THE PATELLA. 



245 



Appears about 



early part of 



first year 



Fuses with shaft 

 about 18-19 years 



Appears about 

 2-3 years 



Usually appears in 

 the 9th month of 

 foetal life 



At birth. 



Fuses with shaft about 20-22 years 

 About 12 years. About 16 years. 



FIG. 244. OSSIFICATION OF THE FEMUR. 



month of foetal life, and is of service from a medico-legal standpoint in determining the age 

 of the foetus. According to -Hartman, it is absent in about 12 per cent, of children at 

 term, and may appear as early as the eighth month of foetal life in about 7 per cent. The 

 proximal extremity, entirely 

 cartilaginous at birth, com- 

 prises the head, neck, and 

 trochanter major. A centre 

 appears for the head during 

 the early part of the first 

 year. It is worthy of note 

 that this epiphysis has a 

 double blood - supply one 

 through the neck, the other 

 through the ligamentum 

 teres. That for the tro- 

 chanter major begins to 

 ossify about the second or 

 third year, whilst the neck 

 is developed as a proximal 

 extension of the body, which 

 is, however, not confined to 

 the neck alone, but forms 

 the distal circumference of 

 the articular head, as may 



be Seen in bones up to the Usually appears in Usually appears 



age of twelve or sixteen; the 9th month of before birth 

 after that, the separate epi- 

 physis of the head begins to 

 overlap it so as to cover it 

 entirely when fusion is com- 

 plete at the age of eighteen 

 or twenty. 



The epiphysis of the greater trochanter unites with the body and neck about eighteen or 

 nineteen, whilst the epiphysis for the trochanter minor, which usually makes its appearance 

 about the twelfth or thirteenth year, is usually completely fused with the body about 

 the age of eighteen. The epiphysis for the distal end, although the first to ossify, is not 

 completely united to the body until from about the twentieth to the twenty-second year. 

 It is worthy of note that the line of fusion of the body and distal epiphysis passes 

 through the adductor tubercle, a point which can easily be determined in the living. 

 The distal end is the so-called "growing end of the bone." 



The Patella. 



The patella, the largest of the sesamoid bones, overlies the front of the knee- 

 joint in the tendon of the quadriceps extensor. Of compressed form and 

 somewhat triangular shape,, its distal angle forms a peak, called the apex 

 patellae, whilst its proximal edge, or base (basis patellae), broad, thick, and 

 sloping forwards and a little distally, is divided into two areas by a transverse 

 line or groove ; the anterior area so defined serves for the attachment of the 

 common tendon of the quadriceps extensor muscle, whilst the posterior, of com- 

 pressed triangular shape, is covered with synovial membrane. The medial and lateral 

 borders, of curved outline, receive the insertions of the vastus medialis and lateralis 

 muscles, respectively, the attachment of the vastus medialis being more extensive 

 than that of the vastus lateralis. The anterior surface of the bone, slightly convex 

 in both diameters, has a fibrous appearance, due to its longitudinal striation, and 

 is pierced here and there by the openings of vascular canals. Oftentimes at the 

 superior lateral angle there is a well-defined area for the tendinous insertion of the 

 vastus lateralis. The posterior or articular surface is divided into two unequal 

 parts (of which the lateral is the wider) by a vertical elevation which glides in the 

 furrow of the patellar surface of the femur, and in extreme flexion passes to occupy 

 the intercondyloid fossa. The lateral of the two femoral surfaces is slightly concave 

 in both its diameters; the medial, though slightly concave proximo -distally, is 



