![掌骨[I] - 手部MRI - 轴 - e-Anatomy](https://cdn.imaios.cn/i/imaios-images/web/images/eanatomy/modules/hand-mr/images/v1/d4083278e0de9069a1ef0fdafee25af01cac343a22c47dd6990497ea8fbe7658?ar=640:670&auto=format,compress&bg=000000&fit=crop&p64=ODksMjg1&t=5o6M6aqoW0ld&tf=Tm90byBTYW5zIFND&tx=89&ty=285&w=350&wk=1&s=c4f01069e029daa5ed1f43e98d2fd810)
掌骨[I]
Os metacarpale [I]
定义
第一掌骨（os metacarpale I；拇指掌骨）比其他掌骨短而粗壮，与腕骨的分离角度更大，其掌侧面朝向手掌。
骨体在背侧面扁平而宽阔，不呈现其他掌骨所具有的嵴；其掌侧面从上向下呈凹形。在其桡侧缘，拇指对掌肌附着于此；其尺侧缘为第一骨间背侧肌外侧头的起点。
底部呈凹凸面，与大多角骨形成关节；其两侧无关节面，但在其桡侧有一结节，为拇长展肌的附着处。
头部的凸度小于其他掌骨的头部，横径（侧-侧方向）大于前后径。在其掌侧面有两个关节隆起，其中外侧者较大，与拇短屈肌腱内的两块籽骨形成关节。
參考資料
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).
![掌骨[I] - 手部MRI - 轴 - e-Anatomy](https://cdn.imaios.cn/i/imaios-images/web/images/eanatomy/modules/hand-mr/images/v1/d4083278e0de9069a1ef0fdafee25af01cac343a22c47dd6990497ea8fbe7658?ar=640:670&auto=format,compress&bg=000000&fit=crop&p64=ODksMjg1&t=5o6M6aqoW0ld&tf=Tm90byBTYW5zIFND&tx=89&ty=285&w=200&wk=1&s=84554c26278dc5e6d3f7cb22d16d49b7 "掌骨[I] - 手部MRI - 轴 - e-Anatomy")
![掌骨[I] - 手部MRI - 矢状 - e-Anatomy](https://cdn.imaios.cn/i/imaios-images/web/images/eanatomy/modules/hand-mr/images/v1/743bcff2a7ecabe64e7b7d56b282f540a4546fcbf1512956ab019c6842483217?ar=640:670&auto=format,compress&bg=000000&fit=crop&p64=Mjk1LDIwMQ&t=5o6M6aqoW0ld&tf=Tm90byBTYW5zIFND&tx=295&ty=201&w=200&wk=1&s=06a9adbf90681cacc1d32c96b0d780fc "掌骨[I] - 手部MRI - 矢状 - e-Anatomy")
![掌骨[I] - 手部MRI - 冠状 - e-Anatomy](https://cdn.imaios.cn/i/imaios-images/web/images/eanatomy/modules/hand-mr/images/v1/3e8c80c025008238dcd5d6e5b1ae1c3f0aca2f46c70da0a50069f53825a70969?ar=640:670&auto=format,compress&bg=000000&fit=crop&p64=MTk4LDIxNA&t=5o6M6aqoW0ld&tf=Tm90byBTYW5zIFND&tx=198&ty=214&w=200&wk=1&s=c13e9ded3cedb1c1bf8138912f650415 "掌骨[I] - 手部MRI - 冠状 - e-Anatomy")
![掌骨[I] - 腕MRI - 轴 - e-Anatomy](https://cdn.imaios.cn/i/imaios-images/web/images/eanatomy/modules/wrist-mri-3d/images/v1/24e14a07435e0e0e8da11e77a50992475161d203c05aae1dbec93a0964d13d3f?ar=640:670&auto=format,compress&bg=000000&fit=crop&p64=MTE0LDI1OQ&t=5o6M6aqoW0ld&tf=Tm90byBTYW5zIFND&tx=114&ty=259&w=200&wk=1&s=a7aeb6c4a9b670bc2a23e2beada28053 "掌骨[I] - 腕MRI - 轴 - e-Anatomy")
![掌骨[I] - 腕MRI - 冠状 - e-Anatomy](https://cdn.imaios.cn/i/imaios-images/web/images/eanatomy/modules/wrist-mri-3d/images/v1/da96e62eca86663ebde0c10bb2e3af1ccfde5b2e7604cd1dc4a309c2a1fe2452?ar=640:670&auto=format,compress&bg=000000&fit=crop&p64=MTUyLDUwOQ&t=5o6M6aqoW0ld&tf=Tm90byBTYW5zIFND&tx=152&ty=509&w=200&wk=1&s=f50aa861b2786e4e893d528eec5ba845 "掌骨[I] - 腕MRI - 冠状 - e-Anatomy")
![掌骨[I] - 腕MRI - 矢状 - e-Anatomy](https://cdn.imaios.cn/i/imaios-images/web/images/eanatomy/modules/wrist-mri-3d/images/v1/e9eb2040539fe05a5678411c1a95c6702186c2108091e7cf8b81d9bbe4fd3bcc?ar=640:670&auto=format,compress&bg=000000&fit=crop&p64=MjczLDQwMQ&t=5o6M6aqoW0ld&tf=Tm90byBTYW5zIFND&tx=273&ty=401&w=200&wk=1&s=1f9d1b8473a41f4973553fd9937d4adb "掌骨[I] - 腕MRI - 矢状 - e-Anatomy")
![掌骨[I] - 腕MRI - 三维 - 侧向旋转 - e-Anatomy](https://cdn.imaios.cn/i/imaios-images/web/images/eanatomy/modules/wrist-mri-3d/images/v1/dc315c7059ff48c7d67329b250ac5d90aa3fbab92afaa4ba09c70b07aebcdcb1?ar=640:670&auto=format,compress&bg=000000&fit=crop&p64=NTU4LDU1NQ&t=5o6M6aqoW0ld&tf=Tm90byBTYW5zIFND&tx=558&ty=555&w=200&wk=1&s=7ee2bd2c8c373c9f9fb3ce818b92549f "掌骨[I] - 腕MRI - 三维 - 侧向旋转 - e-Anatomy")
![掌骨[I] - 腕MRI - 三维 - 垂直旋转 - e-Anatomy](https://cdn.imaios.cn/i/imaios-images/web/images/eanatomy/modules/wrist-mri-3d/images/v1/5633e4f63c8a3cac6e5acb8a9a388217aae097869b9a259dfea3bb6b73d7dafc?ar=640:670&auto=format,compress&bg=000000&fit=crop&p64=NzMsMTE1&t=5o6M6aqoW0ld&tf=Tm90byBTYW5zIFND&tx=73&ty=115&w=200&wk=1&s=0e78a11de0db4d60faae49356ea79df4 "掌骨[I] - 腕MRI - 三维 - 垂直旋转 - e-Anatomy")
