Foundations: Anatomical position & planes, movements, fascia, dermatomes & myotomes, lymphatic drainage patterns.
Upper Limb: Brachial plexus, axilla, arm/forearm compartments, hand spaces & extensor tunnels, shoulder & elbow mechanics.
Lower Limb: Gluteal region & gateways, femoral triangle & adductor canal, knee & popliteal fossa, leg compartments, foot arches & ankle.
Thorax: Wall & intercostals, mediastinum divisions, heart anatomy & coronaries, lungs/pleura, hilar structures.
Abdomen: Peritoneum & mesenteries, foregut/midgut/hindgut supply, portal system & anastomoses, inguinal canal & hernias.
Pelvis & Perineum: Pelvic floor, neurovasculature, ureter & bladder, reproductive organs, perineal pouches.
Head & Neck: Cranial bones & sinuses, cranial nerves, triangles of neck, pharynx & larynx, orbit, ear, autonomics.
Back & Spine: Vertebrae & joints, spinal cord & meninges, arterial supply & venous plexus.
Neuroanatomy: Lobes & functional areas, internal capsule, basal ganglia, thalamus, brainstem, cerebellum, ventricles & CSF.
Histology & Embryology: Tissue archetypes, epithelium types, bone/cartilage, organ microanatomy, germ layers, pharyngeal arches, cardiovascular & GI development.

💪 Upper Limb – innervation & traps

Brachial plexus: Roots (C5–T1) → Trunks (S/M/I) → Divisions → Cords (Lat/Med/Post) around axillary artery → terminal nerves (M, U, R, Ax, Msc). “Randy Travis Drinks Cold Beer”.
Compartments: Arm (ant: musculocutaneous; post: radial). Forearm (ant: median ± ulnar; post: radial). Hand (thenar: recurrent median; interossei: ulnar).
Key lesions: Surgical neck humerus → axillary (deltoid weak, “regimental badge” numb). Mid-shaft → radial (wrist drop). Supracondylar → median (thenar wasting). Medial epicondyle → ulnar (intrinsics).
Spaces: Quadrangular space (axillary n., post circumflex humeral a.); Triangular interval (radial n., profunda brachii a.).

🦵 Lower Limb – gateways & gait

Innervation: Femoral (ant thigh), Obturator (medial thigh), Sciatic (post thigh → tibial & common fibular). Common fibular → superficial (lateral leg, eversion) & deep (anterior leg, dorsiflexion).
Surface spaces: Femoral triangle (NAVeL, lat→med); Adductor canal (femoral a. → popliteal). Popliteal fossa contents: tibial n., popliteal v., a. (deepest).
Gait clues: Superior gluteal n. injury → Trendelenburg; common fibular injury at fibular neck → foot drop.
Arches: Medial longitudinal (spring lig., tibialis posterior/anterior), lateral longitudinal, transverse; plantar aponeurosis supports.

❤️ Thorax – mediastinum & heart

Mediastinum: Superior (great vessels, trachea, oesophagus, thymus); Inferior: anterior (fat/lymph), middle (heart/pericardium), posterior (oesophagus, thoracic duct, azygos, descending aorta).
Heart: Right margin = RA; apex = LV; posterior = LA. Conduction: SA (RA), AV (interatrial septum), His-Purkinje.
Coronaries: RCA → marginal + PDA (often right-dominant); LCA → LAD (anterior IV), circumflex. LAD = “widowmaker”.
Lungs: Right 3 lobes, left 2 + lingula. Pulmonary artery relation: “RALS” (Right Anterior, Left Superior) to main bronchus at hilum.

🍽️ Abdomen – vasculature & portals

Arterial supply: Coeliac (foregut), SMA (midgut), IMA (hindgut). Midgut pain periumbilical (T10); hindgut suprapubic.
Portal–systemic anastomoses: Oesophageal, paraumbilical, rectal, retroperitoneal - enlarge in portal HTN (varices, caput medusae, haemorrhoids).
Inguinal canal: Deep ring (transversalis fascia) → superficial ring (ext oblique aponeurosis). Indirect hernia lateral to inferior epigastrics; direct is medial via Hesselbach’s triangle.
Peritoneal spaces: Lesser sac (omental bursa), epiploic foramen - surgical access routes.

🫀 Pelvis & Perineum – floors & pouches

Pelvic floor: Levator ani (puborectalis, pubococcygeus, iliococcygeus) + coccygeus; supports viscera, maintains continence.
Ureter: “Water under the bridge” - passes under uterine artery/ductus deferens; iatrogenic risk in pelvic surgery.
Perineum: Urogenital vs anal triangles; superficial & deep pouches with erectile tissues and glands.
Pudendal nerve: S2–S4; leaves greater sciatic foramen, re-enters lesser; pudendal block landmark = ischial spine.

🧠 Head & Neck – cranial nerves & spaces

Cranial nerves “SOME SAY MONEY…”: S/M/B pattern. CN III palsy → down & out + ptosis + mydriasis (parasympathetics superficial).
Danger triangle of face: Valveless facial veins → cavernous sinus (risk of thrombosis).
Neck triangles: Anterior (carotid sheath: ICA, IJV, CN X); posterior (brachial plexus trunks; accessory n.).
Autonomics: Horner (ptosis, miosis, anhidrosis) = sympathetic chain lesion.

🧩 Back & Spine – cord levels matter

Spinal cord ends ~L1–L2 (adults). Lumbar puncture at L3–L4 or L4–L5 (iliac crest line).
Vascular supply includes artery of Adamkiewicz (usually left T9–L2); watershed risk in aortic surgery.
Dermatomes: C6 thumb, C7 middle finger, C8 little finger; T4 nipple, T10 umbilicus; L1 groin; L4 knee; S1 lateral foot; S4/5 perianal.

🧬 Neuroanatomy – tracts & nuclei

Motor: Corticospinal decussation at medullary pyramids → lateral CST in cord; UMN vs LMN signs differ (tone, reflexes, Babinski).
Sensory: Dorsal columns (fine touch/proprioception) ascend ipsilaterally → decussate in medulla; spinothalamic (pain/temp) decussate segmentally.
Brainstem syndromes: Weber (midbrain: III + CST), Lateral medullary/Wallenberg (PICA: nucleus ambiguus issues).
CSF: Choroid plexus → lateral → 3rd (Monro) → aqueduct → 4th → median/lateral apertures → subarachnoid → arachnoid granulations.

📏 Core Tables – Landmarks, Innervation & Blood Supply

Region / Structure	Key Facts	Clinical / Exam Pearls
Rotator cuff	SItS: Supraspinatus (abd 0–15°), Infraspinatus (ER), teres Minor (ER), subscapularis (IR)	Painful arc 60–120° (supraspinatus tendon). External rotation weakness → infra/teres minor injury.
Elbow ligaments	Ulnar & radial collateral; annular encircles radial head	Nursemaid’s elbow = radial head subluxation from annular ligament.
Hand spaces	Thenar (recurrent median), hypothenar (deep ulnar), adductor pollicis (deep ulnar)	Carpal tunnel: median nerve; tunnel of Guyon: ulnar nerve.
Femoral triangle	NAVeL (lat→med): Nerve, Artery, Vein, empty space, Lymph	Femoral hernia passes medial to femoral vein through canal; more in females.
Knee	ACL (anterior tibial translation), PCL (posterior); MCL/meniscus linked	Unhappy triad (lateral blow): ACL, MCL, medial meniscus.
Ankle	Lateral ligs (ATFL most injured), medial/deltoid strong	High-ankle sprain = syndesmosis (AITFL) injury.
Coronary arteries	LAD (ant septum/apex), RCA (RV/AV node), LCx (lat LV)	Dominance = PDA origin (R ≈ 70%). AV block in inferior MI (RCA).
Bronchial tree	Right main bronchus wider/shorter/more vertical	Aspiration more often right lower lobe (supine → posterior segment upper lobe).
Foregut–midgut–hindgut	Vagus (fore/mid), pelvic splanchnics (hind); coeliac, SMA, IMA	Watershed at splenic flexure (ischaemic colitis risk).
Inguinal canal	Contents: spermatic cord / round ligament; ilioinguinal n. partially	Indirect hernia: lateral to inf epigastrics (congenital). Direct: medial (Hesselbach).
Pelvic floor	Levator ani sling (puborectalis crucial for continence)	Obstetric tears → pelvic organ prolapse & incontinence.
Circle of Willis	ICA + vertebrobasilar; ACoA & PCoA connect	Berry aneurysm common at ACoA; causes bitemporal hemianopia if compress chiasm.
Cranial foramina (sample)	Cribiform (I); optic canal (II + ophthalmic a.); SOF (III, IV, V1, VI); Rotundum (V2); Ovale (V3); Spinosum (MMA)	Epidural haematoma: MMA tear via pterion fracture (lucid interval).
Sympathetic chain	Thoracolumbar (T1–L2), paravertebral ganglia	Horner from disruption anywhere along pathway.

💪 Comprehensive Muscle Table

How to use: For each muscle: remember one surface landmark, a crisp origin → insertion line, the primary action in anatomical position, and the nerve with root values. Group by compartment to predict function and lesions. UK exam tip: when localising deficits, say “muscle – movement – nerve (+roots)”.

🧑‍🦱 Head & Neck (facial expression, mastication, suprahyoid/infrahyoid)

Muscle	Region	Origin (proximal)	Insertion (distal)	Primary actions	Nerve (roots)
Occipitofrontalis (frontal/occipital bellies)	Face/scalp	Galea aponeurotica; superior nuchal line	Skin of forehead/eyebrows; galea	Elevates eyebrows; wrinkles forehead; retracts scalp	Facial n. (CN VII)
Orbicularis oculi	Eyelids	Medial orbital margin, lacrimal bone	Skin around orbit/eyelids	Closes eyelids (gentle/forceful)	Facial n. (CN VII)
Buccinator	Cheek	Alveolar maxilla/mandible; pterygomandibular raphe	Modiolus (angle of mouth)	Presses cheek against teeth; resists distension	Facial n. (CN VII)
Orbicularis oris	Lips	Maxilla & mandible	Lip mucosa/skin	Closes & protrudes lips	Facial n. (CN VII)
Zygomaticus major	Face	Zygomatic bone	Modiolus	Elevates oral commissure (smile)	Facial n. (CN VII)
Platysma	Superficial neck	Delto-pectoral fascia	Inferior mandible, lower face skin	Tenses neck skin; depresses mandible	Facial n. (CN VII)
Masseter	Mastication	Zygomatic arch	Ramus & angle of mandible (lateral)	Elevates mandible; assists protrusion	V3 (masseteric n.)
Temporalis	Mastication	Temporal fossa & fascia	Coronoid process & anterior ramus	Elevates & retracts mandible	V3 (deep temporal nn.)
Medial pterygoid	Mastication	Medial surface of lat. pterygoid plate; maxillary tuberosity	Medial ramus of mandible	Elevates, protrudes, side-to-side	V3
Lateral pterygoid	Mastication	Lat. pterygoid plate (lateral surface); infratemporal surface sphenoid	Neck of mandible; TMJ disc/capsule	Protrudes; opens jaw with depression	V3
Sternocleidomastoid	Neck	Manubrium; medial clavicle	Mastoid process; superior nuchal line	Ipsilateral SB; contralateral rotation; neck flexion	Spinal accessory (CN XI) + C2–3 proprioception
Ant./Mid./Post. scalenes	Neck	Cervical TPs (ant. tubercles → Anterior; post. tubercles → Middle/Posterior)	1st rib (ant./mid); 2nd rib (post.)	Flex neck; elevate 1st/2nd ribs	Cervical ventral rami (C3–8)
Digastric (ant./post.)	Suprahyoid	Ant: digastric fossa (mandible); Post: mastoid notch	Intermediate tendon → hyoid	Elevates hyoid; depresses mandible	Ant: mylohyoid n. (V3); Post: CN VII
Mylohyoid	Suprahyoid	Mylohyoid line (mandible)	Hyoid & midline raphe	Elevates floor of mouth	Mylohyoid n. (V3)
Stylohyoid	Suprahyoid	Styloid process	Hyoid body	Elevates hyoid	CN VII
Geniohyoid	Suprahyoid	Inferior mental spine	Hyoid	Pulls hyoid anterosuperiorly	C1 via CN XII
Sternohyoid	Infrahyoid	Manubrium & clavicle	Hyoid	Depresses hyoid	Ansa cervicalis (C1–3)
Omohyoid	Infrahyoid	Scapula (sup. border)	Hyoid	Depresses/retracts hyoid	Ansa C1–3
Sternothyroid	Infrahyoid	Manubrium	Thyroid cartilage	Depresses larynx	Ansa C2–3
Thyrohyoid	Infrahyoid	Thyroid cartilage	Hyoid	Depresses hyoid; elevates larynx	C1 via CN XII

🦴 Shoulder Girdle & Back (extrinsic & intrinsic)

Muscle	Region	Origin	Insertion	Actions	Nerve (roots)
Trapezius	Superficial back	Sup. nuchal line, EOP, nuchal lig., C7–T12 SPs	Lateral clavicle, acromion, scapular spine	Elevates, retracts, upwardly rotates scapula	CN XI; C3–4 (sensory)
Latissimus dorsi	Superficial back	T7–L5 SPs, thoracolumbar fascia, iliac crest, ribs	Floor of intertubercular sulcus	Extends, adducts, medially rotates humerus	Thoracodorsal (C6–8)
Levator scapulae	Back	C1–4 TPs	Medial border scapula (sup. angle)	Elevates & downwardly rotates scapula	Dorsal scapular (C5) ± C3–4
Rhomboid minor/major	Back	C7–T1; T2–5 SPs	Medial scapular border	Retract, fix scapula to wall	Dorsal scapular (C4–5)
Serratus anterior	Thoracic wall	Ribs 1–8 (lateral)	Ant. surface medial border scapula	Protracts, upwardly rotates scapula	Long thoracic (C5–7)
Pectoralis major	Pectoral	Clavicle; sternum & costal cart.	Lateral lip intertubercular sulcus	Adducts & medially rotates; clav. head flexes	Lat. & med. pectoral (C5–T1)
Pectoralis minor	Pectoral	Ribs 3–5	Coracoid process	Stabilises scapula (anterior/inferior)	Medial pectoral (C6–T1)
Subclavius	Pectoral	1st rib & costal cartilage	Inferior clavicle	Stabilises clavicle	Nerve to subclavius (C5–6)
Deltoid	Scapulohumeral	Lateral clavicle, acromion, spine	Deltoid tuberosity	Abducts (15–90°); ant. flex/IR; post. ext/ER	Axillary (C5–6)
Supraspinatus	Rotator cuff	Supraspinous fossa	Greater tubercle (sup. facet)	Initiates abduction (0–15°)	Suprascapular (C5–6)
Infraspinatus	Rotator cuff	Infraspinous fossa	Greater tubercle (mid facet)	External rotation	Suprascapular (C5–6)
Teres minor	Rotator cuff	Lateral scapular border	Greater tubercle (inf. facet)	External rotation	Axillary (C5–6)
Subscapularis	Rotator cuff	Subscapular fossa	Lesser tubercle	Internal rotation	Upper & lower subscapular (C5–7)
Teres major	Scapulohumeral	Inferior angle scapula	Medial lip intertubercular sulcus	Adducts & medially rotates	Lower subscapular (C5–7)

💪 Arm & Forearm

Muscle	Compartment	Origin	Insertion	Actions	Nerve (roots)
Biceps brachii (LH/SH)	Arm anterior	Supraglenoid tub.; coracoid	Radial tuberosity; bicipital aponeurosis	Supinates & flexes forearm; weak shoulder flex	Musculocutaneous (C5–6)
Brachialis	Arm anterior	Ant. humerus	Ulnar tuberosity/coronoid	Primary elbow flexor	Musculocutaneous (C5–6) ± Radial
Coracobrachialis	Arm anterior	Coracoid process	Medial mid-humerus	Flexes & adducts shoulder	Musculocutaneous (C5–7)
Triceps brachii (LH/LAT/MED)	Arm posterior	Infraglenoid; post. humerus (above/below groove)	Olecranon	Extends elbow; LH extends/adducts shoulder	Radial (C6–8)
Anconeus	Arm posterior	Lateral epicondyle	Olecranon/prox. ulna	Assists elbow extension; stabilises	Radial (C7–T1)
Pronator teres	Forearm ant. (superficial)	Medial epicondyle; coronoid	Lateral radius	Pronation; weak flexion	Median (C6–7)
Flexor carpi radialis	Forearm ant.	Medial epicondyle	Base 2nd (±3rd) MC	Flexes & abducts wrist	Median (C6–7)
Palmaris longus	Forearm ant.	Medial epicondyle	Palmar aponeurosis	Flexes wrist; tenses palmar fascia	Median (C7–8)
Flexor carpi ulnaris	Forearm ant.	Medial epicondyle; olecranon	Pisiform, hook hamate, base 5th MC	Flexes & adducts wrist	Ulnar (C7–T1)
Flexor digitorum superficialis	Forearm ant. (intermediate)	Med. epicondyle; UCL; coronoid; radius	Middle phalanges 2–5	Flexes PIP (also MCP, wrist)	Median (C7–T1)
Flexor digitorum profundus	Forearm ant. (deep)	Ulna & interosseous memb.	Distal phalanges 2–5	Flexes DIP	Lat. half: AIN (C8–T1); Med. half: Ulnar (C8–T1)
Flexor pollicis longus	Forearm ant. (deep)	Radius & interosseous	Distal phalanx thumb	Flexes IP of thumb	AIN (C8–T1)
Pronator quadratus	Forearm ant. (deep)	Distal ulna	Distal radius	Pronation (prime mover)	AIN (C8–T1)
Brachioradialis	Forearm post. (superficial)	Lat. supracondylar ridge	Radial styloid	Flexes elbow (mid-prone)	Radial (C5–7)
ECR longus/brevis	Forearm post.	Lat. supracondylar ridge; lat. epicondyle	Bases 2nd/3rd MC	Extend & abduct wrist	Radial / Deep radial (C6–7)
Extensor digitorum	Forearm post.	Lateral epicondyle	Extensor expansions 2–5	Extends fingers	PIN (C7–8)
Extensor digiti minimi	Forearm post.	Lateral epicondyle	Extensor expansion 5th	Extends little finger	PIN (C7–8)
Extensor carpi ulnaris	Forearm post.	Lateral epicondyle; ulna	Base 5th MC	Extend & adduct wrist	PIN (C7–8)
Supinator	Forearm post. (deep)	Lateral epicondyle; ligs; supinator crest	Proximal radius	Supination (slow)	Deep radial (C6–7)
Abductor pollicis longus	Forearm post. (deep)	Ulna/radius; interosseous	Base 1st MC	Abducts thumb (CMC)	PIN (C7–8)
Extensor pollicis brevis	Forearm post. (deep)	Radius; interosseous	Base proximal phalanx thumb	Extends MCP thumb	PIN (C7–8)
Extensor pollicis longus	Forearm post. (deep)	Ulna; interosseous	Base distal phalanx thumb	Extends IP thumb	PIN (C7–8)
Extensor indicis	Forearm post. (deep)	Ulna; interosseous	Extensor expansion 2nd	Extends index	PIN (C7–8)

✋ Intrinsic Hand

Muscle	Group	Origin	Insertion	Actions	Nerve (roots)
Abductor pollicis brevis	Thenar	Flexor retinaculum; scaphoid/trapezium	Base prox. phalanx thumb	Abducts thumb (CMC)	Recurrent median (C8–T1)
Flexor pollicis brevis (sup/deep)	Thenar	FR; trapezium/trapezoid/capitate	Base prox. phalanx thumb	Flexes MCP thumb	Sup: Median; Deep: Deep ulnar (C8–T1)
Opponens pollicis	Thenar	FR; trapezium	Lat. 1st MC	Opposition (CMC flexion/IR)	Recurrent median (C8–T1)
Adductor pollicis (oblique/transverse)	Deep	Bases 2–3 MC; shaft 3rd	Base prox. phalanx thumb	Adducts thumb	Deep ulnar (C8–T1)
Abductor digiti minimi	Hypothenar	Pisiform	Base prox. phalanx 5th	Abducts little finger	Deep ulnar (C8–T1)
Flexor digiti minimi brevis	Hypothenar	Hook of hamate; FR	Base prox. phalanx 5th	Flexes MCP 5th	Deep ulnar (C8–T1)
Opponens digiti minimi	Hypothenar	Hook of hamate; FR	5th MC	Opposes little finger	Deep ulnar (C8–T1)
Lumbricals (1–4)	Central	Tendons of FDP	Extensor expansions 2–5	Flex MCP; extend IPs	1–2: Median; 3–4: Ulnar (C8–T1)
Palmar interossei (3)	Central	Shafts 2,4,5 MC	Bases prox. phalanges; expansions	Adduct digits (PAD)	Deep ulnar (C8–T1)
Dorsal interossei (4)	Central	Adjacent MCs	Bases prox. phalanges; expansions	Abduct digits (DAB)	Deep ulnar (C8–T1)
Palmaris brevis	Superficial	Palmar aponeurosis	Skin of hypothenar	Tenses skin, improves grip	Superficial ulnar (C8–T1)

🫁🧱 Thorax, Abdomen & Deep Back

Muscle	Region	Origin	Insertion	Actions	Nerve (roots)
External intercostals	Thoracic wall	Inferior border rib	Superior border rib below	Elevate ribs (inspiration)	Intercostal nn. (T1–11)
Internal/Innermost intercostals	Thoracic wall	Superior border rib	Inferior border rib above	Interosseous: depress; Interchondral: elevate	Intercostal nn.
Transversus thoracis	Thoracic wall	Posterior sternum	Costal cartilages 2–6	Weakly depress ribs	Intercostal nn.
Diaphragm	Respiratory	Xiphoid, costal margin, crura	Central tendon	Primary inspiratory muscle	Phrenic (C3–5)
External oblique	Abdominal wall	Ribs 5–12	Linea alba, pubic tubercle, iliac crest	Flex/rotate trunk; compress viscera	T7–12 (thoracoabdominal)
Internal oblique	Abdominal wall	TL fascia, iliac crest, inguinal lig.	Ribs 10–12, linea alba, pecten	Flex/rotate trunk; compress viscera	T6–12, L1 (iliohypogastric/ilioinguinal)
Transversus abdominis	Abdominal wall	Costal cart 7–12; TL fascia; iliac crest; inguinal lig.	Linea alba, pubic crest, pecten	Compress abdominal contents	T6–12, L1
Rectus abdominis	Abdominal wall	Pubic symphysis & crest	Xiphoid; costal cart 5–7	Trunk flexion; stabilises pelvis	T6–12
Erector spinae (ILS)	Deep back	Common tendon (iliac crest, sacrum)	Ribs, TPs, SPs, skull	Extend & laterally flex spine	Dorsal rami spinal nn.
Transversospinales (semi/multi/rotatores)	Deep back	TPs	SPs (span 2–6 segments)	Stabilise, extend, rotate spine	Dorsal rami
Quadratus lumborum	Post. abdominal wall	Iliac crest; iliolumbar lig.	12th rib; L1–4 TPs	Laterally flex trunk; fix 12th rib	T12–L4 ventral rami
Psoas major / Iliacus	Post. wall	Lumbar bodies/TPs; Iliac fossa	Lesser trochanter (as iliopsoas)	Powerful hip flexor	L1–3 (psoas); Femoral (L2–3) to iliacus

🫀 Pelvic Floor & Perineum

Muscle	Region	Origin	Insertion	Actions	Nerve (roots)
Levator ani (puborectalis, pubococcygeus, iliococcygeus)	Pelvic floor	Body of pubis; tendinous arch; ischial spine	Perineal body; coccyx; anococcygeal raphe	Supports pelvic viscera; maintains continence	N. to levator ani (S3–4) ± pudendal branches
Coccygeus (ischiococcygeus)	Pelvic floor	Ischial spine	Lateral coccyx & sacrum	Supports pelvic floor; flexes coccyx	Ventral rami S4–5
External anal sphincter	Perineum	Perineal body; anococcygeal lig.	Encircles anal canal	Closes anal canal (voluntary)	Inferior rectal (pudendal) S2–4
External urethral sphincter	Deep perineal pouch	Urogenital diaphragm	Encircles urethra	Maintains continence (voluntary)	Deep branch of perineal n. (pudendal) S2–4
Bulbospongiosus	Superficial perineal	Perineal body	Bulb of vestibule/penis; perineal membrane	Aids erection; expels last drops	Deep branch perineal (pudendal) S2–4
Ischiocavernosus	Superficial perineal	Ischiopubic ramus	Crus of clitoris/penis	Maintains erection (compresses crus)	Deep branch perineal (pudendal)
Superficial/deep transverse perineal	Perineum	Ischiopubic rami	Perineal body	Stabilise perineal body	Perineal branches (pudendal)

🦵 Gluteal Region & Thigh

Muscle	Compartment	Origin	Insertion	Actions	Nerve (roots)
Gluteus maximus	Gluteal	Ilium, sacrum, coccyx, sacrotuberous lig.	IT band; gluteal tuberosity	Extends & ER hip; rising from sit	Inferior gluteal (L5–S2)
Gluteus medius/minimus	Gluteal	External ilium	Greater trochanter	Abduct & IR hip; pelvic stabilisers	Superior gluteal (L4–S1)
Tensor fasciae latae	Gluteal	ASIS; iliac crest	IT band → lateral tibia	Abduct/IR hip; tenses fascia	Superior gluteal (L4–S1)
Piriformis	Short rotators	Anterior sacrum	Greater trochanter	ER (neutral); abduction (flexed)	N. to piriformis (S1–2)
Obturator internus	Short rotators	Obturator membrane (internal)	Greater trochanter	ER hip	N. to obturator internus (L5–S1)
Sup./Inf. gemelli	Short rotators	Ischial spine/tuberosity	Blends with OI tendon	ER hip	Sup: N. to OI; Inf: N. to quadratus femoris
Quadratus femoris	Short rotators	Ischial tuberosity	Quadrate tubercle (intertrochanteric crest)	ER hip	N. to quadratus femoris (L5–S1)
Obturator externus	Medial thigh	Obturator membrane (external)	Trochanteric fossa	ER hip	Obturator (L3–4)
Sartorius	Anterior thigh	ASIS	Pes anserinus (medial tibia)	Flex, abduct, ER hip; flex knee	Femoral (L2–3)
Quadriceps (RF, VL, VM, VI)	Anterior thigh	AIIS & ilium (RF); femoral shaft (Vasti)	Tibial tuberosity (via patellar lig.)	Extends knee; RF flexes hip	Femoral (L2–4)
Articularis genu	Anterior thigh	Distal femur	Suprapatellar bursa	Pulls bursa superiorly	Femoral (L3–4)
Pectineus	Medial thigh	Pecten pubis	Pectineal line (femur)	Adducts & flexes hip	Femoral ± Obturator (L2–3)
Adductor longus	Medial thigh	Body of pubis	Linea aspera (mid)	Adducts hip	Obturator (L2–4)
Adductor brevis	Medial thigh	Body & inf. ramus pubis	Pectineal line & proximal linea aspera	Adducts hip	Obturator (L2–4)
Adductor magnus (add./ham.)	Medial thigh	Inf. pubic ramus/ischial ramus; ischial tuberosity	Linea aspera; adductor tubercle	Adducts hip; hamstring part extends	Obturator (L2–4); Tibial (L4)
Gracilis	Medial thigh	Body & inf. ramus pubis	Pes anserinus	Adducts hip; flexes knee	Obturator (L2–3)
Biceps femoris (LH/SH)	Posterior thigh	Ischial tuberosity; linea aspera	Head of fibula	Flex knee; LH extends hip	Tibial (LH); Common fibular (SH) (L5–S2)
Semitendinosus	Posterior thigh	Ischial tuberosity	Pes anserinus	Extend hip; flex/IR knee	Tibial (L5–S2)
Semimembranosus	Posterior thigh	Ischial tuberosity	Post. medial tibial condyle	Extend hip; flex/IR knee	Tibial (L5–S2)

🦶 Leg & Foot

Muscle	Compartment	Origin	Insertion	Actions	Nerve (roots)
Tibialis anterior	Leg anterior	Lateral tibia; interosseous	Medial cuneiform; base 1st MT	Dorsiflexion; inversion	Deep fibular (L4–5)
Extensor hallucis longus	Leg anterior	Ant. fibula; interosseous	Distal phalanx hallux	Extends hallux; dorsiflexion	Deep fibular (L5)
Extensor digitorum longus	Leg anterior	Lateral tibial condyle; fibula	Middle & distal phalanges 2–5	Extends toes; dorsiflexion	Deep fibular (L5–S1)
Fibularis tertius	Leg anterior	Distal fibula	Base 5th MT	Dorsiflexion; eversion assist	Deep fibular (L5)
Fibularis longus	Leg lateral	Head & lat. fibula	Medial cuneiform; base 1st MT	Eversion; plantarflex assist	Superficial fibular (L5–S2)
Fibularis brevis	Leg lateral	Distal lateral fibula	Tuberosity of 5th MT	Eversion	Superficial fibular (L5–S2)
Gastrocnemius (med/lat)	Leg post. superficial	Femoral condyles	Calcaneus (Achilles)	Plantarflexion; knee flexion	Tibial (S1–2)
Soleus	Leg post. superficial	Soleal line (tibia); fibula	Calcaneus	Plantarflexion (posture)	Tibial (S1–2)
Plantaris	Leg post. superficial	Lat. supracondylar line	Calcaneus	Weak PF; proprioception	Tibial (S1–2)
Popliteus	Leg post. deep	Lateral femoral condyle	Posterior tibia	Unlocks knee (ER femur/IR tibia)	Tibial (L4–S1)
Tibialis posterior	Leg post. deep	Tibia/fibula; interosseous	Navicular, cuneiforms, bases 2–4 MT	Inversion; PF; supports arch	Tibial (L4–5)
Flexor digitorum longus	Leg post. deep	Posterior tibia	Distal phalanges 2–5	Flexes toes; PF	Tibial (S2–3)
Flexor hallucis longus	Leg post. deep	Posterior fibula	Distal phalanx hallux	Flexes hallux; PF	Tibial (S2–3)

👣 Intrinsic Foot

Muscle	Layer	Origin	Insertion	Action	Nerve (roots)
Extensor digitorum brevis	Dorsal	Calcaneus	EDL tendons 2–4	Assists toe extension	Deep fibular (L5–S1)
Extensor hallucis brevis	Dorsal	Calcaneus	Base prox. phalanx hallux	Extends hallux (MTP)	Deep fibular
Abductor hallucis	Layer 1	Medial calcaneus	Base prox. phalanx hallux	Abducts & flexes hallux	Medial plantar (S2–3)
Flexor digitorum brevis	Layer 1	Calcaneus	Middle phalanges 2–5	Flexes PIP 2–5	Medial plantar
Abductor digiti minimi	Layer 1	Calcaneus	Base prox. phalanx 5th	Abducts 5th toe	Lateral plantar
Quadratus plantae	Layer 2	Calcaneus	Tendon of FDL	Straightens pull of FDL	Lateral plantar
Lumbricals (1–4)	Layer 2	Tendons of FDL	Extensor expansions 2–5	Flex MTP; extend IP	1: Medial plantar; 2–4: Lateral plantar
Flexor hallucis brevis	Layer 3	Cuboid & lat. cuneiform	Base prox. phalanx hallux (med/lat sesamoids)	Flexes MTP hallux	Medial plantar
Adductor hallucis (oblique/transverse)	Layer 3	Bases 2–4 MT; plantar lig. MTP	Base prox. phalanx hallux	Adducts hallux; supports arch	Lateral plantar (deep)
Flexor digiti minimi brevis	Layer 3	Base 5th MT	Base prox. phalanx 5th	Flexes MTP 5th	Lateral plantar
Plantar interossei (3)	Layer 4	MTs 3–5 (medial)	Bases prox. phalanges 3–5	Adduct digits (PAD)	Lateral plantar
Dorsal interossei (4)	Layer 4	Adjacent MTs	Bases prox. phalanges 2–4	Abduct digits (DAB)	Lateral plantar

🧠 Dermatomes & myotomes – mini map

Dermatomes: C6 thumb, C7 middle, C8 little; T4 nipple, T10 umbilicus; L1 inguinal, L4 medial malleolus, L5 dorsum foot, S1 lateral foot, S2–4 perineum.
Upper limb myotomes: C5 (abduction), C6 (elbow flex/wrist ext), C7 (elbow ext/wrist flex), C8 (finger flex), T1 (interossei).
Lower limb myotomes: L2–3 (hip flex), L3–4 (knee ext), L4–5 (ankle dorsiflex), S1–2 (plantarflex).

🧫 Histology – four tissues & where to find them

Epithelium: Simple squamous (alveoli), stratified squamous (oesophagus/skin), simple columnar (GI), pseudostratified ciliated (trachea), transitional (urothelium).
Connective: Loose (lamina propria), dense regular (tendon), dense irregular (dermis), cartilage (hyaline/elastic/fibro-), bone, adipose, blood.
Muscle: Skeletal (striated, multinucleate), cardiac (intercalated discs), smooth (spindle, no striations).
Nervous: Neurons & glia (astrocytes, oligodendrocytes/Schwann, microglia, ependyma).

👶 Embryology – arches & rotations

Germ layers: Ectoderm (nervous, epidermis), mesoderm (muscle, bone, blood), endoderm (gut epithelium, lungs, liver).
Pharyngeal arches (1–6): Cartilage, muscles, nerves (V, VII, IX, X) - e.g. arch 2 → facial expression (VII); arch 4/6 → laryngeal (X).
Heart: Truncus → outflow tracts; septation defects cause cyanotic lesions. Aortic arch derivatives map to great vessels.
GI rotation: Midgut herniates & rotates 270° counterclockwise around SMA; malrotation → volvulus risk.

🧭 Imaging & Surface Landmarks

Modality / View	What to check	Normal landmarks
Chest X-ray (PA)	Penetration, Inspiration, Rotation, Magnification, Angulation (PIRMA)	Right hemidiaphragm higher; cardiothoracic ratio < 0.5 (PA); costophrenic angles sharp.
CT head (non-contrast)	Symmetry, ventricles, basal cisterns, midline shift, extra- vs intra-axial collections	Grey–white differentiation intact; lens-shaped epidural vs crescent subdural patterns.
FAST ultrasound	RUQ (Morison), LUQ (splenorenal), pelvis (pouch of Douglas), pericardial	Anechoic stripes indicate fluid; free fluid collects dependent.
Abdominal exam lines	9-region grid, Murphy’s, McBurney’s, Rovsing’s	Appendix commonly RLQ at McBurney’s (1/3 ASIS→umbilicus).
Neck	Carotid pulse medial to SCM; IJV between sternal & clavicular heads	Cricoid (C6) landmark for larynx/trachea; emergency airway below cricothyroid membrane.
Spine	Spinous processes & iliac crest line (L4)	Lumbar puncture L3–4 or L4–5 to avoid cord.

🧑‍🏫 Exam hack: On any image, orient first (side/level/phase), then run a fixed checklist; label a minimum of three structures.

Worked example – hilum ID on CXR

Right hilum lower than left; identify pulmonary arteries (left higher), main bronchi, and look for splaying (pulmonary hypertension) or hilar fullness (nodes).

Surface anatomy – quick placements

Liver span mid-clavicular ~6–12 cm; spleen 9th–11th ribs along mid-axillary line; kidneys T12–L3 (right lower).
Heart valves: Aortic (R 2nd ICS), Pulmonic (L 2nd ICS), Tricuspid (L 4th ICS), Mitral (apex, 5th ICS MCL).
Brachial artery pulse medial to biceps tendon in cubital fossa; radial at distal radius lateral aspect.

🩺 Clinical Scenarios & Lesion Logic

Wrist drop after humeral shaft fracture: Radial nerve in spiral groove → loss of wrist/finger extension; dorsal hand numbness (1st web space).
Thenar wasting & loss of thumb opposition: Recurrent motor branch of median (carpal tunnel or laceration) - sensation may be spared in palmar cutaneous branch.
Foot drop after fibular neck injury: Common fibular nerve → weakness dorsiflexion/eversion; sensory loss dorsum foot.
Hoarseness after thyroid surgery: Recurrent laryngeal nerve near inferior thyroid artery; unilateral palsy → breathy voice.
Kehr’s sign: Left shoulder pain from splenic rupture (phrenic nerve C3–5 diaphragmatic irritation → referred pain).

🎯 Worked case – inguinal swellings

Indirect hernia: through deep ring, lateral to inf epigastrics, may reach scrotum; congenital (patent processus vaginalis). Direct hernia: through Hesselbach’s triangle, medial to inf epigastrics; older males, weakness of transversalis fascia.

🧠 Stroke localisation – fast map

MCA: Contralateral face/arm > leg weakness/sensory loss, aphasia (dominant), neglect (non-dominant).
ACA: Contralateral leg > arm weakness; abulia/urinary incontinence possible.
PCA: Contralateral homonymous hemianopia ± macular sparing.
Lacunar (internal capsule): Pure motor hemiparesis.

🧴 Lymph drainage – where malignancy travels

Breast: Mostly to axillary (anterior/pectoral) nodes; medial quadrants to parasternal.
Testes: Para-aortic nodes (not inguinal); scrotum → superficial inguinal.
Glans penis/clitoris → deep inguinal; rest of perineum → superficial inguinal.

🧠 Study & Exam Tips

Map first, then memorise: Sketch nerve/blood routes from origins to targets; add surface landmarks and typical injuries.
Triads & spaces: Learn “gateways” (femoral triangle, quadrangular space, popliteal fossa) - questions cluster there.
Side + level + function: For any cranial/spinal nerve, state side, vertebral/foraminal level, motor/sensory/autonomic function.
Cross-link micro & macro: Histology explains function (e.g., transitional epithelium ↔ bladder stretch).
Active recall: Daily 10-minute “draw-it” drills (plexuses, coronaries, dermatomes) + spaced repetition cards.

🚀 Rapid drill (answers hidden)

Contents of the cubital fossa (med→lat)? Ans: Median n., brachial a., biceps tendon, radial n. (roof: bicipital aponeurosis).
Boundaries of the femoral ring? Ans: Ant: inguinal lig.; post: pectineal lig.; lat: femoral v.; med: lacunar lig.
Which nerve root mediates the Achilles reflex? Ans: S1–S2 (mainly S1).
Which vocal cord muscle abducts the cords? Ans: Posterior cricoarytenoid (the “safety” muscle).
Which artery runs with the radial nerve in the arm? Ans: Profunda brachii (deep brachial).

🧠 Neuroanatomy – Complete Revision Hub

From cortex to peripheral nerves: structures, spatial relations, blood supply, pathways and classic syndromes. Think “map → supply → function → lesion”. 🔥

🔢 Key Areas of Study

Cerebral Cortex & Lobes: Frontal (motor, executive, Broca), Parietal (somatosensory, spatial attention), Temporal (auditory, Wernicke, memory), Occipital (vision). Deep to cortex: white matter tracts funnel to internal capsule-vascularly fragile.
Deep Grey: Basal ganglia (caudate, putamen, globus pallidus) modulate movement through direct/indirect pathways; limbic (hippocampus, amygdala) underpins memory and emotion; thalamus gates sensory/motor flow to cortex.
Diencephalon & Hypothalamus: Thalamic nuclei are modality-specific relays; hypothalamic nuclei are homeostatic controllers with pituitary outputs-small lesions, big endocrine/ANS effects.
Brainstem & Cranial Nerves: Midbrain–pons–medulla house ascending/descending tracts and CN nuclei. Rule of 4s (vascular territories) and “medial vs lateral” help decode stroke patterns.
Cerebellum: Vestibulo-/spino-/cerebrocerebellum coordinate balance, gait and skilled movement; lesions give ipsilateral ataxia due to double decussation.
Spinal Cord: Dorsal columns (position/vibration), spinothalamic (pain/temp), corticospinal (motor). Segmental anatomy explains dermatomes, myotomes and reflex arcs.
Vessels, Meninges & CSF: Circle of Willis, perforators (lenticulostriates), venous sinuses; meninges form spaces and reflections (falx, tentorium) that channel herniation patterns; CSF made in choroid plexus flows to arachnoid granulations.
PNS & Autonomics: Brachial/lumbosacral plexuses, key entrapment sites, craniosacral parasympathetic vs thoracolumbar sympathetic outflow and ganglia.

🗺️ “Relations” you must picture

Pituitary sits in sella beneath optic chiasm (bitemporal hemianopia in superior expansion); lateral = cavernous sinus (III, IV, V1, V2 in wall; VI + ICA in centre).
Pterion (temporal fossa) overlies middle meningeal artery → epidural haematoma risk with temporal trauma.
Facial nerve bends at geniculate ganglion, exits stylomastoid foramen, traverses parotid (but doesn’t innervate it); superficial to external carotid branches.
Radial nerve in spiral groove of humerus; ulnar nerve behind medial epicondyle; common peroneal winds neck of fibula-compression palsies map to these turns.
Trochlear nerve (IV) hugs tentorial edge; susceptible to downward herniation and trauma.

📏 Core Tables & Relations

🧩 Lobes, gyri and classic functions

Lobe/area	Key gyri/areas	Function	Lesion signs
Frontal	Precentral gyrus (M1), premotor/SMA, Broca (44/45, dom)	Volitional movement; motor planning; expressive language	Contralateral UMN weakness; Broca aphasia (non-fluent)
Parietal	Postcentral gyrus (S1), superior parietal lobule	Somatosensation; spatial attention; praxis	Contralateral sensory loss; neglect (non-dom); apraxia
Temporal	Heschl gyrus; Wernicke (22, dom); hippocampus	Audition; receptive language; memory encoding	Wernicke aphasia (fluent, nonsensical); anterograde amnesia
Occipital	Calcarine cortex (V1)	Primary vision	Homonymous visual field defects ± macular sparing (PCA)
Insula	Hidden within lateral sulcus	Interoception, taste, viscerosensory, salience	Dysautonomia, gustatory deficits, integration problems

🏛️ Thalamus & Hypothalamus – nuclei at a glance

Structure	Nucleus	Inputs → Outputs	Function
Thalamus	VPL/VPM	Body/face somatosensory → S1	Touch, pain, proprioception
Thalamus	LGN / MGN	Optic tract / Inferior colliculus → V1 / A1	Vision / Audition
Thalamus	VL/VA	Cerebellum & basal ganglia → M1/premotor	Motor relay
Hypothalamus	Suprachiasmatic	Retinal input → PVN/ANS	Master clock (circadian)
Hypothalamus	Supraoptic / PVN	Osmoreceptors → Posterior pituitary	ADH/oxytocin
Hypothalamus	Arcuate	Metabolic signals → Ant. pituitary	Dopamine, GHRH, GnRH

⚙️ Basal ganglia loops – “go/stop/tune”

Direct pathway (go): Cortex (+) → striatum (−) → GPi (disinhibits thalamus) → cortex ↑ movement (D1 dopamine facilitates).
Indirect pathway (stop): Cortex (+) → striatum (−) → GPe (−) → STN (+) → GPi (−) → thalamus ↓ movement (D2 dopamine inhibits this brake).
Clinical: Parkinson (dopamine loss) → akinesia/rigidity; Huntington (indirect pathway neuron loss) → chorea.

🧵 Internal capsule & vascular supply

Limb	Fibres	Blood supply	Lesion pattern
Anterior limb	Frontopontine, thalamocortical (A→C)	Medial striate (ACA), recurrent artery of Heubner	Dysexecutive/limbic changes, mild motor
Genu	Corticobulbar	Lenticulostriates (MCA)	Dysarthria, lower facial weakness (UMN)
Posterior limb	Corticospinal, somatosensory	Lenticulostriates (MCA); anterior choroidal	Pure motor ± sensorimotor stroke (lacunar)

🦴 Skull base foramina & contents (relations)

Foramen	Contents	Neighbouring relations
Cribriform plate	CN I filaments	Roof of nasal cavity; fracture → CSF rhinorrhoea, anosmia
Optic canal	CN II, ophthalmic artery	Medial to superior orbital fissure; close to sphenoid sinus
Superior orbital fissure	CN III, IV, V1, VI; ophthalmic veins	Lateral wall of cavernous sinus → orbital apex syndrome
Foramen rotundum	V2	To pterygopalatine fossa
Foramen ovale	V3, lesser petrosal n., accessory meningeal a.	To infratemporal fossa (mandibular block)
Foramen spinosum	Middle meningeal artery	Deep to pterion; epidural bleed risk
Jugular foramen	CN IX, X, XI; sigmoid → IJV	Lesions → hoarseness, dysphagia, SCM/trapezius weakness
Hypoglossal canal	CN XII	Tongue deviation toward lesion
Internal acoustic meatus	CN VII, VIII; labyrinthine a.	Cerbellopontine angle masses → hearing loss + facial palsy
Foramen magnum	Medulla, vertebral aa., CN XI roots	Tonsillar herniation compresses medulla → apnoea

🕷️ Cavernous sinus – who runs where?

Lateral wall (superior→inferior): III, IV, V1, V2. Within sinus: VI alongside internal carotid artery (most vulnerable to pressure). Relations: Sits lateral to pituitary; drains via superior/inferior petrosal sinuses.

💧 CSF flow & meninges

Step	Structure	Relation/clinical
Production	Choroid plexus (lat/3rd/4th ventricles)	~500 mL/day; net volume ~150 mL
Flow	Lateral → Foramen of Monro → 3rd → Aqueduct → 4th	Aqueduct stenosis → non-communicating hydrocephalus
Exit	Foramina of Lushka/Magendie → cisterna magna	Subarachnoid space bathing brain and cord
Absorption	Arachnoid granulations → superior sagittal sinus	Impaired absorption → communicating hydrocephalus

🩸 Arterial territories & venous sinuses

Artery	Territory	Classic deficits
ACA	Medial frontal/parietal; leg area M1/S1	Contralateral leg weakness/sensory loss; abulia, urinary incontinence
MCA (superior)	Lateral frontal/parietal	Face/arm weakness; Broca aphasia (dom)
MCA (inferior)	Lateral temporal/parietal	Wernicke aphasia; visual neglect (non-dom)
PCA	Occipital cortex, inferior temporal	Homonymous hemianopia ± macular sparing; alexia without agraphia (splenial)
Basilar perforators	Pons (corticospinal, CN nuclei)	Locked-in (ventral pontine) with large lesions
PICA/AICA/SCA	Lateral medulla/pons/cerebellum	Ataxia + crossed findings (see syndromes)

🩸 Venous sinuses (drainage map)

Superior/inferior sagittal → straight → confluence → transverse → sigmoid → IJV. Cavernous drains via petrosal sinuses. Bridging veins traverse subdural space (tearing → subdural haematoma, crescentic on CT).

🦴 Dermatomes & key reflex roots

Root	Dermatome landmark	Myotome/reflex
C5	Lateral upper arm	Shoulder abduction; biceps reflex (C5/6)
C6	Thumb	Elbow flexion/wrist extension
C7	Middle finger	Elbow extension; triceps reflex
C8	Little finger	Finger flexion
T4	Nipple line	-
T10	Umbilicus	-
L4	Knee, medial malleolus	Knee extension; patellar reflex
L5	Dorsum of foot (1st web space)	Great toe dorsiflexion
S1	Lateral foot	Plantarflexion; Achilles reflex

🧰 Plexuses & dangerous relations

Brachial plexus: Roots C5–T1 → trunks → divisions → cords named to axillary artery; axillary n. wraps surgical neck humerus (deltoid), radial n. in spiral groove (wrist drop), ulnar n. at medial epicondyle (claw), median n. through carpal tunnel (LOAF weakness).
Lumbosacral: Femoral (L2–4) lateral to femoral artery under inguinal ligament; obturator through obturator canal; sciatic under piriformis via greater sciatic foramen; common peroneal at fibular neck.
Autonomic: Sympathetic chain cervical to sacral (superior cervical ganglion → head via carotids); parasympathetic CN III, VII, IX, X and S2–4 pelvic splanchnics.

📈 Pathways & Maps – from receptor to cortex

🦵 Motor (corticospinal) & extrapyramidal

Corticospinal: M1 → corona radiata → internal capsule (posterior limb) → crus cerebri → pyramids (medullary decussation ~85%) → lateral corticospinal tract → anterior horn → LMN. UMN lesion: spasticity, hyperreflexia, Babinski; LMN: flaccid weakness, fasciculations.
Rubro/reticulo/vestibulospinal: Posture and tone modulation; vestibulospinal (medial/lateral) stabilises head/antigravity; reticulospinal sets background tone and locomotor patterns.

🖐️ Somatosensory (DCML & spinothalamic)

DCML: Fine touch/vibration/proprioception → dorsal columns (gracile legs, cuneate arms) → decussate in caudal medulla → medial lemniscus → VPL/VPM → S1 (homunculus).
Spinothalamic: Pain/temp synapse in dorsal horn → decussate within 1–2 segments via anterior commissure → ascend anterolateral → VPL → S1. Central cord lesions hit crossing fibres → cape-like pain/temp loss.

👁️ Visual pathway & pupils

Retina → optic nerve → chiasm (nasal fibres cross) → optic tract → LGN → optic radiations (Meyer loop temporal; Baum loop parietal) → calcarine cortex. Lesions: chiasm (bitemporal), Meyer loop (contralateral upper quadrantanopia).
Pupils: Light → pretectal → bilateral Edinger–Westphal → III → ciliary ganglion → sphincter. Sympathetic: hypothalamus → ciliospinal centre (C8–T2) → superior cervical ganglion → dilator. Horner = ptosis, miosis, anhidrosis.

👂 Auditory/vestibular

Cochlea → CN VIII → cochlear nuclei → bilateral superior olive → inferior colliculus → MGN → A1 (Heschl). Vestibular nuclei project to MLF (VOR), spinal tracts (posture), and cerebellum.

🧪 Brainstem “rule of 4s” (localisation aid)

Midline (medial): Motor pathway (corticospinal), Medial lemniscus, MLF, Motor CN nuclei divisible by 12 (3, 4, 6, 12). Lateral: Spinothalamic, spinocerebellar, sympathetic pathway, sensory CN nuclei.

🩺 Clinical Syndromes & “Pattern Recognition”

🧠 Supratentorial

Lacunar syndromes (small vessel): Pure motor (posterior limb), pure sensory (VPL), ataxic hemiparesis (basis pontis or IC), dysarthria–clumsy hand (genu). Hypertension/diabetes risk; MRI shows small deep infarcts.
Hemorrhage relations: Lobar (amyloid angiopathy, elderly) vs deep (putaminal/thalamic from hypertension). Putaminal bleed → hemiparesis + gaze deviation.
Uncal herniation: CN III compression (down/out pupil), ipsilateral PCA infarct (occipital), contralateral hemiparesis; later Duret haemorrhages in brainstem.

🧢 Brainstem & cerebellum

Syndrome	Artery	Key features (ipsi vs contra)
Weber (midbrain medial)	PCA perforators	Ipsi CN III palsy + contra hemiparesis (corticospinal)
Medial pontine (basis)	Paramedian basilar	Contra weakness + dysarthria; ± gaze palsy
Lateral medullary (Wallenberg)	PICA	Ipsi facial pain/temp loss, ataxia, Horner, palatal weakness; contra body pain/temp loss; spared facial motor
Lateral pontine (AICA)	AICA	Facial nucleus involved (LMN facial palsy), hearing loss, ataxia + crossed sensory findings
Superior cerebellar	SCA	Ipsi limb ataxia, dysarthria; minimal brainstem CN signs

🧵 Spinal cord

Brown-Séquard (hemi-cord): Ipsi motor + DCML loss; contra pain/temp loss 1–2 segments below.
Anterior cord syndrome: Motor + pain/temp loss with preserved posterior columns (infarct anterior spinal a.).
Central cord (cervical): Hand weakness > legs; dissociated pain/temp loss (cape), often from syrinx/trauma in spondylosis.
Cauda equina vs conus: Cauda = LMN, asymmetric radicular pain, late sphincter; Conus = early sphincter dysfunction, mixed UMN/LMN, saddle anaesthesia.

🧠 Cranial nerves – clinical hooks

III palsy: “Down & out” + ptosis; pupil-involving suggests compressive (PCom aneurysm). IV: Vertical diplopia worse on looking down (reading stairs). VI: Lateral rectus palsy-raised ICP stretches long intradural course.
V: Trigeminal neuralgia (V2/V3) often vascular loop; corneal reflex afferent V1, efferent VII.
VII: UMN lesion spares forehead (bilateral cortical innervation); LMN (Bell’s palsy) affects whole face; hyperacusis from stapedius weakness.
VIII: Vestibular neuritis vs BPPV (positional); acoustic neuroma in CPA → progressive unilateral SNHL + absent corneal reflex (V/VII).
IX/X: Dysphagia, palatal droop (uvula points away); recurrent laryngeal under aortic arch (left) and subclavian (right).
XI/XII: XI palsy → trapezius/SCM weakness; XII palsy → tongue deviates toward lesion (LMN).

🩺 Entrapments & tunnels (relations → symptoms)

Site	Structure	Relation	Deficit
Carpal tunnel	Median n.	Under flexor retinaculum with FDP/FDS, FPL	Thenar weakness (LOAF), nocturnal paraesthesiae
Guyon’s canal	Ulnar n.	Between pisiform & hook of hamate	Ulnar claw, sensory loss ulnar digits
Fibular neck	Common peroneal	Wraps fibular neck	Foot drop (DF/Eversion)
Radial groove	Radial n.	Posterior humerus with profunda brachii	Wrist/finger drop; triceps spared (high lesion variable)
Tarsal tunnel	Tibial n.	Posterior to medial malleolus (Tom, Dick ANd Harry)	Plantar sensory loss; intrinsic foot weakness

🧠 Study & Exam Tips

Always say the four: Structure → function → blood supply → neighbours. Most vignettes are solved by a single relation (e.g., chiasm over pituitary).
Localise with symmetry: Long-tract + cranial nerve sign on opposite sides = brainstem; face + arm > leg points to lateral MCA; leg-predominant = ACA.
Use internal capsule logic: Small deep stroke with dense pure motor deficit = posterior limb lacune from lenticulostriates (hypertension).
Think spaces: Extradural (lens-shaped, MMA), subdural (crescent, bridging veins), subarachnoid (sulcal blood, aneurysm) - each implies different source and urgency.
Draw one map/day: Circle of Willis, brainstem cross-section, homunculus, visual pathway, brachial plexus-label two relations and one syndrome.

🚀 Rapid drill (answers hidden)

Which nerve is most at risk in a posterior hip dislocation? Ans: Sciatic nerve.
Superior quadrantanopia localises to which tract? Ans: Meyer loop (temporal optic radiation).
Eye “down & out” with dilated pupil-most likely lesion? Ans: Compressive CN III (PCom aneurysm) until proven otherwise.
Loss of pain/temp in cape distribution with hand weakness? Ans: Cervical central cord/syringomyelia.
Face weak but forehead spared? Ans: Contralateral UMN (corticobulbar) lesion.

Final thought: Anatomy rewards patterns - know the gateways, root values, and relations, and unfamiliar questions become familiar. You’ve got this. 💪

Final thought: Neuroanatomy is geometry plus vascular physics. If you can “see” the space and the artery, the symptom pattern becomes predictable. 💪

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Premed Anatomy

🔢 Key Areas of Study

📏 Core Tables – Landmarks, Innervation & Blood Supply

💪 Comprehensive Muscle Table

🧑‍🦱 Head & Neck (facial expression, mastication, suprahyoid/infrahyoid)

🦴 Shoulder Girdle & Back (extrinsic & intrinsic)

💪 Arm & Forearm

✋ Intrinsic Hand

🫁🧱 Thorax, Abdomen & Deep Back

🫀 Pelvic Floor & Perineum

🦵 Gluteal Region & Thigh

🦶 Leg & Foot

👣 Intrinsic Foot

🧭 Imaging & Surface Landmarks

🩺 Clinical Scenarios & Lesion Logic

🧠 Study & Exam Tips

🧠 Neuroanatomy – Complete Revision Hub

🔢 Key Areas of Study

📏 Core Tables & Relations

🧩 Lobes, gyri and classic functions

🧵 Internal capsule & vascular supply

🦴 Skull base foramina & contents (relations)

💧 CSF flow & meninges

🩸 Arterial territories & venous sinuses

🦴 Dermatomes & key reflex roots

📈 Pathways & Maps – from receptor to cortex

🦵 Motor (corticospinal) & extrapyramidal

🖐️ Somatosensory (DCML & spinothalamic)

👁️ Visual pathway & pupils

👂 Auditory/vestibular

🧪 Brainstem “rule of 4s” (localisation aid)

🩺 Clinical Syndromes & “Pattern Recognition”

🧠 Supratentorial

🧢 Brainstem & cerebellum

🧵 Spinal cord

🧠 Cranial nerves – clinical hooks

🩺 Entrapments & tunnels (relations → symptoms)

🧠 Study & Exam Tips

Categories