Anatomy of the Elbow and Shoulder Joints

The elbow joint is formed by the concave head of the radius articulating with the convex humeral capitulum, and the trochlear notch of the ulna articulating with the trochlea of the humerus.

The fibrous capsule surrounds the elbow joint, providing a protective layer and attaching to specific bony landmarks. It's thin anteriorly and posteriorly, but strengthened by ligaments on the sides.

The radial collateral ligament on the lateral side and the ulnar collateral ligament on the medial side provide stability and prevent excessive movement. They are crucial for preventing the elbow from dislocating.

The annular ligament encircles the head of the radius and holds it in place against the ulna, allowing for rotation of the forearm.

The stability of the elbow joint is achieved by the bony articulations, ligaments, fibrous capsule, and surrounding muscles. All these structures work together to provide support and control movement.

A common shoulder injury caused by repetitive motions and often affects the supraspinatus muscle due to its limited blood supply.

The fibrous capsule, ligaments like the glenohumeral and coracohumeral ligaments, and the rotator cuff muscles (teres minor, subscapularis, supraspinatus, infraspinatus) all contribute to the stability of the shoulder joint.

The shoulder joint allows for flexion and extension, abduction and adduction, medial and lateral rotation, and a combination of these movements called circumduction.

The clavicular fibers of pectoralis major, anterior deltoid fibers, biceps brachii, and coracobrachialis muscles work together to raise the arm forward.

The posterior deltoid fibers, latissimus dorsi, teres major, and other muscles work together to lower and stabilize the arm backwards.

The supraspinatus and middle deltoid fibers work together to raise the arm away from the body.

The teres major, latissimus dorsi, pectoralis major, and other muscles act to pull the arm towards the body.

The infraspinatus, teres minor, and posterior deltoid fibers rotate the arm outwards.

The movement that decreases the angle between the forearm and the upper arm, bringing the hand closer to the shoulder.

The movement that increases the angle between the forearm and the upper arm, straightening the arm.

A network of blood vessels that surround the elbow joint, providing blood supply and supporting joint function.

The ulnar nerve is located on the medial side of the elbow and is vulnerable to injury during elbow dislocations or fractures.

A ligament that stabilizes the medial side of the elbow joint and is commonly injured during dislocations.

The angle between the arm and forearm when the forearm is fully extended and supinated. It disappears when the forearm is pronated. It is estimated to be approximately 170 degrees in males and 160-165 degrees in females.

A branch of the 3rd part of the axillary artery that supplies blood to the posterior aspect of the shoulder joint.

A type of joint where movement occurs in only one plane, like a door hinge.

The part of the shoulder joint formed by the humerus and the ulna bones.

Inflammation of the fluid-filled sac (bursa) located under the acromion bone, often associated with supraspinatus tendinitis.

The shoulder joint, also known as the glenohumeral joint, is a complex ball-and-socket joint that allows for a wide range of motion. It connects the humerus (upper arm bone) to the glenoid cavity of the scapula (shoulder blade).

The glenoid labrum is a ring of fibrocartilage that deepens the shallow glenoid cavity. This deepening helps to increase the stability of the shoulder joint by providing a better fit between the humeral head and the glenoid cavity.

The fibrous capsule is a tough, fibrous sheath that surrounds the shoulder joint. It helps to stabilize the joint and prevent excessive movement. However, it is relatively weak in the inferior part. The long head of the triceps brachii muscle reinforces this area.

The rotator cuff is a group of four muscles that surround the shoulder joint. These muscles help to stabilize the joint, control movement, and prevent injuries. They work together to rotate the arm and control its movement.

The coracoacromial ligament is a strong ligament that extends between the acromion (a bony projection on the shoulder blade) and the coracoid process (another bony projection on the shoulder blade). It protects the humeral head from superior displacement, helping to prevent the shoulder from dislocating upwards.

This joint connects the distal end of the radius and the articular disc of the distal radio-ulnar joint to the scaphoid, lunate, and triquetrum bones in the wrist.

The wrist joint is a type of synovial joint that allows for movement along two axes, like a ball rolling in a socket.

It is a strong fibrous layer that surrounds the wrist joint, attaching to the bones and helping to keep the joint stable.

The wrist joint is strengthened and supported by these structures, which restrict excessive movement and help prevent injuries. These structures are thickenings of the fibrous capsule.

This type of wrist movement involves bending the hand downwards towards the forearm.

The radial collateral ligament on the lateral side and the ulnar collateral ligament on the medial side prevent excessive movement and help stabilize the wrist joint.

The simultaneous action of Flexor carpi ulnaris and Extensor carpi ulnaris muscles moves the wrist towards the pinky finger (ulnar side).

A fracture of the scaphoid bone can occur after a fall on an outstretched hand. Healing is slow due to poor blood supply to the bone.

The simultaneous action of Flexor carpi radialis and Extensors carpi radiales longus and brevis muscles moves the wrist towards the thumb (radial side).

The distal epiphysis of the radius may fracture in children due to falls on the hand. The fracture can be described as transverse with ventral deviation of the wrist.