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The Trunk and Spinal Column

– complex – 24 intricate & complex articulating vertebrae – 31 pairs of spinal – most complex part of body other than CNS Chapter 12 • Abdominal muscles The Trunk and Spinal Column – some sections linked by & tendinous bands – do not attach from to bone Manual of Structural Kinesiology • Many small intrinsic muscles act on , R.T. Floyd, EdD, ATC, CSCS vertebral column, & – assist in spinal stabilization or respiration – too deep to palpate

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Bones

• 24 articulating & 9 fused vertebrae • 3 normal curves within spine – 7 cervical () vertebrae – Thoracic spine curves anteriorly – 12 thoracic (chest) vertebrae – 5 (lower ) vertebrae – Cervical & lumbar spine curve posteriorly – 5 (posterior pelvic girdle) – Spinal curves enable it to absorb blows & vertebrae shocks – 4 ( bone) vertebrae • First 2 - shapes • Vertebrae increase in size from cervical allow for extensive rotary movements to lumbar region due to lower back of head to side, as well as forward & having to support more weight backward movement From Seeley RR, et al: & physiology , ed 3, St. Louis, 1995, Mosby.

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Bones Bones

• First 2 cervical vertebrae - & • Cervical vertebrae • Vertebrae C2 through L5 - similar architecture – body - anterior bony block – central vertebral for – transverse projecting out laterally – spinous process projecting posteriorly

From Anthony CP, Kolthoff NJ: Textbook of anatomy and physiology , ed 9, St. Louis, 1975, Mosby.

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1 Bones Bones

From Anthony CP, Kolthoff NJ: Textbook of anatomy and physiology , ed 9, St. Louis, 1975, Mosby.

From Anthony CP, Kolthoff NJ: Textbook of anatomy and physiology , ed 9, St. Louis, 1975, Mosby.

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Bones Bones

- increased posterior concavity • 12 pairs of of lumbar & cervical curves – 7 pairs of true ribs • - increased anterior concavity of attach directly to thoracic curve • Lumbar kyphosis - reduction of normal – 5 pairs of false ribs lordotic curve, resulting in a flat-back • 3 pairs attach appearance indirectly to sternum • - lateral curvatures or sideward • 2 pairs of floating deviations of spine ribs - ends are free

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Bones Bones

– All ribs attached posteriorly • Key bony landmarks to thoracic vertebrae – muscles of neck • Sternum • mastoid process – Manubrium, body of • transverse processes of cervical spine sternum, & • spinous processes of cervical spine • spinous processes of upper 4 thoracic vertebrae • manubrium of sternum • medial

From Shier D, Butler J, Lewis R: Hole’s anatomy & physiology, ed 9, New York, 2002, McGraw-Hill. © 2007 McGraw-Hill Higher Education. All rights reserved. 12-11 © 2007 McGraw-Hill Higher Education. All rights reserved. 12-12

2 Bones

• Key bony landmarks • Atlantooccipital – posterior muscles of spine – first joint • spinous processes of thoracic spine – formed by occipital of st • transverse processes of thoracic spine sitting on articular of the 1 • posterior ribs – allows flexion & extension – anterior trunk muscles • Atlantoaxial joint • borders of lower 8 ribs – Atlas (C1) sits on axis (C2) • costal of ribs – Most cervical rotation occurs here • – Trochoid or pivot-type joint From Lindsay DT: functional human anatomy , St • pubic crest Louis, 1996, Mosby. – Most mobile joint of any two vertebrae

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Joints Joints

• Minimal movement between any 2 – Intervertebral disks vertebrae (except atlantoaxial joint) • between & adhering to articular – Cumulative effect of combined of vertebral bodies movement from several vertebrae • annulus fibrosus - outer rim of allows for substantial movements dense – Vertebral articulations classified as • nucleus pulposus - central arthrodial gelatinous, pulpy substance From Thibodeau GA, Paton KT: Anatomy & – Gliding-type joints due to limited • compressed elastic material allows physiology, ed 9, St. Louis, 1993, Mosby; Seeley RR, Stephens TD, Tate P: Anatomy & physiology, ed 7, gliding movements compression in all directions along New York, 2006, McGraw-Hill. – Gliding movement between superior with torsion & inferior of facets • become less resilient with age, joints , or improper use, resulting in From Lindsay DT: functional human anatomy , St Louis, 1996, Mosby. a weakened annulus fibrosus

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Joints Joints

– Intervertebral disks • Most movement occurs in cervical & lumbar • herniated nucleus pulposus • Some slight thoracic movement (herniated or “slipped” disk) – nucleus protruding through • Movements of head annulus resulting from – Movement between cranium & 1 st cervical and substantial weakening within other cervical vertebrae combined with compression – protrusion puts pressure – Referred as cervical movements on spinal root, • Trunk movements causing radiating pain, – Lumbar motion terminology describes combined tingling, numbness, and/or weakness in lower motion in thoracic & lumbar extremity From Thibodeau GA, Paton KT: Anatomy & physiology, ed 9, St. Louis, 1993, Mosby; Seeley RR, Stephens TD, Tate P: Anatomy & physiology, ed 7, New York, 2006, McGraw-Hill. © 2007 McGraw-Hill Higher Education. All rights reserved. 12-17 © 2007 McGraw-Hill Higher Education. All rights reserved. 12-18

3 Joints Joints

• Cervical region • Lumbar spine including trunk movement – Flexes 45 degrees – Flexes approximately 80 degrees – Extends 45 degrees – Extends 20 to 30 degrees – Laterally flexes 45 degrees – Rotate approximately 60 degrees

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Joints Movements

• Lumbar spine including trunk movement • Spinal movements are often preceded – Lumbar lateral flexion to 35 degrees by the name given to the region of – Rotation approximately 45 degrees movement • Ex. flexion of trunk at lumbar spine is known as lumbar flexion, & extension of neck is cervical extension • Pelvic girdle rotates as a unit due to movement occurring in & lumbar spine

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Movements Movements

• Spinal flexion • Spinal extension – anterior movement of spine; in – return from flexion or posterior cervical region the head movement of spine; in cervical moves toward chest; in lumbar spine, head moves away from region the thorax moves the chest & thorax moves away toward from pelvis

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4 Movements Movements

• Lateral flexion (left or right) • Spinal rotation (left or right) – sometimes referred to as side – rotary movement of spine in bending; head moves laterally horizontal plane; rotates toward the & thorax from neutral toward shoulder moves laterally toward pelvis & thorax rotates to one side • Reduction – return movement from lateral flexion to neutral

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Trunk & Spinal Column Muscles Trunk & Spinal Column Muscles • A few large muscles & many small muscles • Large abdominal muscles - lumbar • Erector spinae (sacrospinalis) movements – largest muscle – Rectus abdominis, external oblique abdominal, – extends on each side of spinal column from pelvic internal oblique abdominal, & quadratus lumborum region to cranium • Numerous small muscles – divided into 3 muscles – Many originate on one vertebra & insert on next • , , & vertebra • From medial to lateral side, has attachments in lumbar, thoracic, & cervical regions – Important in functioning of spine • Actually made up of 9 muscles • Grouped according to location & • Sternocleidomastoid & splenius muscles – large muscles involved in cervical & head movements

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Trunk & Spinal Column Muscles Trunk & Spinal Column Muscles • Some muscles have multiple segments • Abdominal wall muscles do not go from – one segment of a muscle may be located & bone to bone but attach into an perform movement in one region while another (fascia) around rectus segment of same muscle may be located in another region to perform movements in that abdominis area region – external oblique abdominal, internal • Many muscles of trunk & spinal column oblique abdominal, & transversus function in moving spine & aiding respiration abdominis – All thoracic muscles are primarily involved in respiration

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5 Trunk & Spinal Column Muscles Trunk & Spinal Column Muscles • Muscles that move the head • Muscles that move the head – Anterior – Lateral • Rectus capitis anterior • Rectus capitis lateralis • Longus capitis • Sternocleidomastoid – Posterior • Muscles of the vertebral column • Longissimus capitis • Obliquus capitis superior – Superficial • Obliquus capitis inferior • Erector spinae (sacrospinalis) • Rectus capitis posterior - major & minor – Spinalis - cervicis, thoracis • , superior fibers – Longissimus - capitis, cervicis, thoracis • Splenius capitis – Iliocostalis - cervicis, thoracis, lumborum • Semispinalis capitis • Splenius cervicis

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Trunk & Spinal Column Muscles Trunk & Spinal Column Muscles • Muscles of the vertebral column • Muscles of the thorax – Deep – Diaphragm • Longus colli - superior oblique, inferior oblique, – Intercostalis - external, internal vertical – Levator costarum • Interspinales - entire spinal column – Subcostales • Intertransversales - entire spinal column • Multifidus - entire spinal column – Scalenus - anterior, medius, posterior • Psoas minor – Serratus posterior - superior, inferior • Rotatores - entire spinal column – Transversus thoracis • Semispinalis - cervicis, thoracis

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Trunk & Spinal Column Muscles Nerves • Muscles of the abdominal wall • Cranial nerve 11 and C2 – Rectus abdominis & C3 spinal nerves – External oblique abdominal (obliquus – Sternocleidomastoid externus abdominis) muscles • C4 through C8 posterior – Internal oblique abdominal (obliquus lateral branches internus abdominis) – Splenius muscles – Transverse abdominis (transversus • Posterior branches of abdominis) the spinal nerves – Quadratus lumborum – Entire erector spinae group

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6 Nerves Muscles that Move the Head • of T7 through T12 • All originate on cervical vertebrae & insert on of skull (capitis name) – Rectus abdominis – 3 anterior vertebral muscles – longus capitis, • Intercostal nerves (T8-T12), iliohypogastric rectus capitis anterior, & rectus capitis nerve (T12, L1), & ilioinguinal nerve (L1) lateralis – Internal & external oblique abdominal muscles • All are flexors of head & upper cervical – Same for transverse abdominis except spine innervation begins with T-7 intercostal nerve • Rectus capitis lateralis • Branches from T12 & L1 – laterally flexes head – Quadratus lumborum – assists rectus capitis anterior in stabilizing atlantooccipital joint

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Muscles that Move the Head Muscles that Move the Head • All originate on cervical vertebrae & – Posterior muscles • Rectus capitis posterior major & minor, insert on occipital bone of skull (capitis obliquus capitis superior & inferior, and name) semispinalis capitis • All are extensors of head except obliquus capitis inferior which rotates atlas • Obliquus capitis superior assists rectus capitis lateralis in lateral flexion of head • Rectus capitis posterior major rotates head to ipsilateral side • Semispinalis capitis rotates head to contralateral side • Upper Trapezius extend head & rotate its to ipsilateral side

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Muscles that Move the Head Muscles that Move the Head – Posterior muscles • Splenius capitis & sternocleidomastoid – Much larger & more powerful in moving head & cervical spine • Remaining cervical spine muscles are grouped with muscles of vertebral column

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7 Sternocleidomastoid Muscles Splenius Muscles (cervicis, capitis) Both sides: Both sides: extension of head (splenius capitis) extension of & neck (splenius capitis and capitis) head at atlantooccipital Right side: joint & flexion rotation & of neck lateral flexion to right Right side: rotation to left Left side: & lateral rotation & flexion to right lateral flexion to Left side: left rotation to right & lateral flexion to left

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Muscles of the Vertebral Column Muscles of the Vertebral Column • Cervical area • Posterior – Longus colli muscles – Interspinal-intertransverse group • located anteriorly • lie deep to rotatores • flex cervical & upper thoracic vertebrae • laterally flex & extend • Posterior • do not rotate vertebrae – Interspinales – Erector spinae group, transversospinalis » extensors group, interspinal-intertransverse group, & » connect from spinous splenius process of one vertebra • All run vertically parallel to spinal column to spinous process of adjacent vertebra From Seeley RR, Stephens TD, Tate P: Anatomy & • Location enables them to extend spine and physiology, ed 7, New York, 2006, McGraw-Hill. assist in rotation & lateral flexion

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Muscles of the Vertebral Column Posterior Muscles of the Thorax • Posterior • Involved almost entirely in respiration – Interspinal- – Diaphragm intertransverse group • Responsible for during quiet rest – • As it contracts & flattens, thoracic volume is muscles increased & air is inspired to equalize the » flex vertebral pressure column laterally » connect to • When larger amounts of air are needed, as in transverse , other thoracic muscle have a more processes of significant role in inspiration adjacent vertebrae

From Seeley RR, Stephens TD, Tate P: Anatomy & physiology, ed 6, Dubuque, © 2007 McGraw-Hill Higher Education. All rights reserved. IA, 2003, McGraw-Hill. 12-47 © 2007 McGraw-Hill Higher Education. All rights reserved. 12-48

8 Posterior Muscles of the Thorax (sacrospinalis) • Iliocostalis • (lateral layer) elevate first 2 ribs to • Longissimus increase thoracic (middle layer) volume • Spinalis • External intercostals (medial layer) further expand the chest • Levator costarum & Extension, serratus posterior – lateral flexion, inspiration & ipsilateral • Internal intercostals, rotation of transversus thoracis, & spine & head subcostales contract to Anterior pelvic force expiration rotation Modified from Van De Graaff KM: Human anatomy, ed 4, New York, 1995, McGraw-Hill. Lateral pelvic rotation to contralateral side

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Muscles of the Abdominal Wall Muscles of the Abdominal Wall

• Rectus • Rectus abdominis abdominis • External • External oblique oblique abdominal abdominal • Internal • Internal oblique oblique abdominal abdominal • Transverse • Transverse abdominis abdominis

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Rectus Abdominis Muscle External Oblique Abdominal Muscle Both sides: lumbar flexion Both sides: Posterior pelvic rotation lumbar flexion Right side: lumbar Posterior pelvic lateral flexion to rotation right, rotation to left, & lateral Right side: weak pelvic rotation lateral flexion to left to right Left side: lumbar Left side: weak lateral flexion lateral flexion to left, rotation to left to right, & lateral pelvic rotation to right

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9 Internal Oblique Abdominal Muscle Transversus Abdominis Muscle Both sides: lumbar flexion Posterior pelvic rotation Right side: lumbar Forced expiration lateral flexion to by pulling the right, rotation to abdominal wall right, & lateral inward pelvic rotation to left Left side: lumbar lateral flexion to left, rotation to left, & lateral pelvic rotation to right

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Quadratus Lumborum Muscle Cervical Flexion

Lateral flexion to ipsilateral side Stabilizes pelvis & lumbar spine • Agonists Extension of – Sternocleidomastoid lumbar spine

Anterior pelvic rotation

Lateral pelvic rotation to contralateral side

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Cervical Extension Cervical Lateral Flexion

• Agonists • Agonists – Erector Spinae – Sternocleidomastoid – Erector Spinae

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10 Cervical Rotation Lumbar Flexion

• Agonists • Agonists – Sternocleidomastoid – Rectus abdominis – External oblique abdominal – Internal oblique abdominal

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Lumbar Extension Lumbar Lateral Flexion

• Agonists • Agonists – Erector – Erector spinae spinae – External oblique abdominal – Internal oblique abdominal

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Lumbar Rotation Web Sites

Radiologic Anatomy Browser • Agonists http://radlinux1.usuf1.usuhs.mil/rad/iong – This site has numerous radiological views of the – Rectus musculoskeletal system. abdominis Loyola University Medical Center: Structure of the www.meddean.luc.edu/lumen/meded/grossanatomy/index.htm – External – An excellent site with many slides, dissections, tutorials, etc. for the study of human anatomy oblique University of Arkansas Medical School Gross Anatomy for abdominal Medical Students http://anatomy.uams.edu/anatomyhtml/gross.html – Internal – Dissections, anatomy tables, atlas images, links, etc. oblique Wheeless’ Textbook of Orthopaedics www.wheelessonline.com/ abdominal – This site has an extensive index of links to the fractures, joints, muscles, nerves, trauma, , medical topics, lab tests, and links to orthopedic journals and other orthopedic and medical news. © 2007 McGraw-Hill Higher Education. All rights reserved. 12-65 © 2007 McGraw-Hill Higher Education. All rights reserved. 12-66

11 Web Sites Web Sites

Premiere Medical Search Engine Spine Universe www.medsite.com www.spineuniverse.com – This site allows the reader to enter any medical condition and – Information on the spine for educating the public about it will search the net to find relevant articles. technologies, services, treatments and research available on Virtual Hospital spinal disorders www.vh.org Stabilization Sensibility – Numerous slides, patient information, etc. www.calainc.org/Handouts/Participant_handouts/05_04%20Stab Stability ilization.pdf www.brianmac.demon.co.uk/corestab.htm – A discussion on muscles of the – The muscles of the trunk, training techniques, and Hospital for Joint Spine Center Become Healthy Now.com: The Spine http://www.med.nyu.edu/hjd/hjdspine/musclesandligaments.htm www.becomehealthynow.com/category/bodyspine – Muscles and of the Spine – Anatomy and function of spine

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