Abstract: Objective    To reveal the  neuromuscular subdivision of extraocular muscle  and the body surface projection position, angle and depth for puncture of center of intramuscular nerve dense region (CINDR).    Methods    Twenty-four Chinese adult.cranial specimens were used. The arc line (orbital edge line) on the skin close to the edge of the orbit was designed as the reference line, and the acute angle formed between the puncture needle and the eyelid skin was θ. The Modified Sihler's staining was used for showing the distribution pattern of intramuscular nerves in the extraocular muscles. The CINDRs were labelled with barium sulfate, and the spiral CT scanning and three-dimensional reconstruction was performed. The percentage position of the surface projection point (P point) of CINDR on the reference line, the angle and depth required to penetrate CINDR through P point were measured.    Results    During gross dissection, it was found that there were no blood vessels accompanying at the nerve entry points of the seven extraocular muscles (levator palpebrae superioris, superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique and inferior oblique muscles). After the nerve entered the muscle, it was often divided into two independent primary nerve branches, and then followed by arborized branches. According to their nerve distribution pattern, each muscle could be divided into two neuromuscular compartments. The intramuscular arborized nerve branches formed nerve dense regions, and the body surface projection points of the CINDR were located at 68.42%, 53.43%, 53.21%, 11.76%, 98.56%, 30.15%, and 43.73% on the orbital edge line (medial to lateral), respectively. The puncture angles were 83.54°, 69.75°, 74.15°, 82.98°, 80.58°, 83.69°, and 71.52°, respectively. The puncture depths were 3.05 cm, 2.71 cm, 2.82c m, 3.02 cm, 3.00 cm, 3.09 cm, and 2.18 cm, respectively. There were no statistical differences between left and right sides and between males and females (P>0.05).    Conclusions    These results may provide morphological guidance for correcting strabismus by compartmentalized transplantation of extraocular muscle and intramuscular injection of botulinum toxin A.

Key words: Extraocular muscles; ,  , Intramuscular nerves; ,  , Neuromuscular compartment; ,  , Strabismus, Target localization