DERMATOME OF LOWERLIMB.pptx

dermatome testing is more important assesment in physiotherapy, the above slideshare shows the history of dermatome , testing , dermatome charts , advantage and disadvantage of each chart and clinical conditions

1. DERMATOMES OF LOWERLIMB By S .Christy sopna M.P.T (OBG)

2. INTRODUCTION DERMATOME – in greek derma -skin Tome - section, volume of Dermatome in 2 ways Area of skin innervated by a single spinal cord level. Part of somite that gives rise to the dermis.

3. SOME TYPES OF DERMATOME MAP MAPS SIGNIFICANCE TESTING In 1886, SIR WILMOT HERRINGHAM Found first segmental innervation in cadaver SIR HENRY HEAD Found first dermatome map Clinical observation of referred pain Traumatic SCI Herpes zoster SHERINGTON Found overlaps in dermatome In rhesus monkey JAY KEEGAN and FEDERICK GARETT Hypoalgesia produced by compression of a single nerve root in disc protrusion Injecting Novocain injection LEE ET AL Composite from all maps Experimentally reliable Downs & laporte(2011)

4. SENSORY TESTING Sensory testing is a common noninvasive method evaluating nerve function that relies on the knowledge of skin dermatomes and sensory fields of cutaneous nerves SUPERFICIAL (EXTEROCEPTIVE) SENSATION Pain – pin prick Temperature – 2 test tubes Light touch – swab of cotton Pressure – thumb or index finger pressure Sensory testing typically performed in a distal to proximal sensation .

5. KEY SENSORY POINTS L1- inguinal ligament L2- on the anterior-medial thigh, at the midpoint drawn on an imaginary line connecting the midpoint of the inguinal ligament and the medial femoral condyle L3- at the medial femoral condyle above the knee L4 – over the medial malleolus L5- on the dorsum of foot 3rd metatarsal phalangeal joint. S1 – on the lateral aspect of the calcaneus S2- at the midpoint of the popliteal fossa S3- over the ischial tuberosity or infragluteal fold S4/S5- in the perianal area less than 1 cm lateral to the mucocutaneous junction

6. WHY KEY SENSORY POINTS? Show consistent correlation between specific dermatome and Associated spinal cord nerve level Even with variation in dermatome maps Sensory nerves overlap Key sensory point is consistent Common area in all dermatome map

7. COMMON SENSORY IMPAIRMENTS IMPAIRMENT CONDITION PAIN SENSATION Analgesia ALGESIA complete loss of pain sensitivity. SCI Hyperalgesia Hypalgesia Increased sensitivity of pain decreased sensitivity of pain Causalgia SENSORY PERVERSION painful , burning sensation , usually along the distribution of a nerve Brachial plexus injury Dysesthesia touch sensation experienced as pain Multiple sclerosis Paresthesia abnormal sensation such as numbness , prickling, or tingling, without apparent cause Radiculopathy TEMPERATURE Thermanalgesia THERMESTHESIA Inability to perceive heat Thermanesthesia Inability to perceive sensation of heat and cold

8. CLINICAL IMPORTANCE Diagnosis of radiculopathy Level of spinal cord injury Intraoperative monitoring of nerve root and spinal cord function by dermatomal somatosensory evoked potentials In anesthesiology , to determine sensory limits of regional anesthesia such as before cesarian section In general medicine, dermatomal distribution of referred pain from visceral diseases. Pain due to pleurisy, peritonitis, or gallbladder disease - referred to the skin over the point of the shoulder, halfway down the lateral side of the deltoid muscle. This is because this area of skin is supplied by the supraclavicular nerves (C3 and C4) The varicella zoster dormant in dorsal root ganglion,when it become activated causes vesicular rashes(shingles) in a dermatomal pattern.

9. Cauda equina syndrome – saddle anesthesia (S3,S4,S5) Meralgia paresthetica – lateral cutaneous nerve (L2,L3)- altered sensation,burning Hockey player’s syndrome (ilioinguinal nerve) – L1 dermatome Lumbosacral tunnel syndrome – L5 dermatome Foot drop –(L4,L5,S1,S2) Tarsal tunnel syndrome –(L5,S1) burning sensation over lateral aspect of foot

10. SACRAL SPARING Sacral sparing can be evaluated by 3 tests Great toe flexor activity Rectal motor function – bulbocavernosus reflex Perineal sensation (S3,S4,S5) If the patient maintains sensation around anal region, this is known as sacral sparing S3- ischial tuberosity S4-S5 – perineal/genital area The spinothalamic tract is near the corticospinal tract and preservation of the pin-prick sensation will predict recovery of some of the motor function.

11. DOES RADICULAR PAIN FOLLOW DERMATOME PATTERN? Dermatomal Non-dermatomal Area/nerve root n Percent n Percent Cervical 20 30.3 46 69.7 Lumbar 37 35.9 66 64.1 Lumbar levels dermatomal Non dermatomal n percent n percent L2 2 40.0 3 60.0 L3 4 30.8 9 69.2 L4 8 28.6 20 71.4 L5 8 16.3 41 83.7 S1 24 64.9 13 35.1

12. CONFLICTS IN DERMATOME No proper evidential dermatome map Only little evidence on reliability of dermatome Variability of brachial/lumbosacral plexus -Pre-fixed plexuses(26-48%) and post-fixed plexus(4%) of population

13. REFERENCES Downs & Laporte (2011) conflicting dermatome maps:educational and clinical implications: journal of orthopedic & sport physical therapy 41 (6),427-434. Murphy et al(2009) pain patterns and descriptions in patients with radicular pain:does the pain necessarily follow a specific dermatome? chiropractic & osteopathy17 (9). Susan o Sullivan “ physical rehabilitation ”(2014) jaypee publication 6 th edition. Magee “ orthopedic physical assessment ”(2008) Elsevier publication 6 th edition.

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