The foot, Anatomy notes
From Firenze University Press Journal: Infermieristica Journal
Ferdinando Paternostro, University of Florence
Cristiana Veltro, University of Florence
Jacopo Junio Valerio Branca, University of Florence
Anna Vacca, University of Florence
The skeleton of the foot consists of a group of seven proximal bones, the tarsus, which continues forward with the !ve metatarsal bones which articulate with the phalanges. The set of these three parts constitutes an elongated bony system, rather squat posteriorly that “attens anteriorly due to the parallel arrangement of the metatarsals and the phalanges. The embryonic rotation of the lower limb bud causes the thumb to be lateral in hand and the medial big toe in the foot.Those of the tarsus are seven short or irregular bones organized in two series, one proximal, the astragalus and the calcaneus, one distal, the scaphoid, the cuboid, and the three cuneiform bones (medial, intermediate and lateral).
The astragalus or talo is an irregularly cuboid bone interposed between the bones of the upper leg, the heel at the bottom and behind and the scaphoid forward. There can be distinguished three portions: a back body, a front head and a neck, located between the previous. As a whole, six faces are described in the astragalus: upper, lower, medial, lateral, posterior and anterior.The upper face is entirely occupied by the trochlea, a transverse hemicylindrical relief, wider forward than backwards, crossed by a sagittal throat covered with cartilage that continues on the articular faces for the two malleoli, medial and lateral.The lower face has three articular facets for the calcaneus: the front and the middle contiguous and “at, the rear (behind and laterally) concave in the sagittal sense, transversely “at, separated from the other two by a deep groove.The medial and lateral faces have articular surfaces arranged on a plane close to the sagittal one that relates to the inner surfaces of the two malleoli, respectively, tibial and fibular.
The posterior face is vertically divided into two parts by a sagittal groove intended for the passage of the insertion tendon of the long “exor muscle of the big toe.The front face is occupied by the head, a portion of the sphere that enters into articulation with the scaphoid. It has a continuous cartilaginous coating with that of the anterior calcaneal articular face.The talo is located at the top of the posterior tarsus and distributes the body weight over the entire foot; through its superior articular surface, the astral trochlea articulated with the bimalleolar clamp, it distributes the mechanical stresses in three directions; backwards, towards the heel (the massive tuberosity of the calcaneum) through the rear astragalus-calcaneal joint; forward and medially, in the direction of the inner arch of the plantar vault , through the astragalus-hull articulation; forward and sideways, in the direction of the outer arch of the plantar vault, through the anterior astragalus-calcaneal articulation.
The talo does not have muscular insertions: all the muscles of the leg that are inserted on the foot pass to him to bridge: for this, the astragalus is said “caged” bone.The calcaneus is the most voluminous bone of the tarsus, with the major axis oriented in the anteroposterior direction. It is located under the astragalus, which does not completely cover it but leaves free the rear portion. It describes six faces: the upper one has three facets for the astragalus, of which the rear is the largest, cone-shaped segment with an oblique axis laterally and forward, while the front and middle articular facets are smaller, “at and approach each other at an obtuse angle. The medium articular facet, which is located on the sustentaculum tali is separated from the posterior by the groove of the calcaneum above which the sulcus of the Talo firsts symmetrically: in this way, the so-called sinus of the tarsus forms between the two bones.The lower face, irregular, has two tuberosities, one anterior and one posterior; on the latter, two tubercles are described, the medial and the lateral.On the lateral side, there are two grooves intended for the passage of the tendons of the lateral peronier muscles, long and short. The medial face is characterized by the presence of a long shower in which run tendons, vessels and nerves that from the back face of the leg lead to the sole of the foot and a small apophysis that protrudes medially, the sustentaculum tali.The front face has a saddle joint surface for the homologous surface of the cuboid. The back face corresponds to the projection of the heel; at the bottom is wrinkled for the insertion of the calcaneal tendon.The cuboid is an irregularly cubic bone located in the outer part of the foot in front of the heel, laterally to the scaphoid and third cuneiform, behind the fourth and fith metatarsals.
The upper face is wrinkled and not articular; The plantar is crossed by an oblique groove for the tendon of the long peronier muscle. Behind the groove is the tuberosity of the cuboid. The lateral face is narrow and concave, and the furrow of the long peronier extends there; the medial one is more extended; it has a facet joint for the third bone cuneiform and, sometimes, a smaller facet for the scaphoid. The posterior surface (proximal facet), convex-concave, corresponds to the homologous face of the calcaneum, with which it is articulated. The anterior (distal) surface is divided into two facets that articulate with the bases of the fourth and !#h metatarsal bones. The scaphoid (or navicular) is a bone shaped like a “attened disk or spaceship, placed in front of the head of the astragalus, behind the row of the three cuneiform, medially to the cuboid. It has a front and a rear face, two margins, upper and lower and two ends, medial and lateral. The back face is concave and welcomes the head of the astragalus; The front, convex overall, has three “at veneers for the three cuneiform.The medial extremity is characterized by a prominent tuberosity, on which the main tendon of the posterior tibial muscle is inserted.The cuneiform bones are three and have the form of triangular prisms.They are distinguished in the middle-lateral sense with the name of the first cuneiform or medial, second cuneiform or intermediate and third cuneiform or lateral.The medial cuneiform is the most voluminous; it is articulated forward with the first metatarsal and laterally with the second cuneiform and the second metatarsal bone. The sharp part of the wedge is facing upwards. On the medial, non-particular face, the anterior tibial muscle is inserted.The intermediate cuneiform is distinguished from the other two by being shorter. The sharp margin is facing down and articulates on the sides with its homologues, forward with the second metatarsal. The lateral cuneiform is arranged as the intermediate: anteriorly, it makes contact with the base of the third metatarsal, the medial face has an articular facet for the second cuneiform and one for the second metatarsal, and the lateral face is articulated with the cuboid and thick, forward, with the fourth metatarsal.
DOI: https://doi.org/10.36253/if-1790
Read Full Text: https://riviste.fupress.net/index.php/if/article/view/1790
