| Muscle | Key attachments | Action | Nerve |
|---|---|---|---|
| Splenius capitis | Nuchal ligament/C7-T3 or T4 SP → mastoid/lateral superior nuchal line | Bilateral extension; unilateral ipsilateral rotation/sidebend | Posterior rami cervical nerves |
| Splenius cervicis | T3-T6 SP → C1-C3/4 TP | Bilateral extension; unilateral ipsilateral rotation/sidebend | Posterior rami cervical nerves |
| Rectus capitis posterior major | C2 SP → inferior nuchal line | Head extension/ipsilateral rotation | Suboccipital nerve C1 |
| Rectus capitis posterior minor | C1 posterior tubercle → inferior nuchal line | Head extension | Suboccipital nerve |
| Obliquus capitis superior | C1 TP → occiput | Head extension/sidebend | Suboccipital nerve |
| Obliquus capitis inferior | C2 SP → C1 TP | Ipsilateral head/C1 rotation | Suboccipital nerve |
| SCM | Manubrium/medial clavicle → mastoid/superior nuchal line | Bilateral cervical flexion with upper cervical extension; unilateral contralateral rotation/ipsilateral sidebend | CN XI motor |
| Anterior scalene | C3-C6 TP → first rib | Cervical flexion/sidebend; elevates first rib | Cervical anterior rami |
| Middle scalene | C2-C7 TP → first rib | Sidebend; elevates first rib | Cervical anterior rami |
| Posterior scalene | C4-C6 TP → second rib | Sidebend; elevates second rib | Cervical anterior rami |
Safety: the anterior/lateral neck contains carotid arteries, jugular veins, vagus nerve, brachial plexus roots/trunks and other sensitive structures. Precise anatomy matters more than pressure.
| Masseter | Zygomatic arch → lateral ramus/angle mandible | Elevates mandible; assists protrusion | Mandibular division CN V3 |
| Temporalis | Temporal fossa → coronoid process mandible | Elevates; posterior fibers retract mandible | Deep temporal nerves, V3 |
| Medial pterygoid | Sphenoid/maxillary region → medial mandibular angle | Elevates/protrudes; grinding | V3 |
| Lateral pterygoid | Sphenoid → mandibular neck/TMJ disc-capsule region | Protraction; assists opening and side-to-side movement | V3 |
Intraoral techniques require specific training, consent, hygiene and jurisdictional/school policy. Do not treat inaccessible deep muscles by blindly pressing through other structures.
| Diaphragm | Xiphoid, lower ribs/costal margin, lumbar crura → central tendon | Primary inspiration | Phrenic C3-C5 |
| External intercostals | Between adjacent ribs | Assist inspiration/rib elevation | Intercostal nerves |
| Internal intercostals | Between adjacent ribs | Interosseous portions assist forced expiration; interchondral portions can assist inspiration | Intercostal nerves |
Deglutition involves coordinated tongue, suprahyoid, infrahyoid, pharyngeal and laryngeal muscles under complex cranial/cervical nerve control. For massage students, know that the anterior neck is functionally dense and not an appropriate place for indiscriminate deep pressure.