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First book, 1

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suprascapular vessels lie above the ligament (Fig. 2.10)., 23 The spinoglenoid ligament may bridge the, spinoglenoid notch. The suprascapular vessels and, nerve pass deep to it (Fig. 10.3)., HUMERUS, The humerus is the bone of the arm. It is the longest, bone of the upper limb. It has an upper end, a lower, end and a shaft (Figs 2.13 and 2.14)., OSSIFICATION, The scapula ossifies from one primary centre and, seven secondary centres. The primary centre appears, near the glenoid cavity during the eighth week of, development. The first secondary centre appears in, the middle of the coracoid process during the first, year and fuses by the 15th year. The subcoracoid, centre appears in the root of the coracoid process, during the 10th year and fuses by the 16th to 18th, years (Fig. 2.11). The other centres, including two for, Side Determination, 1 The upper end is rounded to form the head. The, lower end is expanded from side to side and flattened, from before backwards., 2 The head is directed medially, upwards and, backwards., 3 The lesser tubercle projects from the front of the, upper end and is limited laterally by the, intertubercular sulcus or bicipital groove., 12, UPPER LIMB, For subcoracoid centre:, Appearance-1Oth year, Fusion-16th to, 18th year (2), For coracoid process:, Appearance-1st year, Fusion-15th year (1), Two for acromion (3 and 4), Appearance-puberty, Fusion-25th year, For part of glenoid cavity (5), Primary centre during, 8th week of intrauterine life, Medial border (6), Appearance-puberty, Fusion-25th year, Inferior angle (7), Fig. 2.11: Ossification of scapula, Hole in capsule, Greater tubercle, Lesser tubercle, Anatomical neck, Head, Capsular line, Medial lip, Intertubercular sulcus, Lateral lip, Deltoid tuberosity, Medial border, Nutrient foramen, Anterior border, Anterolateral surface, Anteromedial surface, Fig. 2.12: Winging of right scapula, Lateral supra-, condyiar ridge, Coronoid fossa, Radial fossa-, Medial supracondylar, ridge, Features, Lateral epicondyle, Medial epicondyie, Upper End, 1 The head is directed medially, backwards and, upwards. It articulates with the glenoid cavity of the, scapula to form the shoulder joint. The head forms, about one-third of a sphere and is much larger than, the glenoid cavity., 2 The line separating the head from the rest of the, upper end is called the anatomical neck., 3 The lesser tubercle (Latin lump) is an elevation on the, anterior aspect of the upper end (Fig. 2.13)., 4 The greater tubercle is an elevation that forms the, lateral part of the upper end. Its posterior aspect is, marked by three impressions-upper, middle and, lower., 5 The intertubercular sulcus or bicipital groove separates, the lesser tubercle medially from the anterior part of, the greater tubercle. The sulcus has medial and lateral, Capitulum-, Trochlea and its medial, edge, Fig. 2.13: General features of right humerus seen from front, lips that represent downward prolongations of the, lesser and greater tubercles., 6 The narrow line separating the upper end of the, humerus from the shaft is called the surgical neck, (Fig. 2.14)., 7 Morphological neck lies 0.5 cm above surgical neck;, shows the position of epiphyseal line (Fig. 2.14)., Shaft, The shaft is rounded in the upper half and triangular, in the lower half. It has three borders and three surfaces., 2, Section 1 Upper Limb, Section 1 Upper Limb

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BONES OF UPPER LIMB, 13, 3 The posterior surface lies between the medial and, lateral borders. Its upper part is marked by an, oblique ridge. The middle one-third is crossed by, the radial groove (Fig. 2.14)., Head covered with, articular cartilage, Anatomical neck, Capsular line, Epiphyseal line, Surgical neck, Morphological, neck, Lower End, The lower end of the humerus forms the condyle which, is expanded from side to side, and has articular and, nonarticular parts. The articular part includes the, following., 1 The capitulum (Latin little head) is a rounded, projection which articulates with the head of the, radius (Fig. 2.13)., 2 The trochlea (Greek pulley) is a pulley-shaped surface., It articulates with the trochlear notch of the ulna. The, medial edge of the trochlea projects down 6 mm more, than the lateral edge: This results in the formation of, the carrying angle (Fig. 2.13)., The nonarticular part includes the following., 1 The medial epicondyle is a prominent bony projection, on the medial side of the lower end. It is, subcutaneous and is easily felt on the medial side of, the elbow (Fig. 2.13)., 2 The lateral epicondyle is smaller than the medial, epicondyle. Its anterolateral part has a muscular, impression., 3 The sharp lateral margin just above the lower end is, called the lateral supracondylar ridge., 4 The medial supracondylar ridge is a similar ridge on, the medial side., 5 The coronoid fossa is a depression just above the, anterior aspect of the trochlea. It accommodates the, coronoid process of the ulna when the elbow is flexed, (Fig. 2.13)., 6 The radial fossa is a depression present just above the, anterior aspect of the capitulum. It accommodates, the head of the radius when the elbow is flexed., 7 The olecranon (Greek ulna head) fossa lies just above, the posterior aspect of the trochlea. It accommodates, the olecranon process of the ulna when the elbow is, extended (Fig. 2.14)., Oblique ridge, Groove for radial nerve, Deltoid tuberosity, Medial border, Lateral border, Olecranon fossa, Epiphyseal line of, medial epicondyle, Fig. 2.14: Features of right humerus seen from behind, Borders, 1 The upper one-third of the anterior border forms the, lateral lip of the intertubercular sulcus. In its middle, part, it forms the anterior margin of the deltoid, tuberosity. The lower half of the anterior border is, smooth and rounded., 2 The lateral border is prominent only at the lower end, where it forms the lateral supracondylar ridge. In the, upper part, it is barely traceable up to the posterior, surface of the greater tubercle. In the middle part, it, is interrupted by the radial or spiral groove (Fig. 2.13)., 3 The upper part of the medial border forms the medial, lip of the intertubercular sulcus. About its middle it, presents a rough strip. It is continuous below with, the medial supracondylar ridge., Surfaces, Attachments, 1 The anterolateral surface lies between the anterior and, lateral borders. The upper half of this surface is, covered by the deltoid. A little above the middle it is, marked by a V-shaped deltoid (Greek triangular, shaped) tuberosity. Behind the deltoid tuberosity the, radial groove runs downwards and forwards across, the surface., 1 The multipennate subscapularis is inserted into the, lesser tubercle (Fig. 2.15)., 2 The supraspinatus is inserted into the uppermost, impression on the greater tubercle., 3 The infraspinatus is inserted into the middle, impression on the greater tubercle (Fig. 2.16)., 4 The teres minor is inserted into the lower impression, on the greater tubercle (Fig. 2.16)., 5 The pectoralis major is inserted into the lateral lip of, the intertubercular sulcus. The insertion is bilaminar, (Fig. 2.15)., 2 The anteromedial surface lies between the anterior and, medial borders. Its upper one-third is narrow and, forms the floor of the intertubercular sulcus. A, nutrient foramen is seen on this surface in its middle,, near the medial border (Fig. 2.13)., 3, Section 1 Upper Limb

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14, UPPER LIMB, 6 The latissimus dorsi is inserted into the floor of the, intertubercular sulcus., 7 The teres major is inserted into the medial lip of the, intertubercular sulcus., 8 The contents of the intertubercular sulcus are:, a. The tendon of the long head of the biceps brachii, and, its synovial sheath., b. The ascending branch of the anterior circumflex, humeral artery., 9 The deltoid is inserted into the deltoid tuberosity, (Fig. 2.15)., 10 The coracobrachialis is inserted into the rough area, on the middle of the medial border., 11 The brachialis arises from the lower halves of the, anteromedial and anterolateral surfaces of the shaft., Part of the area extends onto the posterior aspect, (Fig. 2.15)., 12 The brachioradialis arises from the upper two-thirds, of the lateral supracondylar ridge (Fig. 2.15)., 13 The extensor carpi radialis longus arises from the lower, one-third of the lateral supracondylar ridge (Fig. 2.15)., 14 The pronator teres (humeral head) arises from the lower, one-third of the medial supracondylar ridge (Fig. 2.15)., 15 The superficial flexor muscles of the forearm arise by a, common origin from the anterior aspect of the medial, epicondyle. This is called the common flexor origin., 16 The superficial extensor muscles of the forearm and, supinator have a common origin from the lateral, epicondyle. This is called the common extensor, origin (Fig. 2.15)., 17 The anconeus (Greek elbow) arises from the posterior, surface of the lateral epicondyle (Fig. 2.16)., 18 Lateral head of triceps brachii arises from oblique, ridge on the upper part of posterior surface above, the radial groove, while its medial head arises from, posterior surface below the radial groove (Fig. 2.16)., 19 The capsular ligament of the shoulder joint is attached, to the anatomical neck except on the medial side, where the line of attachment dips down by about, two centimetres to include a small area of the shaft, Supraspinatus, Head, Subscapularis, (lesser tubercle), Capsular ligament, of shoulder joint, Latissimus dorsi, Pectoralis major, Teres major, Medial head of, triceps brachi, Deltoid, Coracobrachialis, Brachialis, Brachioradialis, Capsular ligament, of elbow, Radial fossa, Pronator teres, Extensor carpi radialis, longus, Coronoid fossa, Common extensor origin, Common flexor origin, Trochlea, Capitulum, Fig. 2.15: Attachments of right humerus: Anterior view, Greater tubercle, Head, Supraspinatus, Infraspinatus, Capsular ligament, of shoulder joint, Teres minor, Lateral head of, triceps brachii, Radial groove, Medial head of, Deltoid, triceps brachi, within the joint cavity. The line is interrupted at the, intertubercular sulcus to provide an aperture, through which the tendon of the long head of the, biceps brachii leaves the joint cavity (Fig. 2.13)., 20 The capsular ligament of the elbow joint is attached to, the lower end along a line that reaches the upper, limits of the radial and coronoid fossae anteriorly;, and of the olecranon fossa posteriorly; so that these, fossae lie within the joint cavity. Medially, the line, of attachment passes between the medial epicondyle, and the trochlea. On the lateral side, it passes, between the lateral epicondyle and the capitulum, (Figs 2.15 and 2.16)., 21 Three nerves are directly related to the humerus and, are, therefore, liable to injury: The axillary at the, Brachialis, Olecranon fossa, Capsular ligament-, of elbow, Anconeus, Fig. 2.16: Attachments of right humerus: Posterior view, 4, Section 1 Upper Limb

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BONES OF UPPER LIMB, 15, CLINICAL ANATOMY, • The common sites of fracture of humerus are the, surgical neck, the shaft, and the supracondylar, region., Supracondylar fracture is common in young age. It, is produced by a fall on the outstretched hand., The lower fragment is mostly displaced, backwards, so that the elbow is unduly prominent,, as in dislocation of the elbow joint. This fracture, may cause injury to the median nerve. It may also, lead to Volkmann's ischaemic contracture caused by, occlusion of the brachial artery (Fig. 2.18)., The three bony points of the normal elbow form, the equilateral triangle in a flexed elbow and are, in one line in an extended elbow (Fig. 2.19)., • The humerus has a poor blood supply at the, junction of its upper and middle thirds. Fractures, at this site show delayed union or nonunion., • The head of the humerus commonly dislocates, inferiorly (Fig. 2.20)., Axillary-, Deltoid muscle, Deltoid tuberosity, Radial nerve, Uinar-, Olecranon fossa, RADIUS, Fig. 2.17: Relation of axillary, radial and ulnar nerves to the back, of humerus, The radius is the lateral bone of the forearm, and is, homologous with the tibia of the lower limb. It has an, upper end, a lower end and a shaft., surgical neck, the radial at the radial groove, and the, ulnar behind the medial epicondyle (Fig. 2.17)., Side Determination, 1 Upper end is having disc shaped head while lower, end is expanded with a styloid process., 2 At the lower end, the anterior surface is in the form, of thick prominent ridge. While the posterior surface, presents four grooves for the extensor tendons., 3 The sharpest border of the shaft is the medial border., Close to neck it presents a radial tuberosity., 4 Lower end presents a tubercle on the posterior, surface called as dorsal tubercle of Lister., OSSIFICATION, The humerus ossifies from one primary centre and, 7 secondary centres. The primary centre appears in, the middle of the diaphysis during the 8th week of, development (Table 2.1)., The upper end ossifies from 3 secondary centres-, one for the head (first year), one for the greater, tubercle (second year), and one for the lesser tubercle, (fifth year). The 3 centres fuse together during the, sixth year to form one epiphysis, which fuses with, the shaft during the 20th year. The epiphyseal line, encircles the bone at the level of the lowest margin, of the head. This is the growing end of the bone, (remember that the nutrient foramen is always, directed away from the growing end)., The lower end ossifies from 4 centres which form, Features, 2 epiphyses. The centres include one for the, capitulum and the lateral flange of the trochlea (first, year), one for the medial flange of the trochlea (9th, year), and one for the lateral epicondyle (12th year):, All three fuse during the 14th year to form one, epiphysis, which fuses with the shaft at about 16, years. The centre for the medial epicondyle appears, during 4-6 years, forms a separate epiphysis, and, fuses with the shaft during the 20th year., Upper End, 1 The head is disc-shaped and is covered with hyaline, cartilage (Fig. 2.21). It has a superior concave surface, which articulates with the capitulum of the humerus, at the elbow joint. The circumference of the head is, also articular. It fits into a socket formed by the radial, notch of the ulna and the annular ligament, thus, forming the superior radioulnar joint., 2 The neck is enclosed by the narrow lower margin of, the annular ligament. The head and neck are free, from capsular attachment and can rotate freely, within the socket., 3 The tuberosity lies just below the medial part of the, neck. It has a rough posterior part and a smooth, anterior part., Section 1 Upper Limb