Irene Gold Associates - Part I Board Review: Spinal Anatomy & Embryology

Flashcards covering spinal anatomy, embryology, neurology, and physiology based on the lecture notes.

Endoderm Derivatives

Organs, gut (stomach, liver, etc.), respiratory tract (lungs), and "tubular structures".

Notochord Derivative

Nucleus pulposus.

Sclerotome

A paraxial mesoderm derivative that develops into the vertebra and ribs.

Epimere

A derivative of the myotome innervated by dorsal primary rami; includes posterior muscles and extensors.

Hypomere

A derivative of the myotome innervated by ventral primary rami; includes anterior muscles and flexors.

Intermediate Mesoderm

Develops into the urogenital system (gonads) and adrenal cortex.

Surface Ectoderm

Derivatives include the epidermis, anterior pituitary, lens of the eye, skin, tooth enamel, and hair.

Neuroectoderm (Neural Tube)

Develops into the brain and spinal cord (CNS), posterior pituitary, retina of the eye, and oligodendrocytes.

Neuroectoderm (Neural Crest)

Develops into the sympathetic chain ganglion, PNS, ANS, dorsal root ganglion, Schwann cells, parafollicular cells of the thyroid, and adrenal medulla.

Spina Bifida Occulta

A pathology where the lamina fail to fuse, often marked by a tuft of hair growth over the site known as a Fawn's beard.

Meningomyelocele

A CNS pathology where both the spinal cord and meninges protrude out.

Arnold Chiari Syndrome Type I

A condition where cerebellar peduncles or tonsils drop or herniate below the foramen magnum.

Anencephaly

The most severe CNS pathology characterized by the absence of a major portion of the brain, skull, and scalp.

Endochondral Ossification

The conversion of mesenchymal tissue to cartilage and then to bone; forms the axial skeleton and long bones.

Foregut

Gastrointestinal embryological division including the oral cavity, pharynx, trachea, esophagus, stomach, liver, gallbladder, spleen, pancreas, and the first 1/3 of the duodenum. It is supplied by the celiac artery and Vagus nerve.

Hindgut Nerve Supply

Pelvic splanchnic nerves ($S2-S4$).

Prosencephalon

A primary brain vesicle that divides into the Telencephalon and Diencephalon.

Cerebral Aqueduct (Aqueduct of Sylvius)

The cavity associated with the Mesencephalon (Midbrain).

1st Mandibular Pharyngeal Arch

Associated with CN 5, the mandible, malleus, incus, muscles of mastication, and tensor tympani.

3rd Thymus Pharyngeal Arch

Associated with CN 9, the greater horn and lower part of the body of the hyoid, and the stylopharyngeus muscle.

Astrocytes

CNS cells responsible for the biochemical control of endothelial cells that form the blood brain barrier.

Schwann Cells

Myelinating cells of the peripheral nervous system derived from the neural crest.

Hirschsprung's Disease

A condition also known as congenital megacolon caused by the absence of the Myenteric (Auerbach's) plexus.

Resting Membrane Potential

The potential of a neuron at rest, typically $-65-70\,mV$, with more potassium ions inside and more sodium ions outside.

Action Potential: Repolarization

The phase where potassium ions rush out of the cell to return toward the resting membrane potential.

Upper Motor Neuron Lesion Signs

Hyperreflexia, spasticity, and clonus.

Lower Motor Neuron Lesion Signs

Hyporeflexia, hypotonia, and fasciculations.

Broca's Area

Located in the frontal lobe; responsible for speech production. Damage leads to difficulty forming words (Broca's aphasia).

Wernicke's Area

Located in the temporal lobe; responsible for comprehension of written and spoken speech. Damage leads to "word salad" (Wernicke's aphasia).

Cerebellum Fastigial Nucleus

One of the cerebellar deep nuclei from which all outputs of the cerebellum originate.

Ventral Posteromedial Nucleus (VPM)

A nucleus in the thalamus that relays sensory information from the face to the somatosensory cortex.

Rubrospinal Tract

A descending motor tract originating in the red nucleus of the midbrain that functions to flex proximal muscles of the upper and lower extremity.

Meissner's Receptors

A beta fiber receptors responsible for fine touch (discriminative touch) and 2-point discrimination.

Fasciculus Gracilis

Part of the dorsal column in the medial spinal cord that carries sensory information from the lower limb ($T6$ and below) to the nucleus gracilis in the medulla.

Lateral Spinothalamic Tract

Carries pain and temperature information to the VPL of the thalamus.

Parasympathetic Stimulation: CN IX

Originates in the inferior salivatory nucleus (medulla), travels to the Otic ganglion, and results in salivation from the parotid gland.

Circle of Willis

Comprised of the anterior cerebral, anterior communicating, internal carotid, posterior cerebral, and posterior communicating arteries.

Wallenberg Syndrome

Caused by damage to the posterior inferior cerebellar artery (PICA), resulting in ipsilateral loss of pain and temperature to the face and contralateral loss to the body.

Epidural Hemorrhage

Bleeding between the inside of the skull and the dura mater, typically caused by damage to the middle meningeal artery.

Conspicuous Contents of the Suboccipital Triangle

Vertebral artery and the suboccipital nerve ($C1$).

Alar Ligament

Known as the "check ligament," it extends from the sides of the dens to the occipital condyles and limits rotation of the axis ($C2$).

Conus Medullaris

The end of the spinal cord, located at the level of $L1/L2$.

Atypical Rib 1

A shorter and wider rib with one facet for $T1$, and grooves for the subclavian vein and artery.

Phrenic Nerve

Derived from nerve roots $C3, C4, C5$; provides motor innervation to the diaphragm.

Meralgia Paresthetica

Sensory impairment to the lateral thigh caused by the lateral femoral cutaneous nerve ($L2, L3$).