Anatomy: Appendicular Skeleton

Bones of Thoracic Limb and Pelvic Limb

The appendicular skeleton is composed of

Clavicle, Scapula, Humerus, Radius, Ulna, Forepaw (Carpus, Metacarpus, Phalanges, Sesamoid Bones)

BONES OF THE THORACIC LIMB

Os Coxae, Femur, Sesamoid bones of Stifle Joints, Tibia, Fibula, Hindpaw (Tarsus, Metatarsus, Phalanges)

BONES OF THE PELVIC LIMB

Clavicle

not articulated with the skeleton in the dog.

Clavicle

It is located at the tendinous intersection of the brachiocephalicus muscle, and its medial end is attached to the sternal fascia by a distinct ligamentous band

Scapula

Large, flat bone of the shoulder joint.

Scapula

Its most dorsal part lies just ventral to the level of the free end of the spinous process of the first or second thoracic vertebra.

Humerus

bone of the arm, or brachium.

Humerus

Proximally it articulates with the scapula in forming the shoulder joint; distally it articulates with the radius and ulna in forming the elbow joint

Shoulder Joint

Scapula + Humerus

Elbow Joint

Humerus + Radius & Ulna

Radius

the main weight-supporting bone of the forearm

Radius

shorter than the ulna, which parallels it and serves primarily for muscle attachment.

Ulna

for descriptive purposes, is divided into a body, or shaft, and two extremities.

Proximal, Distal

Two extremeties of the ulna

Olecranon

Proximal Extremity of Ulna

Head

Distal extremity of Ulna

Forepaw

Includes the bones of the carpus, metacarpus, phalanges, and certain sesamoid bones associated with them.

Carpus

composed of seven bones arranged in two transverse rows, plus a small medial sesamoid bone.

Metacarpus

refers to the region of the manus, or forepaw, located between the carpus and the digits.

Metacarpal Bones

are typically five in number in primitive mammals, although supernumerary metacarpal bones and digits may appear

Phalanges

The digital skeleton of the forepaw consists of five units, of which four are fully developed and one is rudimentary.

Dewclaw

Rudimentary first digit in phalanges

St. Bernard

They have 2 dewclaws

Sesamoid Bones

On the palmar surface of each metacarpophalangeal joint of the main digits are two elongated, slightly curved bones that are located in the tendons of insertion of the interosseus muscles.

Os Coxae

Is composed of four distinct bones developmentally. These are the ilium, ischium, pubis, and acetabular bone.

Femur (os femoris)

Is the heaviest bone in the skeleton.

Femur (os femoris)

In well proportioned breeds it is slightly shorter than the tibia and ulna but is about one fifth longer than the humerus.

Patella

Sesamoid Bones of the Stifle Joint

Patella

Largest Sesamoid Bone in the Body

Patella

It is ovate in shape and curved so as to articulate with the trochlear of the femur.

Tibia

a long, thick bone that lies in the medial part of the crus, or anatomic leg.

Proximally

The tibia articulates with the femur

Distally

The tibia articulates with tarsus

Fibula

long, thin, laterally compressed bone located in the lateral part of the crus.

Fibula

It serves mainly for muscle attachment, as it supports little weight.

Hindpaw

Composed of the tarsal and metatarsal bones, the phalanges, and the sesamoid bones associated with the phalanges

Pes

Another word for Hindpaw

Hallux

First digit, is usually absent in the dog.

Dewclaw

The first digit of the hindpaw, regardless of its degree of development.

Tarsus

consists of seven tarsal bones. The term also applies collectively to the several joints between the tarsal bones, as well as the region between the crus and the metatarsus

Hock

Another name for tarsus

Metatarsus

refers to the region of the pes, or hindpaw, located between the tarsus and the phalanges.

Phalanges

so similar to those of the forepaw that no separate description is necessary, except for the bones of digit 1.