Spring 1 Muscles

Origin of rectus capitis posterior major

SP of C2

Insertion of rectus capitis posterior major

Lateral aspect of inferior nuchal line

Action of rectus capitis posterior major

Extends head and ipsilateral rotation

Innervation of rectus capitis posterior major

PR C1 (suboccipital nerve)

Origin of rectus capitis posterior minor

Posterior tubercle of C1

Insertion of rectus capitis posterior minor

Medial aspect of inferior nuchal line

Action of rectus capitis posterior minor

Extends head

Innervation of rectus capitis posterior minor

PR C1 (suboccipital nerve)

Origin of obliquus capitis superior

TP of C1

Insertion of obliquus capitis superior

Between superior and inferior nuchal lines

Action of obliquus capitis superior

Extension and lateral flexion of head

Innervation of obliquus capitis superior

PR C1 (suboccipital nerve)

Origin of obliquus capitis inferior

SP C2

Insertion of obliquus capitis inferior

TP of C1

Action of obliquus capitis inferior

Rotates atlas, turning head ipsilaterally

Innervation of obliquus capitis inferior

PR C1 (suboccipital nerve)

Superior attachment of platysma

Inferior border of mandible, skin, and subcutaneous tissue of lower face

Inferior attachment of platysma

Fascia covering superior parts of pec major and deltoid muscles

Action of platysma

Draws corners of the mouth inferiorly and widens it, draws skin of neck superiorly

Innervation of platysma

Cervical branch of facial nerve (CN VII)

Superior attachment of anterior scalene

TP C3 - C6

Inferior attachment of anterior scalene

Scalene tubercle of 1st rib

Action of anterior scalene

Neck flexion and elevates 1st rib during forced inspiration

Innervation of anterior scalene

AR C4 - C6

Superior attachment of middle scalene

TP of C2 - C7

Inferior attachment of middle scalene

Superior surface of 1st rib, posterior to groove for subclavian artery

Action of middle scalene

Laterally flexes neck and elevates 1st rib during forced inspiration

Innervation of middle scalene

AR of cervical spinal nerves

Superior attachment of posterior scalene

TP C5 - C7

Inferior attachment of posterior scalene

2nd rib

Action of posterior scalene

Laterally flexes neck and elevates 2nd rib during forced inspiration

Innervation of posterior scalene

AR of C7 - C8

Actions of longus colli

• Bilateral = neck flexion

• Unilateral = flexes neck, laterally flexes neck, and contralateral rotation

Innervation of longus colli

AR C2 - C6

Action of longus capitis

Flexes head

Innervation of longus capitis

AR C1 - C3

Action of rectus capitis anterior

Flexes head

Innervation of rectus capitis anterior

Branches from loop between C1 & C2

Action of rectus capitis lateralis

Flexes head and stabilizes head

Innervation of rectus capitis lateralis

Branches from loop between C1 and C2

Proximal attachment of subclavius

Junction of 1st rib and its costal cartilage

Distal attachment of subclavius

Inferior surface of middle third of clavicle

Action of subclavius

Anchors and depresses clavicle

Innervation of subclavius

Nerve to subclavius C5

Proximal attachment of levator scapulae

TP of C1 - C4

Distal attachment of levator scapulae

Medial border of scapulae superior to root of scapular spine

Action of levator scapulae

Elevates and downwardly rotates scapula

Innervation of levator scapulae

Dorsal scapular nerve C5 and C3, C4

Proximal attachment of masseter

Inferior border and medial surface of maxillary process of zygomatic bone and zygomatic arch

Distal attachment of masseter

Angle and lateral surface of ramus of mandible

Action of masseter

Elevates mandible closing jaws; superficial fibers may make limited contribution to protrusion of mandible

Innervation of masseter

CN V₃ via masseteric nerve

Proximal attachment of temporalis

Temporal fossa and temporal fascia

Distal attachment of temporalis

Coronoid process and anterior border of ramus of mandible

Action of temporalis

Elevates mandible closing jaws. Posterior fibers are primary retractors of the mandible

Innervation of temporalis

CN V₃ via deep temporal branches

Proximal attachment of medial pterygoid

Medial surface of lateral pterygoid plate and pyramidal process of palatine bone and tuberosity of maxilla

Distal attachment of medial

Medial surface of ramus of mandible

Action of medial pterygoid

Elevates mandible, contributes to protrusion; alternate unilateral activity produces smaller grinding movements

Innervation of medial pterygoid

CN V₃ via medial pterygoid nerve

Proximal attachment of lateral pterygoid

Infratemporal surface and crest of greater wing of sphenoid and lateral surface of lateral pterygoid plate

Distal attachment of lateral pterygoid (superior & inferior)

• Superior: articular capsule and disk

• Inferior: pterygoid fovea on neck of condyloid process of mandible

Actions of lateral pterygoid

• Bilaterally: protracts mandible and depresses chin

• Unilaterally: lateral deviation to contralateral side. Alternate unilateral contraction produces larger lateral chewing movements

Innervation of lateral pterygoid

CN V₃ via lateral pterygoid nerve

Superior attachment of intercostals

Inferior border of ribs

Inferior attachment of intercostals

Superior border of ribs below

Action of intercostals

Approximate ribs

Innervation of intercostals

AR T1-T12 (intercostal nerves)

Superior attachment of levator costarum

TP C7-T11

Inferior attachment of levator costarum

Subajacent ribs between tubercle & angle

Action of levator costarum

Elevate ribs

Innervation of levator costarum

PR C8-T11

Proximal attachment of diaphragm

L1-L3, medial & lateral arcuate ligaments, lower 6 ribs & costal cartilages, and xiphoid process

Distal attachment of diaphragm

Central tendon of diaphragm

Action of diaphragm

Flattens central tendon, increasing vertical diameter of thoracic cavity in inspiration

Innervation of diaphragm

Phrenic nerve C3, C4, C5

Origin of rectus abdominis

Pubic symphysis and pubic crest

Insertion of rectus abdominis

Xiphoid process and costal cartilages of 5th - 7th ribs

Action of rectus abdominis

• Flexes trunk (lumbar vertebrae)

• Compresses/supports abdominal viscera

• Stabilizes pelvis

Innervation of rectus abdominis

Thoracoabdominal nerves (AR T6-T12)

Origin of external oblique

External surfaces of 5th - 12th ribs

Insertion of external oblique

Linea alba, pubic tubercle, and anterior half of iliac crest

Actions of external oblique

• Flexes trunk

• Laterally flexes trunk to ipsilateral side

• Rotates trunk to contralateral side (with opposite internal oblique)

• Compresses/supports abdominal viscera

Innervation of external oblique

Thoracoabdominal nerves (AR T6-T12)

Origin of internal oblique

Thoracolumbar fascia, anterior 2/3 of iliac crest, and connective tissue deep to the lateral 1/3 of inguinal ligament

Insertion of internal oblique

Inferior borders of 10th - 12th ribs, linea alba, and pecten pubis via conjoint tendon

Actions of internal oblique

• Flexes trunk

• Laterally flexes trunk to ipsilateral side

• Rotates trunk to ipsilateral side

• Compresses/supports abdominal viscera

Innervation of internal oblique

Thoracoabdominal nerves (AR T6-T12) & L1

Origin of transversus abdominis

Internal surfaces of 7th-12th costal cartilages, thoracolumbar fascia, iliac crest, and connective tissue deep to lateral 1/3 of inguinal ligament

Insertion of transversus abdominis

Linea alba with aponeurosis of internal oblique, pubic crest, and pecten pubis via conjoint tendon

Action of transversus abdominis

Compresses/supports abdominal viscera

Innervation of transversus abdominis

Thoracoabdominal nerves (AR T6-T12) and L1

Proximal attachment of pyramidalis

Linea alba

Distal attachment of pyramidalis

Pubic crest

Action of pyramidalis

Tenses linea alba

Innervation of pyramidalis

AR T12 - L1

Superior attachment of quadratus lumborum (QL)

Medial half of inferior border of 12th ribs and lumbar TPs

Inferior attachment of quadratus lumborum (QL)

Iliolumbar ligament and internal lip of iliac crest

Action of quadratus lumborum (QL)

• Extends and laterally flexes vertebral column

• Fixes 12th rib during inspiration

Innervation of quadratus lumborum (QL)

AR T12 - L4