ELBOW
Definition
- Elbow is the joint between the humerus and radius and ulna bones of the upper limb.
- It is a hinge type joint that provides flexion, extension, and rotation movements.
Structure
- Humerus: The long bone of the upper arm that forms the upper part of the elbow joint.
- Radius: The smaller of the two bones in the forearm that forms the lower part of the elbow joint.
- Ulna: The larger of the two bones in the forearm that forms the lower part of the elbow joint.
- Articular disc: A fibrocartilaginous disc that separates the humerus and radius/ulna bones and allows for smooth movement.
Blood Supply
- Brachial artery: The major artery that supplies blood to the arm, including the elbow joint.
- Radial and ulnar arteries: Branches of the brachial artery that supply blood to the forearm and elbow joint.
Nerve Supply
- Median nerve: The major nerve that supplies the muscles of the forearm and elbow joint.
- Radial and ulnar nerves: Branches of the brachial plexus that supply the muscles of the forearm and elbow joint.
Muscle Action Sequence
- Flexion: Biceps brachii → brachialis → brachioradialis
- Extension: Triceps brachii → anconeus
- Rotation: Biceps brachii → brachialis → brachioradialis (medial rotation) and triceps brachii → anconeus (lateral rotation)
Lymph Drainage
- Axillary lymph nodes: The primary lymph nodes that drain the elbow joint.
- Brachial lymph nodes: Secondary lymph nodes that drain the elbow joint.
Clinical Significance
- Elbow dislocation: A common injury that occurs when the humerus and radius/ulna bones are displaced from their normal position.
- Elbow fracture: A common injury that occurs when the humerus, radius, or ulna bones are broken.
- Tennis elbow: A condition that occurs when the tendons of the forearm muscles are inflamed, causing pain and stiffness in the elbow joint.