Dermatomes + Myotomes Flashcards
What are the three layers during the development of the nervous system?
ectoderm, mesoderm, endoderm
What is a dermatome?
the area of skin innervated by a single spinal cord segment (sensory neurons, dorsal root)
Key test point of dermatome C2?
1cm lateral to occipital protuberance or 3cm behind the ear
Key test point of dermatome C3?
supraclavicular fossa at midclavicular line
Key test point of dermatome C4?
over the acromioclavicular line
Key test point of dermatome C5?
lateral (radial) side of the cubital fossa just proximal to elbow crease
Key test point of dermatome C6?
thumb, dorsal surface, proximal phalanx
Key test point of dermatome C7?
middle finger, dorsal surface, proximal phalanx
Key test point of dermatome C8?
little finger, dorsal surface, proximal phalanx
Key test point of dermatome T1?
medial (ulnar) side just proximal to medial epicondyle of humerus
Key test point of dermatome T2?
apex of axilla
Key test point of dermatome T4?
nipple line at the midclavicular line
Key test point of dermatome T10?
umbilicus midclavicular line
Key test point of dermatome T12?
midpoint of the inguinal ligament
Key test point of dermatome L1?
midway distance between the key sensory points for T12 + L2
Key test point of dermatome L2?
anterior-medial thigh at mid thigh level
Key test point of dermatome L3?
medial femoral condyle above the knee
Key test point of dermatome L4?
medial malleolus
Key test point of dermatome L5?
dorsum of foot at 3rd metatarsophalangeal (MTP) joint
Key test point of dermatome S1?
lateral heel
Key test point of dermatome S2?
midpoint of popliteal fossa
Key test point of dermatome S3?
ischial tuberosity/infragluteal fold
Key test point of dermatome S4-5?
perianal area
What is a myotome?
collection of muscle fibres innervated by the motor neurons from a single spinal segment (ventral root)
Key action for myotome C1+2?
neck flexion and extension
Key action for myotome C3?
neck lateral flexion
Key action for myotome C4?
shoulder shrug
Key action for myotome C5?
arm abduction (deltoid) OR substitution: elbow flexors (biceps brachii, brachialis)
Key action for myotome C6?
elbow flexors (biceps and brachialis) and wrist extensors (ECRL and ECRB)
Key action for myotome C7?
elbow extensors (triceps brachii)
Key action for myotome C8?
finger flexors (FDP) to middle finger
Key action for myotome T1?
small finger abductors (abductor digiti minimi)
Key action for myotome L2?
hip flexors (iliopsoas)
Key action for myotome L3?
knee extensors (quadriceps)
Key action for myotome L4?
ankle dorsiflexors (tibialis anterior)
Key action for myotome L5?
long toe extensors (extensor hallicus longus)
Key action for myotome S1?
ankle plantar flexors (gastrocnemius, soleus)
Key action for myotome S2?
knee flexion (biceps femoris, semitendinous, semimembranous)
What are the 5 stages of neurulation?
notochord, neural plate, neural groove, neural tube, becomes CNS
What are the 3 primary vesicles of the rostral neural tube?
prosencephalon, mesencephalon, rhombencephalon
What are the 5 secondary vesicles of the rostral neural tube?
telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon
