Surface Anatomy and Landmarks

Surface Anatomy and Landmarks

Surface Anatomy and Landmarks

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Shoulder Girdle & Axilla - Bony Bumps & Armpit Secrets

  • Shoulder Girdle Landmarks (Palpable):
    • Clavicle: S-shaped; sternal & acromial ends.
    • Scapula: Acromion (shoulder tip), coracoid process, spine.
    • Humerus (Proximal): Greater & lesser tubercles, intertubercular groove.
  • Axilla (Armpit): Pyramidal neurovascular gateway.
    • Apex: Clavicle, 1st rib, scapula.
    • Anterior wall: Pectoralis major/minor.
    • Posterior wall: Subscapularis, teres major, latissimus dorsi.
    • Medial wall: Serratus anterior, ribs.
    • Lateral wall: Humerus (intertubercular groove).
    • Contents: Axillary vessels, brachial plexus, lymph nodes.

Surface anatomy of shoulder and axilla

⭐ Axillary nerve injury (e.g., surgical neck fracture of humerus) causes deltoid paralysis & sensory loss over regimental badge area.

Arm & Elbow - Muscle Maps & Joint Junctions

  • Arm Compartments:
    • Anterior (Flexors): Biceps brachii, Brachialis, Coracobrachialis (Musculocutaneous N.)
    • Posterior (Extensors): Triceps brachii (Radial N.)
      • Radial groove: Radial N., Profunda brachii A.
  • Elbow Joint (Hinge):
    • Articulations: Humeroulnar, Humeroradial, Proximal radioulnar.
    • Landmarks: Medial & Lateral epicondyles, Olecranon.
    • Carrying angle: ~5-15°. Cubital Fossa Anatomy and Clinical Significance
  • Cubital Fossa (Anterior elbow):
    • Boundaries: Epicondyles (sup.), Pronator teres (med.), Brachioradialis (lat.).
    • Contents (Medial to Lateral - 📌 MBBR): Median N., Brachial A., Biceps tendon, Radial N. (deep).

⭐ Supracondylar fracture of humerus commonly injures the Median nerve and Brachial artery.

Forearm, Wrist & Hand - Pulse Points & Palmistry

  • Pulse Points (Forearm/Wrist):
    • Radial Artery: Lateral to Flexor Carpi Radialis (FCR) tendon. Common for pulse, Arterial Blood Gas (ABG) sampling.
      • Allen's Test: Assesses collateral circulation via ulnar artery before radial artery procedures.
    • Ulnar Artery: Lateral to Flexor Carpi Ulnaris (FCU) tendon, proximal to pisiform bone.
  • Key Palmar Features (Surface Anatomy):
    • Palmar Creases: Proximal & distal transverse creases, longitudinal (thenar) crease.
      • 📌 Simian Crease: Single transverse palmar crease (associated with conditions like Down Syndrome).
    • Thenar & Hypothenar Eminences: Muscle groups at base of thumb and little finger.
  • Important Spaces/Structures:
    • Anatomical Snuffbox:
      • Borders: Extensor Pollicis Longus (EPL) (medially/ulnarly), Extensor Pollicis Brevis (EPB) & Abductor Pollicis Longus (APL) (laterally/radially).
      • Contents: Radial artery, scaphoid bone (floor).
    • Guyon's Canal (Ulnar Canal): Passage for ulnar nerve & artery into the hand.

Wrist anatomy with radial artery access

⭐ Tenderness in the anatomical snuffbox after a fall on an outstretched hand (FOOSH) is highly suggestive of a scaphoid fracture, which may not be visible on initial X-rays and carries a risk of avascular necrosis if missed.

Key Neurovascular Structures - Clinical Hotspots

  • Axilla:
    • Axillary Artery: Palpable; compression point.
    • Brachial Plexus: Vulnerable (Erb's point C5-C6).
  • Arm/Cubital Fossa:
    • Brachial Artery: BP site; pulse.
    • Median Nerve: Medial to brachial artery; supracondylar fracture risk.
    • Radial Nerve (Arm): Mid-shaft humerus fracture → wrist drop.
  • Elbow/Wrist:
    • Ulnar Nerve: Post. to medial epicondyle; Guyon's canal (wrist).
  • Wrist (Arteries):
    • Radial Artery: Pulse (lat. to FCR); snuffbox.
    • Ulnar Artery: Allen's test (palmar arch).
  • Superficial Veins:
    • Cephalic (lat.), Basilic (med.), Median Cubital (venipuncture).

⭐ The anatomical snuffbox, bounded by EPL, EPB & APL tendons, contains the radial artery & superficial radial nerve. Scaphoid fracture tenderness is key here.

Surface Anatomy of the Upper Limb

High‑Yield Points - ⚡ Biggest Takeaways

  • Axillary artery pulsation: felt in axilla, inferior to deltopectoral groove.
  • Brachial artery pulsation: medial to biceps tendon in cubital fossa.
  • Cephalic vein: prominent in deltopectoral groove, pierces clavipectoral fascia.
  • Anatomical snuffbox: borders are EPL, APL, EPB tendons; contains radial artery, scaphoid bone.
  • Ulnar nerve: palpable posterior to medial epicondyle ("funny bone").
  • Median cubital vein: common site for venipuncture in cubital fossa.
  • Radial pulse: felt lateral to flexor carpi radialis tendon at wrist_

Practice Questions: Surface Anatomy and Landmarks

Test your understanding with these related questions

A patient at the orthopedics OPD complains of troubled sleep at night due to numbness and tingling sensation involving his lateral 3 digits. His symptoms are relieved as he lays his arms hanging from the bed. Which of the following options correctly describes his condition and the test used to assess it?

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Flashcards: Surface Anatomy and Landmarks

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Branches of the medial cord of the brachial plexus: M4UM_____ (C8,T1)Medial cutaneous nerve of forearm (C8,T1)Medial cutaneous nerve of arm (C8,T1)Ulnar nerve (C8,T1)Medial root of median nerve (C8,T1)

TAP TO REVEAL ANSWER

Branches of the medial cord of the brachial plexus: M4UM_____ (C8,T1)Medial cutaneous nerve of forearm (C8,T1)Medial cutaneous nerve of arm (C8,T1)Ulnar nerve (C8,T1)Medial root of median nerve (C8,T1)

edial pectoral

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