Expanded Muscle Groups

Pronator teres: medial epicondyle/coronoid region to lateral radius. Pronates forearm and assists elbow flexion.

Flexor carpi radialis: medial epicondyle to bases of 2nd/3rd metacarpals. Wrist flexion and radial deviation.

Palmaris longus: medial epicondyle to palmar aponeurosis/flexor retinaculum. Weak wrist flexion and tenses palmar fascia; congenitally absent in some people.

Flexor carpi ulnaris: medial epicondyle/ulna to pisiform and ulnar-side hand attachments. Wrist flexion and ulnar deviation.

Flexor digitorum superficialis/profundus: flex fingers, with profundus reaching distal phalanges and superficialis middle phalanges.

Supinator: proximal ulna/lateral epicondylar region to proximal radius. Supinates forearm.

Extensor carpi radialis longus/brevis: lateral humeral region to metacarpal bases. Extend wrist and contribute to radial deviation.

Extensor digitorum: lateral epicondyle to extensor expansions. Extends digits and assists wrist extension.

Extensor carpi ulnaris: lateral epicondyle/posterior ulna to fifth metacarpal. Wrist extension and ulnar deviation.

Thenar muscles: move the thumb, including opposition. Hypothenar muscles: move the little finger. Lumbricals: flex MCP joints while extending IP joints through the extensor mechanism. Interossei: dorsal interossei abduct fingers; palmar interossei adduct fingers. Memory cue: DAB, PAD.

Piriformis, obturator internus/externus, superior/inferior gemelli, quadratus femoris form the deep external-rotator region. Most contribute to hip external rotation and stabilization, with action varying by hip position. Their proximity to the sciatic nerve and deep gluteal structures means anatomy matters more than pressure.

Extensor hallucis longus: extends great toe and assists dorsiflexion.

Extensor digitorum longus: extends lateral four toes and assists dorsiflexion/eversion.

Fibularis tertius: assists dorsiflexion and eversion.

Fibularis longus/brevis: evert and assist plantarflexion; longus also crosses under the foot and contributes to arch support.

Tibialis posterior: inversion/plantarflexion and arch support.

Flexor hallucis longus: flexes great toe and assists plantarflexion.

Flexor digitorum longus: flexes lateral four toes and assists plantarflexion.

Popliteus: small posterior knee muscle involved in initiating knee flexion/unlocking mechanics. The popliteal fossa contains important neurovascular structures and is an area of caution.

Diaphragm: primary muscle of quiet inspiration; contraction descends/flattens the dome and increases thoracic volume.

External intercostals: assist rib elevation during inspiration. Internal intercostals: portions contribute to forced expiration, with fiber/function distinctions.

Accessory inspiratory muscles: SCM and scalenes can assist when respiratory demand increases.

Masseter: elevation. Temporalis: elevation and retraction. Medial pterygoid: elevation and grinding movements. Lateral pterygoid: assists protrusion, depression/opening mechanics and side-to-side movement. Intraoral work requires specific training/scope and is not implied by learning the anatomy.

Rectus abdominis: pubic region to xiphoid/costal cartilages; trunk flexion and abdominal compression.

External oblique: trunk flexion, ipsilateral lateral flexion and contralateral rotation.

Internal oblique: trunk flexion, ipsilateral lateral flexion and ipsilateral rotation.

Transversus abdominis: abdominal compression/stabilization.