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Muscles Beginning With S
27 muscles in the reference begin with the letter S. Every name links to a page giving the muscle’s origin, insertion, main actions and nerve supply.
A B C D E F G H I L M N O P Q R S T V Z
| Muscle | Main actions | Nerve supply |
|---|---|---|
| Sartorius | Flexes the thigh and the knee; Moves the thigh outward and rotates it outward (sitting cross-legged) | Femoral nerve (L2–L3) |
| Scalenus Anterior | Elevates the first rib in breathing; Flexes and slightly rotates the neck | Cervical spinal nerves C4–C6 |
| Scalenus Medius | Elevates the first rib in breathing; Tilts the neck to the same side | Cervical spinal nerves C3–C8 |
| Scapular Stabilisers (Group) | Position and rotate the shoulder blade for every arm movement | Accessory, dorsal scapular, long thoracic and pectoral nerves |
| Semimembranosus | Bends the knee (flexion); Extends the thigh | Sciatic nerve, tibial division (L5–S2) |
| Semispinalis Capitis | Extends the head; Turns the face slightly to the opposite side | Dorsal rami of cervical spinal nerves (greater occipital nerve, C2, emerges through it) |
| Semispinalis Thoracis | Extends the thoracic and cervical spine; Rotates the spine to the opposite side | Dorsal rami of spinal nerves |
| Semitendinosus | Bends the knee (flexion); Extends the thigh | Sciatic nerve, tibial division (L5–S2) |
| Serratus Anterior | Holds the shoulder blade flat against the chest wall; Pulls the scapula forward (protraction, as in punching) | Long thoracic nerve (C5–C7) |
| Serratus Posterior Inferior | Depresses ribs 9–12 (helper in breathing out) | Ventral rami of T9–T12 |
| Serratus Posterior Superior | Elevates ribs 2–5 (helper in breathing in) | Intercostal nerves T1–T4 |
| Sesamoid Muscles of the Great Toe (Flexor Hallucis Brevis Heads) | Bend the great toe while the sesamoids protect the flexor hallucis longus tendon and spread load | Medial plantar nerve (S1–S2) |
| Soleal Venous Pump (Soleus and Gastrocnemius) | Compress the deep calf veins with every step, returning blood to the heart | Tibial nerve (S1–S2) |
| Soleus | Points the foot downward (plantarflexion); Maintains posture when standing (works continuously) | Tibial nerve (S1–S2) |
| Spinalis Thoracis | Extends the thoracic spine | Dorsal rami of spinal nerves |
| Splenius Capitis | Extends the head and neck; Turns the face to the same side | Dorsal rami of cervical spinal nerves |
| Splenius Cervicis | Extends the neck; Turns the face to the same side | Dorsal rami of cervical spinal nerves |
| Sternocleidomastoid | Turns the head to the opposite side; Tilts the head to the same side | Accessory nerve (CN XI), with C2–C3 branches |
| Sternohyoid | Depresses the hyoid bone after swallowing | Ansa cervicalis (C1–C3) |
| Sternothyroid | Depresses the larynx (via the thyroid cartilage) | Ansa cervicalis (C2–C3) |
| Subclavius | Anchors and depresses the clavicle; Cushions the subclavian vessels if the clavicle breaks | Nerve to subclavius (C5–C6) |
| Subcostales | Depress the lower ribs slightly in breathing out | Intercostal nerves |
| Subsartorial (Adductor) Canal Contents — Sartorius Roof | Covers the adductor canal carrying the femoral vessels mid-thigh | Femoral nerve (L2–L3) |
| Subscapularis | Rotates the arm inward (medial rotation); Stabilises the shoulder joint | Upper and lower subscapular nerves (C5–C7) |
| Superficial Posterior Compartment of the Leg (Group) | Point the foot downward (plantarflexion) | Tibial nerve (S1–S2) |
| Supinator | Turns the forearm palm-up (supination) when the elbow is straight | Posterior interosseous nerve (C6–C7) |
| Supraspinatus | Starts arm abduction (first ~15 degrees); Stabilises the head of the humerus in the socket | Suprascapular nerve (C5–C6) |
Please note: This page is an anatomy education summary for students and curious readers, not medical advice. Attachment points are given in their classic short form; individual anatomy varies, and detailed dissection-level descriptions belong in an anatomy atlas.