Clinical correlations of upper limb

Brachial Plexus - Nerve Highway Havoc

• Upper Trunk (C5-C6) Injury: Erb-Duchenne Palsy
  • Cause: ↑ angle between neck & shoulder (e.g., birth trauma, fall).
  • Presentation: "Waiter's tip" hand-adducted, internally rotated arm, extended elbow.
• Lower Trunk (C8-T1) Injury: Klumpke's Palsy
  • Cause: Hyperabduction of arm (e.g., grabbing a branch to break a fall).
  • Presentation: Total claw hand (loss of lumbricals).
• Long Thoracic Nerve (C5-C7) Injury
  • Cause: Axillary node dissection (mastectomy), chest trauma.
  • Presentation: "Winging of the scapula."

⭐ Horner's Syndrome (ptosis, miosis, anhidrosis) can accompany Klumpke's palsy due to injury to T1 sympathetic fibers.

📌 Mnemonic: Really Tired? Drink Coffee Black (Roots, Trunks, Divisions, Cords, Branches).

Peripheral Nerve Palsies - Zaps & Traps

• Long Thoracic n. (C5-C7):
  • Injury: Mastectomy, chest tube.
  • Deficit: "Winging" of scapula (Serratus Anterior paralysis).
• Axillary n. (C5-C6):
  • Injury: Anterior humerus dislocation, surgical neck fracture.
  • Deficit: Deltoid paralysis (impaired abduction), sensory loss over deltoid.
• Radial n. (C5-T1):
  • Injury: "Saturday night palsy," crutches, mid-shaft humerus fracture.
  • Deficit: "Wrist drop" (extensor paralysis).
• Median n. (C5-T1):
  • Injury: Carpal tunnel syndrome, supracondylar humerus fracture.
  • Deficit: "Ape hand," loss of thumb opposition.
• Ulnar n. (C8-T1):
  • Injury: Medial epicondyle fracture, hook of hamate fracture.
  • Deficit: "Ulnar Claw" hand (at rest), hypothenar atrophy.

⭐ Ulnar Claw vs. Hand of Benediction: Ulnar Claw is seen at rest. Hand of Benediction (Pope's Blessing) is seen only when a patient with a proximal median nerve lesion tries to make a fist.

Common Fractures - Snap, Crackle, Pop

• Clavicle Fracture:

  • Most common site: Junction of middle and lateral thirds.
  • Nerve at risk: Supraclavicular nerves (loss of sensation over shoulder).
  • Appearance: Shoulder drop, medial fragment pulled superiorly by sternocleidomastoid.

• Humerus Fractures & Nerve Injury (📌 ARM):

  • Axillary nerve: Surgical neck fracture.
  • Radial nerve: Mid-shaft fracture (wrist drop).
  • Median nerve: Supracondylar fracture (Volkmann's ischemic contracture risk).

• Distal Radius Fractures (FOOSH):

  • Colles' Fracture: Dorsal displacement ("dinner fork" deformity).
  • Smith's Fracture: Volar/palmar displacement ("garden spade" deformity).

⭐ Scaphoid Fracture: Most common carpal bone fracture. A fall on an outstretched hand can cause it. High risk of avascular necrosis due to retrograde blood supply. Presents with tenderness in the anatomical snuffbox.

Shoulder Pathology - Tears & Tangles

• Rotator Cuff Tears: Most commonly affects the supraspinatus muscle.

  • Mechanism: Chronic impingement, acute trauma (e.g., fall on an outstretched hand).
  • Clinical Tests: Positive Drop Arm test (inability to hold arm abducted) & Empty Can test.
  • 📌 Mnemonic SITS for rotator cuff muscles: Supraspinatus, Infraspinatus, Teres minor, Subscapularis.

• Adhesive Capsulitis (Frozen Shoulder): Fibrosis and contracture of the glenohumeral capsule.

  • Presentation: ↓ active AND passive range of motion, especially external rotation.
  • Associated with Diabetes Mellitus and thyroid disease.

⭐ Inability to perform active and passive range of motion is a key differentiator for adhesive capsulitis versus a rotator cuff tear, where passive ROM is often preserved.

• Erb's palsy (C5-C6) results in a "waiter's tip" hand from an upper trunk injury.
• Klumpke's palsy (C8-T1) causes intrinsic hand muscle paralysis, leading to a total "claw hand."
• Winged scapula signifies long thoracic nerve injury, paralyzing the serratus anterior muscle.
• Mid-shaft humeral fractures risk radial nerve injury, causing wrist drop.
• Scaphoid fractures present with snuffbox tenderness and risk avascular necrosis.