The back muscles

Interspinalis lumborum

Deep muscle of lower back; Origin: superior margin of lumbar spinous process Insertion: inferior margin of next superior spinous process Action: extend lumbar nerve

Interspinalis cervicis

Deep muscle of upper back; Origin: superior margin of cervical spinous process Insertion: inferior margin of next superior spinous process Action: extend the neck

Rotatores muscle

Lies beneath the multifidus and are present in all spinal regions Origin: transverse processes Insertion: junction of transverse process and lamina, spinous process

Sternocleidomastoid muscle

Origin: manubrium and medial portion of the clavicle Insertion: mastoid process Nerve: accessory nerve

Rhomboid major

Origin:spinous processes of T2-T5 Insertion: medial border of scapula, inferior to the insertion of rhomboid minor muscle Action: retracts and rotate scapula, fix thoracic wall

Three regions of trapezius muscle

1. Superior-descending part 2. Intermediate-transverse part 3. Inferior-ascending part

Erector spinae muscle

1.iliocostalis 2.longissimus muscle 3.spinalis Action: extends the vertebral column

Iliac crest

At vertebral level L4

Nuchal ligament

Extend from occipital protuberance to the spinous process of C7

Internal oblique muscle

Origin: inguinal ligament, iliac crest and lumbodorsal fascis Insertion: linea alba, pecten pubis, ribs 10-12

Obliquus capitis superior muscle

Origin: lateral mass of the atlas bone Insertion: lateral half of inferior nuchal line Action: extends head and flex head to the ipsilateral side

Rectus capitis posterior minor muscle

Origin: Tubercle on the posterior arch of the atlas Insertion: medial part of the inferior nuchal line of occipital bone Action: extends the neck but considered to be more of a sensory organ

Spinalis cervicis muscle

Origin: nuchal ligament and spinous process of C7 Insertion: spinous process of cervical vertebrae except atlas

Splenius capitis muscle

Origin: nuchal ligament and spinous processes of vertebrae C7-T3 Insertion: mastoid process

Longissimus thoracis muscle

Origin: posterior surfaces of the transverse processes of all lumbar vertebrae and the thoracolumbar fascia Insertion: tips of all transverse processes of all thoracic vertebrae and lower nine or ten ribs, between the tubercle and angle

Levator scapulae

Origin: posterior tubercles of transverse processes of vertebrae C1-C4 Insertion: superior part of the medial border of scapula Action: elevates scapula

External oblique muscle

Origin: ribs5-12 Insertion: iliac crest, pubic tubercle, linea alba

Obliquus capitis inferior muscle

Origin: spinous process of axis Insertion: lateral mass of atlas Action: rotation of head and neck

Rectus capitis posterior major muscle

Origin: spinous process of the axis Insertion: inferior nuchal line of the occipital bone Action: ipsilateral rotation of head and extension

Spinalis thoracis muscle

Origin: spinous process of upper lumbar and lower thoracic vertebrae Insertion: spinous process of upper thoracic vertebrae

Rhomboid minor muscle

Origin: spinous processes of C7-T Insertion: medial border of scapula, superior to the insertion of rhomboid major muscle Action: retracts and rotate scapula, fix thoracic wall

Splenius cervicis muscle

Origin: spinous processes of T3-T6 Insertion: transverse processes of C1-C3

Trapezius muscle

Origin: spinous processes of vertebrae C7-T12 Insertion: 1. external occipital protuberance 2. medial superior nuchal line, 3. posterior border of the lateral third of the clavicle 4. Acromion process 5. Spine of scapular Action: rotation, retraction, elevatiom depression of scapula Nerve: accessory nerve

Serratus posterior superior muscle

Origin: spinous processes of vertebrae C7-T3 Insertion: upper borders of ribs 2-5 Action: elevates the ribs to assist inspiration

Serratus posterior inferior muscle

Origin: spinous processes of vertebrae T11-L2 Insertion: inferior border of ribs 9-12 Action: depress the lower ribs to assist force expiration Direction: directed upward and laterally

Latissimus muscle

Origin: spinous processes of vertebrae T7-L5, thoracolumbar fascia, iliac crest, inferior 3 or 4 ribs, inferior angle of scapula Insertion: floor of intertubercular groove of the humerus

Iliocostalis muscle

Origin: superior borders of the angles of lower six ribs, medial to the proximal tendon of the iliocostalis lumborum Insertion:superior borders of the angles of the upper six ribs and the posterior aspect of the transverse process of C7

Supraspinatus muscle

Origin: supraspinatous fossa of scapula Insertion: superior facet of greater tubercle of humerus

Multifidus muscle

Origin: the sacral region-from back of sacrum, aponeurosis of origin of sacrospinalis, medial surface of the posterior superior sacroiliac ligament The lumbar region-all the mamillar processes The thoracic region-all the transverse processes The cervical region-articular processes of the lower four vertebrae Insertion: spinal process of the vertebral above

Semispinalis cervicis

Origin: transverse process of the T1-T5 Insertion: spinous processes of vertebrae C2-C5

Levatores costarum

Origin: transverse processes of C7-T12 vertebrae Insertion: superior surfaces of the ribs immediately inferior to the preceding vertebrae Action: assists in elevation of the thoracic rib cage

Semispinalis thoracis

Origin: transverse processes of the T6-T10 Insertion: spinous processes of C6-T4

Longissimus capitis

Origin: transverse processes of vertebrae T1-4; articular processes of C4-C7 Insertion: posterior margin of mastoid process, beneath the splenius capitis and sternocleidmastoideus

Semispinalis capitis muscle

Origin: transverse processes of vertebral C7-T7, articular process of vertebral C4-C6 Insertion: area between superior and inferior nuchal line

Scapula

Spine of scapula: at vertebral level T3 Inferior angle of scapula: at vertebral level T7