Muscles of the Back: Thoracolumbar Fascia

Muscles of the back part 1 Thoracolumbar fascia • • • • Description - Large roughly diamond shaped area pf connective tissue that is made up by the thoracic and lumbar pats of the deep fascia enclosing the intrinsic back muscles. Course - Extends from the vertebrae to the sacrum. Functions - Separates the paraspinal muscles from the muscles of the posterior abdominal wall. - Divides muscles into compartments. - Serves as an attachment site for various muscles of the back. - Involved in the movement and lad transfer between the trunk and the limbs. - Houses several deep muscles of the back such as the quadratus lumborum. Transersospinalis, spinal erectors and multifidus. - Contains several nociceptive nerve endings that may be responsible for some forms of the pack pain. Attachments - Nuchal ligaments, spinous process, supraspinous ligament, median crest f sacrum Superficial Muscles of the back IMPORTANT NOTE: THESE ATTACH FROM THE UPPER LIMB TO THE VERTEBRAL COLUMN Muscles Trapezius Latissimus dorsi Levator scapulae Rhomboid minor Rhomboid major Origin Sup. Nuchal line external occipital protuberance, spinous processes C712 Spinous processes T712, thoracolumbar fascia + post. Iliac crest Transverse process C14 Ligamentum nuchae, spinous processes C7T1 Spinous processes of T2-5 Insertion Spine of the scapula Innervation Spinal accessory nerve (CN XI) + C3-4 Function Descending: elevate scapula Middle: retract scapula Ascending: depress scapula Adduction, med. Rotation + extension Intertubercular groove Dorsal scapular nerve + C3-4 Medial border of scapula (superior) Medial border of scapula (upper) Dorsal scapular nerve + C3-4 Elevate scapula Dorsal scapular nerve Retract + elevate scapula Medial border of scapula (lower) Dorsal scapular nerve Retract + elevate scapula Muscles of the intermediate back IMPORTANT NOTE: MUSCLES WHICH ATTACH TO THE RIBS FOR RESPIRATION Serratus posterior superior Serratus posterior inferior Origin Nuchal ligament, spinous processes of vertebrae C7-T3 Spinous processes of vertebrae T11-L2 Insertion Superior borders of ribs 2-5 Innervation 2nd-5th Intercostal nerves Function Elevates the ribs Inferior borders of ribs 9-12 Anterior rami of spinal nerves T9-T12 (a.k.a. 9th-11th Intercostal nerves + subcostal nerve) Depresses ribs/ Draws ribs inferoposteriorly Deep back muscles IMPORTANT NOTE: THESE ARE KNOWN AS THE INTRSIC MUSCLS OF THE BACK Erector spinae group (long muscles) Iliocostalis Longissimus Origin • Iliocostalis cervicis: Angle of ribs 3-6 • Iliocostalis thoracis: Angle of ribs 7-12 • Iliocostalis lumborum: Lateral crest of sacrum, medial end of iliac crest, thoracolumbar fascia • • Insertion • Iliocostalis cervicis: Transverse processes of vertebrae C4C6 • Iliocostalis thoracis: Angles of ribs 1-6, transverse process of vertebra C7 • Iliocostalis lumborum: Angle of ribs 512, transverse processes of vertebrae L1-L4 (+ Adjacent thoracolumbar fascia Longissimus • Longissimus capitis: Transverse capitis: Mastoid processes of process of vertebrae C4-T5 temporal bone Longissimus • Longissimus cervicis: Transverse cervicis: processes of Transverse vertebrae T1-T5 processes of Innervation Lateral branches of posterior rami of spinal nerves Function Bilateral contraction: Extension of spine Unilateral contraction: Lateral flexion of spine (ipsilateral) Lateral branches of posterior rami of spinal nerves Entire muscle: Bilateral contraction Extension of spine Unilateral contraction Lateral flexion of spine (ipsilateral) Longissimus capitis only: • Spinalis • • • Longissimus thoracis: Lumbar part Lumbar intermuscular aponeurosis, medial part of sacropelvic surface of ilium, Posterior sacroiliac ligament Thoracic part Spinous and transverse processes of vertebrae L1-L5, median sacral crest, posterior surface of sacrum and posterior iliac crest Capitis: spinous processes of C7 – T1 vertebrae Cervicis: spinous processes of C7 – T1 vertebrae; nuchal ligament Thoracis: spinous process of T11 – L2 vertebrae C2C6 • Longissimus thoracis: Lumbar part Accessory and transverse processes of vertebrae L1-L5 Thoracic part Transverse process of vertebrae T1-T12, Angles of ribs 7-12 • • • Capitis: occipital bone (midline) Cervicis: spinous process of C2 – C4 vertebrae Thoracis: spinous process of T2 – T8 vertebrae Bilateral contraction Extension of head and neck Unilateral contraction Lateral flexion and rotation of head (ipsilateral) Lateral branch of posterior rami of spinal nerves • • Bilateral contraction: extension of head, cervical and thoracic spines Unilateral contraction: ipsilateral lateral flexion of cervical and thoracic spine