NEET PG Anatomy Syllabus

List the coverings of the spermatic cord from superficial to deep and their parental layers.

External spermatic fascia (external oblique), Cremasteric fascia (internal oblique), Internal spermatic fascia (transversalis fascia).

What is the lesser sac (omental bursa) and how does it communicate with the greater sac?

The lesser sac is the peritoneal space behind the stomach; it communicates with the greater sac via the epiploic foramen (of Winslow).

Name the boundaries of the epiploic foramen of Winslow.

Anterior: free edge of lesser omentum (with portal triad); Posterior: IVC; Superior: caudate lobe of liver; Inferior: first part of duodenum.

Which peritoneal recess is the most dependent in a supine patient, and why is it clinically important?

The hepatorenal recess (Morrison's pouch). It is the most dependent part of the peritoneal cavity in the supine position, so fluid/pus/blood collects here.

What three veins unite to form the portal vein, and where?

Superior mesenteric vein and splenic vein unite behind the neck of the pancreas; the inferior mesenteric vein typically drains into the splenic vein.

Name the four major sites of porto-systemic anastomosis and their clinical manifestations.

Lower esophagus (esophageal varices), anal canal (rectal varices/hemorrhoids), umbilicus (caput medusae), retroperitoneal/bare area. Portal hypertension causes engorgement.

What forms the pelvic diaphragm and what is its function?

Levator ani (puborectalis, pubococcygeus, iliococcygeus) and coccygeus muscles. It supports pelvic viscera and maintains continence.

Differentiate the contents of the superficial and deep perineal pouches in the male.

Superficial pouch: bulbospongiosus, ischiocavernosus, superficial transverse perineal muscles, root of penis, Bartholin's homolog (bulbourethral ducts pass through). Deep pouch: external urethral sphincter, deep transverse perineal muscle, bulbourethral (Cowper's) glands, membranous urethra.

What is the arterial supply to the foregut, midgut, and hindgut, and where are their watershed transitions?

Foregut: celiac trunk (to 2nd part duodenum/ampulla). Midgut: superior mesenteric artery (to splenic flexure 2/3). Hindgut: inferior mesenteric artery (to upper rectum).

Describe the lymphatic drainage watershed of the anal canal.

Above the pectinate line: drains to internal iliac nodes. Below the pectinate line: drains to superficial inguinal nodes.

Which cranial nerve nuclei are located in the midbrain?

Oculomotor (CN III) nucleus and Edinger-Westphal nucleus, plus the Trochlear (CN IV) nucleus (at inferior colliculus). The trochlear is the only CN to exit dorsally and decussate.

A patient has a 'down and out' eye with ptosis and a dilated pupil. Which nerve is lesioned?

Oculomotor nerve (CN III). Loss of medial/superior/inferior recti and inferior oblique gives down-and-out gaze; levator loss gives ptosis; parasympathetic loss gives mydriasis.

What is the difference between an upper motor neuron and lower motor neuron facial nerve lesion?

UMN lesion: spares the forehead (bilateral cortical input to upper face) — contralateral lower face weakness. LMN (Bell's palsy): affects the entire ipsilateral half of face including forehead.

Name the four major triangles formed by the division of the posterior triangle of the neck.

Posterior triangle is divided by the omohyoid into occipital (above) and supraclavicular/subclavian (below). The anterior triangle subdivides into submental, submandibular (digastric), carotid, and muscular triangles.

Name the layers of the deep cervical fascia of the neck.

Investing (encircles trapezius & sternocleidomastoid), pretracheal (encloses thyroid, trachea, esophagus), prevertebral (encloses vertebral muscles), and the carotid sheath (condensation containing carotid, IJV, vagus).

What three structures are carried within the carotid sheath?

Common/internal carotid artery, internal jugular vein, and the vagus nerve (CN X). (Deep cervical lymph nodes lie along it.)

List the limbs of the internal capsule and a key tract in each.

Anterior limb (frontopontine, anterior thalamic radiation), genu (corticobulbar fibers), posterior limb (corticospinal tract — somatotopic, plus sensory radiations), retrolentiform (optic radiation), sublentiform (auditory radiation).

Name the components of the basal ganglia.

Caudate nucleus, putamen, globus pallidus (together = corpus striatum); functionally also the subthalamic nucleus and substantia nigra. Lentiform nucleus = putamen + globus pallidus.

What are the major sensory relay (specific) nuclei of the thalamus and their functions?

VPL (body somatosensation), VPM (face somatosensation + taste), LGB/LGN (vision), MGB/MGN (hearing), VL & VA (motor relay from cerebellum/basal ganglia).

Trace the pathway of the dorsal column-medial lemniscus tract.

Fine touch/proprioception: 1st-order neuron ascends ipsilaterally (fasciculus gracilis/cuneatus) to nucleus gracilis/cuneatus in medulla; 2nd-order decussates (internal arcuate fibers) as medial lemniscus to VPL thalamus; 3rd-order to sensory cortex.

Where does the lateral spinothalamic tract decussate, and what does it carry?

Carries pain and temperature. First-order neurons synapse in the dorsal horn; second-order fibers decussate within 1-2 segments via the anterior white commissure, then ascend contralaterally to VPL of thalamus.

Where does the lateral corticospinal tract decussate, and what does its lesion produce?

Decussates at the pyramidal decussation in the lower medulla (about 85% of fibers). Lesion produces ipsilateral (below the decussation) UMN signs: spastic paralysis, hyperreflexia, Babinski sign.

How many ventricles are there and what connects the lateral ventricles to the third ventricle?

Four: two lateral, third, and fourth. The lateral ventricles connect to the third via the interventricular foramina (of Monro); the third to the fourth via the cerebral aqueduct (of Sylvius).

Trace the circulation of CSF from production to absorption.

Produced by choroid plexus → lateral ventricles → foramina of Monro → 3rd ventricle → aqueduct of Sylvius → 4th ventricle → foramina of Luschka (2 lateral) & Magendie (1 median) → subarachnoid space → absorbed by arachnoid granulations into the dural venous sinuses (superior sagittal sinus).

Name the three meningeal layers from outermost to innermost.

Dura mater (pachymeninx), arachnoid mater, and pia mater. CSF lies in the subarachnoid space between arachnoid and pia.

Describe the components and clinical importance of the circle of Willis.

Anastomotic ring at the base of the brain: anterior communicating, two anterior cerebral, two internal carotid, two posterior communicating, two posterior cerebral arteries. Provides collateral flow between carotid and vertebrobasilar systems.

Which artery supplies the lateral surface of the brain including the motor area for the face and hand, and what does its occlusion cause?

Middle cerebral artery (MCA). Occlusion causes contralateral hemiparesis/hemisensory loss greatest in face and upper limb, and aphasia if the dominant hemisphere is involved.

What is the difference between spermatogenesis and oogenesis in terms of timing and gamete yield?

Spermatogenesis: continuous from puberty, one primary spermatocyte yields 4 spermatozoa. Oogenesis: begins in fetal life and arrests (prophase I until ovulation, metaphase II until fertilization); one primary oocyte yields 1 ovum + polar bodies.

Where does normal fertilization occur and what is the structure formed immediately after sperm-oocyte fusion?

In the ampulla of the uterine (fallopian) tube. Fusion completes meiosis II and forms the zygote (fertilized ovum with restored diploid number and two pronuclei).

When and where does implantation normally occur, and what cell layer mediates it?

Around day 6-7 after fertilization (blastocyst stage), in the posterior superior wall of the uterine body endometrium. The syncytiotrophoblast invades the endometrium.

List the principal derivatives of the three germ layers.

Ectoderm: epidermis, nervous system, neural crest. Mesoderm: muscle, bone, connective tissue, cardiovascular, urogenital, blood. Endoderm: epithelial lining of GI/respiratory tract, liver, pancreas, thyroid, bladder.

What are the derivatives of the pharyngeal arches' nerves (CN supply of arches 1-6)?

Arch 1: CN V (trigeminal); Arch 2: CN VII (facial); Arch 3: CN IX (glossopharyngeal); Arch 4 & 6: CN X (vagus — superior laryngeal from 4, recurrent laryngeal from 6).

What are the derivatives of the pharyngeal (endodermal) pouches 1-4?

Pouch 1: middle ear cavity + Eustachian tube; Pouch 2: palatine tonsil; Pouch 3: inferior parathyroids + thymus; Pouch 4: superior parathyroids + ultimobranchial body (parafollicular C cells).

What is a teratogen, and what defines the period of greatest teratogenic susceptibility?

A teratogen is an agent that causes structural/functional birth defects. Greatest susceptibility is the embryonic period (weeks 3-8) of organogenesis; weeks 1-2 follow an 'all or none' effect.

Classify epithelium by shape and layers, giving one example of simple columnar and stratified squamous epithelium.

By layers: simple (one) vs stratified (multiple); by shape: squamous, cuboidal, columnar. Simple columnar example: lining of the GI tract/stomach. Stratified squamous example: epidermis, esophagus, oral mucosa.

What distinguishes exocrine from endocrine glands, and how are exocrine glands classified by secretory mechanism?

Exocrine secrete via ducts onto a surface; endocrine are ductless and secrete hormones into blood. By mechanism: merocrine (exocytosis, e.g. salivary), apocrine (apical pinching, e.g. mammary), holocrine (cell rupture, e.g. sebaceous).

Name the major fiber types of connective tissue and their composition.

Collagen fibers (type I — tensile strength), reticular fibers (type III — supportive meshwork in organs), and elastic fibers (elastin + fibrillin — recoil in vessels/lungs).