What is the anatomy of the upper limb?

Anatomy of the Upper Limb

The upper limb is a complex anatomical structure consisting of the shoulder complex, arm, forearm, and hand, primarily designed to position the hand in space for functional activities.

Shoulder Complex

• The shoulder complex consists of four components: glenohumeral joint, acromioclavicular joint, sternoclavicular joint, and scapulothoracic gliding mechanism 1
• These components work together to provide the upper limb with a range of motion exceeding any other joint mechanism in the body 1
• The clavicular joints allow the scapula to move against the chest wall during arm movements, enabling the glenoid fossa to follow the humeral head 1
• Common postural impairments affecting shoulder function include thoracic kyphosis, increased chest anterior-posterior diameter, shoulder elevation and protraction, and trunk flexion 2

Muscles of the Upper Limb

• Upper limb muscles include the biceps, triceps, deltoids, latissimus dorsi, and pectorals 2
• These muscles are essential for both strength and functional movements of the upper extremity 2
• Resistance training for upper limb muscles has been shown to increase strength and improve performance in related functional tasks 2

Functional Considerations

• The primary purpose of the upper limb is to place and control the position of the hand in the visual work space in front of the body 1
• The functional interrelationships between the glenohumeral, scapulothoracic, and clavicular joint mechanisms are critical for providing full range of motion 1
• Many activities of daily living involve the upper extremities, including dressing, bathing, shopping, and household tasks 2

Clinical Implications

• Pathological conditions affecting any component of the upper limb will disturb overall function 1
• For patients with thin skin, particularly elderly patients, careful handling of the upper extremities is essential to prevent damage 3
• When evaluating upper limb function, assessment should include surface topography, underlying soft tissues, skeletal structures, and functional integrity of skin, vessels, muscle-tendon units, joints, and nerves 4

Rehabilitation Approaches

• Task-specific training with repeated, challenging practice of functional, goal-oriented activities is recommended for upper limb rehabilitation 2
• Upper limb resistance training improves strength and can translate to improvements in functional tasks 2
• For individuals with stroke, constraint-induced movement therapy (CIMT) has been demonstrated to improve upper extremity activity when there is baseline ability to control wrist and finger extension 2
• Robotic therapy can provide benefit for upper limb function in individuals with more severe paresis 2

Vascular Considerations

• When planning vascular access for the upper limb, a peripheral-to-central sequence should be followed to preserve future access sites 2
• Evaluation of peripheral pulses, skin integrity, and signs of arterial or venous disease is important when assessing upper limb vascular status 3

Understanding the complex anatomy and function of the upper limb is essential for proper assessment, diagnosis, and management of upper limb conditions across various medical specialties.