HUMERUS
🔹 Bone of Arm
🔹 Longest Bone of Upper Limb 🦴
UPPER END
🔘 HEAD:
➡Directed medially, backwards, upwards
➡ Articulates with glenoid cavity of scapula
(Head is larger than the glenoid cavity)
🔘 NECK:
📍 Anatomical neck - Separates head from upper end
📍 Surgical neck - Narrow line below the head
📍 Morphological neck - 0.5 cm above surgical neck (Shows epiphyseal line)
🔘 Lesser Tubercle : Small anterior elevation
🔘 Greater Tubercle : Larger lateral elevation
🔹Posterior aspect: Has 3 impressions ( Upper, Middle, Lower)
🔘 Intertubercular Sulcus (Bicipital Groove) :
🔹Groove separating lesser tubercle from greater tubercle
🔹Has medial & lateral lips
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SHAFT :
🔹Round in upper half
🔹Triangular in lower half
🔹Has 3 Borders & 3 Surfaces
A. BORDERS :
🔸 Anterior:
✅ Upper 1/3rd forms lateral lip of intertubercular sulcus
✅ Middle forms margin of deltoid tuberosity
✅ Lower is smooth & rounded
🔸 Lateral:
✅ Prominent at lower end (lateral supracondylar ridge)
✅ Middle part has radial/spiral groove
🔸 Medial:
✅ Upper forms medial lip of intertubercular sulcus
✅ Middle is rough
✅ Continues to medial supracondylar ridge
B. SURFACES :
🔹 Anterolateral:
🔸 Upper 1/2 covered by deltoid muscle
🔸 Above middle: V-shaped deltoid tuberosity
🔸 Behind tuberosity: Radial groove
🔹 Anteromedial:
🔸 Upper 1/3 forms floor of intertubercular sulcus
🔸 Middle: Nutrient foramen
🔹 Posterior:
🔸 Upper part: Oblique ridge
🔸 Middle 1/2 crossed by radial groove
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LOWER END :
✅ Forms a Condyle
Articular Part ⚙:
🔹Capitulum - Articulates with radial head
🔹 Trochlea - Articulates with trochlear notch of ulna
🔹 Medial edge projects 6mm more (forms carrying angle) 🏌
Non-Articular Part :
🔹 Medial epicondyle 🦴 - Large projection (medial)
🔹 Lateral epicondyle 🦴 - Smaller projection (lateral)
🔹Lateral supracondylar ridge - Ridge on lateral side
🔹 Medial supracondylar ridge - Ridge on medial side
📍 Coronoid Fossa (above trochlea):
➡ Accommodates coronoid process of ulna during elbow flexion
📍 Radial Fossa (above capitulum):
➡ Accommodates radial head during elbow flexion
📍 Olecranon Fossa (posterior to trochlea):
➡ Accommodates olecranon process of ulna during elbow extension
