Neuroanatomy: Spinal Cord Peripheral Nerves Flashcards
What is a spinal segment?
the functional unit of the spinal cord = the area to/from which one set of spinal nerves is connected. Includes roots, rootlets, ganglion, and spinal cord that is connected to the rootlets
What are the modalities of the dorsal roots?, ventral roots?, spinal nerves?
There are 4 modalities, 2 motor and 2 sensory. The dorsal root has somatic and visceral afferent and the ventral root has visceral and somatic efferent.
What is the cauda equina?
horse tail, a bundle of spinal nerves at end of spinal cord (best area for spinal tap)
Define a dermatome
a specific part of the body surface that each spinal nerve innervates. They overlap and contain multiple cutaneous fields
Define a cutaneous field
an area of skin that a dorsal root ganglion neuron innervates.
define a motor unit
the number of muscle fibers innervated by one alpha motor neuron
What is a plexus?
a net of nerves between ganglion and dermatome
What regions are served by each of the plexuses?
There are 4 plexuses; cervical (sensory innervation to the head and neck and motor innervation to the infrahyoid muscles and diaphragm), brachial (motor and sensory innervation to the upper extremity), lumbar (motor and sensory innervation to the lower abdomen, anterior and medial thigh), and sacral (motor and sensory innervation to the posterior thigh, leg, and pelvis)
What are the terminal branches of each plexus?
Cervical branches (greater auricular, lesser occipital, transverse cervical, supraclavicular, phrenic); Brachial branches (axillary, musculocutaneous, median, radial, ulnar); Lumbar branches (Iliohypogastric, Ilioinguinal, Genitofemoral, Lateral cutaneous, femoral, obturator); Sacral Branches (Superior gluteal, inferior gluteal, nerve to piriformis, sciatic (tibial and common fibular), posterior cutaneous, pudendal)
Divisions of the terminal Branches
roots, trunks, divisions, cords, branches (Robert Taylor Drinks Cold Beer)
