DEEP BACK MUSCLESDEEP BACK MUSCLES

Deep Back MusclesDeep Back Muscles

Epaxial muscles.Epaxial muscles.Hypaxial muscles.Hypaxial muscles.Pharyngeal arch muscles.Pharyngeal arch muscles.

Cutaneous Nerves of the BackCutaneous Nerves of the Back

Along either side of the midline of the Along either side of the midline of the back:back:

Innervated by dorsal (posterior) rami of Innervated by dorsal (posterior) rami of thoracic spinal nerves.thoracic spinal nerves.

More laterally:More laterally:Innervated by lateral cutaneous branches Innervated by lateral cutaneous branches

of of the intercostal nerves.the intercostal nerves.

Thoracolumbar FasciaThoracolumbar Fascia

Triangular-shaped sheet of tough Triangular-shaped sheet of tough connective tissue.connective tissue.

Partial site of origin of latissimus dorsi and Partial site of origin of latissimus dorsi and abdominal oblique muscles.abdominal oblique muscles.

Thoracolumbar Fascia LaminaeThoracolumbar Fascia Laminae

Posterior lamina to lumbar spinous Posterior lamina to lumbar spinous processes.processes.

Middle lamina to lumbar transverse Middle lamina to lumbar transverse processes.processes.

Anterior lamina (deepest) to lumbar Anterior lamina (deepest) to lumbar transverse processes.transverse processes.

Arrangement of Back MusclesArrangement of Back Muscles

Three groups:Three groups:Superficial:Superficial:

Extrinsic.Extrinsic.

Intermediate:Intermediate:Extrinsic.Extrinsic.

Deep:Deep:Intrinsic.Intrinsic.

Superficial Extrinsic MusclesSuperficial Extrinsic Muscles

Connect limb to axial skeleton.Connect limb to axial skeleton. Innervated by ventral rami or CN XI.Innervated by ventral rami or CN XI. Include:Include:

Trapezius.Trapezius.

Latissimus dorsi.Latissimus dorsi.

Levator scapulae.Levator scapulae.

Rhomboideus major.Rhomboideus major.

Rhomboideus minor.Rhomboideus minor.

Intermediate Extrinsic MusclesIntermediate Extrinsic Muscles

Respiratory muscles.Respiratory muscles. Innervated by ventral (anterior) rami.Innervated by ventral (anterior) rami.Serratus posterior group:Serratus posterior group:

Serratus posterior superior.Serratus posterior superior.

Serratus posterior inferior.Serratus posterior inferior.Refer to Syllabus: Table II, p. 71.Refer to Syllabus: Table II, p. 71.

INTRINSIC (DEEP) BACK INTRINSIC (DEEP) BACK MUSCLESMUSCLES

Intrinsic Back MusclesIntrinsic Back Muscles

True intrinsic muscles of the back are True intrinsic muscles of the back are innervated by dorsal (posterior) rami.innervated by dorsal (posterior) rami.

Three groups:Three groups:SuperficialSuperficial

IntermediateIntermediate

DeepDeepRefer to Table III, p 73 of Syllabus.Refer to Table III, p 73 of Syllabus.

Spinotransversalis SystemSpinotransversalis System

Consists of the Splenius group:Consists of the Splenius group:Long muscles.Long muscles.Originate from ligamentum nuchae and Originate from ligamentum nuchae and

spinous processes.spinous processes.

Spinotransversalis SystemSpinotransversalis System

Run laterally upward to transverse Run laterally upward to transverse processes and skull.processes and skull.

Run laterally and upward to insertion.Run laterally and upward to insertion.Two parts:Two parts:

Splenius capitis.Splenius capitis.

Splenius cervicis.Splenius cervicis.

Superficial Intrinsic MusclesSuperficial Intrinsic Muscles

Splenius capitis:Splenius capitis:O:O: spinous processes of C7 and T1-4.spinous processes of C7 and T1-4. I:I: superior nuchal line and mastoid.superior nuchal line and mastoid.

Splenius cervicis:Splenius cervicis:O:O: spinous processes of T3-6.spinous processes of T3-6. I:I: C1-C4 transverse processes with C1-C4 transverse processes with

levator scapulae.levator scapulae.Spinotransversalis SystemSpinotransversalis System

Intermediate IntrinsicIntermediate Intrinsic

Sacrospinalis system:Sacrospinalis system:Erector spinae.Erector spinae.

Run longitudinally upward:Run longitudinally upward:Transverse processes to rib.Transverse processes to rib.

Rib to rib.Rib to rib.

Rib to cervical transverse processes.Rib to cervical transverse processes.

Spinous processes to spinous processes.Spinous processes to spinous processes.

Intermediate Layer of Intrinsic Deep Back MusclesIntermediate Layer of Intrinsic Deep Back Muscles

Components:Components:Iliocostalis.Iliocostalis.

Longissimus.Longissimus.

Spinalis.Spinalis.Refer to Syllabus:Refer to Syllabus:

Table III.Table III.

P 73.P 73.

Intermediate IntrinsicIntermediate Intrinsic

Iliocostalis:Iliocostalis:Origin =Origin = ilium and sacrum.ilium and sacrum.

Insertion =Insertion = most of the ribs.most of the ribs.

Lateral part of the erector spinae group.Lateral part of the erector spinae group.

Extends back; keeps erect posture.Extends back; keeps erect posture.

Components:Components:

Lumborum.Lumborum.

Thoracis.Thoracis.

Cervicis.Cervicis.

Intermediate IntrinsicIntermediate Intrinsic

Longissimus:Longissimus:Origin =Origin = transversus processes and transversus processes and

sacrum.sacrum.

Insertion = Insertion = most of ribs.most of ribs.

Middle portion of erector spinae group.Middle portion of erector spinae group.

Components:Components:

Thoracis.Thoracis.

Cervicis.Cervicis.

Capitis.Capitis.

Intermediate IntrinsicIntermediate Intrinsic

Spinalis:Spinalis:Origin =Origin = spinous processes of T11-L2.spinous processes of T11-L2.Insertion =Insertion = spinous processes of thoracic spinous processes of thoracic and lower cervical vertebrae.and lower cervical vertebrae.Components:Components:

Thoracis.Thoracis.Cervicis:Cervicis:

Usually absent.Usually absent.

Capitis:Capitis:Part of semispinalis capitis.Part of semispinalis capitis.

Deep Intrinsic MusclesDeep Intrinsic Muscles

Transversospinalis system:Transversospinalis system:From transverse processes to transverse From transverse processes to transverse processes.processes.Concealed by erector spinae.Concealed by erector spinae.Muscles arise laterally and insert medially.Muscles arise laterally and insert medially.Components:Components:

Semispinalis.Semispinalis.Multifidus.Multifidus.Rotatores.Rotatores.

SemispinalisSemispinalis

Traverse a couple of vertebral levels.Traverse a couple of vertebral levels.Components:Components:

Thoracis.Thoracis.

Cervicis.Cervicis.Origin =Origin = T1-4.T1-4.

Insertion =Insertion = C3-5.C3-5.

Largely covered by semispinalis capitis.Largely covered by semispinalis capitis.

SemispinalisSemispinalis

Components:Components:Capitis:Capitis:

Origin =Origin = T1-6 and C4-7.T1-6 and C4-7.

Insertion =Insertion = between superior and inferior between superior and inferior nuchal lines.nuchal lines.

MultifidusMultifidus

Thick muscle mass.Thick muscle mass.Arises from sacrum and surrounding Arises from sacrum and surrounding

structures and from transverse processes structures and from transverse processes up to C4.up to C4.

Including mammillary processes of lumbar Including mammillary processes of lumbar vertebrae.vertebrae.

Traverses 3 segments.Traverses 3 segments. Inserts on spinous processes C2-L5.Inserts on spinous processes C2-L5.

RotatoresRotatores

Pass from root of transverse process to Pass from root of transverse process to root of superior spinous process.root of superior spinous process.

Long:Long:Span two segments.Span two segments.

Short:Short:Span one segment.Span one segment.

Intrinsic Segmental MusclesIntrinsic Segmental Muscles

Interspinales. Interspinales. Intertransversarii.Intertransversarii.