Objective By observing and measuring the relevant data of the buccal branch of the facial nerve,the parotid duct and the facial artery,the positional relationship among the three was analyzed to avoid accidental injury to the buccal branch of the facial nerve and the parotid duct when ligaturing the facial artery during the operation.Methods Forty adult head and neck specimens were dissected to observe the relationship between the buccal branch of the facial nerve and the parotid duct,the course and positional relationship of the facial artery,and the relationship between the buccal branch of the facial nerve and the peripheral vascular network.The relevant diameters were measured with a vernier caliper.Results The buccal branch of the facial nerve was divided into the superior buccal branch and the inferior buccal branch,and there was no direct anastomosis or connecting fiber between the buccal branch of the facial nerve and the parotid duct.The superior buccal branch was relatively thick,and it has a relatively constant position,which was parallel to the parotid duct.The position of the inferior buccal branch was not constant and it ran on or slightly above the plane of angulus oris.The superior buccal branch was located(10.76±5.54)mm from the parotid duct,while the inferior buccal branch was positioned(6.84±4.06)mm away from the parotid duct.The course of the main trunk of the facial artery was relatively fixed.Moreover,if the branch of the facial artery was missing,other branches of the facial artery would extend to replace the missing branch artery.The main trunk of the facial artery had a diameter of(2.34±0.83)mm,and its branches formed anastomoses with the buccal branch of the maxillary artery,creating a vascular network in the parotid and buccal regions.There was a vascular network around the buccal branch of the facial nerve,which was mostly small branches of the facial artery and the superficial temporal artery.Conclusion The buccal branch of the facial nerve exhibits a consistent anatomic relationship with the parotid duct and the facial artery.During the ligation of the facial artery,the parotid duct can serve as a landmark to accurately locate the buccal branch of the facial nerve,thereby significantly reducing the risk of inadvertent injury to the buccal branch of the facial nerve and the parotid duct.

Objective To deeply understand the anatomical basis of temporomandibular joint disorders,and explore and master the pathological characteristics of anterior displacement of temporomandibular joint disc through cadaveric dissection and 3D printing technology.Methods By dissecting the temporomandibular joints of 40 head and neck specimens,the bilateral structures of the temporomandibular joints were measured to obtain condyle and articular disc data.3D modeling was carried out using 3ds Max software and printed out a model of temporomandibular joint.The pathological model of the anterior disc displacement with reduction(ADDwR)was simulated by adjusting the opening degree,the position of the articular disk,and the position of the condyle of the model.Results The precise data of the right and left temporomandibular joint discs and condyle were successfully obtained by dissection and measurement.The thickness of the anterior band of left temporomandibular joint discs was(2.02±0.57)mm,the thickness of the middle band was(1.46±0.33)mm,the thickness of the posterior band was(3.00±0.46)mm,the anterior-posterior diameter was(9.60±0.72)mm,and the internal-external diameter was(17.73±0.84)mm.While the thickness of the anterior band of right temporomandibular joint discs was(1.84±0.35)mm,and the thickness of the middle band was(1.43±0.28)mm,the thickness of posterior band was(3.08±0.49)mm,the anterior-posterior diameter was(9.30±0.88)mm,and the internal-external diameter was(17.38±1.10)mm.The internal-external diameter of the left temporomandibular joint condyle was(18.97±0.41)mm,and the anterior-posterior diameter was(8.56±0.43)mm;the internal-external diameter of the right temporomandibular joint condyle was(18.86±0.75)mm,and the anterior-posterior diameter was(8.40±0.30)mm.The standard temporomandibular joint model was printed out by the measured data.The model was utilized to simulate the physiological state of temporomandibular joint under normal conditions,as well as the three pathological states of closed mouth,closed mouth to open mouth,and open mouth in the case of ADDwR.Conclusion The temporomandibular joint model can more intuitively present the changes of anatomical structure in reversible temporoman-dibular joint disorders,which is helpful for understanding and mastering the different classification of this disease.

Objective To explore the effects of different concentrations of simvastatin on nerve regeneration after sciatic nerve injury.Methods Rats were randomly divided into the normal group,the control group,the low-dose group and the high-dose group,with 3 rats in each group.Except for the normal group,adult rat sciatic nerve crush injury models were established in the other groups.Rats in the normal group and the control group were orally administered with water,while those in the low-dose group and high-dose group were orally administered with 98%simvastatin at dosages of 4 mg/mL and 40 mg/mL,respectively.The sciatic nerve regeneration in rats was evaluated by sciatic function index(SFI),HE staining,luxol fast blue(LFB)staining and immunofluorescence staining,etc.Results The SFI of rats in the high-dose group 7 days and 14 days after surgery were higher than those in the control group(P<0.05);there was no significant difference in SFI of rats between the low-dose group and the control group 7 days and 14 days after surgery(P>0.05).HE staining and LFB staining results showed that compared with the control group,the number of neurons of rats in the high-dose group increased,the nerve fibers and myelin were clearer and denser,and the nerve function was significantly restored;while no significant improvement was observed in the sciatic nerve of rats in the low-dose group.The immunofluorescence staining results showed that compared with the control group,the immunofluorescence intensity in the high-dose group increased,while that in the low-dose group decreased,the differences were statistically significant(P<0.05).Conclusion High-dose simvastatin can promote peripheral nerve regeneration by regulating the expression of M2 macrophages.

Objective By observing and measuring the relevant data of the buccal branch of the facial nerve,the parotid duct and the facial artery,the positional relationship among the three was analyzed to avoid accidental injury to the buccal branch of the facial nerve and the parotid duct when ligaturing the facial artery during the operation.Methods Forty adult head and neck specimens were dissected to observe the relationship between the buccal branch of the facial nerve and the parotid duct,the course and positional relationship of the facial artery,and the relationship between the buccal branch of the facial nerve and the peripheral vascular network.The relevant diameters were measured with a vernier caliper.Results The buccal branch of the facial nerve was divided into the superior buccal branch and the inferior buccal branch,and there was no direct anastomosis or connecting fiber between the buccal branch of the facial nerve and the parotid duct.The superior buccal branch was relatively thick,and it has a relatively constant position,which was parallel to the parotid duct.The position of the inferior buccal branch was not constant and it ran on or slightly above the plane of angulus oris.The superior buccal branch was located(10.76±5.54)mm from the parotid duct,while the inferior buccal branch was positioned(6.84±4.06)mm away from the parotid duct.The course of the main trunk of the facial artery was relatively fixed.Moreover,if the branch of the facial artery was missing,other branches of the facial artery would extend to replace the missing branch artery.The main trunk of the facial artery had a diameter of(2.34±0.83)mm,and its branches formed anastomoses with the buccal branch of the maxillary artery,creating a vascular network in the parotid and buccal regions.There was a vascular network around the buccal branch of the facial nerve,which was mostly small branches of the facial artery and the superficial temporal artery.Conclusion The buccal branch of the facial nerve exhibits a consistent anatomic relationship with the parotid duct and the facial artery.During the ligation of the facial artery,the parotid duct can serve as a landmark to accurately locate the buccal branch of the facial nerve,thereby significantly reducing the risk of inadvertent injury to the buccal branch of the facial nerve and the parotid duct.

Objective To deeply understand the anatomical basis of temporomandibular joint disorders,and explore and master the pathological characteristics of anterior displacement of temporomandibular joint disc through cadaveric dissection and 3D printing technology.Methods By dissecting the temporomandibular joints of 40 head and neck specimens,the bilateral structures of the temporomandibular joints were measured to obtain condyle and articular disc data.3D modeling was carried out using 3ds Max software and printed out a model of temporomandibular joint.The pathological model of the anterior disc displacement with reduction(ADDwR)was simulated by adjusting the opening degree,the position of the articular disk,and the position of the condyle of the model.Results The precise data of the right and left temporomandibular joint discs and condyle were successfully obtained by dissection and measurement.The thickness of the anterior band of left temporomandibular joint discs was(2.02±0.57)mm,the thickness of the middle band was(1.46±0.33)mm,the thickness of the posterior band was(3.00±0.46)mm,the anterior-posterior diameter was(9.60±0.72)mm,and the internal-external diameter was(17.73±0.84)mm.While the thickness of the anterior band of right temporomandibular joint discs was(1.84±0.35)mm,and the thickness of the middle band was(1.43±0.28)mm,the thickness of posterior band was(3.08±0.49)mm,the anterior-posterior diameter was(9.30±0.88)mm,and the internal-external diameter was(17.38±1.10)mm.The internal-external diameter of the left temporomandibular joint condyle was(18.97±0.41)mm,and the anterior-posterior diameter was(8.56±0.43)mm;the internal-external diameter of the right temporomandibular joint condyle was(18.86±0.75)mm,and the anterior-posterior diameter was(8.40±0.30)mm.The standard temporomandibular joint model was printed out by the measured data.The model was utilized to simulate the physiological state of temporomandibular joint under normal conditions,as well as the three pathological states of closed mouth,closed mouth to open mouth,and open mouth in the case of ADDwR.Conclusion The temporomandibular joint model can more intuitively present the changes of anatomical structure in reversible temporoman-dibular joint disorders,which is helpful for understanding and mastering the different classification of this disease.

Objective To explore the effects of different concentrations of simvastatin on nerve regeneration after sciatic nerve injury.Methods Rats were randomly divided into the normal group,the control group,the low-dose group and the high-dose group,with 3 rats in each group.Except for the normal group,adult rat sciatic nerve crush injury models were established in the other groups.Rats in the normal group and the control group were orally administered with water,while those in the low-dose group and high-dose group were orally administered with 98%simvastatin at dosages of 4 mg/mL and 40 mg/mL,respectively.The sciatic nerve regeneration in rats was evaluated by sciatic function index(SFI),HE staining,luxol fast blue(LFB)staining and immunofluorescence staining,etc.Results The SFI of rats in the high-dose group 7 days and 14 days after surgery were higher than those in the control group(P<0.05);there was no significant difference in SFI of rats between the low-dose group and the control group 7 days and 14 days after surgery(P>0.05).HE staining and LFB staining results showed that compared with the control group,the number of neurons of rats in the high-dose group increased,the nerve fibers and myelin were clearer and denser,and the nerve function was significantly restored;while no significant improvement was observed in the sciatic nerve of rats in the low-dose group.The immunofluorescence staining results showed that compared with the control group,the immunofluorescence intensity in the high-dose group increased,while that in the low-dose group decreased,the differences were statistically significant(P<0.05).Conclusion High-dose simvastatin can promote peripheral nerve regeneration by regulating the expression of M2 macrophages.

Objective To investigate the feasibility of translocation of pedicled buccal fat pad in the treatment of the temporomandibular joint ankylosis(TMJA)by measuring the diameter of buccal fat pad and related anatomical structures of the transverse blood vessels,nerves and temporomandibular joint.Methods A total of 40 adult head and neck specimens were randomly divided into group A and group B,with 20 cases in each group.The morphology of the buccal fat pad in group A was observed,and its size and compression diameter through blood vessels and nerves were measured.The anatomical structures of the temporomandibular joint in group B were observed and measured.Results The volume of buccal fat pad in group A was(10.10±1.10)mL on the left side and(9.70±1.50)mL on the right side.The longitudinal axis length of buccal fat pad was(28.18±1.35)mm on the left side and(29.47±1.12)mm on the right side;Transverse axis length of buccal fat pad was(18.56±1.67)mm on the left side and(18.97±1.73)mm on the right side;There are facial artery,facial vein,maxillary artery branch,facial nerve buccal branch and so on through the buccal fat pad.In group B,the sagittal section of the temporomandibular joint disc presented S-type in 15 cases(75.0%),L-type in 3 cases(15.0%),and transitional type in 2 cases(10.0%).Anterior and posterior diameter of the articular disc was(14.42±1.94)mm on the left side and(15.34±1.37)mm on the right side;inside and outside diameter of the articular disc was(20.18±1.77)mm on the left side and(19.57±1.32)mm on the right side.Branches of maxillary artery and superficial temporal artery were respectively distributed within and outside the joint.Conclusion The pedicled buccal fat pad has a constant anatomical position,abundant blood supply,strong tissue repair,anti-infection ability and"buffer pad"function,which can reduce the formation of scar after surgery for TMJA,reduce the postoperative recurrence rate,and contribute to the recovery of joint function after surgery.

Objective To observe the course and diameter of facial artery branches and its adjacent structures in nasolabial groove area and the positional relationship,so as to provide reference for clinicians to carry out facial cosmetic repair surgery.Methods A total of 40 adult head and neck specimens were dissected on the spot,and the course and position of the facial artery branches,facial vein and facial nerve in the nasolabial groove area were observed,their diameters were measured,and relevant data were recorded.Results There were 4 types of facial artery branches in the nasolabial groove area:type Ⅰ(upper lip type)accounted for 12.5%,type Ⅱ(nasal type)accounted for 62.5%,type Ⅲ(classical type)accounted for 20.0%,and type Ⅳ(double severe type)accounted for 5.0% .There were 4 kinds of positional relationship between the facial artery and the facial vein in the nasolabial groove area:42.5% of the orofacial artery was located on the medial side of the facial vein,32.5% of the orofacial artery was located on the lateral side of the facial vein,17.5% of the two were close to and wrapped in a fascial sheath,7.5% of the orofacial artery and the main trunk of the facial vein were crossed,and the vein was located in the deep surface of the artery.There were 3 kinds of positional relationship between the facial artery and the marginal mandibular branch of the facial nerve:87.5% of the facial artery was deep on the marginal mandibular branch of the facial nerve,7.5% of the facial artery was superficial on the marginal mandibular branch of the facial nerve,and 5.0% of the facial artery was held or surrounded by two branches of the marginal mandibular branch of the facial nerve on the superficial or deep surface.Conclusion The positional relationship among facial artery,facial vein and facial nerve in the nasolabial groove area is complicated.Familiarity with its positional relationship can avoid damaging blood vessels and nerves during the nasorabial groove surgery,reduce surgical complications and improve surgical safety.