Anatomy and Physiology of the Upper Limb

Page 1: Introduction to Anatomy and Physiology of the Upper Limb\n\nThis document provides an exhaustive overview of the anatomy and physiology of the human upper limb, as presented by the University of Wolverhampton. It details the bony structures, joints, ligaments, muscles, and tendons ranging from the shoulder to the hand.\n\n# Page 2: Bony Anatomy of the Shoulder\n\nThe shoulder complex is comprised of $3$ primary bones:\n\n* Humerus: The bone of the upper arm.\n* Scapular (Scapula): The shoulder blade.\n* Clavicle: The collarbone.\n\nAdditional Anatomical Considerations: Because the clavicle articulates with the sternum (breastbone), the sternum is sometimes included in discussions regarding the bony anatomy of the shoulder complex.\n\n# Page 3: The Humerus (Proximal and Distal Articulations)\n\nThe humerus is the long bone of the arm that serves as the central structural component between the shoulder and the elbow.\n\n* Proximal Articulation: The humerus articulates proximally at the glenohumeral joint.\n* Distal Articulation: It articulates distally with the radius and the ulna at the elbow joint.\n* The Head of the Humerus: This structure forms the \"ball\" or spherical component of the ball and socket joint known as the glenohumeral joint.\n* Tubercular Anatomy: The humerus features two prominent projections:\n * Greater Tubercle\n * Lesser Tubercle\n * Spatial Orientation: Both tubercles are located distal to the anatomical neck of the humerus and proximal to the surgical neck.\n\n# Page 4: The Scapula (Scapular)\n\nThe scapula is characterized as a flat, triangular bone located on the posterior aspect of the thorax. It serves as a critical site providing attachment to several muscles of the upper limb and trunk.\n\n* Clinical Note: Scapular fractures are noted to be rare occurrences.\n* The Acromion: This specific area of the shoulder is where the scapula meets the clavicle to form the acromioclavicular (AC) joint.\n* The Coracoid Process: This hook-like structure, along with the acromion and various ligaments, works to stabilize the shoulder joint.\n\n# Page 5: The Clavicle\n\nThe clavicle forms the anterior portion of the shoulder complex.\n\n* Distinctive Characteristic: The clavicle is unique as it is the only long bone in the human body that lies in a horizontal orientation.\n* Articulations and Terminals:\n * Lateral End: Forms the acromioclavicular (AC) joint.\n * Medial End: Forms the sternoclavicular (SC) joint.\n\n# Page 6: Joints of the Shoulder\n\nThe shoulder complex includes $4$ distinct joints:\n\n1. Sternoclavicular Joint (SC)\n2. Acromioclavicular Joint (AC)\n3. Glenohumeral Joint\n4. Scapulothoracic Joint\n\n# Page 7: Sternoclavicular Joint (SC)\n\nThe sternoclavicular joint is classified as a saddle joint. It facilitates the following movements of the shoulders:\n\n* Elevation: Moving the shoulders upward.\n* Depression: Moving the shoulders downward.\n* Protraction: Moving the shoulders forward.\n* Retraction: Moving the shoulders backward.\n\n# Page 8: Acromioclavicular Joint (AC)\n\nThe acromioclavicular joint is the junction between the clavicle and the acromion of the scapular (scapula).\n\n* Classification: A plane joint.\n* Movement: It allows for specific gliding movements along two primary axes:\n * Superior/Inferior glide.\n * Anterior/Posterior glide.\n\n# Page 9: Glenohumeral Joint\n\nThis joint represents the articulation between the scapula and the humerus. It is highly mobile and supports a wide range of movements:\n\n* Extension\n* Flexion\n* Abduction\n* Adduction\n* Internal rotation\n* External rotation\n* Circumduction (a conical movement involving a combination of the above).\n\n# Page 10: Ligaments of the Shoulder\n\nThe ligaments surrounding the shoulder serve two primary functional roles:\n\n1. Restrict Movement: They limit the range of motion at the glenohumeral joint to maintain structural integrity.\n2. Prevent Dislocation: They provide essential stability to help prevent the humerus from dislodging from the glenoid cavity of the scapula.\n\n# Page 11: Muscles of the Shoulder\n\nThe shoulder's muscular system is divided into individual major muscles and a functional group known as the rotator cuff:\n\n* Deltoid\n* Teres Major\n* Rotator Cuff Muscles:\n * Supraspinatus\n * Infraspinatus\n * Subscapularis\n * Teres Minor\n\n# Page 12: Deltoid Muscle\n\nThe deltoid muscle is a large, triangular muscle that covers the shoulder joint. It is attached to the acromion, the scapula, and the clavicle. Its primary movements include:\n\n* Flexion\n* Extension\n* Abduction\n\n# Page 13: Teres Major\n\nThe Teres Major is a thick muscle of the shoulder joint. According to the transcript, it is attached to the inferior portion of the clavicle and to the humerus. The movements attributed to this muscle are:\n\n* Abduction\n* Extension\n* Medial rotation of the arm.\n\n# Page 14: Rotator Cuff Muscles\n\nThe rotator cuff is a group of muscles that attach the scapula to the humerus, providing stability and strength to the glenohumeral joint. Their specific movements are as follows:\n\n* Supraspinatus: Facilitates Abduction.\n* Infraspinatus: Facilitates Lateral rotation of the arm.\n* Subscapularis: Facilitates Medial rotation of the arm (located on the anterior aspect).\n* Teres Minor: Facilitates Lateral rotation of the arm (located on the posterior aspect).\n\n# Page 15: Bony Anatomy of the Elbow\n\nThe elbow joint complex is formed by the articulation of $3$ bones:\n\n1. Humerus (the distal end).\n2. Radius (the lateral bone of the forearm).\n3. Ulna (the medial bone of the forearm).\n\n# Page 16: Distal Humerus Articulations\n\nThe distal end of the humerus features specific landmarks for articulation with the forearm bones:\n\n* Capitulum: The capitulum of the humerus articulates with the head of the radius.\n* Trochlear: The trochlear of the humerus articulates with the trochlear notch of the ulna.\n\n# Page 17: Radius\n\nThe radius is the bone on the lateral (thumb) side of the forearm.\n\n* Head of Radius: Articulates with the capitulum of the humerus.\n* Radial Tuberosity: This landmark serves as the attachment point for the biceps tendon.\n\n# Page 18: Ulna and Detailed Forearm Markings\n\nThe ulna is the medial bone of the forearm. Its primary articulation feature is the trochlear notch, located on the anterior aspect of the olecranon, which articulates with the trochlear of the humerus.\n\nKey Landmarks of the Ulna and Radius:\n* Ulnar Structures: Radial notch, Ulnar tuberosity, Shaft of ulna (anterior surface), Interosseous border, Trochlear notch, Olecranon, Styloid process of ulna, Coronoid process, Head of ulna, Posterior border, Medial surface, Posterior surface.\n* Radial Structures: Shaft of radius (anterior surface), Articular circumference, Head of radius, Styloid process (distal end).\n\n# Page 19: Elbow Joint Anatomy (Visual Identification)\n\nThe elbow joint consists of critical landmarks that define its structure when viewed from various angles:\n\n* Lateral Epicondyle (Humerus)\n* Medial Epicondyle (Humerus)\n* Capitellum (also known as the Capitulum)\n* Head of the Radius\n* Ulna\n\n# Page 20: Ligaments of the Elbow\n\nThe elbow joint is stabilized by three primary ligaments:\n\n1. Radial Collateral Ligament (RCL): Attached to the lateral epicondyle of the humerus and the annular ligament.\n2. Annular Ligament (AL): Connected to the RCL and attaches to the proximal radioulnar joint, encircling the head of the radius.\n3. Ulnar Collateral Ligament (UCL): Attaches to the medial epicondyle of the humerus and the olecranon of the ulna.\n\n# Page 21: Muscles of the Elbow\n\nThe muscles acting on the elbow facilitate the bending and straightening of the arm:\n\n* Muscles of Flexion:\n * Biceps\n * Brachialis\n * Brachioradialis\n* Muscle of Extension:\n * Triceps brachii (located on the back of the arm).\n\n# Page 22: Proximal and Distal Radioulnar Joints\n\nThe radius and ulna articulate with each other at two points within the forearm:\n\n* Proximal Radioulnar Joint: The articulation between the radial head and the radial notch of the ulna.\n* Distal Radioulnar Joint: The articulation between the ulna notch of the radius and the ulnar head.\n* Joint Classification: Both are classified as pivot joints.\n* Movement Facilitated: These joints allow for supination (palm up) and pronation (palm down).\n\n# Page 23: Bones of the Hand and Wrist\n\nThere are a total of $27$ bones found in the hand and wrist complex. These are divided into three distinct groups:\n\n1. Carpals\n2. Metacarpals\n3. Phalanges\n\n# Page 24: Carpals\n\nThe carpals form the bones of the wrist. There are $8$ carpal bones arranged in two rows:\n\n* Bones: Hamate, Capitate, Pisiform, Triquetrum, Lunate, Scaphoid, Trapezoid, Trapezium.\n* Joints: Intercarpal joints connect these bones.\n* Classification and Movement: Mostly plane joints that allow for limited sliding movements.\n\n# Page 25: Metacarpals\n\nThe metacarpals are the bones of the palm of the hand.\n\n* Carpometacarpal (CMC) Joints: Joints between the carpals and metacarpals. They are plane synovial joints. The thumb CMC joint is the most flexible.\n* Metacarpophalangeal (MCP) Joints:\n * Commonly known as the knuckles.\n * Classification: Condyloid synovial joints.\n * Movements: Flexion, Extension, Adduction, Abduction, and Rotation (restricted to the thumb only).\n\n# Page 26: Phalanges\n\nThe phalanges are the bones that comprise the fingers.\n\n* Quantity: There are $14$ phalanges in each hand.\n* Classification: The joints between phalanges are hinge joints.\n* Specific Joints:\n * Proximal Interphalangeal Joints (PIP)\n * Distal Interphalangeal Joints (DIP)\n * Interphalangeal Joint of the Thumb\n\n# Page 27: Ligaments of the Wrist (The Carpal Tunnel)\n\nA critical structure in the wrist is the transverse carpal ligament. This ligament forms the roof of the carpal tunnel, a narrow passageway that contains:\n\n* The Median Nerve.\n* $9$ individual tendons.\n* The surrounding carpal bones.\n\n# Page 28: Tendons of the Hand and Wrist\n\nTendons in the hand are classified based on their location and function:\n\n* Extensor Tendons: Located on the dorsum (back) of the hand. They allow for the straightening of the fingers.\n* Flexor Tendons: Located on the palmer (palm) aspect of the hand. They allow the fingers to bend inward.\n\n# Page 29: References\n\n* Tortora, G., (2023). Principles of anatomy and physiology. 16th ed. University of Wolverhampton.","title":"Anatomy and Physiology of the Upper Limb"}