Muscles of the Back Flashcards
Trapezius Origin
Spinous processes (C7, thoracic vertebrae)
Nuchal ligament
External occipial protuberance
Trapezius Insertion
Superior: Lateral 3rd of clavicle
Middle: Acromion, spine of scapula
Inferior: Middle end of spine of scapula
Trapezius Action
Superior: Elevates scapula
Middle: Retracts and rotates scapula
Inferior: Depresses scapula
Trapezius Arterial Supply
Superficial branch of transverse cervical artery
Trapezius Innervation
Motor: Cranial nerve XI (spinal accessory nerve)
Latissimus Dorsi Origin
Spinous processes of thoracic vertebrae Thoracolumbar fascia Iliac crest Ribs 9-12 (Scapula)
Latissimus Dorsi Insertion
Lesser tubercule of humerus (Intertubercular groove on anterior side of humerus)
Latissimus Dorsi Action
Extends, adducts, medially rotates humerus, elevates body
Latissimus Dorsi Arterial Supply
Thoracodorsal artery
Latissimus Dorsi Innervation
Thoracodorsal nerve (C6-8)
Received near the insertion point
Rhomboid Minor Origin
Spinous processes of C6 & C7
Deep to the trapezius
Rhomboid Minor Insertion
Medial border of scapula at level of spine
Rhomboid Minor Action
Connects scapula to spinal column
Retracts and rotates scapula down and towards the spine
Rhomboid Minor Arterial Supply
Dorsal scapular artery (either from subclavian artery or deep branch of transverse cervical artery)
Rhomboid Minor Innervation
Dorsal scapular nerve (ventral rami of C5)
Rhomboid Major Origin
Spinous processes of T1-T4
Lies deep to trapezius
Rhomboid Major Insertion
Medial border of scapula inferior to spine
Rhomboid Major Action
Connects scapula to spinal column
Retracts and rotates scapula down and toward spine
Rhomboid Major Arterial Supply
Dorsal scapular artery (either from subclavian artery or deep branch of transverse cervical artery)
Rhomboid Major Innervation
Dorsal scapular nerve (ventral rami of C4 & C5)
Levator Scapulae Origin
Transverse processes of cervical vertebrae
Lies deep to trapezius in same plane as rhomboids
Levator Scapulae Insertion
Superior angle of scapula
Levator Scapulae Action
Elevates and rotates scapula
Levator Scapulae Arterial Supply
Dorsal scapular artery (either from subclavian artery or deep branch of transverse cervical artery)
Levator Scapulae Innervation
Dorsal scapular nerve (ventral rami of C3-5)
Serratus Posterior Superior Origin
Spinous processes of C7 and upper thoracic vertebrae
Lower nuchal ligament
Lies deep to rhomboids
Serratus Posterior Superior Insertion
Superior border of ribs 2-5
Serratus Posterior Superior Action
Elevates ribs, assists forced inspiration
Serratus Posterior Superior Arterial Supply
Intercostal arteries
Serratus Posterior Superior Innervation
Ventral rami of intercostal nerves T2-T5
Serratus Posterior Inferior Origin
Spinous processes of T11-L2
Lies deep to the latissimus dorsi
Serratus Posterior Inferior Insertion
Inferior border of ribs 9-12
Serratus Posterior Inferior Action
Depresses ribs, assists forced expiration
Serratus Posterior Inferior Arterial Supply
Intercostal arteries
Serratus Posterior Inferior Innervation
Ventral rami of intercostal nerves T9-T12
<p>Splenius Cervicis Origin</p>
<p>Spinous processes of T3-T6 Lower nuchal ligament Lies deep to trapezius</p>
Splenius Cervicis Insertion
Tubercules of transverse processes of C1-C3 (directed superior and lateral)
Splenius Cervicis Action
Acting alone: Laterally flex neck and rotate head to side of active muscles
Acting together: Extend head and neck
Splenius Cervicis Innervation
Dorsal rami of spinal nerves
Splenius Capitis Origin
Spinous processes of C7-T3
Lower nuchal ligament
Lies deep to trapezius
Differs from cervicis at insertion
Splenius Capitis Insertion
Mastoid process of temporal bone
Lateral third of superior nuchal line
Directed superior and lateral
Splenius Capitis Action
Acting alone: Laterally flex neck and rotate head to side of active muscles
Acting together: Extend head and neck
Splenius Capitis Innervation
Dorsal rami of spinal nerves
Divisions of Erector Spinae (Medial to Lateral)
Spinalis > Longissimus > Iliocostalis
Spinalis Origin
Spinous processes of lower cervical, thoracic and upper lumbar regions
Spinalis Insertion
Spinour processes in cervical and thoracic regions
Spinalis and Longissimus Arterial Supply
Lateral sacral artery
Divisions of Erector Spinae (Superior to Inferior)
Capitis > Cervicis > Thoracis > Lumborum
Longissimus Origin
Sacrum
Longissimus Insertion
Ribs
Transverse processes of T & C vertebrae
Mastoid Process
Iliocostalis Origin
Sacrum
Iliac crest
Iliocostalis Insertion
Inferior border of ribs
C4-C7 transverse processes
Iliocostalis Arterial Supply
Intercostal and lumbar arteries
Erector Spinae Action
Acting alone: Laterally flex vertebral column to side of active muscles
Acting together: Extend vertebral column and head
Erector Spinae Innervation
Dorsal rami of spinal nerves
Muscles of Transversospinal Group
Semispinalis (capitis and cervicis), multifidus & rotatores
Semispinalis Capitis/Cervicis Origin
Transverse processes of lower cervical vertebrae and thoracic vertebrae
Semispinalis Capitis Insertion
Occipital bone between superior and inferior nuchal lines
Semispinalis Cervicis Insertion
Cervical and thoracic spinous processes
Semispinalis Capitis/Cervicis Action
Extend and contralaterally rotate head and thoracic/cervical region of vertebral column
Rotatores Origin
Transverse processes in thoracic and lumbar regions (best developed in thoracic region)
Rotatores Insertion
Attach to junction of lamina and transverse processes
OR
Spinous process of vertebra immediately (brevis) or 2 segments (longus) superior to vertebra of attachment
Multifidus & Rotatores Action
Assists with stabilization, extension, & contralateral rotation of head, neck, & vertebral column
Innervation of Transversospinal Group
Dorsal Rami of Spinal Nerves
Semispinalis Capitis - Greater Occipital Nerve (C2)
Interspinalis Origin
Superior surface of spinous processes of cervical and lumbar vertebrae
Interspinalis Insertion
Inferior surface of spinous processes of vertebrae directly above
Interspinalis Action
Extension of vertebral column
Interspinalis Innervation
Dorsal rami of spinal nerves