Thoracic and Pelvic Limb Bones

Thoracic Limb Bones

• Scapula - The shoulder blade, a large, flat bone.
• Humerus - The bone of the upper arm.
  • Head - Articulates with the scapula.
  • Greater & Lesser Tubercles - Muscle attachment points.
  • Lateral Epicondylar Crest - Muscle attachment point.
  • Humeral Condyles - Articulates with the radius and ulna.
• Radius - The bone on the thumb side of the forearm.
  • Articular Fovea - Connects to the humerus.
  • Radial Tuberosity - Muscle attachment.
  • Styloid Process - Connects to the carpal bones.
• Ulna - The bone on the little finger side of the forearm.
  • Olecranon Process - Forms the point of the elbow.
  • Styloid Process - Connects to the carpal bones.
• Carpals - Seven bones in the wrist.
• Metacarpals - Five bones in the palm of the paw.
• Digits - Five fingers, each with three phalanges (except the dewclaw).

Pelvic Limb Bones

• Hip Bone - The pelvic girdle, comprised of the ilium, ischium, and pubis.
• Femur - The thigh bone.
  • Head - Articulates with the hip socket.
  • Greater & Lesser Trochanters - Muscle attachment points.
  • Third Trochanter - Muscle attachment point.
  • Femoral Condyles - Articulates with the tibia.
  • Femoral Trochlea - Articulates with the patella.
• Tibia - The larger bone of the lower leg.
  • Condyles - Articulates with the femur.
  • Tibial Tuberosity - Muscle attachment point.
  • Medial Malleolus - Forms the inner ankle bone.
• Fibula - The smaller bone of the lower leg.
  • Lateral Malleolus - Forms the outer ankle bone.
• Tarsals - Seven bones in the ankle.
• Metatarsals - Five bones in the foot, the first one is atypical.
• Digits - Five toes, each with three phalanges (except the dewclaw).

Splanchnic/Heterotopic Skeleton

• Os Penis (Baculum) - Bone present in the male dog, found in the penis and passing through the bulbus glandis.

Axial Skeleton

• Vertebrae - The bones of the spine, consisting of the cervical, thoracic, lumbar, sacral, and caudal vertebrae.

Cervical Vertebrae (Neck)

• Atlas - The first cervical vertebra, supports the skull.
  • Modified Articular Processes - Cup the exoccipital condyles of the skull.
  • Wings - Lateral extensions.
  • Lack of a Spinous Process - Distinguishes the atlas from other vertebrae.
  • Ventral Arch - Replaced the body of the vertebra.
  • Transverse Foramen - A canal passing through the transverse process.
• Axis - The second cervical vertebra.
  • Dens - A bony projection that fits into the atlas.

Thoracic Vertebrae (Chest)

• Spinous Processes - Project dorsally, with the spine of T11 being nearly perpendicular.
• Transverse Processes - Short and blunt, with articular facets for the ribs.
• Mamillary Processes - Small projections found on the transverse processes.
• Accessory Processes - Found on the midthoracic vertebrae.
• Articular Processes - Located at the junctions of the pedicles and laminae.

Lumbar Vertebrae (Loin)

• Large size and long transverse processes distinguish lumbar vertebrae from other vertebrae.
• Spinous Processes - Highest and most massive in the midlumbar region.
• Transverse Processes - Directed cranially and ventrally, longest in the midlumbar region.
• Accessory Processes - Well-developed on the first few lumbar vertebrae.
• Articular Processes - Lie in sagittal planes, with mamillary processes on the cranial processes.

Sacral Vertebrae

• Fused vertebrae forming the sacrum.
• Median Sacral Crest - Forms from the fusion of the spinous processes.

Caudal Vertebrae (Tail)

• Number varies between animals.
• Spinous Processes - Become smaller and reduced caudally.

Ribs

• Costal facets - Allow ribs to articulate with the vertebrae.
• Neck - The narrow part of the rib.
• Tubercle - A prominence on the rib that articulates with the transverse process of the vertebra.
• Angle - A lateral eminence distal to the tubercle.
• Costal Groove - A groove on the inner surface for the intercostal vessels and nerves.
• Costal Cartilage - Connects the ribs to the sternum.

Sternum (Breastbone)

• Sternebrae - Eight bones forming the sternum.
• Manubrium Sterni - The first sternebra.
• Xiphoid Process - The last sternebra.
• Xiphoid Cartilage - A cartilaginous extension of the xiphoid process.

Appendicular Skeleton

• Thoracic/Pectoral Limb - Bones of the forelimb.
• Pelvic Limb - Bones of the hind limb.

Thoracic Girdle

• Scapula - The shoulder blade, a large, flat bone.
• Clavicle - Not present in all animals.
• Coracoid - A small bone.

Arm/Brachium

• Humerus - The bone of the upper arm.

Forearm/Antebrachium

• Radius - The bone on the thumb side of the forearm.
• Ulna - The bone on the little finger side of the forearm.

Forepaw/Manus

• Carpus - The wrist bones.
• Metacarpals - The bones in the palm of the paw.
• Phalanges - The bones of the fingers.
• Palmar Sesamoid Bones - Small bones located in the palm of the paw.

Pelvic Girdle

• Hip Bone - The pelvis, comprised of the ilium, ischium, and pubis.

Thigh

• Femur - The thigh bone.

Lower Leg

• Tibia - the larger bone of the lower leg.
• Fibula - The smaller bone of the lower leg.

Foot

• Tarsus - The ankle bones.
• Metatarsals - The bones in the sole of the foot.
• Phalanges - The bones of the toes.
• Sesamoid Bones - Small bones located in the foot.