USMLE Step 1 Review/Addendum Module: More Through Anatomy Notes

Anatomy

(Adapted from the USMLE Review

BRACHIAL PLEXUS

Rugby Teams Drink Cold Beer for: Roots, Trunks, Divisions, Cords, Branches

CRANIAL NERVES

I-olfactory, II-optic, III-oculomotor, IV-trochlear, V-trigeminal, VI-abducens, VII-facial, VIII-acoustic (vestibulocochlear), IX-glossopharyngeal, X-vagus, XI-spinal accessory, XII-hypoglossal

• On Old Olympus Towering Tops, A Finn And German Viewed Some Hops
• Oh Oh Oh To Touch And Feel Very Good Velvet, Absolute Heaven
• OOOPTAFAGVAH 1-olfactory 2- optic 3- occlumotor 4-pathetic(trochlear) 5- trigeminal 6-abducence 7-facial 8-auditory(vestibulocochlear) 9- glossopharyngeal 10- vagus 11- accessory (spinal) 12- hypoglossal
• You have I nose. You have II eyes. (I - Olfactory; II -- Optic)
• Innervation of extraocular Muscles:
• LR6 (SO4) 3
• LR6--Lateral rectus--> VI abductens
• SO4--Superior Oblique--> IV Trochlear
• 3--The remaining 4 eyeball movers = III
• Some Say Marry Money, But My Brother Says Big Brains Matter More (what cranial nerve is Motor, Sensory, or Both)

BRANCHES OF FACIAL NERVE

Temporal, Zygomatic, Buccal, Mandibular, Cervical

• Two Zebras Bit My Chihuahua
• Ten Zebras Bought My Car
• To Zanzibar By Motor Car
• Tell Ziggy Bob Marley Called

CERVICAL SPINAL NERVES

• c345 keeps the phrenic alive (innervation of phrenic nerve)
• c345 keep the diaphragm alive (innervation of diaphragm)
• c5-6-7 raise your arms to heaven (nerve roots of long thoracic nerve innervate serratus anterior)
• c5-6-7 keeps your wings from going to heaven (as above, prevents winging of the scapula)

LOCATION OF THORACIC DUCT

• The duck is between two gooses (duck = thoracic duct)
• 2 gooses = azyGOUS and esophaGOUS

ATTACHMENTS OF CHEST MUSCLES

• A lady between two majors.
• Pectoralis major attaches to lateral lip of bicipital groove.
• Teres major attaches to medial lip of bicipital groove.
• Latissimus dorsi attaches to the floor of bicipital groove.
• The "lati" is between two "majors."
• A Loose Damsel (Latissimus Dorsi) lays between two Majors (Pectoralis Major and Teres Major).

INNERVATION OF PENIS

• Parasympathetic causes erection. Sympathetic causes ejaculation. "Point and Shoot."
• "S2, 3, 4 keep the penis off the floor"
• Innervation of the penis by branches of the pudental nerve, derived from spinal cord levels S2-4
• "Lateral is less, medial is more."
• Lateral pectoral nerves goes through pectoralis major while medial p.n. goes though both pec major and minor

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AORTIC BRANCHES

• ABC'S
• Aortic arch gives off the Bracheiocephalic trunk, the left Common Carotid, and the left Subclavian artery.

ORDER OF THINGS IN THIGH

• "NAVEL"
• nerve, artery, vein, empty space, lymphatics

Tarsal bones "Tall Californian Navy Medical Interns Lay Cuties": • In order (right foot, superior to inferior, medial to lateral): Talus Calcanous Navicular Medial cuneiform Intermediate cuneiform Lateral cuneiform Cuboid

Atrioventricular valves"LAB RAT": Left Atrium: Bicuspid Right Atrium: Tricuspid

Tarsal tunnel: contents "Tiny Dogs Are Not Hunters": • From superior to inferior: T: Tibialis posterior F: flexor Digitorum longus A: posterior tibial Artery N: tibial Nerve H: flexor Hallucis longus

Vagal nerve: path into thoraxVagus nerve, unlike phrenic, continues through diaphragm with esophagus--it is "Not Left Behind": • The left vagus is anterior, right is posterior [behind].

Inguinal canal: walls"MALT: 2M, 2A, 2L, 2T": • Starting from superior, moving around in order to posterior: Superior wall (roof): 2 Muscles: • internal oblique Muscle • transverse abdominus Muscle Anterior wall: 2 Aponeuroses: • Aponeurosis of external oblique • Aponeurosis of internal oblique Lower wall (floor): 2 Ligaments: • inguinal Ligament • lacunar Ligament Posterior wall: 2Ts: • Transversalis fascia • conjoint Tendon

Bronchopulmonary segments of right lung "A PALM Seed Makes Another Little Palm": • In order from superior to inferior: Apical Posterior Anterior Lateral Medial Superior Medial basal Anterior basal Lateral basal Posterior basal

Tarsal bones "Traverse City (is) Noted (for) MIchigan's Lovely Cherries": Talus Calcaneus (new row) Navicular (new row) Medial Intermediate cuneiforms Lateral cuneiform Cuboid

Aorta vs. vena cava: right vs. leftAorta and right each have 5 letters, so aorta is on the right. Vena and cava and left each have 4 letters, so vena cava is on the left.

Hip: lateral rotators"Play Golf Or Go On Quaaludes": • From top to bottom: Piriformis Gemellus superior Obturator internus Gemellus inferior Obturator externus Quadratus femoris • Alternatively: "P-GO-GO-Q".

Facial bones"Virgil Can Not Make My Pet Zebra Laugh!": Vomer Conchae Nasal Maxilla Mandible Palatine Zygomatic Lacrimal

Scalp layers SCALP: • From superficial to deep: Skin Connective tissue Aponeurosis Loose areolar tissue Pericranium

Thoracoacromial artery branches"CAlifornia Police Department": Clavicular Acromial Pectoral Deltoid

Ankle: anterior compartment of leg contents "The Hamptons Are Never Dull Parties": • From medial malleolus: Tibialis anterior tendon (Extensor) Hallacus longus Artery (anterior tibial) Nerve (deep peroneal) (Extensor) Digitorum Peroneus tertius

Erector spinae muscles "I Love Sex": • From lateral to medial: Iliocostalis Longissimus Spinalis • Alternatively: "I Long for Spinach" • "Sex" helps you think of "Erector", but "Long" and "Spinach" help you remember the muscles' names.

Leg: anterior muscles of leg"The Hospitals Are Not Dirty Places": T: Tibialis anterior H: extensor Hallucis longus A: anterior tibial Artery N: deep fibular Nerve D: extensor Digitorum longus P: Peronius tertius [aka fibularis tertius]

Nasal cavity components "Never Call Me Needle Nose!": Nares [external] Conchae Meatuses Nares [internal] Nasopharynx • Note mnemonic sentence is nasally-related.

Rotator cuff muscles"The SITS muscles": • Clockwise from top: Supraspinatus Infraspinatus Teres minor Subscapularis • A pro baseball pitcher has injured his rotator cuff muscles. As a result, he SITS out for the rest of the game, and then gets sent to the minor leagues.

Radial nerve: muscles innervated "Try A Big Chocolate Chip Sundae, Double Dip Cherries And Peanuts Preferably Included": • In order of their innervation, proximal to distal: Triceps Anconeus Brachioradialis ext. Carpi radialis longus ext. Carpi radialis brevis Supinator ext. Digitorum ext.Digiti minimi ext. Carpi ulnaris Abductor poll. longus ext. Poll. brevis ext. P poll. longus ext. Indicis • For the neighboring words that start with the same letter (eg: chocolate and chip), notice that the longer word in the mnemonic, corresponds to the longer of the two muscle names (ex: ext. carpi radialis longus and ext. carpi radialis brevis)

Deep tendon reflexes: root supply • God designed body reflexes according to a nursery rhyme: One, two-- buckle my shoe. Three, four-- kick the door. Five, six-- pick up sticks. Seven, eight-- shut the gate. S1,2 = ankle jerk L3,4 = knee jerk C5,6 = biceps and brachioradialis C7,8 = triceps

Penis autonomic innervation actions "Parasympathetic Puts it up. Sympathetic Spurts it out". Alternatively: "Point and Shoot": Parasympathetic Points it, Sympathetic Shoots out the semen. • Erection and Ejaculation (Emission).

Internal iliac artery: anterior branches What Bill admitted to Hilary: "I Milked Our Insatiable Intern's Udders Under the Desk": Inferior gluteal Middle rectal Obturator Inferior vesical artery Internal pudendal artery Umbilical U/D=Uterine artery (female)/ Deferential artery (male)

Muscles: potentially absent ones• Muscles which may be absent but may be important: 5 P's: Palmaris longus [upper limb] Plantaris [lower limb] Peroneus tertius [lower limb] Pyramidalis [anterior abdominal wall] Psoas minor [posterior abdominal wall]

Carpal bones"Stop Letting Those People Touch The Cadaver's Hand": • Proximal row, lateral-to-medial: Scaphoid Lunate Triquetrum Pisiform • Distal row, lateral-to-medial: Trapezium Trapezoid Capitate Hamate

Carpal bones"She Looks Too Pretty; Try To Catch Her": • Proximal row then distal row, both lateral-to-medial: Scaphoid Lunate Triquetrium Pisiform Trapezium Trapezoid Capate Hamate • Alternatively: "She Likes To Play; Try To Catch Her".

Flexor digitorum muscles: how they insert onto fingers• A little rhyme: Superficialis Splits in two, To Permit Profundus Passing through.

Scrotum layers "Some Damn Englishman Called It The Testis": • From superficial to deep: Skin Dartos External spermatic fascia Cremaster Internal spermatic fascia Tunica vaginalis Testis

Femoral triangle: contents NAVY: • In order from lateral to medial: Nerve Artery Vein Y of the groin • Alternatively: Y = Y-fronts [male underwear].

Vagus nerve: path into thorax"I Left my Aunt in Vegas": Left Vagus nerve goes Anterior descending into the thorax.

Supine vs. prone body position Know SUPination is your hand while carrying a bowl of SOUP. Your face follows where your palm is facing [i.e. up]. Put a handpuppet on your hand while hand is in supination and the puppet will be the supine position. • See diagram.

Axillary artery branches "Suzy Thompkins Loves Sex, Alcohol, and Pot": • From proximal to distal: Superior thoracic Thoracacromial Lateral thoracic Subscapular Anterior circumflex humeral Posterior circumflex humeral

Horner's syndrome componentsSPAM: Sunken eyeballs/ Symphathetic plexus (cervical) affected Ptosis Anhydrosis Miosis

Voicebox: names of parts in sagittal cross-section "There's 3 V's in your Voicebox": Vestibular fold Ventricle Vocal fold • Note: Vestibular and Vocal cord also known as false and true cords respectively.

Serratus anterior: innervation SALT: Serratus Anterior = Long Thoracic.

Hip: lateral rotators "Piece Goods Often Go On Quilts": Piriformis Gemellus superior Obturator internus Gemellus inferior Obturator externus Quadratus femoris

Thigh: innervation by compartment" MAP OF Sciatic": Medial compartment: Obturator Anterior compartment: Femoral Posterior compartment: Sciatic • So all the thigh muscles in that compartment get innervated by that nerve.

Internal jugular vein: tributaries"Medical Schools Let Confident People In": • From inferior to superior: Middle thyroid Superior thyroid Lingual Common facial Pharyngeal Inferior petrosal sinus

Genu valgum vs. genu vargum Genu valGUM (knock-knee): knees are GUMmed together. • Varum (bowleg) is the other by default, or Far rhymes with Var, so knees are far apart.

Erector spinae muscles"I Like Standing": • From lateral to medial Illiocostalis Longissimus Spinalis

Cubital fossa contents "N-MAN": • From lateral to medial: Nerve Muscle Artery Nerve • Specifics are radial Nerve, biceps Muscle tendon, brachial Artery, median Nerve.

External carotid artery branches"Suzy Always Lays Flat On Pillows Making Sex Terrific": Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior auricular Maxillary Superficial Temporal

Median nerve: recognizing it in an opened axillaThe Median nerve is the Middle of a giant capital "M" formed by the musculocutaneous and ulnar nerves.

Trigeminal nerve: where branches exit skull"Standing Room Only": Superior orbital fissure is V1 foramen Rotundum is V2 foramen Ovale is V3

Dermatome C7 locationC7 gives the finger to heaven (as in middle finger).

External carotid artery branches"Some Angry Lady Figured Out PMS": Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior auricular Maxillary Superficial temporal

Brachioradialis: function, innervation, one relation, one attachment BrachioRadialis: Function: Its the Beer Raising muscle, flexes elbow, strongest when wrist is oriented like holding a beer. Innervation: Breaks Rule: it’s a flexor muscle, But Radial. (Radial nerve usually is for extensors: Recall BEST rule: B was for brachioradialis). Important relation: Behind it is the Radial nerve in the cubital fossa. Attachment: Attaches to Bottom of Radius.

Pleura surface markings"All the even ribs, in order: 2,4,6,8,10,12 show its route": Rib2: sharp angle inferiorly Rib4: the left pleura does a lateral shift to accommodate heart Rib6: both diverge laterally Rib8: midclavicular line Rib10: midaxillary line Rib12: the back • See diagram.

Aortic arch: major branch order "Know your ABC'S": Aortic arch gives rise to: Brachiocephalic trunk left Common Carotid left Subclavian • Beware though trick question of 'What is first branch of aorta?' Technically, it's the coronary arteries.

V3 innervated muscles (branchial arch 1 derivatives) "M.D. My TV": Mastication [masseter, temporalis, pterygoids] Digastric [anterior belly] Mylohyoid tensor Tympani tensor Veli palatini

Foramen ovale contents MALE: Mandibular nerve Accessory meningeal artery Lesser petrosal nerve Emissary veins

Pterygoid muscles: function of lateral vs. medial "Look at how your jaw ends up when saying first syllable of 'Lateral' or 'Medial' ": "La": your jaw is now open, so Lateral opens mouth. "Me": your jaw is still closed, so medial closes the mandible.

Supine vs. prone body position"Supine is on your spine. Therefore, prone's the "other" one. • Also, prone to suffocate in prone position.

Meckel's diverticulum details 2 inches long. 2 feet from end of ileum. 2 times more common in men. 2% occurrence in population. 2 types of tissues may be present. • Note: "di-" means "two", so diverticulum is the thing with all the twos.

Perineal vs. peroneal Perineal is in between the legs. Peroneal is on the leg.

Anterior forearm muscles: superficial groupThere are five, like five digits of your hand. Place your thumb into your palm, then lay that hand palm down on your other arm, as shown in diagram. Your 4 fingers now show distribution: spells PFPF [pass/fail, pass/fail]: Pronator teres Flexor carpi radialis Palmaris longus Flexor carpi ulnaris Your thumb below your 4 fingers shows the muscle which is deep to the other four: Flexor digitorum superficialis.

Carpal tunnel syndrome causes MEDIAN TRAP: Myxoedema Edema premenstrually Diabetes Idiopathic Agromegaly Neoplasm Trauma Rheumatoid arthritis Amyloidosis Pregnancy • Mnemonic fits nicely since median nerve is trapped.

Lumbar plexus "I, I Get Laid On Fridays": Iliohypogastric [L1] Ilioinguinal [L1] Genitofemoral [L1, L2] Lateral femoral cutaneous [L2, L3] Obtruator [L2, L3, L4] Femoral [L2, L3, L4] • Alternatively: "I twice Get Laid On Fridays". • Alternatively: "Interested In Getting Laid On Fridays?"

Elbow: muscles that flex it Three B's Bend the elBow: Brachialis Biceps Brachioradialis

Cavernous sinus contents O TOM CAT: O TOM are lateral wall components, in order from superior to inferior. CA are the components within the sinus, from medial to lateral. CA ends at the level of T from O TOM. • See diagram. Occulomotor nerve (III) Trochlear nerve (IV) Ophthalmic nerve (V1) Maxillary nerve (V2) Carotid artery Abducent nerve (VI) T: When written, connects to the T of OTOM.

Bronchi: which one is more vertical"Inhale a bite, goes down the right": Inhaled objects more likely to lodge in right bronchus, since it is the one that is more vertical

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Carotid sheath contents "I See 10 CC's in the IV": I See (I.C.) = Internal Carotid artery 10 = CN 10 (Vagus nerve) CC = Common Carotid artery IV = Internal Jugular Vein

V3 innervated muscles "My A$$ Meets The Toilet": Mylohyoid Anterior digastric Muscles of Mastication Tensor veli palatini Tensor tympani

Inferior vena cava tributaries "I Like To Rise So High": Illiacs Lumbar Testicular Renal Suprarenal Hepatic vein. • Think of the IVC wanting to rise high up to the heart.

Spleen: dimensions, weight, surface anatomy "1,3,5,7,9,11": Spleen dimensions are 1 inch x 3 inches x 5 inches. Weight is 7 ounces. It underlies ribs 9 through 11.

Heart valve sequence "Try Pulling My Aorta": Tricuspid Pulmonary Mitral Aorta

Liver: side with ligamentum venosum/ caudate lobe vs. side with quadrate lobe/ ligamentum teres "VC goes with VC": The Venosum and Caudate is on same side as Vena Cava [posterior]. Therefore, quadrate and teres must be on anterior by default. • See inferior-view diagram.

Cranial bones "PEST OF 6": Parietal Ethmoid Sphenoid Temporal Occipital Frontal • The 6 just reminds that there's 6 of them to remember.

Thyroid: isthmus location "Rings 2,3,4 make the isthmus floor": Isthmus overlies tracheal rings 2,3,4

Cervical plexus: arrangement of the important nerves "GLAST": • 4 compass points: clockwise from north on the right side of neck: Great auricular Lesser occipital Accessory nerve pops out between L and S Supraclavicular Transverse cervical • See diagram.

Lumbar plexus roots "2 from 1, 2 from 2, 2 from 3": 2 nerves from 1 root: Ilioinguinal (L1), Iliohypogastric (L1). 2 nerves from 2 roots: Genitofemoral (L1,L2), Lateral Femoral (L2,L3). 2 nerves from 3 roots: Obturator (L2,L3,L4), Femoral (L2,L3,L4).

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Joints in the midline "SC": In medial line, below Second Cervical, joints are Secondary Cartilaginous and usually have a diSC. • Notes: secondary cartilaginous is also known as symphysis. The one that doesn't have a disc is xiphi-sternal.

Anterior forearm muscles: superficial group "Pimps F*ck Prostitutes For Fun": Pronator teres Flexor carpi radialis Palmaris longous Flexor carpi ulnaris Flexor digitorum superficialis

Inversion vs. eversion muscles in leg Second letter rule for inversion/eversion: • Eversion muscles: pErineus longus pErineus brevis pErineus terius • Inversion muscles: tIbialis anterior tIbialis posterior

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