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Humerus Anatomy

Key Features of the Humerus

• Head

  • The rounded upper end of the humerus that articulates with the glenoid fossa of the scapula.

• Olecranon Fossa

  • A deep triangular cavity on the posterior side of the humerus. It accommodates the olecranon of the ulna during elbow extension.

• Coronoid Fossa

  • A shallow cavity located anteriorly on the humerus that receives the coronoid process of the ulna during elbow flexion.

• Greater and Lesser Tubercles

  • Projections found at the proximal end of the humerus:
  • Greater Tubercle: A large projection that serves as an attachment for rotator cuff muscles.
  • Lesser Tubercle: A smaller projection located anteriorly, also serving as an attachment for rotator cuff muscles.

• Anatomical Neck

  • A constricted area just below the head of the humerus; it marks the site of the epiphyseal line in adults.

• Trochlea

  • A spool-shaped structure on the distal end of the humerus that articulates with the trochlear notch of the ulna, allowing for hinge movement at the elbow.

• Surgical Neck

  • The region below the tubercles, often where fractures occur; it is proximal to the diaphysis.

• Capitulum

  • A rounded structure on the distal end of the humerus that articulates with the head of the radius.

• Deltoid Tuberosity

  • A roughened area located on the lateral side of the shaft of the humerus, serving as the attachment for the deltoid muscle.

• Intertubercular Sulcus

  • A groove between the greater and lesser tubercle where the tendon of the long head of the biceps brachii passes through.

Structures Passing Through Intertubercular Sulcus

• The tendon of the long head of the biceps brachii muscle passes through this sulcus, which is important for shoulder function.

Ulna Anatomy

• Olecranon Process

  • A prominent bony projection at the proximal end of the ulna; it forms the elbow's bony tip.

• Styloid Process

  • A pointed projection at the distal end of the ulna, providing attachment for ligaments and muscles.

• Coronoid Process

  • A projection that forms part of the elbow joint and is located anterior to the olecranon process.

• Radial Notch of Ulna

  • A depression that articulates with the head of the radius, facilitating the rotation of the radius around the ulna during pronation and supination.

• Trochlear Notch

  • A large, curved space on the proximal end of the ulna that articulates with the trochlea of the humerus, enabling hinge movement.

Radius Anatomy

• Head

  • The rounded proximal end of the radius that articulates with the capitulum of the humerus and the radial notch of the ulna.

• Neck

  • The narrowed area just below the head of the radius.

• Radial Tuberosity

  • A bony prominence located just below the neck, serving as the insertion point for the biceps brachii muscle.

• Styloid Process of Radius

  • A prominent projection at the distal end of the radius, which is easily palpable and provides attachment for wrist ligaments.

Scapula Anatomy

• The scapula, commonly known as the shoulder blade, connects the humerus with the clavicle and supports the arm.

Hip Bone

• The hip bone consists of three fused bones (ilium, ischium, and pubis) and forms the pelvic girdle, articulating with the femur at the hip joint.