Comprehensive Human Anatomy and Embryology Review -

Comprehensive vocabulary flashcards covering neuroanatomy, embryology, gross anatomy, and histology from the lecture notes.

Cranial Nerve Functional Columns in the Brainstem

The medial-to-lateral organizational arrangement of motor and sensory nuclei in the floor of the fourth ventricle: $\text{GSE} \rightarrow \text{SVE} \rightarrow \text{GVE} \rightarrow \text{GVA} \rightarrow \text{SVA} \rightarrow \text{GSA} \rightarrow \text{SSA}$.

Edinger-Westphal Nucleus Pathway

Parasympathetic pathway in which pre-ganglionic fibers travel via $\text{CN III}$ to the ciliary ganglion, giving rise to post-ganglionic fibers via short ciliary nerves to innervate the ciliary muscles and sphincter pupillae.

Superior Salivatory Nucleus Pathway

Parasympathetic pathway in which pre-ganglionic fibers travel via $\text{CN VII}$ to synapse in the pterygopalatine ganglion (supplying the lacrimal gland via the zygomatic branch of $\text{V2}$) and the submandibular ganglion (supplying sublingual and submandibular glands via the lingual nerve).

Inferior Salivatory Nucleus Pathway

Parasympathetic pathway in which pre-ganglionic fibers travel via $\text{CN IX}$ to the otic ganglion, projecting post-ganglionic secretomotor fibers via the auriculotemporal nerve to the parotid gland.

Dorsal Motor Nucleus of Vagus ($\text{CN X}$)

Parasympathetic nucleus supplying pre-ganglionic fibers to terminal ganglia that regulate the heart, lungs, and upper gastrointestinal tract.

General Somatic Afferent (GSA) Trigeminal Nuclei

Sensory nuclei of $\text{CN V}$ organized by modality: Mesencephalic nucleus mediates proprioception; Principal (chief) sensory nucleus mediates touch and pressure; Spinal nucleus mediates pain and temperature.

Cranial Fossae of the Skull Base

The three stepwise depressions of the cranial base: the anterior cranial fossa (lodging the frontal lobes), middle cranial fossa (lodging the temporal lobes and pituitary gland), and posterior cranial fossa (lodging the brainstem and cerebellum).

Superior Orbital Fissure and Common Tendinous Ring Structures

Structures outside the common tendinous ring include the lacrimal nerve, frontal nerve, trochlear nerve ($\text{CN IV}$), and superior ophthalmic vein; structures inside the ring include the superior and inferior divisions of the oculomotor nerve ($\text{CN III}$), nasociliary nerve, abducens nerve ($\text{CN VI}$), and optic canal structures (optic nerve and ophthalmic artery).

Jugular Foramen Subdivisions on Axial CT

A base-of-skull aperture divided by the jugular spine into an anteromedial pars nervosa (transmitting $\text{CN IX}$ and the inferior petrosal sinus) and a posterolateral pars vascularis (transmitting $\text{CN X}$, $\text{CN XI}$, and the internal jugular vein / sigmoid sinus junction).

Ventral Aspect of the Brainstem (Fig. 21.4)

Ventral surface displaying the infundibulum (1), mammillary body (3), basilar pons (4), abducens nerve (5), olive (7), rootlets of hypoglossal nerve (10), trigeminal nerve (19), pyramid (23), and motor decussation of pyramids (24).

Pterion

The H-shaped junction of the frontal, parietal, temporal, and greater wing of the sphenoid bones; overlies the anterior branch of the middle meningeal artery, damage to which causes an epidural hematoma (EDH).

Trochlear Nerve ($\text{CN IV}$)

The cranial nerve characterized by internal decussation, dorsal brainstem exit, the longest intracranial course, and the thinnest/smallest caliber among all cranial nerves.

Abducens Nerve ($\text{CN VI}$)

The cranial nerve that possesses the longest intradural course, passing through Dorello's canal beneath the petroclival ligament.

Facial Nerve ($\text{CN VII}$)

The cranial nerve characterized by the longest intraosseous course, passing through the Fallopian canal within the petrous temporal bone.

Uvular Deviation in Vagus Nerve ($\text{CN X}$) Lesion

Asymmetric elevation of the soft palate upon phonation where the uvula deviates toward the normal (unaffected) contralateral side due to unilateral levator veli palatini weakness.

Tongue Deviation in Hypoglossal Nerve ($\text{CN XII}$) Lesion

Hemi-atrophy and deviation of the protruded tongue toward the ipsilateral (affected) side caused by unopposed action of the contralateral genioglossus muscle.

Papez Circuit Limbic Structures

The classical emotional and memory circuit: Hippocampus $\rightarrow$ Fornix $\rightarrow$ Mammillary bodies $\rightarrow$ Anterior nucleus of the thalamus (via mammillothalamic tract) $\rightarrow$ Cingulate gyrus $\rightarrow$ Entorhinal cortex $\rightarrow$ Hippocampus.

Central Part of the Lateral Ventricle

Ventricular body bounded superiorly (roof) by the trunk of the corpus callosum, medially by the septum pellucidum, and inferiorly (floor) by the caudate nucleus, stria terminalis, thalamostriate vein, and dorsal thalamus.

Inferior Horn of the Lateral Ventricle

Temporal extension bounded superiorly and laterally (roof) by the stria terminalis, tail of the caudate nucleus, and tapetum; bounded inferiorly and medially (floor) by the hippocampus, alveus, and collateral eminence.

Posterior Horn of the Lateral Ventricle

Occipital extension bounded medially by the bulb of the posterior horn (fibers of forceps major) and calcar avis (produced by the calcarine sulcus); bounded laterally and superiorly by the tapetum and optic radiation.

Lateral Ventricles

C-shaped paired ventricular cavities located within each cerebral hemisphere, connecting to the third ventricle via the foramen of Monro (interventricular foramen).

Floor of the Fourth Ventricle (Rhomboid Fossa)

Dorsal brainstem surface displaying the median sulcus, sulcus limitans, facial colliculus (overlying abducens nucleus and looped facial nerve fibers), hypoglossal triangle, and vagal triangle.

Pituitary Fossa (Sella Turcica) on Sagittal T2 MRI

Bony depression in the sphenoid bone housing the pituitary gland, situated directly inferior to the optic chiasm and anterior to the dorsum sellae and basilar artery.

Internal Capsule Tracts

Compact white matter pathway comprising the anterior limb (anterior thalamic radiation, frontopontine fibers), genu (corticobulbar tract), posterior limb (corticospinal tract, superior thalamic radiation), retrolentiform part (optic radiation), and sublentiform part (auditory radiation).

Cranio-Vertebral Junction Ligaments (Sagittal Section)

Deep stabilizing ligaments of the atlanto-axial and atlanto-occipital complex, consisting from anterior to posterior of the anterior atlanto-occipital ligament, apical ligament, cruciate ligament, tectorial membrane, and posterior atlanto-occipital ligament.

Cruciate Ligament of the Atlas

The primary stabilizer of the cranio-vertebral junction, comprising a strong transverse ligament holding the odontoid process (dens) against the anterior arch of the atlas, along with superior and inferior longitudinal bands.

Genioglossus Muscle

The 'safety muscle' of the tongue; originates from the superior mental spine of the mandible and protrudes the tongue forward, preventing it from falling back and obstructing the airway.

Hyoglossus Muscle

Extrinsic depressor muscle of the tongue arising from the greater horn and body of the hyoid bone, serving as an essential anatomical landmark for the lingual artery (deep) and lingual nerve / hypoglossal nerve (superficial).

Coronal Section of the Tongue and Floor of the Mouth (Fig. 31.7)

Section showing extrinsic tongue muscles (genioglossus, hyoglossus, styloglossus), floor muscles (geniohyoid, mylohyoid, anterior belly of digastric), sublingual gland, submandibular duct, lingual nerve, and platysma.

Innervation of the Tongue

Sensory mapping: Anterior $2/3$ general sensation by lingual nerve ($\text{CN V}_3$) and taste by chorda tympani ($\text{CN VII}$); Posterior $1/3$ general sensation and taste by glossopharyngeal nerve ($\text{CN IX}$); Posterior-most root/vallecula by internal laryngeal nerve ($\text{CN X}$).

Temporalis and Masseter Muscles

Primary jaw elevator muscles innervated by the mandibular nerve ($\text{CN V}_3$); the temporalis retracts and elevates the mandible, while the masseter forcefully elevates it.

Lateral and Medial Pterygoid Muscles

Pterygoid muscles of mastication; the lateral pterygoid is the only depressor (jaw opener), protrudes the mandible, and inserts into the articular disc and capsule of the TMJ; the medial pterygoid elevates and assists in side-to-side chewing movements.

Branches of the Maxillary Artery

Branches divided into three parts: 1st/bony part (Deep auricular, Anterior tympanic, Middle meningeal, Accessory meningeal, Inferior alveolar — 'DAMIA'); 2nd/muscular part (masseteric, deep temporal, pterygoid, buccal); 3rd/pterygopalatine part (posterior superior alveolar, infraorbital, greater palatine, pharyngeal, artery of pterygoid canal, sphenopalatine).

Danger Area of the Face

Triangular zone bounded by the bridge of the nose and the corners of the mouth; retrogradely connects via the facial vein and ophthalmic veins or deep facial vein / pterygoid plexus to the cavernous sinus, providing a potential route for cavernous sinus thrombosis.

Carotid Sheath Cross-Sectional Relations

Fascial sheath in the neck enclosing the internal jugular vein laterally (A), common carotid artery medially (B), and vagus nerve posteriorly in the groove between them (C); the sympathetic trunk lies embedded behind the sheath (D).

Triangles of the Neck

Anatomical neck regions divided by the sternocleidomastoid muscle into the anterior triangle (subdivided into submental, submandibular, carotid, and muscular triangles) and the posterior triangle (bounded by SCM, trapezius, and clavicle).

Structure of the Human Spermatozoon (Fig. 80-4)

Specialized male gamete consisting of a head covered by an acrosome containing hydrolytic enzymes, a neck, a middle piece (body) containing a spiral mitochondrial sheath for energy production, a chief piece of the tail containing the axoneme (microtubules), and an end piece.

Stages of Oogenesis

Female gametogenesis in which primary oocytes enter Meiosis I before birth and remain arrested in the diplotene stage of prophase I until puberty; each month, ovulation yields a secondary oocyte arrested at metaphase of Meiosis II, which completes meiosis only upon fertilization.

Formation of Intraembryonic Mesoderm (Day 16)

Gastrulation process where epiblast cells migrate through the primitive streak and invaginate into the space between the epiblast and definitive endoderm to form the third germ layer: the intraembryonic mesoderm.

Primitive Streak and Gastrulation

Linear band of proliferating epiblast cells ending cranially in Hensen's node (primitive knot) and the blastopore; establishes the longitudinal cranial-caudal embryonic axis and generates all three primary germ layers.

Early Embryonic Somites and Neural Tube Development

Developing embryo showing closure of the neural tube between the anterior and posterior neuropores, flanking paraxial mesoderm segmenting into somites, and intermediate/lateral plate mesoderm.

Surface Ectoderm Derivatives

Structures arising from surface ectoderm, including anterior pituitary (Rathke's pouch), lens and corneal epithelium of the eye, external acoustic meatus and internal ear placodes, anal canal lining below the pectinate line, epidermis, olfactory epithelium, enamel of teeth, and parotid, sweat, and mammary glands.

Stages of Lung Development

Five developmental phases: Embryonic (weeks $4\text{--}7$), Pseudoglandular (weeks $5\text{--}17$; respiration impossible), Canalicular (weeks $16\text{--}25$; pneumocytes develop, surfactant begins week $20$, respiration capable week $25$), Saccular (weeks $24\text{ to birth}$), and Alveolar (weeks $36\text{ to }8\text{ years}$).

Mesonephric (Wolffian) Duct Derivatives

Male genital tract structures derived under testosterone influence: Epididymis, Vas deferens, Seminal vesicles, and Ejaculatory duct; also gives off the ureteric bud forming the renal collecting system.

Paramesonephric (Müllerian) Duct Derivatives

Female reproductive organs that form in the absence of Müllerian-inhibiting factor (MIF): Fallopian (uterine) tubes, Uterus, Endocervix, and the upper $1/3$ of the vagina.

Pharyngeal Pouch Derivatives

Internal endodermal derivatives: 1st pouch forms middle ear cavity and Eustachian tube; 2nd forms epithelial crypts of the palatine tonsil; 3rd forms thymus and inferior parathyroids; 4th forms superior parathyroids and ultimobranchial body.

Boundaries of the Epiploic Foramen (Foramen of Winslow)

Communication between greater and lesser peritoneal sacs: bounded superiorly by the caudate process of the liver, posteriorly by the inferior vena cava, anteriorly by the free margin of the lesser omentum (containing hepatic artery, bile duct, portal vein), and inferiorly by the first part of the duodenum.

Embryonic Gut Tube and Associated Ducts

Primitive gut showing foregut (giving rise to lung bud and liver bud), midgut opening into the yolk sac via the vitelline duct (omphalomesenteric duct), and hindgut projecting the allantois.

Intestinal Malrotation and Midgut Volvulus

Failure of complete $270^\circ$ counterclockwise physiological midgut rotation, resulting in peritoneal Ladd's bands crossing and compressing the duodenum, narrow mesenteric base, and predisposition to life-threatening midgut volvulus.

Aberrant Right Subclavian Artery (Arteria Lusoria)

Vascular anomaly caused by obliteration of the right 4th aortic arch with persistence of the caudal right dorsal aorta, creating an aberrant retroesophageal right subclavian artery that can cause dysphagia lusoria.

Internal Anatomy of the Right Atrium and Triangle of Koch

Right atrial landmark bounded by the tricuspid septal leaflet, Tendon of Todaro, and the ostium of the coronary sinus; houses the atrioventricular (AV) node.

Thoracic Duct and Lymphatic Trunks

Major lymphatic pathway beginning at the cisterna chyli (receiving lumbar and intestinal lymph trunks), ascending through the posterior and superior mediastinum, and emptying into the junction of the left internal jugular and left subclavian veins.

Hilum of Right and Left Lungs

Medial lung root arrangement: the right lung has an eparterial bronchus situated highest, above the pulmonary artery; the left lung has the pulmonary artery situated highest, above the single left main bronchus; pulmonary veins are most anterior and inferior in both.

Brachial Plexus Architecture

Somatic nerve plexus formed by ventral rami $\text{C5}\text{--}\text{T1}$, organized into 5 Roots, 3 Trunks (Upper, Middle, Lower), 6 Divisions (3 Anterior, 3 Posterior), 3 Cords (Lateral, Posterior, Medial), and terminal Branches (Musculocutaneous, Axillary, Radial, Median, Ulnar).

Erb's Palsy

Upper trunk ($\text{C5}\text{--}\text{C6}$) brachial plexus traction injury presenting with the classic 'waiter's tip' posture: arm adducted, internally rotated, elbow extended, and forearm pronated.

Klumpke's Palsy

Lower trunk ($\text{C8}\text{--}\text{T1}$) brachial plexus injury causing paralysis of the intrinsic muscles of the hand, leading to a total claw hand presentation.

Medial vs Lateral Scapular Winging

Medial winging results from long thoracic nerve ($\text{C5}\text{--}\text{C7}$) injury paralyzing the serratus anterior; Lateral winging results from spinal accessory nerve ($\text{CN XI}$) injury to the trapezius or dorsal scapular nerve injury to the rhomboids.

Extrinsic Muscles of the Back

Superficial back muscles connecting the axial skeleton to the shoulder girdle: Trapezius, Latissimus dorsi, Levator scapulae, Rhomboid minor, and Rhomboid major.

Cubital Fossa Contents and Boundaries

Triangular space at the anterior elbow bounded medially by the pronator teres and laterally by the brachioradialis; contains from medial to lateral: Median nerve, Brachial artery, Biceps brachii tendon, and Radial nerve ('MBBR').

Deep Neck Dissection and Root of the Neck Arteries

Anatomy showing the thyrocervical trunk, internal thoracic artery, vertebral artery, phrenic nerve descending across anterior scalene, and relations of the subclavian artery and brachial plexus trunks.

Posterior Relations of the Kidneys

Muscular and skeletal bed of the kidneys: diaphragm superiorly (related to rib $11$ and $12$ on the left; rib $12$ only on the right), and psoas major, quadratus lumborum, and transversus abdominis from medial to lateral inferiorly.

Couinaud Liver Segments on Axial CT (Fig. 67.6)

Functionally independent hepatic segments ($\text{I}\text{--}\text{VIII}$): Segment $\text{I}$ (caudate lobe) lies between IVC and portal vein; left portal vein separates segment $\text{II}$ (superior) from $\text{III}$ (inferior); right portal vein divides segments $\text{VII}$ and $\text{VIII}$ (superior) from $\text{VI}$ and $\text{V}$ (inferior).

Levator Ani and Pelvic Diaphragm

Muscular pelvic floor composed of the puborectalis (forms a sling around the anorectal junction), pubococcygeus, iliococcygeus, and coccygeus (ischiococcygeus).

Nerves of the Posterior Abdominal Wall

Lumbar plexus branches emerging from psoas major: subcostal nerve ($\text{T12}$), iliohypogastric and ilioinguinal ($\text{L1}$), lateral femoral cutaneous ($\text{L2}\text{--}\text{L3}$), femoral ($\text{L2}\text{--}\text{L4}$), genitofemoral ($\text{L1}\text{--}\text{L2}$ on anterior surface), and obturator ($\text{L2}\text{--}\text{L4}$ medially).

Pelvic Apophyses and Muscle Attachments on Radiograph

Sites of traction epiphyses and avulsion: Iliac crest (abdominal muscles), ASIS (sartorius), AIIS (rectus femoris), Greater trochanter (gluteus medius/minimus), Lesser trochanter (iliopsoas), Ischial tuberosity (hamstrings), and Pubic symphysis (adductors).

Frog Leg Posture in Poliomyelitis

Posture of ease maintained during the acute/convalescent phase with flexed knees, flexed hips, and completely externally rotated extremities; causes secondary iliotibial band contracture and permanent fixed flexion contracture (FFC) of hip and knee.

Tarsal Tunnel Contents

Structures passing posterior to the medial malleolus beneath the flexor retinaculum: Tibialis posterior, Flexor digitorum longus, Posterior tibial artery, Posterior tibial vein, Tibial nerve, and Flexor hallucis longus ('Tom, Dick And Very Nervous Harry').

Arterial Pulse Palpation in the Ankle and Foot

Dorsalis pedis artery (DPA) palpated on the dorsum of the foot between the extensor hallucis longus (EHL) and extensor digitorum longus (EDL) tendons; Posterior tibial artery (PTA) palpated midway between the medial malleolus and Achilles tendon, behind FDL and FHL.

Sciatic and Tibial Nerve Motor Branches

Nerve course where the sciatic nerve divides into tibial and common fibular nerves; the tibial nerve innervates hamstrings (except biceps short head), superficial posterior calf (gastrocnemius, soleus, plantaris), deep posterior calf (popliteus, tibialis posterior, FDL, FHL), and divides into medial and lateral plantar nerves.

First Layer of the Plantar Foot

Most superficial intrinsic muscle layer of the sole: Abductor hallucis, Flexor digitorum brevis, and Abductor digiti minimi.

Second Layer of the Plantar Foot

Plantar foot layer consisting of the Quadratus plantae (flexor accessorius), 4 Lumbrical muscles, and the long flexor tendons of Flexor digitorum longus (FDL) and Flexor hallucis longus (FHL).

Conus Medullaris Syndrome vs Cauda Equina Syndrome

Conus medullaris involves $\text{L1}\text{--}\text{L2}$ vertebral levels (sacral cord), presenting with sudden, bilateral, symmetrical signs, early bowel/bladder incontinence, and mixed UMN/LMN features; Cauda equina involves $\text{L2}\text{ to sacrum}$ roots, presenting gradually with asymmetrical saddle anesthesia, severe radicular pain, and pure LMN signs.

Mechanisms of Exocrine Gland Secretion

Merocrine (eccrine): secretion via exocytosis with intact cell membranes (e.g., submandibular gland); Apocrine: apical portion of cytoplasm pinches off with product (e.g., mammary gland); Holocrine: entire disintegrating cell discharges as product (e.g., sebaceous gland).

Hyaline Cartilage Histology

Cartilaginous tissue displaying an amorphous, basophilic ground substance containing type II collagen, with chondrocytes organized in rounded isogenous groups located in lacunae.

Histology of Muscle Types

Skeletal muscle features unbranched, multinucleated fibers with peripheral nuclei and prominent striations; Cardiac muscle features branching fibers, central nuclei, and intercalated discs; Smooth muscle features non-striated, spindle-shaped cells with single central nuclei.

Anterior Pituitary Histology

High-power histology of the adenohypophysis demonstrating acidophils (pink cytoplasm; GH, PRL), basophils (dark purple cytoplasm; ACTH, TSH, FSH, LH), and chromophobes (pale, non-staining cytoplasm), interspersed among fenestrated sinusoidal capillaries.

Small Intestine Mucosa Histology

Microscopic view of the small bowel featuring mucosal projections (villi) and intestinal crypts (crypts of Lieberkühn); duodenum features broad leaf-like villi with Brunner's glands, jejunum features long tongue-shaped villi, and ileum features flat villi with Peyer's patches.

Pulmonary Histology: Respiratory Bronchioles and Alveoli

Transition from terminal bronchiole (simple cuboidal with club cells) to respiratory bronchioles (interrupted by outpocketing alveoli), leading into alveolar ducts, alveolar sacs, and individual alveoli lined by type I and type II pneumocytes.

Transitional Epithelium (Urothelium) Histology

Specialized distensible stratified epithelium lining the renal calyces, ureter, urinary bladder, and prostatic urethra; characterized by dome-shaped superficial 'umbrella cells'.

Squamocolumnar Junction of the Uterine Cervix

The histological transition zone where non-keratinized stratified squamous epithelium of the ectocervix meets mucus-secreting simple columnar epithelium of the endocervix.

Spleen Histology

Lymphoid organ architecture featuring a fibroelastic capsule and trabeculae enclosing white pulp (periarteriolar lymphoid sheaths [PALS] and lymphoid follicles with germinal centers) and red pulp (splenic cords of Billroth and venous sinuses).

Thymus Histology and Hassall's Corpuscles

Histological section of the thymic lobule showing an outer dark cortex densely packed with T lymphocytes and an inner pale medulla containing eosinophilic, concentrically laminated Hassall's (thymic) corpuscles.

Fourth Cervical Vertebra ($\text{C4}$) Anatomy (Fig. 43.29)

Typical cervical vertebra featuring a small body (1), posterior tubercle of transverse process (2), pedicle (3), lamina (4), bifid spinous process (5), anterior tubercle (6), foramen transversarium (7), superior articular facet (8), and triangular vertebral foramen (9).

Fourth Thoracic Vertebra ($\text{T4}$) Anatomy (Fig. 43.22)

Typical thoracic vertebra characterized by a heart-shaped body derived from the centrum (2) and neural arch (7), round vertebral foramen (8), costal facet on the transverse process (9), and a long, downward-sloping spinous process (6).

Thoracic Cross-Section at $\text{T7}$ Level

Axial cadaveric section showing the four-chamber cardiac view: right atrium (RA), right ventricle (RV), left atrium (LA), aorta (A), pulmonary lobes, esophagus, descending thoracic aorta, and azygos vein.

Axial Cross-Section of the Upper Abdomen

Cross-section illustrating the dome of the liver on the right, stomach, spleen on the far left, abdominal aorta, inferior vena cava, and lower thoracic / upper lumbar vertebral body.

Transpyloric Plane ($\text{L1}$) Axial Cross-Section

Key abdominal cross-sectional plane demonstrating both kidneys (right lower than left), renal veins and arteries, pancreas head and neck, duodenum, superior mesenteric artery (SMA), abdominal aorta, and IVC.

$25\,\text{cm}$ Anatomical Structures

Group of anatomical organs measuring approximately $25\,\text{cm}$ in length: Esophagus, Duodenum, Ureter, and Descending colon.

$45\,\text{cm}$ Anatomical Structures

Group of anatomical organs measuring approximately $45\,\text{cm}$ in length: Spinal cord, Thoracic duct, Vas deferens, Sartorius muscle, Femur, and Transverse colon.

Composite (Hybrid) Muscles

Muscles receiving dual motor innervation: Digastric (anterior belly: $\text{V}_3$; posterior belly: $\text{VII}$); Flexor digitorum profundus (medial half: ulnar; lateral half: anterior interosseous); Adductor magnus (adductor part: obturator; hamstring part: tibial); Biceps femoris (long head: tibial; short head: common peroneal); Pectineus (femoral and obturator nerves).