contraction - Compresses abdominal viscera Unilateral contraction - Trunk rotation (ipsilateral) Exhalation

Rectus Abdominis Attachments: Xiphoid process Costal cartilages of ribs 5 -7 Pubic symphysis Function: Trunk flexion Compresses abdominal viscera Exhalation

Psoas Major Attachments: Vertebral bodies of T 12 -L 4 Transverse processes of L 1 -L 5 vertebrae Lesser trochanter of femur as iliopsoas tendon Function: Flexion of the femur/trunk External rotation of femur Lateral flexion of trunk

Iliacus Attachments: Iliac fossa Lesser trochanter of femur Function: Open-chain: Flexion of femur Closed-chain: Flexion of trunk External rotation of femur

Quadratus Lumborum Attachments: Iliac crest Inferior border of rib 12 Transverse processes of vertebrae L 1 -L 4 Function: Bilateral contraction - fixes Ribs 12 during inspiration, trunk extension Unilateral contraction - lateral flexion of trunk (ipsilateral)

Erector Spinae Attachments: Transverse processes of vertebrae Sacrum Posterior iliac crest Function: Bilateral contraction - extension of spine Unilateral contraction - lateral flexion of spine (ipsilateral)

Glute Max Attachments: Posterolateral aspect of the sacrum and coccyx Sacrotuberous ligament Ilium (behind the posterior gluteal line) Thoracolumbar fascia Function: Primary hip extensor & external rotator Superior fibers: Hip abduction Inferior fibers: Hip adduction, extension

Gluteus Medius Attachments: Gluteal surface of ilium Lateral aspect of greater trochanter of femur Function: Anterior fibers: abduct, assist in flexion and medial rotation of hip (maximized at 90 degrees of hip flexion) Middle fibers: abduction Posterior fibers: abduct, assist in extension and lateral rotation of pelvis

Gluteus Minimus Attachments: Gluteal surface of ilium Anterior aspect of greater trochanter of femur Function: Abduction of femur Internal rotation of femur (at 60+ degrees of hip flexion)

Piriformis Attachments: Anterior surface of the sacrum Apex of the greater trochanter Function: Within hip extension: External rotation of femur Within hip flexion: Abduction of hip ◦ Internal rotator around 90 degrees of hip flexion

Obturator Externus Attachments: Anterior surface of obturator membrane Trochanteric fossa of femur Function: Within hip extension: External rotator of femur Within hip flexion: Abduction of femur

Obturator Internus Attachments: Posterior surface of the obturator membrane Medial surface of greater trochanter of femur Function: Within hip extension: External rotator of femur Within hip flexion: Abduction of femur

Superior Gemellus Attachments: Ischial spine Medial surface of greater trochanter of femur Function: Within hip extension: External rotator of femur Within hip flexion: Abduction of femur

Inferior Gemellus Attachments: Ischial tuberosity Medial surface of greater trochanter of femur Function: Within hip extension: External rotator of femur Within hip flexion: Abduction of femur

Adductors Attachments: Body of pubis Middle third of linea aspera of femur (medial lip) Function: Femoral adduction ~0 -40 degrees of hip flexion: Hip flexion, external rotation and femur/pelvis ~70 -100 degrees hip flexion: Hip extension, internal rotation of femur/pelvis

Rectus Femoris Attachments: Anterior inferior iliac spine Tibial tuberosity Patella Function: Flexion of femur Extension of femur External rotation of femur in anterior pelvic orientation

Vastus Quads Attachments: Intertrochanteric line Greater trochanter Tibial tuberosity Patella Function: Extension of femur Vastus Lateralis can act as secondary internal rotator

Tensor Fasciae Latae Attachments: Anterior superior iliac spine (ASIS) Iliotibial band Function: Internal rotation of femur Secondary abduction, flexion, and extension of femur

Biceps Femoris Attachments: Long head: Ischial tuberosity, sacrotuberous ligament Short head: Linea aspera of femur (lateral lip), lateral supracondylar line of femur Both heads: Lateral head of fibula Function: Proximal fibers: Hip extension, external rotation of femur Distal fibers: Flexion of femur, external rotation of femur

Semitendinosus Attachments: Ischial tuberosity Proximal end of tibia below medial condyle Function: Proximal fibers: Hip extension, internal rotation of femur Distal fibers: Flexion of femur, internal rotation of femur

Semimembranosus Attachments: Ischial tuberosity Medial condyle of tibia Function: Proximal fibers: Hip extension, internal rotation of femur Distal fibers: Flexion of femur, internal rotation of femur

Gastrocnemius Attachments: Lateral & medial condyle of the femur Posterior surface of the calcaneus Function: Plantar flexion Flexion of knee

Soleus Attachments: Medial border of tibia Head of fibula Posterior surface of the calcaneus Function: Plantar flexion

Tibialis Anterior Attachments: Lateral border of tibia Base of big toe (metatarsal bone 1) Function: Dorsiflexion Inversion