Comments on: Visualizing Anatomy https://blog.wolfram.com:443/2017/03/10/visualizing-anatomy/ News, views, and ideas from the front lines at Wolfram Research. Wed, 18 Sep 2019 07:01:03 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Phil https://blog.wolfram.com:443/2017/03/10/visualizing-anatomy/comment-page-1/#comment-125024 Phil Tue, 21 Mar 2017 20:48:48 +0000 https://blog.internal.wolfram.com/?p=35450#comment-125024 There are definitely muscles in the hand. The abductor digiti minimi muscle is located on the medial side of the hand. That muscle is the distal endpoint of the Deep Back Arm Line (DBAL), a line starting in the upper back and responsible for outward rotation of the arm and hand. You can identify this muscle when you execute a Vulcan "live long and prosper!" salute and feel along the side of your hand. There's a good Wikipedia article on this muscle as well as a summary article "muscles of the hand". I had learned about the abductor digiti minimi muscles when I started exercising my arm rotators and that tiny muscle was noticeably sore. You are right: the vast majority of the muscles for flexing and extending our fingers are located far up the arm. Tension-transmitters (i.e., tendons and ligaments) are cheap and have a small diameter; tension-adjustors (i.e., muscles) are expensive and have a far greater diameter. By having our finger's function controlled by distant muscles, we're able to use our hands for both high strength and precise manipulations. In "The Mote in God's Eye", Niven and Pournelle, created aliens with two tool-manipulating hands and one club-like hand. I don't think they realized the trick that nature pulled off in multi-purpose human hands. OTOH, our carpal tunnel is a very busy place; inflammation of this tendon-channel can be debilitating. There are definitely muscles in the hand. The abductor digiti minimi muscle is located on the medial side of the hand. That muscle is the distal endpoint of the Deep Back Arm Line (DBAL), a line starting in the upper back and responsible for outward rotation of the arm and hand. You can identify this muscle when you execute a Vulcan “live long and prosper!” salute and feel along the side of your hand. There’s a good Wikipedia article on this muscle as well as a summary article “muscles of the hand”. I had learned about the abductor digiti minimi muscles when I started exercising my arm rotators and that tiny muscle was noticeably sore.

You are right: the vast majority of the muscles for flexing and extending our fingers are located far up the arm. Tension-transmitters (i.e., tendons and ligaments) are cheap and have a small diameter; tension-adjustors (i.e., muscles) are expensive and have a far greater diameter. By having our finger’s function controlled by distant muscles, we’re able to use our hands for both high strength and precise manipulations. In “The Mote in God’s Eye”, Niven and Pournelle, created aliens with two tool-manipulating hands and one club-like hand. I don’t think they realized the trick that nature pulled off in multi-purpose human hands. OTOH, our carpal tunnel is a very busy place; inflammation of this tendon-channel can be debilitating.

]]> By: Anonymous https://blog.wolfram.com:443/2017/03/10/visualizing-anatomy/comment-page-1/#comment-124954 Anonymous Tue, 14 Mar 2017 09:11:21 +0000 https://blog.internal.wolfram.com/?p=35450#comment-124954 Either Out[19] is an alien, or it's just very very wrong. Humans don't have muscles in the fingers, only tendons (the only exception is tiny muscles attached to hair follicles). Either Out[19] is an alien, or it’s just very very wrong. Humans don’t have muscles in the fingers, only tendons (the only exception is tiny muscles attached to hair follicles).

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