Axial Skeleton Friday, December 2 nd

Skull Bones Review Mental Foramen

The Teeth Human teeth show a morphology mainly differentiated by : – 1. The shape of their upper surface = crown – 2. The number of tooth roots – 3. The purpose of each tooth type Cutting Shredding Grinding

The Teeth

Incisors – Cutting teeth – 8 incisors – Very front of the mouth – Rather flat surfaces – A straight sharp horizontal edge for cutting and biting – 1 long conical root

The Teeth Canines – 4 – Very strong, pointed corner teeth – Used for tearing and shredding – Larger and stronger than the incisors – 1 single root – Upper canines are sometimes called “eyeteeth”

The Teeth Premolars – 8 – Used for chewing foot – Placed lateral to and behind the canine teeth – Flat upper surface – 1-2 roots – Crown has 2 cusps

The Teeth Molars – 12 – Back of the mouth – Large and flat upper surface – 2-4 roots – Largest of the permanent teeth – Used for final chewing and grinding before swallowing – 3 rd molars = Wisdom teeth

The Auditory Ossicles 3 smallest bones in the body Ossicles mean “tiny bones” Contained within the middle ear space Serve to transmit sounds from the air In order from the eardrum to the inner ear (superficial to deep) – 1. Malleus – 2. Incus – 3. Stapes

The Auditory Ossicles Malleus – Hammer – Articulates with the incus and is attached to the eardrum (or tympanic membrane) Incus – Anvil – Connected to the other ear bones Stapes – Stirrup – Articulates with the incus

The Auditory Ossicles Malleus Incus

The Auditory Ossicles Stapes

The Auditory Ossicles

The Vertebral Column Major Functions – Cervical – Support the weight of the head and trunk – Thoracic – Protect spinal cord – Lumbar – Allow spinal nerves to exit spinal cord – Sacral – Site for muscle attachment

The Vertebral Column Abormalities – Scoliosis Lateral curvature of spine (usually in children )

The Vertebral Column Abormalities – Lordosis Exaggerated anterior curve of lumbar spine (barrel chest)

The Vertebral Column Abormalities – Kyphosis Exaggerated posterior curve of thoracic spine (humpback)

The Vertebral Column Each bone consists of: – A body – An arch – Several processes

The Vertebral Column Body – Weight bearing portion Vertebral arch – Surround vertebral foramen – Formed from joining laminae and pedicales Vertebral foramen – All form the vertebral canal = spinal cord

The Vertebral Column Transverse Process – Extends laterally from each side of the arch between the pedicle and lamina 2 Laminae – Extend from transverse processes to spinous process

The Vertebral Column Articular Processes – Where vertebrae articulates with each other Spinous Process – Extends dorsally from 2 laminae

The Vertebral Column Intervertebral discs – Dense fibrous connective tissue – Drying along with the weakening of ligaments of the vertebral column Predisposes older people to herniated discs – slipped discs

The Vertebral Column Cervical - 7 – 1 st – Atlas “Yes” motion No body – 2 nd – Axis “No” motion

The Vertebral Column Cervical – Small bodies – Each transverse process has transverse foramen – Whiplash – hyperextension of the cervical vertebrae

The Vertebral Column Thoracic - 12 – Long, thin spinous processes – Articulates with the ribs

The Vertebral Column Lumbar - 5 – Large, thick bodies – Heavy rectangular transverse and spinous processes – Sturdiest of the vertebrae

The Vertebral Column Sacrum – Alae – wings – Articulates with the hip bones – 5 fused vertebrae

The Vertebral Column Coccyx – Tailbone – Usually 4 fused vertebrae – Very reduced bodies – No foramina or processes

The Bony Thorax The Rib Cage – Bony and cartilaginous structure – Supports the pectoral girdle – Provides attachments for the muscles of the neck, thorax, upper abdomen and back – Consists of 24 ribs The sternum 12 thoracic vertebrae

The Bony Thorax The rib parts: – Head – end of the rib closest to the vertebral column – Neck - is the flattened portion which extends lateralward – Tubercle - articulates with the transverse process – Angle – bending portion

The Bony Thorax Manubrium – the broad, upper part of the sternum – articulates with the clavicles and first 2 ribs Body – The lengthier and narrow part of the sternum – Below the manubrium

The Bony Thorax Xiphoid Process – Small cartilaginous process of the lower sternum – Ossified in adults Costal Cartilage – Bars of hyaline cartilage – Push ribs forward – Contribute to the elasticity of the rib cage

The Bony Thorax Vertebrosternal or “True Ribs” – Upper 7 ribs – Attached to the sternum (costal cartilage) – Allow movement (breathing) False ribs – 5 sets of ribs below true ribs – Has no direct attachment to the sternum

The Bony Thorax Vertebrocostal ribs – Those ribs connected to the lower thoracic vertebrae with costal cartilage – Ribs 7 or 8 down to rib 10 – Each rib is attached to the costal cartilage of the rib located superiorly to it (above it) – AKA “False ribs” because their costal cartilage does not attach directly to the sternum