Comparison of the Superior and Inferior Rectus Muscles in Humans: An Anatomical Study with Notes on Morphology, Anatomical Variations, and Intramuscular Innervation Patterns

Table 2

Descriptive statistics for the data collected based on the measurements of the superior rectus muscle and its motor nerve branches.

Variable	Min (mm)	Max (mm)	Mean (mm)	Median (mm)	SD (mm)
1	41.2	49.3	43.7	42.9	2.5
2	3.7	5.4	4.6	4.7	0.6
3	6.1	10.9	8.1	8.4	1.6
4	8.1	11.5	9.6	9.5	1.1
5	1.8	3.1	2.5	2.6	0.4
6	20.5	33.4	24.6	23.2	3.7
	Min (%)	Max (%)	Mean (%)	Median (%)	SD (%)
7	47.2	74.7	58.2	56	8
8	34.8	46.6	40.9	40.8	3.2

1: the superior rectus muscle’s length measured between its origin and the distal tendon’s end; 2: origin’s width; 3: muscle’s width at midlength; 4: muscle’s insertion width; 5: muscle’s thickness at midlength; 6: distance at which the motor nerve subbranches penetrated the internal muscle’s surface measured from the muscle’s insertion; 7: distance between the muscle’s insertion and the location where the oculomotor nerve’s muscular subbranches penetrated the muscle’s internal surface referenced (a quotient) to the muscle’s total length expressed as a percentage; 8: distance between the muscle’s insertion and the anterior-most terminations of the nerves’ subbranches referenced (a quotient) to the muscle’s total length.