MUSCLES OF THE BACK

1. Extrinsic Back Muscles (superficial and intermediate) Superficial m: [N.160] attach upper extremity to vertebral column

1. 1. Trapezius m. deep to surface:  Spinal accessory nerve (CN XI)

Superficial branch of the transverse cervical artery & vein

1. 1. Latissimus dorsi m.
   2. Levator scapulae m.
   3. Rhomboid major and minor m.
   4. Triangle of ascultation

trapezius m., latissimus dorsi m, medial border of scapula

1. 1. Lumbar triangle

latissimus dorsi m., external abdominal oblique m., iliac crest

Intermediate m: [N.161] attach ribs to vertebral column & assist in respiration

1. 1. Serratus posterior superior m.
   2. Serratus posterior inferior m.
   3. Levatores costarum m.

1. Intrinsic Back Muscles [N.162]

Function: postural, movement and stabilization of the vertebral column

Innervation:  dorsal rami of spinal nerves & dermatome map

Blood Supply: posterior branches of segmental arteries

1. 1. splenius capitis m.: spine of upper vertebral column to transverse processes and base of skull
   2. splenius cervicis m.:  same as above
   3. erector spinae

a.      Iliocostalis m.: lumborum, thoracis, cervicis

Lateral-iliac crest to rib

b.      Longissimus m.:  thoracis, cervicis, capitus

Intermediate- sacrum to rib

c.      Spinalis m.:  thoracis, cervicis, capitis

Medial- spine to spine

1. 1. transversospinalis

a.      semispinalis m:  thoracis, cervicies, capitis

b.      multifundus m.

c.      rotatores m.

1. 1. interspinales
   2. intertransversarii
   3. (levatores costarum)

1. Sub-Occipital Muscles [N.164]

Function:  extension and rotation of head

Innervation:  dorsal rami of CI, sub-occipital nerve

Blood Supply:  ascending branches of subclavian artery

1. 1. retus capitis (posterior) minor m.
   2. retus capitis (posterior) major m.
   3. superior oblique m.
   4. inferior oblique m.
   5. suboccipital triangle

rectus capitis major m., inferior oblique m., superior oblique m.

1. 1. occipital artery
   2. vertebral artery
   3. greater and lesser occipital nerve
   4. posterior ramus of C1 and C3

1. Clinical Correlates
   1. back strain:  results from extreme movements of vertebral column; stretching of muscle and/or ligaments of lumbar intervertebral joints.
   2. winding course of vertebral arteries through suboccipital triangle significant when blood flow through them is reduced. For example, arteriosclerosis: prolonged turning of head may cause dizziness and other  symptoms from interference with blood supply to brainstem
   3. cervical region is susceptible to trauma.  Particularly vuln. Is the occipito-atlanto-axial joint.  If

the dens is broken and driven posteriorly into the cord resulting in death or paralysis.

Tags: inerior oblique muscle, latissimus dorsi, levator scapulae, lumbar triangle, rectus capitis major, rhomboid, superior oblique muscle, trapezius muscle

This entry was posted on Saturday, January 24th, 2009 at 4:08 am and is filed under Gross Anatomy. You can follow any responses to this entry through the RSS 2.0 feed. Responses are currently closed, but you can trackback from your own site.