pgs. 184-193 Flashcards
Internal Bones of the Cranium
Sphenoid and Ethmoid Bones
Sphenoid Bone
Forms the bottom of the cranium, housing the pituitary fossa for the pituitary gland. Resembling a bat, it also contains the sphenoidal sinus in most animals.
Ethmoid Bone
Located in front of the sphenoid, it has the cribriform plate for olfactory nerve branches and an ethmoidal sinus in humans and horses.
Ear Bones (Ossicles)
Malleus, Incus, Stapes: These small bones transmit sound vibrations from the eardrum to the cochlea, where they are converted into nerve impulses for the brain to interpret as sound.
External Bones of the Face
Incisive, nasal, maxillary, lacrimal, zygomatic, mandible
Incisive Bones
Hold upper incisor teeth, absent in ruminants (cattle, sheep, goats).
Nasal Bones
Form the bridge of the nose, shape varies with breed/species (e.g., long and thin in horses, triangular in short-faced breeds like Pekingese).
Maxillary Bones
Form the upper jaw, house upper canine and cheek teeth, and form the hard palate along with the palatine bones.
Lacrimal Bones
Small bones part of the eye orbit, housing the lacrimal sac for tear drainage.
Zygomatic Bones
Form the cheekbones and contribute to the zygomatic arch with temporal bones. Easily palpable under the eyes.
Mandible
The lower jaw, the only movable skull bone, houses lower teeth. In some animals, it has two separate bones fused by cartilage (e.g., dogs, cats, cattle). Its ramus supports jaw muscles.
Internal Bones of the Face
Palatine, pterygoid, vomer, turbinates (nasal conchae)
Palatine Bones
Form the back portion of the hard palate, separating the mouth from the nasal cavity.
Pterygoid Bones
Support the pharynx (throat) walls.
Vomer Bone
Forms part of the nasal septum.
Turbinates (Nasal Conchae)
Scroll-like bones inside the nasal cavity that condition air by warming, humidifying, and filtering.
Hyoid Bone
Supports the base of the tongue, pharynx, and larynx, aiding in swallowing. It consists of several parts connected by cartilage and attaches to the temporal bone.
Spinal Column
Made up of vertebrae, divided into cervical (neck), thoracic (chest), lumbar (abdomen), sacral (pelvis), and coccygeal (tail) regions. Each region is numbered for identification (e.g., C5 for the 5th cervical vertebra).
Vertebrae Structure
Composed of a body, arch (forms the spinal canal), and processes (spinous, transverse, and articular). Vertebrae form joints for flexibility.
Cervical Vertebrae
All mammals have seven cervical vertebrae. The first (C1) is the atlas, holding up the head. The second (C2) is the axis, allowing head rotation.
Thoracic Vertebrae
Located in the chest region, often matching the number of rib pairs. They have tall spinous processes and lateral facets for rib articulation.
Lumbar Vertebrae
Large and bulky, supporting abdominal organs without rib assistance.
Sacral Vertebrae
Fused into a single structure (sacrum), forming joints with the pelvis.
Coccygeal Vertebrae
Form the tail. In humans, they fuse into a single bone called the coccyx.
Ribs
Flat bones forming the thoracic wall, with dorsal joints to thoracic vertebrae. Their cartilaginous ends attach to the sternum or adjacent ribs, with some ending in muscle (floating ribs).
Sternum
The breastbone, formed of sternebrae. The first is the manubrium, and the last is the xiphoid process, which extends with cartilage.
Appendicular Skeleton
Composed of the limbs, with the thoracic limb (front) and pelvic limb (hind).
Thoracic Limb
Lacks direct bony connection to the axial skeleton, supported by muscles and tendons. The scapula is the main proximal bone.
Scapula
A flat triangular bone forming part of the shoulder joint, with a prominent ridge (spine) and glenoid cavity for the humerus.
Humerus
The upper arm bone. Its head forms part of the shoulder joint. Its distal end forms the elbow joint, with landmarks like the medial and lateral epicondyles. The “funny bone” is the ulnar nerve, not a bone.
