Applied Anatomy and Clinical Correlations

Applied Anatomy and Clinical Correlations

Applied Anatomy and Clinical Correlations

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Shoulder & Axilla: Clinicals - Joint & Axilla Jams

  • Shoulder Dislocation:
    • Anterior (>95%): Axillary n. risk (deltoid palsy, regimental badge anesthesia). Arm abducted, ext. rotated.
    • Posterior: Seizures, electrocution. Arm adducted, int. rotated.
  • Rotator Cuff (SITS) Tears: Supraspinatus most common. Painful arc (60-120°). Drop arm test.
  • Adhesive Capsulitis (Frozen Shoulder): Diffuse pain, ↓ active & passive ROM.
  • Axillary Nerve Injury: Due to shoulder dislocation or surgical neck humerus fracture.
  • Long Thoracic Nerve Injury (C5,6,7): Winging of scapula. (📌 "C5,6,7 keep the wings to heaven")
  • Axillary Lymphadenopathy: Infection or malignancy (e.g., breast cancer mets).

    ⭐ In anterior shoulder dislocation, the humeral head often lies subcoracoid. Axillary nerve vulnerability is key. Anterior shoulder dislocation & axillary nerve

Brachial Plexus: Injuries - Nerve Network Nightmares

  • Upper Trunk (C5, C6) - Erb-Duchenne Palsy
    • Cause: ↑ neck-shoulder angle (birth, falls).
    • Sign: "Waiter's tip" hand: arm adducted, medially rotated; forearm extended, pronated.
    • Muscles: Deltoid, supraspinatus, infraspinatus, biceps.
    • 📌 ERB's: Elbow extended, Rotated arm (medially), Biceps weak.
  • Lower Trunk (C8, T1) - Klumpke's Palsy
    • Cause: Hyperabduction of arm (e.g., grabbing branch).
    • Sign: Claw hand (intrinsic muscle paralysis).

    ⭐ Often with Horner's syndrome (ptosis, miosis, anhydrosis) if T1 sympathetic fibers involved.

  • Long Thoracic N. (C5,C6,C7) Injury
    • Cause: Mastectomy, stab.
    • Sign: Winging of scapula (serratus anterior palsy).
  • Axillary N. (C5,C6) Injury
    • Cause: Shoulder dislocation, humerus surgical neck fracture.
    • Sign: Deltoid paralysis (abduction 15-90° loss); regimental badge anesthesia.

Symptoms of Brachial Plexus Palsy in Infants

Elbow & Forearm: Clinicals - Twists & Traps

  • Elbow Joint:

    • Tennis Elbow (Lat. Epicondylitis): ECRB. Pain: resisted wrist extension.
    • Golfer's Elbow (Med. Epicondylitis): Common flexor origin. Pain: resisted wrist flexion.
    • Olecranon Bursitis (Student's): Bursa inflammation.
    • Pulled Elbow (Nursemaid's): Radial head subluxation. Children < 5 yrs. Reduce: supination + flexion.
  • Nerve Entrapments:

    • Cubital Tunnel (Ulnar N.): At elbow. Sensory: medial 1.5 fingers. Motor: hypothenar, interossei. Froment's.

      ⭐ Ulnar Paradox: Proximal lesion → less clawing (FDP paralysis) vs. distal.

    • Pronator Syndrome (Median N.): By pronator teres. Forearm pain. No night symptoms.
    • AIN Syndrome (Median N. motor): "OK" sign weak (FPL, FDP I/II). No sensory loss.
    • PIN Syndrome (Radial N. motor): Arcade of Frohse. Finger/wrist drop. No sensory loss.
  • Fractures/Dislocations:

    • Supracondylar Fx (Humerus): Children. Risk: Brachial A., Median N. → Volkmann's.
    • Elbow Dislocation: Posterior common. Risk: Ulnar N.
    • Forearm Fx: 📌 MUGR: Monteggia-Ulna fx (proximal) + radial head disloc.; Galeazzi-Radius fx (distal) + DRUJ disloc.

Wrist & Hand: Clinicals - Grip Grievances

  • Power Grip Impairment:
    • Ulnar N. injury: Weakness of interossei, hypothenars. Positive Froment's sign (IPJ flexion of thumb via FPL).
    • Median N. injury: Affects thenar eminence, FDS, lateral FDP.
  • Precision Grip Impairment:
    • Median N. injury: Loss of opposition (Ape hand deformity), weak pinch. AIN syndrome: "OK" sign weakness.
    • Ulnar N. injury: Affects adductor pollicis, interossei; difficulty with key grip.
  • Common Causes:
    • Carpal Tunnel Syndrome (CTS): Median N. compression; nocturnal paresthesia, thenar atrophy. Positive Phalen's/Tinel's.
    • De Quervain's Tenosynovitis: APL & EPB inflammation; radial wrist pain. Positive Finkelstein's test.
    • Trigger Finger: Flexor tendon stenosing tenosynovitis; locking/catching. Ulnar Claw Hand and Ape Hand deformities

⭐ Froment's sign (ulnar N. palsy): thumb IPJ flexion via FPL (median N.) compensates for weak adductor pollicis during pinch grip tests an ulnar nerve lesion effectively testing the adductor pollicis muscle..

High‑Yield Points - ⚡ Biggest Takeaways

  • Erb's palsy (C5-C6) results in waiter's tip deformity.
  • Klumpke's palsy (C8-T1) causes total claw hand.
  • Radial nerve injury leads to wrist drop (e.g., Saturday night palsy).
  • Median nerve compression in carpal tunnel causes ape thumb deformity.
  • Long thoracic nerve injury results in winged scapula.
  • Supracondylar humerus fracture risks median nerve and brachial artery injury.
  • Scaphoid fracture presents with anatomical snuffbox tenderness and avascular necrosis risk.
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Practice Questions: Applied Anatomy and Clinical Correlations

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Finkelstein test is used for diagnosis of?

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Flashcards: Applied Anatomy and Clinical Correlations

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Musculocutaneous nerve injury commonly occurs in the setting of:- trauma (ex _____ dislocation)- bullet shot to the anterior biceps- strenous upper extremity exercise (ex. baseball pitching)

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Musculocutaneous nerve injury commonly occurs in the setting of:- trauma (ex _____ dislocation)- bullet shot to the anterior biceps- strenous upper extremity exercise (ex. baseball pitching)

shoulder

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