The Skeletal System

ANML SC 512

Functions of the skeletal system

• Support

• Protect

  • Thorax

  • Skull and spinal cord

• Levers (movement)

• Storage (mineral)

• Blood cell formation

  • Hematopoiesis

Bone shapes

• Long

  • Femur (upper arm), humerus (thigh bone)

• Irregular

  • Vertebrae

  • Sesamoids (small, near joints)

• Flat

  • Skull, scapula

• Short

  • Cuboid bones (lateral part of the foot)

Axial skeleton

Central axis

• Skull, hyoid, ribs/sternum, spine/tail

Thoracic skeleton

Thoracic and pelvic limbs

Skull - General calvarium anatomy

• Occipital [1]

  • back and lower part of skull

• Temporal [2]

  • protects temporal lobe of the brain

• Parietal/interparietal [2/2]

  • dorsal to the temporal bones/in between the parietal bones

• Frontal [2]

  • forms forehead and dorsal-caudal part of orbits

Skull - Further calvarium anatomy

Occipital [1]

• Foramen magnum

  • Opening that connects the spinal cord to the brain

• Occipital condyles [2]

  • Protuberances of the occipital bone that articulate (connect) with the atlas vertebra, lateral to foramen magnum

Temporal [2]

• Tympanic bulla

  • Bony structure in the middle ear that forms part of the tympanic cavity

• Acoustic meatus

  • External acoustic meatus and the internal acoustic meatus, auditory passage located on the lateral side of the cranium, forming part of the temporal bone, small bony canal that serves as a passage for nerves and vessels

Parietal/interparietal [2/2]

Frontal [2]

Skull - General maxilla anatomy

• Incisive [2]

  • Rostral end of the head, carries the upper incisor teeth

• Nasal [2]

  • Forms dorsal part of the roof of the nasal cavity; caudal to incisive bones

• Maxillary [2]

  • Largest(?) bones of the face, carries upper molars, forms part of the face, nasal cavity, orbit, and hard palate; lateral to nasal bones

• Lacrimal [2]

  • Forms the medio-rostral border of the orbit, fused to the frontal, nasal, zygomatic and maxillary bones

• Zygomatic [2]

  • AKA the cheekbone, forms facial structure and protects eyes

• Nasal septum

  • Divides nasal cavity into two halves, cartilaginous/bony depending on species

• Turbinates

  • Structures found in nasal cavity that are covered by soft tissue, help filter, warm, and humidify air that enters, can also help enhance olfaction