Muscle | Origin | Insertion | Movement | Joint | Misc. Info |
Lateral pterygoid | Sphenoid | Mandibular condyle (and TMJ joint capsule) | Protraction | Temporomandibular (deep) | Combined with medial pterygoid-lateral excursion (chewing) |
Medial pterygoid | Sphenoid | Ramus, angle of mandible (medial) | Elevation (slight protraction) | Temporomandibular (deep) | Combined with lateral pterygoid-lateral excursion (chewing) |
Sternocleidomastoid | Sternum (side of jugular notch); medial third of clavicle | Mastoid process of mandible | Flexion (bilateral activation); contralateral rotation (unilateral activation) | Neck (anterior) | |
Scalene-anterior | Transverse process of cervical vertebrae | Superior surface of first rib | Ipsilateral lateral flexion; elevation of ribs for inspiration (if head is stabilized by other muscles) | Neck (anterior) | Scalenes |
Scalene-medius | Transverse processes of cervical vertebrae | Superior surface of first rib | Ipsilateral lateral flexion; elevation of ribs for inspiration (if head is stabilized by other muscles) | Neck (anterior) | Scalenes |
Scalene-posterior | Transverse processes of cervical vertebrae | Superior surface of second rib | Ipsilateral lateral flexion; elevation of ribs for inspiration (if head is stabilized by other muscles) | Neck (anterior) | Scalenes |
Longus capitis | Cervical vertebrae | Occipital bone (anterior/lateral to foramen magnum) | Flexion; lateral flexion | Neck (anterior) | Prevertebral; deeper, weaker than scalenes/sternocleidomastoid |
Longus colli | Thoracic vertebrae | Bodies of cervical vertebrae | Flexion; lateral flexion | Neck (anterior) | Prevertebral; deeper, weaker than scalenes/sternocleidomastoid |
Rectus capitis anterior | Atlas (anterior transverse process) | Occipital bone (lateral to insertion points of longus capitis) | Flexion; lateral flexion | Neck (anterior) | Prevertebral; deeper, weaker than scalenes/sternocleidomastoid |
Rectus capitis lateralis | Atlas (anterior transverse process) | Occipital bone (lateral to insertion points of longus capitis) | Flexion; lateral flexion | Neck (anterior) | Prevertebral; deeper, weaker than scalenes/sternocleidomastoid |
Rectus abdominis | Pubic crest and symphysis | Xiphoid process and costal cartilages (5-7) | Flexion (first 1/3, rest is gravity and momentum) (thoracic/lateral regions of spine) | Trunk (anterior) | 3 tenindous inscriptions (divides muscle into 4 bellies=8-pack abs); rectus sheath (sheath of connective tissue covering abs); linea alba (line of connective tissue in the middle, crosses navel); "abs" |
External oblique | Lower 8 ribs | Iliac crest; aponeurosis (rectus) from ribs to linea alba | (Ipsilateral) flexion; lateral flexion; contralateralrotation (with legs flexed) | Trunk(anterior, superficial) | Runs downward and forward; continuous with external intercostals |
Internal oblique | Iliac crest; thoracolumbar fascia | Aponeurosis, costal cartilage (10-12) | Flexion; lateral flexion; ipsilateral rotation (with legs fixed) | Trunk (anterior) | Directly under external oblique; runs downward and backward; role in forced expiration |
Transversus abdominis | Iliac crest; thoracolumbar fascia; ribs (6-12) | Linea alba via abdominal aponeurosis | Compression of abdomen | Trunk (anterior) | Not really used in movement |
Psoas Major | Lumbar transverse processes | Greater trochanter | Flexion | Trunk (anterior, deep) | Wraps around head of femur |
Splenius capitis | Spinous process of cervical and thoracic vertebrae | Mastoid process of occipital bone | Extension; ipsilateral rotation | Neck (posterior, intermediate) | Superior/anterior to splenius cervicis |
Splenius cervicis | Spinous process of cervical and thoracic vertebrae | Transverse processes of cervical vertebrae | Extension; ipsilateral rotation | Neck (posterior, intermediate) | Inferior/posterior to splenius capitis |
Erector spinae group | Posterior iliac crest and sacrum | | | Trunk (posterior, intermediate) | Antagonist to rectus abdominus |
Rectus capitis posterior major | Spinous processes of cervical vertebrae | Inferior nuchal lines | Extension; ipsilateral rotation | Neck (posterior, deep) | Suboccipital muscle; broad attachment at nuchal line |
Rectus capitis posterior minor | Spinous process of atlas (C1) | Inferior nuchal lines | Extension | Neck (posterior, deep) | Suboccipital muscle; under rectus capitis posterior major |
Obliquus capitis superior | Transverse process of atlas (C1) | Superior nuchal lines | Extension; lateral flexion | Neck (posterior, deep) | Suboccipital muscle |
Obliquus capitis inferior | Spinous process of axis (C2) | Transverse process of atlas (C1) | Ipsilateral rotation | Neck (posterior, deep) | Suboccipital muscle |
Semispinalis | | | | | Transversospinalis muscle; semispinalis capitis/cervicis/thoracis |
Multifidus | Transverse process of vertebrae | Spinous process of vertebrae above (next superior) | | Trunk (posterior, deep) | Transversospinalis muscle |
Rotatores | Transverse process of vertebra x | Brevis: spinous process of vertebra x-1; longus: spinous process of vertebra x-2 | | Trunk (posterior, deep) | Transversospinalis muscle |
Interspinales | Spinous processes of vertebrae | Spinous process of adjacent vertebrae | Extension | Trunk (posterior, deep) | Segmental muscle |
Intertransversarius | Transverse processes of vertebrae | Transverse process of adjacent vertebrae | Lateral flexion | Trunk (posterior, deep) | Segmental muscle |
Quadratus lumborum | Iliac crest | Lower rib; transverse processes of lumbar vertebrae (L1-L4) | Lateral flexion | Trunk (posterior, deep) | |
Masseter | Zygomatic arch (medial) | Ramus, angle of mandible (lateral) | Elevation | Temporomandibular (superficial) | Wraps around angle; feel angle with clenched teeth; spasms=grinding teeth |
Temporalis | Lateral skull (frontal, parietal, temporal) | Coronoid process of mandible | Elevation, retraction | Temporomandibular (superficial) | Broad origin; feel side of head with clenched teeth; spasms=grinding teeth |