HUMAN ANATOMY ATLAS - G.L. Bilich - 2014

MUSCULOSKELETAL SYSTEM

SKELETAL SYSTEM

BONES OF THE UPPER LIMB

Bones of the Pectoral Girdle

The clavicle (clavicula) is a long, S-shaped, curved tubular bone positioned between the clavicular notch of the Sternum and the acromial process of the scapula. The clavicle consists of a rounded body (corpus claviculae) and two extremities: a thickened sternal end (extremitas sternalis) and an expanded, flattened acromial end (extremitas acromialis), which serves as an attachment site for a portion of the trapezius Muscle fibers as well as the subclavius muscle (Fig. 86). The sternal end of the clavicle features a saddle-shaped sternal articular surface (facies articularis sternalis) for articulation with the sternum. The flat articular surface located on the acromial end of the clavicle forms a joint with the corresponding articular surface of the acromion of the scapula (the acromioclavicular joint). Two elevations are visible on the Inferior surface of the clavicle: the conoid tubercle (tuberculum conoideum) and the trapezoid line (linea trapezoidea), which serve as attachment sites for the conoid and trapezoid ligaments stretched between the clavicle and the coracoid process of the scapula. The clavicle effectively holds the shoulder joint away from The thoracic cage, allowing for a greater range of arm mobility.

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Fig. 84. Appendicular Skeleton, anterior view (A — right upper limb, B — left upper limb, C — right lower limb, D — left lower limb):

1 — Clavicle; 2 — Scapula; 3 — Humerus; 4 — Arm; 5 — Ulna; 6 — Radius; 7 — Forearm; 8 — Carpal Bones; 9 — Metacarpals [ I—V]; 10 — Phalanges; 11 — Hand; Bones of hand; 12— Pelvis; 13 — Femur; Tliigh bone; 14 — Thigh; 15 — Fibula: 16 — Tibia; 17 — Leg: 18— Tarsal Bones; 19 — Metatarsals [I—V]; 20 — Phalanges; 21 — FOOT; Bones of foot

Fig. 85. Appendicular skeleton, posterior view (A — left upper limb, B — right upper limb, C — left lower limb, D — right lower limb):

1 — Clavicle; 2 — Scapula; 3 — Humerus; 4 — Arm; 5 — Ulna; 6 — Radius; 7 — Forearm; S— Carpal bones; 9 — Metacarpals [I —V]; 10 — Phalanges; 11 — Hand; Bones ofhand; 12— Pelvis; 13 — Femur; Thigh bone; 14 — Thigh; 15 — Fibula; 16 — Leg; 17 — Tibia; 18 — Tarsal bones; 19 — Melatarsals [I—V]; 20— Phalanges; 21 — Foot; Bones of foot

Fig. 86. Right clavicle (A — superior view, B — inferior view):

1 — Acromial end; 2 — Sternal facet; 3 — Conoid tubercle; 4 — Shaft of clavicle; 5 — Sternal end; 6 — Subclavian groove; 7— Impression for costoclavicular ligament; Groove for subclavius; 8 — Acromial facet; 9 — Trapezoid line

The scapula is a flat, triangular bone that lies against the posterolateral wall of the Thorax, extending from the second to the seventh rib. The scapula has three angles: the inferior angle (angulus inferior), lateral angle (angulus lateralis), and superior angle (angulus superior); and three borders: the medial border (margo medialis), facing THE Vertebral Column; the lateral border (margo lateralis), directed laterally and inferiorly; and the superior border (margo superior), which features the scapular notch (incisura scapulae) for the passage of the suprascapular artery and nerve (Fig. 87).

The anterior costal surface of the scapula (facies costalis) forms a slightly concave subscapular fossa (fossa subscapularis), which houses the muscle of the same name. The dorsal surface (facies dorsalis) is convex and features a transversely oriented spine of the scapula (spina scapulae). Above the spine lies the supraspinous fossa (fossa supraspinata), containing the supraspinatus muscle. Below the spine is the infraspinous fossa (fossa infraspinata), which serves as the origin for the infraspinatus muscle. In the region of the lateral angle, the free end of the spine expands and flattens to form the acromion (acromion), to which—along with the spine of the scapula—the fibers of the trapezius muscle attach. The tip of the acromion bears a flat acromial articular surface (facies articularis acromialis) that articulates with the acromial end of the clavicle. Just beyond a slight constriction (the neck of the scapula, collum scapulae), the lateral angle of the scapula becomes thickened and features a flattened glenoid cavity (cavitas glenoidalis) that articulates with the HEAD of the humerus to form the shoulder joint. Above the glenoid cavity is the supraglenoid tubercle (tuberculum supraglenoidale), which gives rise to the long head of the biceps brachii muscle. Below the glenoid cavity is the infraglenoid tubercle (tuberculum infraglenoidale), which serves as the origin for the long head of the triceps brachii muscle. Projecting from the superior border of the scapula, slightly medial to its neck, is the curved coracoid process (processus coracoideus), which anchors the coracoclavicular ligament and serves as the origin for the coracobrachialis muscle and the short head of the biceps brachii muscle.