Corpus: Metatarsal bones

The term metatarsus' refers to the entirety of all metatarsal bones (ossa metatarsalia) on the distal hind limb of domestic mammals.

The metatarsus is very similar to the metacarpus. The original five rays - similar to the forelimb - are only preserved in carnivores. The first metatarsal bone is only present as a rudiment in the cat. In dogs, it varies in length and is subject to major breed-related differences in its shape. Large dog breeds may even have a more or less complete toe, known as the dewclaw or wolf claw.

Terminology[Bearbeiten]

In contrast to "palmar" on the forelimb, the term "plantar" is used to describe the position of the hind limb towards the sole. As a result, the facies palmaris and the sulcus longitudinalis palmaris of the pastern bones are renamed facies plantaris and sulcus longitudinalis plantaris respectively on the hind limb. The vascular canals are also referred to as the proximal and distal metatarsal canals.

Morphology[Bearbeiten]

The bones of the metatarsus are slimmer, longer and significantly more developed in their wall structure than those of the forehand. The main metatarsal bone of the hind limb of the horse shows a longitudinal oval to roundish cross-section, whereas the corresponding bone on the forelimb is more transversely oval. In cattle, a sesamoid bone (Os sesamoideum metatarsale) can also occur proximally on the hind metatarsus.

The proximal, medial and distal phalanx of the hind and forelimb are also similar. In horses, however, the coffin bone on the hind limb is more pointed and narrower, and the lateral wall surfaces are also steeper than those of the forelimb.

Joints[Bearbeiten]

The metatarsus is articulated proximally and distally with the neighbouring bones.

• proximal: with the ossa tarsi (tarsal bones) via the articulatio tarsometatarsea (tight joint)
• distal: depending on the radius, with the first phalanx (proximal phalanx) via the articulatio metatarsophalangealis (hinge joint)

• Salomon, Franz-Viktor, Hans Geyer, Uwe Gille. Anatomy for veterinary medicine. Georg Thieme Verlag, 2015.
• König, Horst Erich, and Hans-Georg Liebich. Anatomy of Domestic Mammals: Textbook and Colour Atlas for Study and Practice. Schattauer Verlag, 2014.
• Nickel, Richard, August Schummer, Eugen Seiferle. Volume I: Musculoskeletal system. Textbook of the anatomy of domestic animals. Parey, 2004