as best seen in fig6 the human nose 10 is essentially a pyramid that is divided into three compartments , namely , the bony vault 12 , the upper cartilaginous vault 14 , and the lower cartilaginous vault 16 . the vaults 12 , 14 and 16 have a common supporting partition , the bony and cartilaginous septum 18 . the bony vault 12 forms the principal structural base for the nose 10 . it is made up of upward projections of the frontal process of the maxilla 20 , from which a pair of nasal bones 21 and 22 extend to form an arch at the union thereof . the posterior border of the bony vault 12 is continuous with the maxilla 20 . if the nose 10 is thought of as being cantilevered , the bony vault 12 forms a stable base , with its arch an extension of the skull . stated in another manner , the bony vault 12 , with its cantilevered upper cartilaginous vault 14 , fuses with the dorsal edge 23 of the septum 18 to form a structural &# 34 ; i beam &# 34 ; extending from the radix 30 of the skull to the lower cartilaginous vault 16 . the upper cartilaginous vault 14 is made up of paired , triangular cartilages 31 and 32 that extend from the bony vault 12 as a cantilever and are attached along the dorsal border of the septum by a dense fibrous union . the cartilages 31 and 32 are attached to the undersurface of the lateral walls of the bony vault 12 by a membrane . the dorsal segment 23 or upper edge of the upper cartilaginous vault 14 is the bridge that connects the two upper lateral cartilages 31 and 32 to give them stability . the lower cartilaginous vault 16 forms the base of the nose 10 and is made up of tissues caudal to the free edge of the upper lateral cartilages 31 and 32 . although the lower vault 16 is relatively independent of the vaults 12 and 14 , it shares with them the dorsal edge 23 of the septum 18 and the connective tissue attachments to the upper lateral cartilages 31 and 32 . as shown diagramatically in fig1 - 3 , as well as in fig4 and 5 , during rhinoplasty the dorsum 18 is resected , separating the dorsal edge 23 of the bony and cartilaginous vaults 12 and 14 from the walls thereof . thereafter , the cartilaginous vaults 12 and 14 must rely on the remaining attachment to the nasal bones 21 and 22 for their support and lateral distraction . the change in the nasal pyramid 10 can be visualized by recognizing that the nasal pyramid 10 forms equilateral triangles of increasing size , the smallest being at the radix 30 and the largest at the caudal end of the nasal bones 21 and 22 . following dorsal resection , the loss of the dorsal edge 23 produces an open pyramid . in order to close the open pyramid as well as reconstruct a smaller pyramid , the nasal bones 21 and 22 must first be separated from the maxilla at their bases . therefore , the nasal bones 21 and 22 are fractured to reform the nasal pyramid 10 . the tool of the instant invention facilitates controlled fracture of the nasal bones 21 and 22 . preferably the line of separation of the nasal bones 21 and 22 from their base follows the bases 33 and 34 thereof , leaving a narrow unfractured cephalic segment 35 in the area of the medial canthal ligament extending from the lateral osteotomy to the dorsum . it is this cephalic segment 35 that must be fractured , along a controlled line 36 extending from a point high in the nasion to a point above and anterior to the attachment of the medial canthal ligament as shown in fig5 and 8 . because bone continuity is important for a natural postoperative nasal contour , the fracture line 36 in the cephalic segment is preferably an undisplaced impacted fracture . as best seen in fig7 a surgical instrument 40 in accordance with the instant invention comprises what may be characterized as a forceps having scissor portions 44 and 46 joined to one another by a pivot pin 48 . the scissor portions 44 and 46 have curved handles 50 and 52 , respectively , that are normally biased apart by a spring 54 . the scissor portion 44 has a relatively blunt nose or outer jaw portion 56 , while the scissor portion 46 has a chisel edge inner jaw portion 58 . in addition , the scissor portion 46 has an anvil 60 at the opposite end thereof from the chisel portion 58 to facilitate driving of the chisel edge of the jaw portion 58 into the bony structure above the septum to a position high in the nasion adjacent the radix 30 of the bony vault 12 . as best seen in fig8 the chisel edge portion 58 of the scissor portion 46 is inserted lengthwise and parallel to the nasal bone 22 and tapped into position with the chisel edge thereof high in the nasion at the inside of the nasal bone 22 , the blunt jaw portion 56 of the scissor portion 44 following along the outer wall of the nasal bone 22 with the flat inner sides of the jaws positioned to clamp the nasal bone therebetween as shown in fig8 . as best seen in fig9 the handle portions 52 and 50 of the instrument 40 are thereafter compressed towards one another against the bias of the spring 54 closing the nose 56 against the wall 22 of the bony vault 12 and chisel portion 58 of the instrument 40 . thereafter the instrument 40 is rotated clockwise , as seen in fig9 of the drawings , to effect a controlled undisplaced impacted fracture of the wall 22 of the bony vault 12 parallel to the chisel edge of the jaw 58 , thereby conditioning the &# 34 ; open pyramid &# 34 ; to be closed by &# 34 ; swinging &# 34 ; or moving the bone 22 towards the resected dorsum 18 . as best seen in fig1 , a modified embodiment of the instant invention comprises a tool 62 having scissor portions 64 and 66 joined to one another by a pivot pin 68 . the scissor portions 64 and 66 have curved handles 70 and 72 that are normally biased apart as by a spring 74 . the scissor portion 64 has a relatively blunt nose portion 76 , with a pivoted pad 78 thereon , while the scissor portion 66 has a chisel edge 80 thereon . the scissor portion 66 has an anvil 82 at the opposite end of the chisel portion 80 to facilitate driving of the chisel edge into position adjacent the radix 30 of the bony vault 12 . the pad 78 is articulated relative to the nose portion 76 to insure that a firm even grip is obtained on the nasal bone 22 of the bony vault 12 upon rotation of the instrument 62 to effect fracture of the bone 22 . it is understood that the foregoing description is that of the preferred embodiment of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention , as defined in the appended claims .
the disclosure relates generally to aesthetic rhinoplasty and more particularly to an instrument and technique for fracturing the lateral walls of the bony vault of the nose in a precise manner without tearing the periosteal attachments in the region of the nasion or double fracturing of the lateral walls of the bony vault .