Back muscles Flashcards
Trapezius (Superficial – associated with movements of the shoulder)
Attachments:
Originates from the skull, ligamentum nuchae and the spinous processes of C7-T12. The fibres attach to the clavicle, acromion and the scapula spine.
Innervation:
Motor innervation is from the accessory nerve. It also receives proprioceptor fibres from C3 and C4 spinal nerves.
Actions:
Elevates, depresses, retracts and upwardly rotates scapula
Blood supply:
Occipital artery (descending part), superficial or transverse cervical artery (transverse part), dorsal scapular artery (ascending part)
Latissimus Dorsi (Superficial – associated with movements of the shoulder)
Attachments:
Has a broad origin – arising from the spinous processes of T6-T12, thoracolumbar fascia, iliac crest, and the inferior three ribs. The fibres converge into a tendon that attaches to the intertubercular sulcus of the humerus.
Innervation:
Thoracodorsal nerve.
Actions:
Extends, adducts and medially rotates the upper limb.
Blood supply:
Thoracodorsal artery, perforating arteries of the 9th-11th posterior intercostal arteries, and 1st-3rd lumbar arteries
Levator Scapulae (Superficial – associated with movements of the shoulder)
Attachments:
Originates from the transverse processes of the C1-C4 vertebrae and attaches to the medial border of the scapula.
Innervation:
Dorsal scapular nerve.
Actions:
Elevates the scapula.
Blood supply:
Transverse cervical and ascending cervical arteries (branches of the thyrocervical trunk)
Rhomboid Major (Superficial – associated with movements of the shoulder)
Attachments:
Originates from the spinous processes of T2-T5 vertebrae. Attaches to the medial border of the scapula, between the scapula spine and inferior angle.
Innervation:
Dorsal scapular nerve.
Actions:
Retraction, elevation and downward rotation of the scapula.
Blood supply:
Dorsal scapular artery, deep branch of transverse cervical artery, dorsal branch of upper five or six posterior intercostal arteries
Rhomboid minor (Superficial – associated with movements of the shoulder)
Attachments:
Originates from the spinous processes of C7-T1 vertebrae. Attaches to the medial border of the scapula, at the level of the spine of scapula.
Innervation:
Dorsal scapular nerve.
Actions:
Elevation, Retraction and downward rotation of the scapula.
Blood supply:
Dorsal scapular artery, deep branch of transverse cervical artery, dorsal branch of upper five or six posterior intercostal arteries
Serratus Posterior Superior (Intermediate – associated with movements of the thoracic cage.)
Attachments:
Originates from the lower part of the ligamentum nuchae, and spinous process C7 – T3. The fibres pass in an inferolateral direction, attaching to ribs 2-5.
Actions:
Elevates ribs 2-5.
Innervation:
Intercostal nerves.
Blood supply:
posterior intercostal arteries.
Serratus Posterior Inferior (Intermediate – associated with movements of the thoracic cage.)
Attachments:
Originates from the thoracic and lumbar spines (usually T11 – L3). The fibres pass in a superolateral direction, attaching to ribs 9-12.
Actions:
Depresses ribs 9-12.
Innervation:
Intercostal nerves.
Blood supply:
posterior intercostal arteries.
Semispinalis capitis (deep-associated with movements of the vertebral column.)
Attachments:
Originates from the transverse processes of C4-T10. The fibres ascend 4-6 vertebral segments, attaching to the spinous processes of C2-T4, and to the occipital bone of the skull.
Innervation:
Posterior rami of the spinal nerves.
Actions:
Extends and contralaterally rotates the head and vertebral column.
Blood supply:
Occipital artery
Multifidus (deep-associated with movements of the vertebral column.)
Attachments:
Has a broad origin – arises from the sacrum, posterior iliac spine, common tendinous origin of the erector spinae, mamillary processes of lumbar vertebrae, transverse processes of T1-T3 and articular processes of C4-C7. The fibres ascend 2-4 vertebral segments, attaching to the vertebral spinous processes.
Innervation:
Posterior rami of the spinal nerves.
Actions:
Stablises the vertebral column.
Blood supply:
Vertebral artery, deep cervical artery, occipital artery, posterior intercostal arteries, subcostal artery, lumbar ateries and lateral sacral arteries
Rotatores (deep-associated with movements of the vertebral column.)
Attachments:
Originates from the vertebral transverse processes. The fibres ascend, and attach to the lamina and spinous processes of the immediately superior vertebrae.
Innervation:
Posterior rami of the spinal nerves.
Actions:
Stablises the vertebral column, and has a proprioceptive function.
Blood supply:
Dorsal branches of posterior intercostal and lumbar arteries
Iliocostalis (Intermediate – associated with movements of the thoracic cage.)
Attachments:
Arises from the common tendinous origin, and attaches to the costal angle of the ribs and the cervical transverse processes.
Innervation:
Posterior rami of the spinal nerves.
Actions:
Acts unilaterally to laterally flex the vertebral column. Acts bilaterally to extend the vertebral column and head.
Blood supply:
Iliocostalis cervicis: occipital, deep cervical and vertebral arteries
Iliocostalis thoracis: dorsal branches of posterior intercostal and subcostal arteries
Iliocostalis lumborum: dorsal branches of lumbar and lateral sacral arteries
Longissimus (Intermediate – associated with movements of the thoracic cage.)
Attachments:
Arises from the common tendinous origin, and attaches to the lower ribs, the transverse processes of C2 – T12, and the mastoid process of the skull.
Innervation:
Posterior rami of the spinal nerves.
Actions:
Acts unilaterally to laterally flex the vertebral column. Acts bilaterally to extend the vertebral column and head.
Blood supply:
Longissimus capitis and cervicis: vertebral artery, deep cervical artery, occipital artery, transverse cervical artery
Longissimus thoracis: superior intercostal, posterior intercostal and subcostal arteries; lateral sacral and median sacral arteries
Spinalis (Intermediate – associated with movements of the thoracic cage.)
Attachments:
Arises from the common tendinous origin, and attaches to the spinous processes of C2, T1-T8 and the occipital bone of the skull.
Innervation:
Posterior rami of the spinal nerves.
Actions:
Acts unilaterally to laterally flex the vertebral column. Acts bilaterally to extend the vertebral column and head.
Blood supply:
Posterior branch of posterior intercostal artery
Deep cervical artery
Muscular branches of vertebral artery
