HSF/Clinical correlations

From ViridisWiki

• Denervation of the serratus anterior (such as by paralysis of the long thoracic nerve) causes winging of the scapula.
• Lung sounds can (allegedly) be best heard by placing the stethoscope on the triangle of auscultation.
• Hernias can (uncommonly) form in the lumbar triangle.

Contents 1 Lambert-Eaton syndrome 2 Myasthenia gravis 3 Erb-Duchenne paralysis 4 Klumpke paralysis 5 Winging of scapula 6 Spina bifida

Lambert-Eaton syndrome

• Autoimmune disease against presynaptic voltage-gated calcium channels
• ↓Ca²⁺ released upon stimulation → ↓neurotransmitter released → muscle weakness

Myasthenia gravis

• Autoimmune disease against nicotinic acetylcholine receptors (nAChRs) at NMJ
• ↓nAChRs → ↓fiber response to stimulus

Erb-Duchenne paralysis

• C5,6 damage
• Nerves affected:
  • Axillary (C5,6)
  • Musculocutaneous (C5,6,7)
  • Suprascapular (C5,6)
• Muscles affected:
  • Deltoid, teres minor (axillary n.)
  • Supraspinatus, infraspinatus (suprascapular n.)
  • Biceps brachii, coracobrachialis, brachialis (musculocutaneous n.)
• Clinical presentation:
  • Medial rotation of humerus (lost deltoid and teres minor, lateral rotators)
  • Pronation of forearm (lost biceps brachii, a supinator)
  • Adduction of humerus (lost deltoid and supraspinatus, shoulder abductors)

Klumpke paralysis

• C8,T1 damage
• Nerves affected:
  • Ulnar (C8,T1)
• Muscles affected:
  • Extensors of elbow
  • Extensors of wrist
  • Extensors of digits
  • Intrinsic muscles of hand
• Clinical presentation:
  • Claw hand
  • Flexed elbow (?)
  • Flexed digits (?)

Winging of scapula

• Serratus anterior m. damage
• Eg, due to C5,6,7 damage or long thoracic n. lesion

Spina bifida

• Literally "split spine"
• Results from incomplete closure of caudal neuropore
• Types:
  • Spina bifida occulta
    • Single vertebra fails to fuse
    • Overlying ectoderm closes completely
    • Aside from a tuft of hair overlying the skin covering the vertebra, there are no clinical consequences
  • Meningocoele
    • Vertebrae and ectoderm fail to close
    • Meninges (hence meningo-) protrude through skin of back
  • Meningomyelocoele
    • Vertebrae, ectoderm, and neural tube fail to close completely
    • Meninges and spinal cord (myelo-) are visible through opening in back
    • Associated with Arnold-Chiari malformation (herniation of medulla and cerebellum through foramen magnum)