BIO 160: Chapter 8: The Skeletal System Flashcards
Define: Axial Skeleton
The axial skeleton forms the CENTRAL supporting axis of the body, includes: Skull Auditory Ossicles Hyoid bone Vertebral column, Thoracic cage (ribs and sternum).
Define: Appendicular Skeleton
Think appendages, includes:
bones of the upper limb and pectoral girdle and bones of the lower limb and pelvic girdle.
How many bones at birth?
270
How many bones in adult?
206
What is a sesamoid bone?
They are bones that form within some tendons in response to strain. The patella (knee cap) is the largest of these; most of the others are small, rounded bones in such locations as the hands and feet.
What are extra bones in the skull called?
Sutural ( think of the ‘sutures’ found there) or wormian bones.
Break down: Sesamoid
Sesam= sesame seed; oid= resembling
What is an articulated skeleton?
It is a skeleton where dried bones are held together by wires and rods to show their spatial relationships to each other.
What is a Disarticulated bones
Bones taken apart so their surface features can be studied in more detail.
Condyle
A rounded knob that articulates with another bone. ( occipital condyles of the skull)
Facet
A smooth, flat, slightly concave or convex articular surface (articular facets of the vertebrae)
Head
The prominent expanded end of a bone, sometimes rounded (head of the femur)
Which Anatomical Features of bones are Articulations?
Condyle
Facet
Head
What anatomical features of bones are classed as Extensions and projections?
Crest Epicondyle Line Process Protuberance Spine Trochanter Tubercle Tuberosity Depressions Alveolus Fossa Fovea Sulcus
Crest
A narrow ridge (iliac crest of the pelvis)
Epicondyle
An expanded region superior to a condyle (medial epicondyle of the femur)
Line
A slightly raised, elongated ridge (nuchal lines of the skull)
Process
Any bony prominence (mastoid process of the skull
Protuberance
A bony outgrowth or protruding part (mental protuberance of the chin)
Spine
A sharp, slender, or narrow process (mental spines of the mandible)
Trochanter
Two massive processes unique to the femur
Tubercle
A small, rounded process (greater tubercle of the humerus)
Tuberosity
A rough elevated surface (tibial tuberosity)
What Anatomical features of bones are classed as Depressions?
Alveolus
Fossa
Fovea
Sulcus
Alveolus
A pit or socket (tooth socket)
Fossa
A shallow, broad, or elongated basin (mandibular fossa)
Fovea
A small pit (fovea capitis of the femur)
Sulcus
A groove for a tendon, nerve, or blood vessel (interubercular sulcus of the humerus)
What anatomical features of bones are classed as Passages and cavities?
Canal Fissure Foramen Meatus Sinus
Canal
A tubular passage or tunnel in a bone (auditory canal of the skull)
Fissure
A slit through a bone (orbital fissures behind the eye)
Foramen
A hole through a bone, usually round (foramen magnum of the skull)
Meatus
An opening into a canal (external acoustic meatus of the ear)
Sinus
An air-filled space in a bone (frontal sinus of the forehead)
What are sutures?
Immovable joints, that are visible as seams on the surface.
Cranial Cavity
encloses the brain
Orbits
eye sockets (cavities)
Bones of the skull have foramina - singular, foramen - holes, what are they for?
Foramen holes are to allow the passage for nerves and blood vessels.
Cranial Bones
Are those that enclose the brain; collectively they compose the CRANIUM (braincase)
What are the 4 sinus bones called?
Sphenoid Sinus Frontal Sinus Ethmoid Sinus Maxillary Sinus They are connected with the nasal cavity, lined by mucous membranes, and filled with air
What are the cavities that make up the skull?
Cranial Cavity Orbits (eye sockets) Nasal Cavity Oral (buccal) Cavity Middle- and inner-ear cavities Paranasal sinuses
The delicate brain tissue does not come directly into contact with the bones, but is separated from them by three membranes called the _____
Meninges (Meh-NIN-jeez) The thickest and toughest of these, the Dura Mater, lies loosely against the inside of the cranium in most places but is firmly attached to it at a few points.
Dura= strong; Mater= mother
The cranium is a rigid structure with an opening, the ____ _________ meaning “large hole”, where the spinal cord meets the brain.
Foramen Magnum (Large hole)
The cranium consists of 2 major parts=
The Calvaria (skullcap) is not a single bone, but simply the dome of the top of the skull; it is composed of parts of multiple bones that form the roof and walls. The Base (floor) of the cranial cavity, which exhibits 3 paired depressions called cranial fossae (p242)
Anterior cranial fossa
The anterior cranial fossa is crescent-shaped and accommodates the frontal lobes of the brain.
Middle cranial fossa
The middle cranial fossa drops abruptly deeper than the anterior cranial fossa, is shaped like a pair of outstretched bird’s wings and accommodates the temporal lobes.
Posterior cranial fossa
The posterior cranial fossa is deepest and houses a large posterior division of the brain called the cerebellum.
What are the 8 cranial bones?
Page 238 1 frontal bone..Orange 2 parietal bones..Pink 2 temporal bones..Purple 1 occipital bone..Green 1 sphenoid bone..Blue 1 ethmoid bone..Light green
Frontal Bone
Extends from the forehead back to a prominent Coronal Suture, which crosses the crown of the head from right to left and joins the frontal bone to the parietal bones. The Frontal bone forms the anterior wall and about 1/3 of the roof of the cranial cavity.
Supraorbital margin
Deep to the eyebrows the frontal bone has a ridge called the supraorbital margin. Each margin is perforated by a single supraorbital foramen which provides passage for a nerve, artery, and veins.
Glabella
The smooth area of the frontal bone just above the root of the nose.
Parietal bones
The right and left parietal bones form most of the cranial roof and part of its walls. It has 4 sutures that connect them to other neighbouring bones: Sagittal suture-pink/pink, coronal suture-orange/pink, lambdoid suture-pink/green, squamous suture-purple/pink. (p 238/240). The parietal bones have markings where the bone has moulded around blood vessels of the meninges.
Parietal Foramen
Externally, the parietal bones have few features, a parietal foramen sometimes occurs near the corner of the lambdoid and sagittal sutures.
Temporal lines
A pair of slight thickenings, the superior and inferior temporal lines form an arc across the parietal and frontal bones (large arches around ear p.238) They mark the attachment of the large fan-shaped temporalis muscle, a chewing muscle that inserts on the mandible.
Temporal Bones
Forms the lower wall and part of the floor of the cranial cavity. It has 4 parts:
1) The squamous part (flat and vertical)
:Zygomatic process (back of cheek bone)
:Mandibular fossa (jaw joint)
2) The tympanic part (a small ring of bone)
:External acoustic meatus (opening of ear canal)
:Styloid process (pointed spine)
3) The mastoid part
:Mastoid process (prominent lump behind earlobe)
:Mastoid notch (origin of the digastric muscle, which opens the mouth
4) The petrous part (cranial floor, looks like a mountain range dividing the middle cranial fossa from the posterior fossa)
:Internal acoustic meatus
:Carotid canal (passage for internal carotid artery)
:Jugular foramen (blood from the brain drains through this foramen into the internal jugular vein of the neck.
Occipital bone
The occipital bone forms near the rear of the skull and much of its base.
Foramen Magnum
Allows the spinal cord to enter the cranial cavity and provides a point of attachment for the dura mater. In head injuries, swelling of the brain can force the brainstem out through the foramen magnum, usually having fatal consequences.
Occipital Condyle
On either side of the foramen magnum is a smooth know called the occipital condyle, where the skull rests on the vertebral column.
