Snell - Orthopedic Quiz Chapter 3: Upper Limb

Proximal End of Humerus Fracture

• Humeral head fractures can occur with anterior and posterior shoulder dislocations.
• The glenoid labrum can jam into fractures, complicating shoulder joint reduction.

Greater Tuberosity Fracture

• Caused by direct trauma or dislocation; may be avulsed by supraspinatus muscle contractions.
• Key attachments to rotator cuff muscles (supraspinatus, teres minor, infraspinatus).
• Severe rotator cuff tearing can cause posterior displacement after shoulder reduction, necessitating surgery.

Lesser Tuberosity Fracture

• May occur with posterior shoulder dislocation.
• The fractured bone fragment serves as the insertion for the subscapularis tendon.

Surgical Neck Fracture

• Located just below the lesser tuberosity; susceptible to direct blows or falls.
• Potential damage to the axillary nerve and circumflex humeral vessels.

Shaft of Humerus Fracture

• Common fracture site; displacement is influenced by muscle attachments.
• Proximal fractures lead to adduction by pectoralis major, latissimus dorsi, and teres major.
• Distal fractures result in abduction by the deltoid, while biceps and triceps pull the distal fragment proximally.
• Radial nerve injury is possible due to its proximity along the humerus.

Distal End of Humerus Fracture

• Supracondylar fractures are frequent in children; injuries usually result from falls.
• May damage median, radial, or ulnar nerves, with function typically restored post-reduction.
• Risks include brachial artery damage and potential Volkmann's ischemic contracture.

Ulna and Radius

• The ulna lies medially in the forearm, articulating with the humerus and radius.
• The olecranon serves as the triceps insertion, forming the elbow's "point."
• Radius fractures can occur from falls and can be associated with significant displacement.

Ulnar and Radial Fractures

• Radius head fractures typically arise from falls on an outstretched hand, causing splintering.
• Neck fractures more common in children, similarly from falls.
• Shaft fractures may affect radius and ulna together or separately, involving muscle pull dynamics.

Monteggia and Galeazzi Fractures

• Monteggia fracture is characterized by ulna shaft fracture with radial dislocation.
• Galeazzi fracture features radial neck fracture with distal ulna dislocation.

Olecranon Process Fractures

• Result from falls on a flexed elbow or direct trauma.
• Fractures can displace due to triceps muscle traction on the bony fragment.

Scapular Fractures

• Often linked to severe trauma (e.g., vehicle accidents) and commonly co-occurring with rib fractures.
• Scapular fractures often require minimal treatment due to muscle support.

Dropped Shoulder and Winged Scapula

• Dropped shoulder results from trapezius paralysis; winged scapula from serratus anterior paralysis.
• These conditions can be identified through physical examination.

Important Features of the Humerus

• Key anatomical landmarks include the anatomical neck, surgical neck, greater and lesser tubercles.
• Each region correlates with specific muscular attachments and articulations.

Clavicle Overview

• The clavicle connects the upper limb to the axial skeleton and is prone to fractures due to its exposed position.
• Most frequently fractured bone, commonly resulting from falls on the shoulder.

Mechanism of Clavicle Fracture

• Fractures typically occur at the junction of the middle and outer thirds, leading to characteristic lateral displacement.
• Proximity to supraclavicular nerves might cause post-fracture pain complications.### Clavicular Compression and Upper Limb Anatomy
• Clavicular compression occurs between the clavicle and first rib, affecting the brachial plexus, subclavian artery, and subclavian vein.
• Understanding upper limb anatomy is essential for diagnosing injuries, pain, motor deficits, and congenital issues.

Learning Objectives in Upper Limb Anatomy

• Identify major bones: clavicle, scapula, humerus, radius, ulna, carpal, metacarpal, and phalangeal bones.
• Understand anatomical regions: shoulder, arm, forearm, wrist, and hand.
• Explore female breast anatomy, lymphatic drainage, and implications of mastectomy.
• Define axilla and cubital fossa boundaries and contents.
• Explain the development of the upper limb and components of the shoulder complex.
• Identify rotator cuff muscles and significant anatomical spaces (quadrangular, triangular).
• Understand osseofascial compartments, including muscle innervation and function.
• Describe movements of the wrist and hand, carpal tunnel, and synovial sheaths.
• Outline the brachial plexus, peripheral nerves, blood flow, and lymphatic drainage patterns.

Overview of Upper Limb

• The upper limb functions as a multijointed lever, primarily for hand manipulation.
• The hand's unique structure allows it to grasp objects with precision, largely due to thumb opposition.
• Organized into defined sections: shoulder region, arm, forearm, wrist, and hand, each with specific muscle compartments.

Osteology

• Clavicle: S-shaped, subcutaneous, connects arm to thorax, first bone to ossify.
• Scapula: Provides attachment for shoulder muscles, plays a key role in arm movement.
• Humerus: Largest bone in the arm, connects forearm bone to shoulder.
• Radius and Ulna: Form forearm bones with distinct roles in movement and stability.
• Carpal bones: Form the wrist, provide flexibility and support.
• Metacarpals and Phalanges: Form the structure of the hand and fingers.

Clinical Case Example

• A 64-year-old woman presented with left shoulder pain and sensory deficits after a fall.
• Diagnosis: Subcoracoid dislocation of the shoulder, impacting the axillary and radial nerves.
• Symptoms: Loss of shoulder curvature due to humeral displacement, resulting in significant skin sensation loss along specific areas.

Anatomical and Physiological Relationships

• Shoulder joint anatomy knowledge is crucial for accurate diagnosis of nerve injuries.
• The distribution of the axillary and radial nerves is vital for understanding upper limb function.

Chapter Outline Components

• Sections include Osteology, Upper Limb Regions, Muscles, Nerves, Vasculature, Lymphatics, and Joints.
• Highlights include the specific roles of cranial and spinal nerves and the significance of vascular supply and lymphatic drainage.

Summary of Movements and Functions

• Pronation and supination involve coordinated muscle action for effective arm usage.
• The carpal tunnel's arrangement is clinically significant, particularly in carpal tunnel syndrome.

Clinical Relevance

• Knowledge of anatomical relationships aids in injury management and therapeutic strategies to preserve upper limb function.
• Attention to wrist and hand injuries is crucial due to the thumb's role in grasping and fine motor skills.

Test your knowledge on upper limb fractures, focusing on lesser tuberosity and surgical neck injuries. Understand the implications of these fractures on shoulder joint function and the role of the rotator cuff. Enhance your orthopedic expertise with this quiz!