Spinal Muscles (Origin, Insertion, Function)

Rectus abdominis

Crest of pubis and pubic symphysis TO cartilage of 5-7th ribs and xiphoid process. *Compresses abdominal cavity and flexes vertebral column.

External oblique

Lower 8 ribs TO Iliac crest and linea alba *compresses abdominal cavity and laterally flexes and rotates vertebral column.*

External Intercostals

Lower margin of upper 11 ribs TO Superior border of *rib below* (these do not go on costal cartilage) *pull ribs toward one another to ELEVATE rib cage*

Middle scalene

Upper surface of 1st rib to transverse process of *C2-C7*. *above will raise 1st rib, below will laterally flex neck*

Anterior Scalene

Upper surface of 1st rib to transverse processes of *C3-C6*. *bends cervical portion of vertebral column forward and laterally*

Subcostals

angle of rib (halfway) TO inner surface of 2nd or 3rd rib below. *draws ventral ribs downward* (Deep and synergistic to intercostals)

Internal oblique

Anterior 2/3 of Iliac crest TO last 3 ribs. *compresses abdominal contents, laterally bends and rotates vertebral column, helps flex vertebral column.

Transverse abdominus

Iliac crest and cartilage of lower 6 ribs to linea alba. *constricts abdomen and supports viscera.

Transverse thoracis

Inner surface of body of sternum to inner surface of costal cartilages of 2-6th ribs. *draws ventral part of rib downward)

Internal Intercostals

Inner surface of rib and costal cartilage to rib below. *draws ribs together and depress rib cage.* (difference between external and internal is that external does not go all the way medial like internal)

Diaphragm

L1-3, lower 6 costal cartilages and xiphoid process TO form central tendon. *flattens on contraction, increasing vertical dimensions of thorax*

Longus colli (Spinal flexor)

Origin: Anterior surfaces of cervical/thoracic Insertion: Transverse processes Action: Flexes/rotates

Longissimus thoracis (Intermediate)

Origin: Broad aponeurosis joining iliocostalis Insertion: Superior thoracic/lumbar transverse processes and inferior surfaces of lower 10 ribs Action: Extension; ipsilateral flexion

Longus capitis (Spinal flexor)

Origin: C4-6 transverse processes Insertion: Occipital bone Action: Flexion; ipsilateral rotation

Semispinalis cervicis (Deep)

Origin: C4-T6 transverse processes Insertion: C2-5 spinous processes Action: Extend and contra laterally rotate

Semispinalis capitis (Deep)

Origin: C4-T7 transverse processes Insertion: Nuchal line of Occipital bone Action: Extend; contralateral rotation

Spinalis cervicis (Intermediate)

Origin: C7 spinous process Insertion: C1, 3-4 spinous process Action: Extension

Quadratus lumborum (Spinal flexor)

Origin: Iliac crest Insertion: Last rib/transverse processes of L1-L4 Action: Depress ribs; lateral flexion

Iliocostalis lumborum (Intermediate)

Origin: Iliac, sacral crests; lumbar spinous processes Insertion: Inferior surface of ribs 6-12 Action: Extends vertebra; depresses ribs

Multifudus (Deep)

Origin: Sacrum, PSIS and transverse processes Insertion: *Spinous* processes of *superior* vertebrae Action: Extend and contra laterally rotate

Splenius capitis (Superficial)

Origin: Spinous process of C7-T4 TO Mastoid. *Extend neck; ipsilaterally rotate/laterally flexes head*

Interspinales (Deep)

Origin: Spinous processes Insertion: Spinous processes of next superior vertebra *gaps between C7-T1, T12-L1* Action: Extension

Iliocostalis thoracis (Intermediate)

Origin: Superior border of 6-12 ribs Insertion: Superior ribs and C7 transverse process Action: Stabilize thorax in extension

Iliocostalis cervicis (Intermediate)

Origin: Superior border of vertebrosternal ribs Insertion: C4-6 transverse processes Action: Extends vertebra; depresses ribs

Longissimus cervicis (Intermediate)

Origin: Superior thoracic vertebrae transverse process Insertion: Middle/superior cervical transverse process Action: Extend; ipsilateral rotation, flexion

Spinal thoracis (Intermediate)

Origin: T11-L2 spinous process Insertion: superior thoracic spinous processes Action: Extends

Semispinalis thoracis (Deep)

Origin: T7-T12 transverse processes Insertion: C6-T4 spinous processes Action: Extend and contra laterally rotate

Rotatores (Deep)

Origin: Transverse processes Insertion: Spinous processes one above and 2 above. Action: Extend and contra laterally rotate

Intertransversarii (Deep)

Origin: Transverse processes Insertion: Transverse processes superiorly Action: Lateral flexion

Longissimus capitis (Intermediate)

Origin: inferior cervical/superior thoracic transverse process Insertion: Mastoid process Action: Extend; ipsilateral rotation, flexion

Posterior Scalene

Outer surface of *2nd* rib to posterior transverse process of *C4-C6*. *Raises 2nd rib or bends lower cervical portion to same side*

Rectus Capitus POsterior Minor

Post tubercle of C1 (has no spinous process) TO straight up to medial nuchal line. *extends the head*

Rectus Capitis posterior Major

Spinous C2 then sup lateral to nuchal line *extends and rotates head to same side*

Obliquus Capitis Inferior

Spinous process of C2 to transverse process of C1. *rotates head*

Serratus posterior Superior

Spinous process of C6-T3 TO upper border of ribs 2-5. *raises ribs during inspiration* (deep to rhomboids)

Spinalis Thoracic

Spinous process of T11-L2 TO T1-T8. *Extends vertebral column*

Serratus posterior inferior

Spinous process of T11-L3 TO inferior borders and outer surfaces of lower 4 ribs (by angle) *depressess last 4 ribs.

Splenius cervicis

Spinous process of* T3-T6* TO transverse process of *C1-C3* *Extend neck , ipsilateral lateral flex and rotation*

Longus Colli

Superior: transverse 3-5 to atlas Medial: one big long line from C3-T2 Inferior: side of medial colli T1-3 to Transverse C5-6 *Flex neck, laterally bends, rotates opposite side*

pSOAS minor

T12 and L1 to Superior ramus of pubis

Rectus Capitus Lateralis

Transverse C1 straight up to occipital bone. (muscle is just lateral to Rec. capit Anterior) *bends head laterally*

Rectus Capitus Anterior

Transverse C1 then superior medial to occipital bone. *flexes head*

Obliquus Capitis Superior

Transverse C1 to oblique medial. *bends head backward and laterally to same side*

Spinalis Capitis

Transverse process of C4-T7 TO superior and inferior nuch al lines. *extends vertebral column*

Levatores Costarum

Transverse process of c7-T11 TO costal angle of next lower rib. *raises rib and laterally flexes and rotates vertebral column.