Definitions
Synergist
a muscle/group that work together to produce a movement or which prevent unwanted movements.
Iliocostalus Lumbordum
ORIGIN: Iliac crest and tuberosity, sacrum, spinous process of T11-L5 and supra spinous ligaments.
RUNS: Up and out
INSERTION: Lower 6 ribs
ACTION: Ipsilateral side flexion, Bilateral trunk extension
NS: Adjacent Posterior Primary rami
Rotatores
ORGIN: Transverse proceses
RUNS: up and in
INSERTION: Laminae 1-2 levels above
ACTION: Contralateral rotation, bilateral trunk extension, stabilizer
NS: primary adjacent posterior rami
Rectus Abdominus
ORIGIN: Pubic crest, Pubic symphysis
RUNS: Up and wider
INSERTION: Xiphoid process, costal cartilage of ribs 5-7
ACTION: Flexes trunk
NS: Anterior primary ramie of T6-T12
ORIGIN: Superior pubic ramus, pubic tubercle, iliopubic eminence
RUNS: Down, lateral, posterior
INSERTION: Pectineal line of femur
ACTION: Hip adduction, hip flexion
NS: Femoral nerve L2-4, Obturator nerve L2-4
Agonist
the muscle proves the major force to complete the movement. also known as a prime mover
Longissimus Thoracis
ORGIN: Transverse process of all lumbar vertebrae and adjacent fascia
RUNS: Up and out
INSERTION: Transverse processes of all thoracic vertebrae, lower 10 ribs
ACTION: Ipsilateral side flexion, Bilateral trunk extension
NS: Adjacent primary Posterior rami
Interspinalis
ORIGIN: Fibers run between adjacent spinous processes
RUNS: vertically
INSERTION: Spinous process
ACTION: Stabilization, trunk extetnsion
NS: Adjacent primary posterior rami
External oblique
ORIGIN: Outer border of lower 8 ribs and coastal cartilage
RUNS: Down and medial
INSERTION: Pubic tubercle, linea alba, iliac crest, forms inguinal ligament
A: Contralateral rotation, ipsilateral side flexion, Bilateral trunk flexion, increase intra abdominal pressure
NS: Anterior primary rami T7-T12
ORGIN: Adductor part: ischiopubic ramus, Hamstring part: Inferior surface of Ischial tuberosity
RUNS: Down and lateral
INSERTION: Whole linea aspera, adductor tubercle, supracondylar ridge of medial femur
ACTION: Hip extension, Hip Adduction
NS: Adductor part: Obturator L2-4, Hamstring tibial division of sciatic L4-S3
Antagonist
Directly opposes the prime mover/agonist
Spinalis Thoracis
ORIGIN: Spinous processes of T11-L2
RUNS: Up
INSERTION: Spinous processes of T1-T6
ACTION: Ipsilateral side flexion, bilateral trunk extension
NS: Adjacent primary posterior rami
Intertransversarii
ORIGIN: Transverse processes of lumbar vertebrae
RUNS: Vertically
INSERTION: transverse processes of lumbar vertebrae
ACTION: Stabilizer, ipsilateral trunk lateral flexion
NS: adjacent Anterior or posterior primary rami
Internal Oblique
ORGIN: Thoracolumbar fascia, lateral 2/3 of inguinal ligament, iliac crest
RUNS: Up and medial
INSERTION: Lower 4 ribs, linea alba, forms rectus sheath, pubic tubercle
ACTION: unilateral: ipsilateral side flexion, bilateral trunk flexion, Increase intra-abdominal pressure
NS: Anterior Primary rami T7-L1
Vastus Medialis
ORGIN: Lower part of intertrochanteric line, medial lip of linea aspera, tendon of adductor Magnus, medial supracondylar ridge, anterior surface of inter muscular septum
RUNS: Down and horizontally
INSERTION: Patella via Quad tendon, tibial tuberosity via patella tendon, medial border of patella and front of tibia
ACTION: Extends knee
NS: Femoral neve L2-4
Fixator
a muscle that acts as a stabilizer. eg rec abdominus
Semispinalis Thoracis
ORGIN: Transverse processes of lower thoracic vertebrae T6-T10
RUNS: Up
INSERTION: Spinous processes C6-T2
ACTION: Unilateral: contralateral rotation
bilateral trunk extension
NS: Adjacent primary posterior rami
Piriformis
ORGIN: Sacral segments 2-4, gluteal surface of ilium, sacrotuberrous ligament
RUNS: Down, forward, lateral
INSERTION: via tendon to medial aspect of greater trochanter
ACTION: Keep head of femur in acetabulum, External rotation of hip, Abduction of flexed hip
NS: Ventral rami L5-S2
Transverse Abdominis
ORIGIN: Thoracolumbar fascia, iliac crest, lateral 1/3 inguinal ligament, costal cartilage of lower 6 ribs
R: horizontally
INSERTION: Linea alba, rectus sheath, pubic crest
ACTION: Increase intra-abdominal pressure, non direction specific activattion
NS: Anterior primary rami T7-L1
Vastus Intermedius
ORGIN: Upper 2/3 anterior lateral surface of femoral shaft
RUNS: DOWN
INSERTION: quad tendon, patella, lateral margin of patella, tibial tuberosity
ACTION: Knee extension
NS: Femoral nerve L2-4
Sciatic Nerve
-Arises from ventral rami L4-5 And ventral rami S1-3
-Leaves the pelvis via the inferior part of greater sciatic notch
-runs deep to glutei max, entering the thigh between greater trochanter and ischial tuberosity
-passes down back of the thigh
-at apex of the knee/ popliteal fossa splits into tibial and common perineal
Multifidus
ORGIN: Sacrum, transverse processes, fascia overlying erector spinae
RUNS: Up and in
INSERTION: All spinious processes L5-C2
Fibers span 1-5 vertebrae
deepest layer: the vertebrae immediately above
Middle layer: vertebrae 2-3 above
Superficial: vertebrae 3-4 above
ACTION: unilateral: contralateral rotation, bilateral trunk extension
NS: Primary adjacent posterior rami
Plantaris
ORGIN: Lateral supracondylar ridge, popliteal foss, Knee joint capsule
RUNS: Obliquely down
INSERRTION: Medial calcaneous via achilles tendon'
ACTION: Plantar flexion, knee flexion (weak)
NS: Tibial nerve L4-S3
Gemellous superior
ORIGIN: Ischial spine, gluteal surface
RUNS: Down lateral
INSERTION: Tendon of obturator internus
ACTION: Aids obturator internus: external rotation, abducts flexed hip
NS: Nerve to obturator internus L5-S2