Upper Limb Anatomy: Osteology and Articulations

• Focus is on anatomy and the osteology and articulations of the upper limb

Division of the Upper Limb

• The upper limb is divided into 4 segments:
• The Scapular girdle; which is the root of the upper member and is the link to the trunk
• Scapula
• Clavicle
• Arm, the space between the shoulder and elbow
• Humerus
• Forearm which is the space between the elbow and wrist
• Cubit or Ulna, medial. Oriented towards the little finger
• Radius, lateral. Oriented towards the thumb
• Hand
• Proximal part of the hand (carpus) consists of 8 bones united to each other
• Palm of the hand (metacarpus) consists of 5 parallel bones
• Fingers
• Lateral Pollux, performs opposition movement and is independent with 2 phalanges
• Fingers 2-5 has 3 phalanges that function as a single unit
• Phalanges can be
• Proximal which is near the root or close to the scapular girdle
• Middle
• Distal which is further from the root of the member or further from the scapular girdle
• Each bone is paired; one right and one left

Scapular Girdle

• Osteology of Clavicle
• Flat "S" shaped bone
• Superior face is smooth
• Anterior and posterior borders are smooth
• Inferior face from medial to lateral
• Costal tuberosity
• Subclavian groove
• Conoid tubercle
• Trapezoid line
• Sternal end is medial and voluminous and inserts into the sternum
• Acromial end is lateral and flattened
• Position the conoid tubercle inferiorly, laterally and posteriorly with the sternal end towards the center
• Osteology of Scapula
• Irregular shaped bone in the form of a triangle
• Borders
• Superior
• Medial
• Lateral
• Angles
• Superior (1)
• Inferior (2)
• Lateral (3), articulates with the humerus and has bony prominences - Glenoid Cavity which articulates with the humeral head - Lateral Concavity - Covered in articular cartilage - Glenoid Labrum around - Supraglenoid tubercle attachment of the biceps brachii - Infraglenoid tubercle
• Coracoid apophysis - Finger shaped - Under the clavicle - Insertion for the muscle and ligaments
• Acromion - Lateral continuation of spine - Medial surface which articulates with the clavicle
• Anterior face of the scapula has a smooth subscapular fossa over the ribs
• Posterior face makes contact with the skin
• Eminence of scapular spine - Supraspinous fossa - Infraspinous fossa

Articular System

• Sternoclavicular Joint
• Saddle joint with 2 degrees of freedom
• Capable of elevation, depression, circumduction, protraction, and retraction
• Articular faces
• Clavicle
• Clavicular notch which is concave from anterior to posterior and convex from superior to inferior
• Sternum first costal cartilage
• Ligaments
• Costoclavicular ligament from the 1st costal cartilage and 1st rib to the costoclavicular tubercle
• Interclavicular ligament covering the jugular notch and joining the clavicles
• Anterior sternoclavicular ligament joining the clavicle and manubrium in the front, reinforces the capsule in the front
• Posterior sternoclavicular ligament which reinforces the capsule from above
• Intrinsic fibers of the capsule - anterior sternoclavicular ligament, can also be posterior
• Acromioclavicular Joint
• Arthrodial (plane) which usually has a meniscus or disc
• Articular faces
• Acromial end of the clavicle is oval
• Acromial face of the scapula is oval
• Coracoclavicular ligaments which unite the clavicle and scapula from the superior face of the coracoid to the inferior face of the clavicle
• Trapezoid ligament from the coracoid to the trapezoid line which is anterior to the conoid ligament
• Conoid ligament from the coracoid to the conoid tubercle
• Acromioclavicular ligament that reinforces the capsule from above
• Proper Scapular Ligaments which joint the different parts of the scapula to allow passage of other structures
• Superior Transverse ligament which closes the scapular notch on the upper border of the scapula
• Suprascapular nerve passes in front of the ligament
• Suprascapular artery passages behind the ligament
• Inferior Transverse Ligament from the lateral border of the spine to the posterior border of the glenoid cavity
• Suprascapular nerve and suprascapular artery between here and the notch
• Coracoacromial ligament from the coracoid to the acromion
• Scapulothoracic Joint
• NOT a true articulation, it is simply a plane where the scapula slides
• Elevation
• Depression
• Retropulsion - scapula moves medially and the arm moves forward
• Antepulsion - scapula moves laterally and the arm moves back
• BAsiculation; where the serratus anterior moves the inferior angle laterally; this movement orients the glenoid cavity superiorly
• Parts
• Subscapular Muscle
• Serratus Anterior Muscle
• Omoserratus is the space between the omoplate and serratus anterior
• Serratothoracic space

Arm

• Humerus: Long bone with 2 epiphysis consisting of a proximal and distal and one diaphysis
• Diaphysis
• Radial groove, posterior face
• Bicipital groove, anterior face
• Proximal Epiphysis
• Greater tubercle (trochiter) which is lateral used for muscle insertion continues as the lateral crest of the bicipital groove
• Lesser tubercle which is inferior to the greater tubercle used for subscapular insertion and whose inferior continuation is the medial crest of the bicipital groove
• Humeral head which is covered in cartilage with superior, posterior and medial orientation and articulates with glenoid cavity of the shoulder
• Anatomical neck between the head and tubercles that terminates the articular cartilage
• Surgical neck marks imaginary line that divides the tubercles and diaphysis, there are circumflex arteries and the axillary nerve
• Distal Epiphysis
• Lateral epicondyle is the bony eminence for insertion of muscles and ligaments
• Medial epicondyle is the bony eminence for insertion of muscles and ligaments; this projection is larger and posterior to it is a groove for the ulnar nerve
• Supracondylar crests which are medial and lateral above the epicondyles
• Capitulo-trochlear groove between the capitulum and trochlea is a conoid zone
• Coronoid fossa on the anterior face above the trochlea or head of the radius when flexed
• Radial fossa on the anterior face above the capitulum where the radio head fits in flexion
• Olecranon fossa is a posterior face above the trochlea for the ulna (cubit in extension)
• Articular surfaces are cartilage for forearm bones that form elbow
• Trochlea in shape of a pulley with the medial part sloping further down for the ulna
• Capitulum spherical and condylar for the radius
• Transverse Cut is triangular in shape
• Faces
• Posterior
• Radial groove for radial nerve and deep brachial artery laterally for the lateral head of the triceps and medially for the medial head of the triceps
• Anterolateral
• Deltoid tuberosity insertion for the deltoid
• Smooth surface for brachial insertion
• Anteromedial
• End of the intertubercular groove
• Insertion for the coracobrachialis
• Smooth surface for the brachialis

Forearm

• Ulna Bone
• The Ulna or Cubit is a Medial bone that more voluminous proximally
• Diaphysis has ulnar tuberosity
• Proximal epiphysis
• Trochlear notch is superior to the olecranon and inferior to the coronoid apophysis
• Olecranon is a vertical apophysis with articular cartilage on its anterior face
• Coronoid apophysis is horizontal with articular cartilage on its superior face and has a radial notch of the ulna and supinator crest
• Distal Epiphysis
• Head of the ulna with cartilage laterally
• Ulnar styloid process is medial and posterior to the head, above it is the insertion of the carpal ligament
• Radius
• The Radius is a lateral bone more voluminous distally
• Lateral face has a pronator crest
• Proximal epiphysis
• Head is oval shaped with smooth surface and articulates with the capitulum of the humerus
• Neck is oblique caudally and medially
• Radial tuberosity is between the neck and body, and on the anteromedial side the biceps brachii inserts
• Distal Epiphysis
• Anterior face is smooth and concave
• Inferior face is divided by a crest
• Lateral is for the scaphoid bone
• Medial is for the semilunar bone
• Posterior face is rough with the dorsal tubercle and grove of the carpal extensor tendons
• Lateral face has the radial styloid process which articulates with the carpal side of the biceps brachii ligament
• Medial face has the ulnar notch for the ulna head

Shoulder Articulation

• The glenohumeral or scapulohumeral joint
• Enarthrosis (ball and socket joint)
• Articular faces
• Humeral head covered in cartilage, in cranial, medial and posterior direction
• Glenoid cavity lined with cartilage towards the caudal, lateral and anterior direction
• Glenoid Labrum, or fibrocartilaginous ring. Ring of cartilage that covers or surrounds the glenoid notch to facilitate articular coupling and increase the surface area of contact
• Union Mediums that allow for very lax movement
• Articular capsule is very lax
• Scapular insertion on the glenoid cavity
• Humeral insertion on the anatomical part of the neck but not inferior face
• Indirect Mediums
• Long head of biceps tendon that enters in the articulation through protection of the bicipital canal and synovial sheath
• Transverse Humeral Ligament that joins humeral tubercles and covers the exiting long head of the biceps
• Ligaments
• Glenohumeral; intrinsic on anterior surface, tense in lateral rotation and relaxation in medial rotation
• Coracohumeral; unites coracoids and humerus (upper part of the shoulder). It extends from the subscapularis tendon to the supraspinatus tendon.

Rotator Cuff

• Several openings: oval window, subcoracoid window,
• Rotator Cuff: Tendons of the supraspinatus, infraspinatus, teres minor, and subscapularis protect the glenohumeral joint from dislocation

Elbow

• It describes the effect of movements on the functional complex as described by the resistance to muscle contractions during movement
• Active Flexion - volume occupied by muscle is larger which result in less flexion
• Passive Flexion - volume occupied by muscle is compressed, which results in more flexion
• Extension is the tension of anterior components
• Flexion is the tension of posterior components

Elbow Articulations

• The 3 articulations that form the articular complex along with the joint capsules, articular cavity, and the ligaments.

1. Humero-cubital is a trochlear joint (ginglymus) between trochlea and trochlear notch for flexion and extension
2. Humero-radial is an enarthrosis between the humeral head and capitulum for movement of the other 2 articulations
3. Radio-cubital is a proximal trochoid between the articular circumference of the radius and the radial notch for pronation and supination -Articular Surfaces

• The humerus consist of the trochlea, the condyle, and the capitular-trochlear groove
• The Cubit or Ulna is made of the trochlear notch
• The head of the radium and the annular ligament
• Union Mediums
• Articular capsule
• Cranial limit to the coronoid, radial, ulnar fossa and epicondyle bones
• The caudal limit is the neck of the radium, the coronoid apophysis, and the radial notch
• Synovial Membrane coats the deep face
• Intrinsic Ligaments
• There is an anterior ligament that connects the medial epicondyle to the annular ligament
• Posterior Ligaments
• Radial Collateral Ligaments: connects lateral humeral epicondyle with the radial annular ligament
• Ulnar Collateral Ligaments which connects medial humeral epicondyle with the ulna

Radio Ulna Articulations

• Radius connects to neck, is connected to the capitulum of the humerus and allows:
  • pronation
  • supination
• It describes ligamentum Teres that connect humerus, radius, and ulna that allows:
• flexion with varying degrees.
• Radio ulnar distal: articulation to the cubital allows for:
  • Trochoid Surfaces
  • Articular
    • Head in cubital
    • Cubital anterior to articulation
    • Radius movement of adduction

Wrist Joint Complex

• Consist of the wrist bones within single the capsule: I) - Radio-carpiana II) - Intercarpiana III) - carpometacarpal IV) - intermetacarpal

Radio-Carpal Joint

• Union in antebrachium and carpal bones where triangular ligaments are in a pyramidal shape
• Condyle of Carpal consist of cartilage in the proximal and radioulnar directions
• Ligaments Interosseous
• Articulation with the anteriors in the:
  • Radioulnar joints in a palmar orientation to the large carpals
  • cubitocarpal in a plamar orientation to the large carpals

Intercarpal Articulations

• Joints connect bones, 3 ligaments in an articular direction
  • dorsal direction
  • palmar direction
  • interosseous direction
• mid carpal : -summation of carpals in the same direction:
• Radiate joint from the proximal limiting dorsal flexions joint

Metacarpalphalangeal Joints

• The 5 metacarpals connect to the dorsal, and palmar bones
• the 2-5 unit of metacarpal function is the 1st that allows abductions and adductions and is independent functions

Digits of hands

• Metacarpals are small bones
• The articulation of metacarpals convex to the proximal area
• articulations wIth adyacent carpals

Carpal Ligaments

• Trapezium shape for carpal articlar
• Abduction of the 1 joint
• Distal from trapezium, trapezoideum

Metacarpals

• Each bone articulate withe carpal
• Short in width.
• lateral articulates
• mid articulated allows
• Distal for medial articulations

Motion on the hand

• Abduction 3
• adduction proximla 3

Arches in palmar of hand

• Proximal side in flexion the palm
• Ligments on palmar side of hand for motion on the palmar side.
• Transverse carpal: uniton on the palmar side of the hand allows motion and joint movement.

Explore the anatomy of the upper limb, focusing on osteology and articulations. This lesson covers the scapular girdle, arm, forearm, and hand, detailing the bones and their arrangements. Understand the structure and function of the upper limb.