The MBs were consistently delineated in all 72 patients, revealing varying morphologies. The appearance of MB pairs could be classified into four types based on their size and relative levels: symmetrical, right-side dominant, left-side dominant, and uneven. The uneven type indicated MBs located at different levels (Fig. 3). The symmetrical type was the most frequent and was found in 40 (56%) patients, followed by the right-side dominant, left-side dominant, and uneven types, which were identified in 14 (19%), 14 (19%), and 4 (6%) patients, respectively (Table 1). In 50 (69%), the IMDupp was discernable and measured 0.7 ± 0.4 mm (range: 0.2–1.9 mm), while it was not discernable in 22 (31%) due to the presence of intermammillary connection (IMC) and adhesion (IMA). The intermammillary relationships showed five patterns, designated as types a-e. Type a showed an IMC with the height of the IMC (HIMC)/height of the MB (HM) > 1/2. Type b showed IMC with HIMC/HM < 1/2. Type C showed IMA with a height of IMA (HIMA)/HM > 1/2. Type d showed an IMA with HIMA/HM < 1/2. Finally, type e showed separate MBs without IMC or IMA (Fig. 4). Types a, b, c, d, and e accounted 17 of 72 (24%), 5 (7%), 25 (35%), 10 (14%), and 15 (21%) patients, respectively. In the Wilcoxon signed-rank test, the age distribution showed no difference between the populations with (mean age: 50 ± 17 years, range:13–78 years) and without (mean age:44 ± 19 years, range: 9–73 years) discernible IMDupp (p > 0.05). The measured IMDlow was 4.4 ± 0.9 mm (range: 3.0–7.6 mm). Statistically, the length of the IMDlow did not differ between both sexes (p > 0.05), but was significantly longer in those in their 70s (0.01 < p < 0.05) compared to the population younger than 20 years. Other age groups did not show any significant differences from the control population (Table 3). The frequency of type e MBs and separate MBs showed no sex difference (men, N = 7, mean age:50 ± 24 years; women, N = 8, mean age: 48 ± 15 years, p > 0.10). Furthermore, in five patients (7%), the MB was considerably compressed by the cerebral arteries. These patients comprised three men and two women with a mean age of 50 years (range: 29–62 years). The offending vessel was the left posterior cerebral artery in four patients, and the basilar artery in one patient (Fig. 5). No temporal sclerosis was found in any of these five patients.
Table 1
Appearance of both mammillary bodies
Symmetrical
|
40/72 (56%)
|
Right dominant
|
14/72 (19%)
|
Left dominant
|
14/72 (19%)
|
Uneven
|
4/72 (6%)
|
Table 2
Five types of intermammillary relationships
|
Type
|
Frequency
|
MBs with IMC
|
a
|
17/72 (24%)
|
|
b
|
5/72 (7%)
|
MBs with IMA
|
c
|
25/72 (35%)
|
|
d
|
10/72 (14%)
|
Separate MBs
|
e
|
15/72 (21%)
|
Table 3
Mean intermammillary distances at the lowest site of the mammillary bodies (IMDlow) in populations of 10-year increments and their comparisons with a population younger than 20 years
Age range (years)
|
Mean IMDlow (mm)
|
p value
|
0–20 (N = 6)
|
4.1 ± 0.6 (3.3–5.1)
|
Control
|
21–30 (N = 6)
|
3.8 ± 0.3 (3.3–4.2)
|
p > 0.05
|
31–40 (N = 16)
|
4.1 ± 0.5 (3.2–5.2)
|
p > 0.05
|
41–50 (N = 9)
|
4.2 ± 0.6 (3.3–5.2)
|
p > 0.05
|
51–60 (N = 11)
|
4.3 ± 0.7 (3.2–5.6)
|
p > 0.05
|
61–70 (N = 17)
|
4.7 ± 0.9 (3.0-7.6)
|
p > 0.05
|
71–80 (N = 7)
|
5.7 ± 1.3 (3.9–7.3)
|
0.01 < p < 0.05
|