Cadaveric and MRI study of the musculotendinous contributions to the capsule of the symphysis pubis

OBJECTIVE. The purpose of this article is to define the relations of the symphysis pubis and capsular tissues to the adductor and rectus abdominis soft-tissue attachments on cadaver dissection and correlate with MRI of the anterior pelvis. SUBJECTS AND METHODS. Seventeen cadavers (8 males and 9 females; mean age, 80 years) were dissected bilaterally. Rectus abdominis and adductor muscles were traced to the pubis and further attachments to the pubic symphysis were defined. Ten asymptomatic (mean age, 17; age range, 16.5-29 years) male athletes underwent 1.5-T MRI of the anterior pelvis with two surface microcoils (each 42 mm in diameter). An axial T2-weighted turbo spin-echo (TSE) sequence (TR/TE, 2,609/106; voxel size, 0.4 mm) was obtained. Axial and sagittal 3D T1-weighted fast-field echo (FFE) sequences (25/4.9; voxel size, 0.3 mm) were obtained. Sequences were repeated incorporating fat suppression and IV gadolinium. The relation of the symphysis pubis, disk, and capsular tissues to the insertions of the rectus abdominis, adductor muscles, and gracilis were independently evaluated by two experienced radiologists blinded to all clinical details. RESULTS. In all 17 cadaver specimens, the adductor longus and rectus abdominis attached to the capsule and disk of the symphysis pubis, whereas the adductor brevis had an attachment to the capsule in seven specimens and the gracilis in one. All adductor tendons attached to the pubis. In all 10 athletes, the adductor longus and rectus abdominis bilaterally contributed to the capsular tissues and disk. This was only the case for the adductor brevis in four athletes. No other tendons involved the capsular tissues. CONCLUSION. Cadaver and MRI findings show an intimate relationship between the adductor longus; rectus abdominis; and symphyseal cartilage, disk, and capsular tissues.