5. The inferior sesamoid ligament ([Figs. 11, d′], [12, d, d′], and [13, d′, E]). This originates at the lowest part of the sesamoid bones and intersesamoid ligament, and consists of three parts or branches. The median branch (d) is the longest and strongest, and takes its lower attachment in the middle of the fibro-cartilaginous lip found on the upper border of the posterior face of the second phalanx. The two lateral branches (d′) approach each other as they descend, and terminate on the sides of the roughened triangle on the posterior face of the first phalanx.
6. The deep inferior sesamoid ligament ([Fig. 13, e]) is quite short, and consists of a number of distinct, thin fibrous bands lying directly against the bone and entirely covered by the median and lateral inferior sesamoid ligaments. These fibrous bands cross one another in passing from the sesamoids to the first phalanx.
II. The coronary joint is the simplest of the three articulations of the foot. The long pastern furnishes two condyles and the short pastern two glenoid cavities. Besides a capsular ligament there are—
1. Two lateral coronary ligaments (k) and,
2. Six posterior coronary ligaments,—namely, two superior coronary ligaments (h), two median coronary ligaments (h′), and two inferior coronary ligaments (g).
III. The pedal articulation (“coffin” joint) is an imperfect hinge-joint, and is formed by the condyles at the lower end of the short pastern and the two glenoid cavities in the united upper surfaces of the pedal and navicular bones. Besides the capsular ligament ([Figs. 12] and [13, l]), which binds all three bones together, there are the following accessory ligaments:
1. Two strong lateral ligaments, an external and an internal ([Fig. 11, i]), whose posterior borders are lost in the lateral cartilages which cover them.
2. Two lateral suspensory ligaments of the navicular bone (k). They begin on the posterior border and ends of the navicular bone, and terminate on the lower part of the anterior surface of the os suffraginis, where they are lost in the lateral ligaments of the coronary articulation.
3. The lateral ligaments of the lateral cartilages, navicular bone, and os pedis. They are short, and unite the navicular bone with the os pedis and lateral cartilages.
Of the three phalangeal articulations, the pedal is the only one that permits of any lateral movement; hence it is an imperfect hinge-joint.