Veterinary Gross Anatomy

Metatarsals

METATARSAL BONES
(Ox, Sheep and Goat, Horse, Pig, Dog, Rabbit, Fowl)

Ox

The metatarsus has two bones -the large (third and fourth) and the medial small (second) metatarsal bones.

Large metatarsal bone (third and fourth)

• It resembles the large metacarpal except for the following differences
• The bone is longer than metacarpal.
• The shaft is four sided.
• The dorsal metatarsal groove is deeper.
• The plantar face presents a shallow groove. Commencing at the upper part of the groove is a vascular tunnel passing obliquely upward and forward through the proximal extremity to open on the articular face of the extremity behind and between the facets.
• The proximal extremity presents a flattened facet laterally for the fused central and 4th tarsal and a large facet on the medial aspect for the fused 2nd and third tarsal behind which is another small facet for the first tarsal. At its postero medial aspect, this extremity presents a facet for the small metatarsal bone.
• The dorso-medial aspect presents a tuberosity for the attachment of the tendon of the peroneus tertius.
• The distal extremity resembles that of the large metacarpal.

Medial small metatarsal

• The medial small metatarsal is disc shaped piece of bone situated at postero-medial aspect of the proximal extremity of the large metatarsal bone.
• It presents small facet on its dorsal face for the large metatarsal. The rest of the bone is rough.

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Sheep and Goat

• Resembles that of Ox.

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Horse

It has three metatarsal -one large (third) and two small (second and fourth) medial and lateral metatarsals.

• The large metatarsal resembles the large metacarpal.
• The vertical groove presents in the ox are absent.\
• The proximal extremity presents facets for the third tarsal, the fourth tarsal and sometimes the second tarsal. The shaft is cylindrical.
• The small metatarsals, each has two small facets in front for the large metatarsal.
• The lateral (fourth) metatarsal is relatively massive, especially in its upper part.
• The proximal extremity is large and outstanding and bears one facet above for the fourth tarsal.
• The medial bone (second metatarsal) is much more slender than the lateral especially in its proximal part, which bears two facets above for the first the second tarsal and sometimes one for the third tarsal.

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Pig

• Four in number and resembles that of the metacarpal of the forelimb.
• The second and fifth are placed more towards the plantar aspect of the large bones.

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Dog

• Five metatarsals are present.
• The first is small and the other four are well developed and resemble the metacarpals.

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Rabbit

• Four in number.
• They are very narrow rod shaped structures.

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Fowl

• The tarso-metatarsus is a single bone formed by the fusion of the distal row the tarsals with the second, third and fourth metatarsals.
• The proximal extremity presents two glenoid cavities for the distal end of the tibio-tarsus.
• The shaft is two-sided.
• The first metatarsal is attached by ligament to the postero-medial border of the large metatarsus. In the male, a conical projection arises from the medial aspect of the body of the metatarsus and serves as a core for the horny spur or calcar.
• The distal extremity divides into three processes.
• Each process is in the form of an articular convexity. The medial one is the shortest and articulates with the second digit.
• The middle one is the longest and articulates with the third-digit.
• The lateral one articulates with the fourth digit.

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