Ostéologie du membre thoracique

• Module 5 focuses on the anatomy of specialities in medicine and kinesitherapy, specifically osteology of the thoracic limb.

SKELETON OF THE UPPER LIMB

• The upper limb skeleton is also referred to as the thoracic limb.
• It is part of the appendicular skeleton.
• It is attached to the scapular girdle, which comprises the scapula and clavicle.
• This limb is specialized for grasping (prehension) due to bipedal posture.
• This makes it somewhat fragile and prone to traumas.

COMPOSITION OF THE UPPER LIMB SKELETON

• The arm consists of a single long bone: the humerus.
• The forearm consists of a pair of long bones: the radius (lateral) and ulna (medial).
• The radius and ulna are not parallel but curved.
• They allow relative rotation during pronosupination.
• Fractures of these bones require treatment to maintain their curvature for proper pronosupination.
• The wrist and hand skeleton consist of the carpus, metacarpals, and phalanges.
• The carpus is an assembly of 8 short bones forming the wrist.
• The metacarpals form the skeleton of the hand.
• The phalanges form the bones of the fingers.

CLAVICLE

• The clavicle is a long bone.
• It is superficial, making it prone to fractures, especially in sports accidents.
• In anterior view, it appears ventral and straight.
• In superior view, it has an "S" shape.
• It forms the sterno-costo-clavicular joint: articulating with the manubrium sterni and first costal cartilage.
• This medial end is voluminous representing the only direct bony attachment of the upper limb to the thorax.
• The lateral (acromial) end forms the acromioclavicular joint.
• It articulates with the acromion of the scapula and is flattened.
• It has an oval articular surface facing downwards and laterally.

SCAPULA

• The scapula is a flat, triangular bone.
• It has two faces and three borders: superior, medial, and lateral.
• Three angles: superior, inferior, and lateral.
• It is linked to the thoracic cage via a muscular junction without a conventional articulation.

SCAPULA FACES

• The ventral (costal) face is concave, forming the subscapular fossa, and molds to the thoracic cage.
• The dorsal face features the spine of the scapula, dividing it into the supraspinous and infraspinous fossae.
• The spine of the scapula is a perpendicular extension on the superior third of the scapula, prolonged by the acromion which extends dorsally and laterally.
• The acromion articulates with the lateral end of the clavicle and the spine is divided in two parts.
• The supraspinous fossa lies above the spine.
• The infraspinous fossa lies below the spine.
• These fossae accommodate several shoulder muscles.

SCAPULA STRUCTURES ON LATERAL ANGLE

• The coracoid process is hook-shaped, projecting laterally and downwards.
• The insertion of the coracoid process is bordered by the scapular notch and closed by a ligament, through which a nerve passes.
• The glenoid cavity has an oval articular surface coated with cartilage, oriented forward, upward, and laterally, forming the scapulohumeral joint.
• It articulates with the head of the humerus, providing significant shoulder mobility.
• It works synergistically with the sternocostoclavicular joint and the scapulothoracic junction.
• It is connected to the rest of the scapula by a narrow neck.

HUMERUS PROXIMAL EPIPHYSIS

• The humeral head has a cartilage-covered articular surface, representing 1/3 of a sphere.
• It articulates with the glenoid cavity of the scapula, points upwards, medially, and backwards.
• It aligns within a 30 mm radius sphere and forms a 130° angle with the diaphyseal axis.
• The shaft must be intact when performing surgical interventions to conserve the function of the scapulohumeral articulation.
• The anatomical neck separates the humeral head from the tubercles.
• The greater tubercle is located on the lateral surface of the humerus being visible on both ventral and dorsal faces.
• The lesser tubercle is located on the anterior surface of the humerus, and is only visible on the ventral side.
• The tubercles are the insertion points for muscles.
• The intertubercular groove is a groove limited by the two tubercles through which the long head tendon of the biceps brachii passes.

HUMERUS METAPHYSIS

• The metaphysis separates the proximal epiphysis from the diaphysis and includes the surgical neck.
• The zone of bone growth occurs at the surgical neck.

HUMERUS DIAPHYSIS

• The diaphysis has a triangular cross-section.
• It has three borders and faces, with its dorsal face being oblique in a downwards and lateral direction.
• It features the radial nerve groove, which is responsible for extending the arm and hand.
• Radial paralysis can occur following a diaphyseal fracture of the humerus.

HUMERUS DISTAL EPIPHYSIS

• The distal epiphysis is flattened
• It has several reliefs including the humeral condyle, which has an articular surface covered with cartilage.
• The epicondyles are medial and lateral projections surmounting the condyle, which serve as insertion points for muscles and ligaments.
• Epicondylitis is a painful inflammatory condition secondary to repetitive movements, like tennis elbow.

PARTS HUMERAL CONDYLE

• The capitulum is lateral and hemispherical, continuous with the radial fossa, and forms the humeroradial joint by articulating with the articular fovea of the radius.
• The capitulotrochlear zone is situated between the capitulum and trochlea being present only on the anterior face of the humerus.
• The trochlea is medial, pulley-shaped and present on the ventral and dorsal aspects of the humerus featuring two fossae: the coronoid and olecranon fossae.
• These two fossae helps avoid bone bumping during the bend/extension movements of the elbow, which forms the humeroulnar joint by articulating with the trochlear notch of the ulna.

RADIUS PROXIMAL EPIPHYSIS

• The radial head is situated on the superior surface, cup-shaped that forms the humeroradial joint through articulation.
• It articulates with the capitulum of humerus and cylindrical through the radio-ulnar proximal articulation and annular ligament on the elbow.
• It is surrounded by the radial circumference through the ulnar notch.
• The radial neck is a constricted zone separating the radial head from the bicipital tuberosity.
• The bicipital tuberosity faces dorsally and medially, serving as the insertion point for the biceps brachii muscle, the main flexor of the elbow.

RADIUS DIAPHYSIS

• The diaphysis is triangular in shape, featuring the interosseous border and anterios border.
• The Interosseous border inserts the interosseous membrane and connects it to the ulna.

RADIUS DISTAL EPIPHYSIS

• The distal epiphysis is quadrangular in shape, where the radius widens distally.
• Its lateral face extends to form the styloid process.
• The medial face presents the ulnar notch, which forms the distal radioulnar joint in contact with the head of the ulna.
• The anterior and posterior faces bear grooves for tendons.
• The inferior face is smooth, widening to articulate with the carpal bones.
• This face is divided into two by a sagittal crest with which the scaphoid articulates to connect to the lunate.

ULNA PROXIMAL EPIPHYSIS

• The olecranon and coronoid process compose its structure and the ulnar tuberosity and notch.
• The olecranon is placed dorsally and prolongs the posterior border of the diaphysis representing another additional formation of the diaphysis that is connected to the ulna.
• The coronoid process lies on the anterior face of the proximal epiphysis, which inserts muscles and articulates surfaces.
• The trochlear notch articulates with the humerus forming the humeroulnar and ulnar joints.
• The radial notch is laterally carried out by the coronoid formation of distal radioulnar proximal articulation.

ULNA DIAPHYSIS

• The body of the ulna is triangular in shape that curves and extends to the interosseous membrane, where inserts onto and links the ulna to the radius.

ULNA DISTAL EPIPHYSIS

• It is covered with cartilage on the sides to form the distal ulnar articulation surface.
• It also presents the radioulnar articulation, articulating with the ulnar notch of the radius.
• The ulnar styloid process is positioned dorsally and medially, where practical application is applied for the fracture of the arms (styloid radial).

UPPER LIMB JOINTS

• There are three articular joints of the elbow.
• Capitulum for the humeroradial joint.
• The trochlea for the humeroulnar joint.
• Circumference of the radial head for the radioulnar joint.

MEMBRANE OF THE WRIST AND HAND

• The function of the hand is to prehend the surrounding objects.
• The arrangement of the bones are in the carpus, metacarpus, and phalanges.
• Proximal row: scaphoid, lunate, triquetrum, and pisiform.
• Distal row: hamatum, capitatum, trapezoid, and trapezium.
• The bases, bodies, and heads are composed of bone.
• The os of the carpe articulates with the proximinal os, metacarpals of distal side.
• The metacarpals of the carpe articulates with the proximinal side, phalanges of the distal end.
• The phalanges articulates with the metacarpals of the proximinal side.

CARPE

• Carpus is in between the forearms and the hand that consist of eight arranged bones from the proximinal or the distal locations.
• The distal location are proximinal with four bones
• The first four bone in the wrist creates the proximal location bones.
• It consist cartilage to form ellipsoidal shaped wrist.
• It consist the tubercles form by the trapezoid, and scaphiod.
• Pisforme and hamatum are inserted from the hamulus and the retinaculum which allow for muscle flexor to attach.

CANAL CARPIEN

• It is a throughway that passes in the proximinal throughway where the groove is ventral concave made of bones and is protected by a retinaculum of the flexors.
• Canal carpien allows flexor tendons and surrounding median nerves to be involved in motion and sensitivity.
• Compresssion causes carpal tunnel syndrome that is linked sensitivty that releases nerves and opens retnaculum to relieve nerve endings.

MÉTACARPES

• This has cuboid bases and shafts with a three edge triangle.
• Cartilage with rounded heads that is in the base that is linked to flexor.

SKELETON OF THE TOES

• Composed of I-V, where 1 is the thumb and V is the last toe.
• Consist of 3 phalanx types: proxminal, intermediate, and distal.
• Has 2 types with a proximal and a distal, with base as a base from a semi cyindrical shape.
• Plane is articulated with the head of a bone for its structure.