Sinus tarsi syndrome was also described by Duchenne in the late 1860's.
(It wasn't called that but he described pain in that location being relate to the position of the STJ.)
It's always good to look at the anatomy, but you have to look at function and forces as well.
In my opinion sinus tarsi pain is the result of end of range of motion of the joint resisting high external pronation moments.
I use to Dx more Sinus Tarsi Syndromes then I do now.
When I began performing Ankle Scopes about 10 years ago I started to appreciate how extensive ankle synovitis can be. I now think that some of the Sinus Tarsi I use to Dx may have in fact been ankle synovitis in the anteriolateral area.
I have evacuated Sinus Tarsi's a few times. Difficult to say what the pathology might have been but they all did well! I would imagine when you remove all the contents of the Sinus Tarsi (nerve included) you'll most likely remove whatever was symptomatic.
Here's the article that I submitted for publication to JAPMA 20 years ago where I first described the mechanical association between large magnitudes of subtalar joint pronation moments and sinus tarsi syndrome (Kirby KA:
Rotational equilibrium across the subtalar joint axis.
JAPMA, 79: 1-14, 1989).
Subtalar arthroscopy for sinus tarsi syndrome: arthroscopic findings and clinical outcomes of 33 consecutive cases.
Lee KB, Bai LB, Song EK, Jung ST, Kong IK. Arthroscopy. 2008 Oct;24(10):1130-4.
Distribution of sensory nerve endings around the human sinus tarsi: a cadaver study
Susanne Rein, Suzanne Manthey, Hans Zwipp, Andreas Witt Journal of Anatomy; Early View
Anatomy of the Tarsal Canal and Sinus in Relation to the Subtalar Joint Capsule
Reiko Yamaguchi, MD, Akimoto Nimura, MD, PhD, Kentaro Amaha, MD, ... Foot & Ankle International July 27, 2018
Sinus Tarsi Syndrome on Bone Scintigraphy With SPECT/CT: Spectrum of Findings
Patrick Martineau, Matthieu Pelletier-Galarneau Clin Nucl Med. 2021 Feb 1;46(2):e103-e105