Overview of Arm Anatomy

Overview of Arm Anatomy

• The arm is the region of the upper limb between the shoulder and the elbow.
• It comprises bones, muscles, tendons, nerves, and blood vessels.
• It enables essential functions like lifting, grasping, and pushing.

Bones of the Arm

• The humerus is the long bone of the upper arm.
  • It articulates with the scapula at the glenohumeral joint (shoulder).
  • It articulates with the radius and ulna at the elbow joint.
• The radius and ulna are the forearm bones.
  • The radius is on the thumb side of the forearm.
  • The ulna is on the pinky finger side of the forearm.
  • These bones articulate at the proximal and distal radioulnar joints.

Muscles of the Arm

• Anterior muscles (flexors):
  • Biceps brachii: Primarily flexes the elbow.
  • Brachialis: A strong elbow flexor.
  • Brachioradialis: Flexes the elbow, assists biceps.
• Posterior muscles (extensors):
  • Triceps brachii: Extends the elbow joint.
• Shoulder muscles:
  • Deltoids: Crucial for arm abduction (lifting away from the body).
  • Rotator cuff muscles (supraspinatus, infraspinatus, teres minor, subscapularis): Stabilize and control shoulder movement.

Joints of the Arm

• Glenohumeral joint (shoulder): A ball-and-socket joint for a wide range of motion.
• Elbow joint: A hinge joint for flexion and extension of the forearm.
• Proximal radioulnar joint: A pivot joint allowing forearm rotation.

Nerves and Blood Vessels

• Nerves: Radial, ulnar, and median nerves supply sensation and motor function to the arm and hand.
• Blood vessels: Arteries (brachial, radial, ulnar) and veins transport oxygen, nutrients, and remove waste.
• The nervous system controls arm function.

Additional Considerations

• Ligaments: Connect bones, stabilize joints, prevent dislocation.
• Tendons: Connect muscles to bones, enabling movement.
• Fascia: Fibrous connective tissue layer, surrounds muscles, provides support.
• Cartilage: Cushions joints, found in articular cartilage.
• Bone marrow: Located in bones, produces blood cells.

Clinical Relevance

• Common injuries: Dislocations, fractures, sprains, strains, nerve injuries.
• Conditions: Tendonitis, bursitis, arthritis, carpal tunnel syndrome.
• Treatment: Varies by injury/condition, from physical therapy to surgery.