All Nerves — Roots · Motor · Sensory · Clinical
Every nerve from the five lectures in one table: 12 cranial nerves, spinal nerves, brachial/lumbar/sacral/cervical plexuses, phrenic and intercostal nerves. Type a nerve name, root (e.g. "C5", "S2"), or muscle in the search box to filter.
How to use: Cranial nerves have columns No · Nerve · Type · Function/Target; peripheral nerves have Nerve · Roots · Motor · Sensory/Area · Clinical. The Roots (blue) and Clinical (red) columns are the most exam-critical.
CRANIAL NERVES (12 pairs)
| No | Nerve | Type | Function / Target |
|---|---|---|---|
| I | Olfactory | Sensory | Smell — nose |
| II | Optic | Sensory | Vision — eye |
| III | Oculomotor | Motor | All eye muscles except IV and VI |
| IV | Trochlear | Motor | Superior oblique muscle |
| V | Trigeminal | Mixed | Sensory: face, sinuses, teeth · Motor: muscles of mastication |
| VI | Abducent | Motor | Lateral (external) rectus muscle |
| VII | Facial | Mixed | Motor: muscles of facial expression |
| VIII | Vestibulocochlear | Sensory | Hearing & balance — inner ear |
| IX | Glossopharyngeal | Mixed | Motor: pharyngeal muscles · Sensory: posterior 1/3 of tongue, tonsil, pharynx |
| X | Vagus | Mixed | Heart, lungs, bronchi, trachea, larynx, pharynx, GI tract, external ear (motor & sensory) |
| XI | Accessory | Motor | Sternocleidomastoid & trapezius muscles |
| XII | Hypoglossal | Motor | Muscles of the tongue |
Name mnemonic (I→XII): "On Old Olympus' Towering Tops A Finn And German Viewed Some Hops".
Type mnemonic (S=Sensory, M=Motor, B=Both): "Some Say Marry Money But My Brother Says Big Brains Matter Most" → S S M M B M B S B B M M.
Eye muscles: "LR6 SO4" → Lateral Rectus = VI, Superior Oblique = IV, rest = III.
Type mnemonic (S=Sensory, M=Motor, B=Both): "Some Say Marry Money But My Brother Says Big Brains Matter Most" → S S M M B M B S B B M M.
Eye muscles: "LR6 SO4" → Lateral Rectus = VI, Superior Oblique = IV, rest = III.
SPINAL NERVES (general)
| Topic | Information | Note | |
|---|---|---|---|
| Total number | 31 pairs | — | 8 cervical · 12 thoracic · 5 lumbar · 5 sacral · 1 coccygeal |
| Formation | Dorsal (sensory) root + Ventral (motor) root | — | Autonomic fibres also contribute |
| Axon types carried | GSA · GSE · GVA · GVE | — | General Somatic/Visceral Afferent/Efferent |
| Rami | Dorsal ramus + Ventral ramus | — | Dorsal ramus → back skin/muscles; ventral ramus → plexuses (except thoracic → intercostal) |
| Plexuses | Cervical · Brachial · Lumbar · Sacral | — | Thoracic ventral rami form no plexus → intercostal nerves |
| Sensory ganglion | Dorsal root (spinal) ganglion | — | 31 pairs; cranial sensory e.g. trigeminal ganglion |
BRACHIAL PLEXUS & UPPER LIMB NERVES
| Nerve | Roots | Motor (muscles) | Sensory / Area | Clinical / Note |
|---|---|---|---|---|
| Musculocutaneous | C5–C7 | Anterior arm: biceps brachii, brachialis, coracobrachialis | Lateral cutaneous n. of forearm | Pierces coracobrachialis; motor ends at elbow |
| Axillary | C5–C6 | Deltoid & teres minor | Superior lateral cutaneous n. of arm | Passes through quadrangular space; injured in humeral surgical neck fracture |
| Radial | C5–T1 | Triceps, anconeus, brachioradialis, ECRL (all extensors) | Posterior arm/forearm skin | Humeral shaft fracture → wrist drop |
| Median | C6–T1 | Forearm flexors (except 2) + thenar muscles + lateral 2 lumbricals | Lateral 3.5 digits (palmar) + tips | Passes through carpal tunnel; CTS → "ape hand", central palm sensation spared |
| Ulnar | C8–T1 | Hypothenar, adductor pollicis, interossei, medial 2 lumbricals | Medial 1.5 digits (5th + half of 4th) | Passes through Guyon's canal; "claw hand" |
| Thoracodorsal | C6–C8 | Latissimus dorsi | — | Branch of posterior cord |
| Long thoracic | C5–C7 | Serratus anterior | — | Injury → "winged scapula" |
| Dorsal scapular | C5 | Rhomboid major/minor, levator scapulae | — | — |
| Suprascapular | C5–C6 | Supraspinatus & infraspinatus | — | — |
| Medial & lateral pectoral | C5–T1 | Pectoralis major & minor | — | — |
| (Exception) Accessory n. → trapezius | CN XI | Trapezius (+ SCM) | — | Only upper-limb muscle NOT from the brachial plexus |
Plexus backbone: Roots (C5-T1) → Trunks → Divisions → Cords → Branches ("Read That Damn Cadaver Book").
Trunks: C5+C6 = Superior · C7 = Middle · C8+T1 = Inferior.
Cord → terminal branch: Posterior cord → Axillary + Radial · Lateral cord → Musculocutaneous + Median (lateral root) · Medial cord → Ulnar + Median (medial root). 5 branches = MARMU.
Trunks: C5+C6 = Superior · C7 = Middle · C8+T1 = Inferior.
Cord → terminal branch: Posterior cord → Axillary + Radial · Lateral cord → Musculocutaneous + Median (lateral root) · Medial cord → Ulnar + Median (medial root). 5 branches = MARMU.
LUMBAR PLEXUS (L1–L4)
| Nerve | Roots | Motor (muscles) | Sensory / Area | Clinical / Note |
|---|---|---|---|---|
| Iliohypogastric | L1 | Internal oblique & transversus abdominis (lower) | Suprapubic & gluteal skin | — |
| Ilioinguinal | L1 | Internal oblique & transversus abdominis (lower) | Inguinal region, scrotum/labium skin | — |
| Genitofemoral | L1–L2 | Cremaster muscle | Upper anterior thigh & genital skin | — |
| Lateral femoral cutaneous | L2–L3 | — | Lateral skin of thigh | Entrapment → meralgia paraesthetica |
| Femoral nerve | L2–L4 | Anterior thigh muscles (iliacus, sartorius, quadriceps, pectineus) | Anteromedial thigh; saphenous → medial leg & foot | Largest nerve of lumbar plexus; injury → weak knee extension + loss of patellar reflex |
| Obturator nerve | L2–L4 | Medial thigh adductors (adductor longus/brevis, gracilis, adductor part of adductor magnus) | Medial thigh skin | — |
| Muscular branches | L1–L4 | Quadratus lumborum, psoas major/minor | — | — |
Branch mnemonic: "I, I Get Leftovers On Fridays" → Iliohypogastric, Ilioinguinal, Genitofemoral, Lateral femoral cutaneous, Obturator, Femoral. Location: behind psoas major, in the posterior abdominal wall.
SACRAL & COCCYGEAL PLEXUS (L4–Co)
| Nerve | Roots | Motor (muscles) | Sensory / Area | Clinical / Note |
|---|---|---|---|---|
| Superior gluteal nerve | L4–S1 | Gluteus medius, gluteus minimus, TFL | — | Injury → Trendelenburg gait |
| Inferior gluteal nerve | L5–S2 | Gluteus maximus | — | — |
| Sciatic nerve | L4–S3 | Posterior thigh (hamstrings) + (via branches) all leg & foot muscles | Almost all skin of leg & foot (except medial) | Largest nerve in the body; exits via greater sciatic foramen; injured by incorrect gluteal IM injection → all muscles below knee paralysed |
| ↳ Tibial nerve (branch) | L4–S3 | Posterior leg + sole of foot (medial & lateral plantar) | Sole, heel | Medial branch of sciatic |
| ↳ Common peroneal (branch) | L4–S2 | Anterior/lateral leg (deep & superficial peroneal), foot dorsum | Anterolateral leg + foot dorsum | Superficial at fibular neck → injury "foot drop" |
| Posterior femoral cutaneous | S1–S3 | — | Posterior thigh & popliteal skin | — |
| Pudendal nerve | S2–S4 | External anal sphincter & perineal muscles | Anal & genital region skin | Main nerve of perineum ("S2,3,4 keeps the pelvis off the floor") |
| Direct muscular branches | L4–S2 | Piriformis, quadratus femoris, obturator internus, gemelli, levator ani, coccygeus | — | — |
| Anococcygeal nerves (coccygeal plexus) | S4–Co | — | Small area of coccygeal skin | Coccygeal plexus = S4 (part) + S5 + coccygeal nerve |
Sacral plexus formation: Lumbosacral trunk (L4-5) + S1, S2, S3 + S4 (part). Location: posterior wall of lesser pelvis, closely related to piriformis.
CERVICAL PLEXUS & OTHER TRUNK NERVES
| Nerve | Roots | Motor (muscles) | Sensory / Area | Clinical / Note |
|---|---|---|---|---|
| Ansa cervicalis | C1–C3 | Infrahyoid muscles (sternohyoid, sternothyroid, omohyoid) — except thyrohyoid | — | Superior root C1 (within hypoglossal) + inferior root C2-3 |
| Phrenic nerve | C3–C5 (mainly C4) | Diaphragm (motor) | Pleura & pericardium (sensory) | "C3-4-5 keep the diaphragm alive"; passes in front of anterior scalene |
| Lesser occipital | C2 | — | Skin behind ear & occipital region | Sensory |
| Great auricular | C2–C3 | — | Skin over ear & parotid | Sensory |
| Transverse cervical | C2–C3 | — | Anterior neck skin | Sensory |
| Supraclavicular | C3–C4 | — | Skin over clavicle & upper chest | Sensory |
| Motor (prevertebral) branches | C1–C4 | Prevertebral muscles, geniohyoid, thyrohyoid (C1) | — | — |
| Suboccipital nerve | C1 (dorsal ramus) | 4 suboccipital muscles (rectus capitis post. major/minor, obliquus capitis sup./inf.) | — | Suboccipital triangle |
| Intercostal nerves | T1–T11 | Intercostal muscles; lower 6 to abdominal muscles | Skin of thorax & abdominal wall | Thoracic ventral rami (form no plexus) |
| Subcostal nerve | T12 | Abdominal wall muscles (e.g. pyramidalis) | Lower abdominal skin | — |
Cervical plexus = C1–C4 (deep to SCM & IJV). 4 sensory branches (G-L-T-S): Great auricular, Lesser occipital, Transverse cervical, Supraclavicular.
Erb's point (punctum nervosum): midpoint of the posterior border of SCM — where the cutaneous branches become superficial; target for superficial cervical plexus block.
Erb's point (punctum nervosum): midpoint of the posterior border of SCM — where the cutaneous branches become superficial; target for superficial cervical plexus block.
No matching nerve found — try a different term.