cremaster muscle Origin- inguinal ligament Insertion- Action- genitofemoral nerve Innervation- raise and lower the scrotum First two layers of the back 1st layer: A. Trapezius B. Latissimus Dorsi Ventral Primary Rami ( hypomere) Motor Dorsal Primary Rami (epimere) Sensory What are the respiratory muscles of the back? 1. Serratus posterior Superior 2. Serratus posterior inferior Serratus Posterior superior (A,O,I, INN) Origin- C7- T3 Spinous process Insertion- Ribs Action- Elevate Ribs ( Inspiration) Innervation- Ventral Primary Rami Serratus Posterior Inferior Origin- T11- L3 Spinous process Insertion- Ribs ( lower) 9-12 Action- Depress Ribs ( expiration) Innervation- Ventral Primary Rami True Back Muscles Groups:Splenious Erector Spinae Transversospinalis Splenius Capitus Origin- Ligamentus Nuche Insertion- Mastoid and Nuchal Line Action- Bilateral Flexion and Rotation to the same side Innervation- Dorsal Primary Rami Splenius Cervicis Origin- Spinous Process T1-T6 Insertion- Transverse Process C1- C4 Action- Bilateral Flexion and rotate neck to the same side Innervation Dorsal Primary Rami Erector Spinae Group (I.. Luv.. S(word).. Action: Bilaterally flex, extend and rotate head ( to same side) and vertebral column. -Ilicostalis -longissimus -spinalis Spinalis Origin- Illiac Crest, Sacrum Insertion- Spinous Process Action- Bilaterally flex, extend and rotate head ( to same side) and vertebral column Innervation- Dorsal Primary Rami of Spinal nerves Iliocostalis Origin- Sacrm, Illiac Crest, Lumbar Spinous Process Insertion- Ribs Action- Bilaterally flex, extend and rotate head ( to same side) and vertebral column Innervation- Dorsal Primary Rami Longissimus Origin- Sacrm, Illiac Crest, Lumbar Spinous Process Insertion- Transverse Process Action-Bilaterally flex, extend and rotate head ( to same side) and vertebral column Innervation- Dorsal Primary Rami Transversospinalis Semispinalis Capitis Multifidi Rotartory Semispinals Capitis Origin- Transverse Process t6-t7 Insertion- Opcipital Bone/ Nuchal Ridges Action- Extends head Innervation- Dorsal Primary Rami Segmental sensory innervation on a deramtomes of the Nipple T-5 Segmental sensory innervation on a deramtomes of the Belly Button T-10 The thoracic wall has 3 muscles layers: 1. external intercostal 2. internal intercostal 3. innermost intercostal a. transverse thoracis b. subcostal External Intercostal Muscle Origin- upper rib, inferior border Insertion- lower rib, upper border Action- : inspiration, (maintains intercostal space) Innervation- intercostal nerves Internal Intercostal Muscle Origin- lower rib,upper border Insertion- upper rib, inferior border Action- force expiration, (maintains intercostal space) Innervation- : intercostal nerves Innermost Intercostal Origin: rib above Insertion: rib below Action: ? Innervation: intercostal nerves External Abdominal Oblique Origin: lower 8 ribs Insertion: linea alba pubic tubercle & crest iliac crest Actions: a. laterally flexes & rotates spine b. increase abdominal pressure c. fixes ribs during forced expiration Nerves: lower intercostal nerves Internal Abdominal Oblique Origin: lumbar fascia iliac crest inguinal ligament Insertion: linea alba last 4 ribs pubic crest Actions: a. laterally flexes & rotates spine b. increase abdominal pressure c. assists forced expiration Nerves: lower intercostal nerves Transverse Abdominis Origin: lumbar fascia iliac crest inguinal ligament cartilages of lower 6 ribs Insertion: linea alba pubic crest Actions: laterally flexes & rotates spine increase abdominal pressure assists respiration Nerves: lower intercostal nerves Rectus Abdominis Origin: pubic bone Insertion: xiphoid process lower 6 ribs Actions: laterally flexes (unilateral) flexes spine (bilateral), assists forced expiration, increases abdominal pressure Nerves: lower intercostal nerves Tendinous Intersections Tendons that run to form the abdominals... 6 pack linea alba The line that goes through the median of the abdomen The inguinal canal passes through three abdominal muscles or their aponeuroses external oblique internal oblique transverse abdominis cremaster muscle Origin- inguinal ligament Insertion- Action- genitofemoral nerve Innervation- raise and lower the scrotum