Stapes

Studies (see references) have shown that the stapes exhibits show marked variations. The head diffcrs in the prominence of its margins, shape of the articular facet and degree of inclination in relation to crural arches. No correlation can be made between the length of the stapcs and its weight. There may be a better relationship between breadth and weight of the ossicle. In the majority of cases, the posterior crus was found to be thicker, larger, and more curved than the anterior crus. The junction of the anterior crus with the base is thinner than the junction of the posterior crus in most cases studied.

Stapes: Length, Breadth and Width From Dass, Grewal and Thapar (1966)

Author

Year

Speciments

Length mm.

Breadth mm.

Weight mg.

Urbantschitsch

1876

50

Maximum Minimum Average

4.50 3.02 3.70

3.50 1.80 2.30

- -

Anson and Bast

1949

-

Maximum Minimum Average

3.78 2.50 3.06

- - -

4.35 2.05 2.86

Dass, Greval, Thapar

1966

165

Maximum Minimum Average

3.93 2.80 3.29

2.72 1.36 2.25

5.45 1.60 3.02

Table 2

Stapes: Measurement of Crura from Dass, Grewal and Thapar (1966)

Author

Year

No. of Bones

Length of Anterior Crus mm.

Length of Posterior Crus mm,

Breadth of Anterior Crus mm.

Breadth of Posterior Crus mm.

Urbantschitsch

1876

50

Maximun Minimum Average

3.4 1.4 2.2

3.7 1.4 2.7

1.0 0.5 0.6

1.0 0.5 0.8

Anson, Karabin and Martin

1939

-

Maximum Minimum Average

2.90 2.30 2.57

2.68 2.13 1.4

- - -

- - -

Dass, Grewal and Thapar

1966

165

Maximum Minimum Average

2.52 1.60 1.98

2.44 1.70 2.03

3.07 0.30 0.27

0.62 0.40 0.38

Table 3

Stapes: Length and Breadth of the Stapes Footplate From Dass, Grewal and Thapar (1966) Length (mm) Breadth (mm)

Av.

Maximum

Minimum

--

Av.

Maximum

Minimum

Urbantschitsch

(1876)

3.00

3.5

2.6

--

1.5

2.5

1.2

Anson, et al.

(1939)

2.47

2.71

2.0

--

1.5

1.37

0.78

Bast and Anson

(1949)

2.99

3.36

2.64

--

1.41

1.66

1.08

Dass, et al.

(1966)

2.79

3.30

2.29

--

1.43

1.94

0.42

Urbantschitsch (1876) has provided detailed measurements of the malleus, incus and the stapes.

Stapes; Plan of Measurements

Anson, B.J., Karabin, J.E. and J. Martin. (1939) Stapes, fissula ante fenestram. and associated structures in man. Arch. Otolaryngol. 29:939-973.

Bast, T.H. and B.J. Anson. (1949) The Temporal Bone and the Ear. CC Thomas, Springfield, Illinois.

Dass, R., Grewal, B.S. and S.P. Thapar. (1966) Human stapes and its variations. 1. General Features. The Journal of Laryngology and Otology 80(l):11-25.

Dass, R., Grewal, B.S. and S.P. Thapar. (1966) Human stapes and its variations. 11. Footplate. The Journal of Laryngology and Otology 80(5):471-480.