Bones of the Upper Limb 2024.pdf

BONES OF THE UPPER LIMBS Clinical Anatomy School of Laboratory Medicine and Medical Sciences UKZN INSPIRING GREATNESS  OBJECTIVES  Cover the bones of the upper limbs (i.e. scapula, humerus, radius & ulna)  Describe each bone with its fea...

BONES OF THE UPPER LIMBS Clinical Anatomy School of Laboratory Medicine and Medical Sciences UKZN INSPIRING GREATNESS  OBJECTIVES  Cover the bones of the upper limbs (i.e. scapula, humerus, radius & ulna)  Describe each bone with its features and attachments  Include ossification and side determination  LOCATION OF UPPER LIMB BONES Upper limb is connected to the axial skeleton Axial skeleton – skull, vertebral column and thoracic cage Appendicular skeleton is the bones of the upper and lower limb. REGIONS OF THE UPPER LIMBS OSTEOLOGY OF THE UPPER LIMB Shoulder: includes pectoral, deltoid and scapular regions Arm/brachium Forearm/antebrachium Hand includes wrist, palm, dorsum of hand, digits INDIVIDUAL BONES SCAPULA  Thin, triangular and posterolaterally placed. 2 surfaces 3 angles, 3 borders and 3 processes.  OSSIFICATION OF SCAPULA Ossifies from one primary centre and seven secondary centres Appear near glenoid cavity at 8th intrauterine 1st: Appear during first year (middle of coracoid process) 2nd: Appears during 10th year (at root of coracoid) 3-7: Appear at puberty 1st: fuses by 15th year 2nd: fuses by 16-18 years 3 to 7: fuses by 25th year  TWO SURFACES OF SCAPULA Costal surface (or subscapular fossa) Concave Directed medially and forwards Has 3 longitudinal ridges Acts as lever for action of serratus anterior Dorsal surface Attachment for spinous process  Smaller supraspinous fossa  Larger infraspinous fossa  THREE BORDERS OF SCAPULA Superior border Thin & shorter Medial border Presents suprascapular notch next to root of Presents infraglenoid tubercle at upper end Extends from superior to inferior angle. Thin coracoid process Lateral border Thick From Anatomy-Medicine.com  THREE ANGLES OF SCAPULA Superior angle Covered by trapezius muscle Inferior angle Covered by latissimus dorsi From Anatomy-Medicine.com Lateral or glenoid angle Broad, has glenoid cavity  THREE PROCESSES OF SCAPULA Directed forwards and laterally Has a facet for clavicle Divides the dorsal into two fossa  SIDE DETERMINATION Lateral angle (glenoid) large facing laterally and bears glenoid cavity. Lateral border is thickest Dorsal surface is convex with spinous process.  ATTACHMENTS OF THE SCAPULA Coracobrachialis from medial tip Short head of biceps from lateral tip Key: Blue = insertion points Red = origin points LIGAMENT ATTACHMENTS OF THE SCAPULA Suprascapular ligament Suprascapular ligament bridges over suprascapular notch = suprascapular foramen for suprascapular nerve Suprascapular vessels are above this ligament HUMERUS HUMERUS Bone of the arm Longest of the UL bones Has upper end, shaft and lower end  OSSIFICATION OF HUMERUS Ossifies from one primary centre and seven secondary centres Centre for medial epicondyle: appears during 4-6 years Forms separate epiphysis which fuse with shaft at 20th year Appear near middle of diaphysis at 8th intrauterine 1st (for head): Appears at first year 2nd (for greater tubercle): Appears at second year 3rd (for lesser tubercle): Appear at fifth year Fuse at 6th year to form epiphysis of humerus which fuses with shaft at 20th year 1st (for capitulum and lateral flange of trochlea): Appears at first year 2nd (for medial flange of trochlea): Appears at 9th year 3rd (for lateral epicondyle): Appear at 12th year Fuse at 14th year to form epiphysis of humerus which fuses with shaft at 16th year  ENDS OF HUMERUS Upper (Proximal) end Greater and lesser tubercles provide attachment to four rotator cuff muscles Lower (Distal) end Condyles- capitulum (articulates with radius), trochlea ( articulates with ulna) Epicondyles: medial and lateral lies above trochlea and capitulum. Medial epicondyle is prominent and palpable. The ulna nerve passes posterior to medial epicondyle  SHAFT OF HUMERUS 3 Borders 3 Surfaces Posterior surface (not shown in picture) From Jaypee Digital  IMPORTANT FEATURES Surgical neck of humerus- important site clinically as the humerus fractures here commonly. The axillary nerve and posterior circumflex artery (branch of axillary artery) passes posterior to the surgical neck of humerus and can be damaged during fractures in this region ATTACHMENTS TO HUMERUS Contents of intertubercular groove: tendon of long head of biceps & anterior circumflex humeral artery Middle of medial border – insertion for coracobrachialis Anconeus arises from posterior surface of lateral epicondyle  SIDE DETERMINATION Upper end rounded to form head Head is directed medially and backwards Lower end is expanded and flattened Lesser tubercle projects from upper end and limited by intertubercular groove laterally.  Greater and lesser tubercles provide attachment to four rotator cuff muscles (i.e. SSIT) These muscles are important for stabilizing the shoulder joint  Intertubercular sulcus (bicipital groove)- lies between two tubercles Lateral and medial lips of sulcus provide attachment for pectoralis major and teres major respectively Lateral lip continues inferiorly as deltoid tuberosity- deltoid muscle attachment RADIUS  RADIUS Lateral bone of forearm (homologous with tibia in LL) Has upper end, shaft and lower end. UPPER END:  Head- disc shaped, neck-short and narrow, radial tuberosity- attachment of biceps brachii SHAFT (has 3 borders and 3 surfaces) is triangular in cross section Anterior and posterior surfaces are smooth LOWER END: Laterally- radial styloid process  SHAFT OF RADIUS 3 Borders 3 Surfaces Posterior surface (not shown in picture) Anterior border: Has anterior oblique line Medial or Interosseous border: Has interosseous membrane Has nutrient foramen Posterior border: Has posterior oblique line From Jaypee Digital  OSSIFICATION OF RADIUS Ossifies from one primary centre and two secondary centres For shaft: appears at 8th intrauterine For lower end: appears during first year Fuses at 20 years (it is the growing end of the bone) For upper end: appears during 4th year Fuses at 18 years  SIDE DETERMINATION Smaller circular and upper end rounded is concave Constricted neck just below head and has radial tuberosity below it. Styloid process on lateral aspect. Interosseous border is thin and sharp. ATTACHMENTS TO RADIUS ULNA  ULNA Medial bone of forearm (homologous with fibula in LL) Has upper end, shaft and lower end. UPPER (PROXIMAL) END SHAFT-TRIANGULAR LOWER (DISTAL) END (NARROWER)  SHAFT OF ULNA 3 Borders 3 Surfaces Posterior surface (not shown in picture) Anterior border: Thick and rounded Lateral or Interosseous border: Has interosseous membrane Continuous with supinator crest Has nutrient foramen Posterior border: Subcutaneous  OSSIFICATION OF ULNA Ossifies from one primary centre and two secondary centres For shaft and most of upper end: appears at 8th intrauterine For superior part of olecranon: appears during 10th year Fuses by 16 years with the rest of the bone For lower end: appears during 5th year Fuses with shaft by 18 years (it is the growing end of the bone)  SIDE DETERMINATION Upper end is hook-like Lateral border is sharp an crest-like Pointed styloid process lies medial to rounded head of ulna ATTACHMENTS TO ULNA  Please direct to [email protected] via Learn platform or direct email.