Chapter 7: The Skeletal System - Lab Studies

Flashcards covering key anatomical vocabulary and definitions from Chapter 7: The Skeletal System.

Axial Skeleton

The division of the skeleton consisting of $80$ bones forming three major regions: the skull, vertebral column, and thoracic cage.

Appendicular Skeleton

The division of the skeletal system comprising the bones of the upper and lower limbs and their attached girdles (pectoral and pelvic).

Cranial Vault (Calvaria)

The superior portion of the cranium that encloses the brain within the cranial cavity.

Coronal Suture

The articulation joint between the parietal bones and the frontal bone.

Sagittal Suture

The articulation joint located medially between the right and left parietal bones.

Lambdoid Suture

The joint connecting the parietal bones with the posterior occipital bone.

Squamous Suture

The articulation between a parietal bone and a temporal bone on each lateral side of the skull.

Frontal Bone

The cranial bone forming the anterior portion of the cranium, most of the anterior cranial fossa, the superior wall of the orbits, and containing the air-filled frontal sinus.

Occipital Bone

The cranial bone that forms most of the skull's posterior wall and posterior cranial fossa, articulates with the first vertebra, and serves as an attachment site for the ligamentum nuchae.

Temporal Bones

Paired cranial bones forming inferolateral aspects of the skull and parts of the cranial floor, divided into squamous, tympanic, mastoid, and petrous regions.

Sphenoid Bone

A complex, bat-shaped keystone cranial bone that articulates with all other cranial bones and features greater wings, lesser wings, and pterygoid processes.

Ethmoid Bone

The deepest cranial bone, forming the superior part of the nasal septum, roof of the nasal cavity, and contributing to the medial walls of the orbits.

Sutural Bones

Tiny, irregularly shaped bones that occasionally appear within the cranial sutures.

Mandible

The lower jawbone; it is the largest and strongest bone of the face and forms the temporomandibular joint, the only freely movable joint in the skull.

Maxillary Bones (Maxillae)

Medially fused keystone facial bones forming the upper jaw and central facial skeleton, articulating with all facial bones except the mandible and containing the largest paranasal sinuses.

Zygomatic Bones

Facial bones commonly called cheekbones that form the inferolateral margins of the orbits.

Lacrimal Bones

Small facial bones located in the medial walls of the orbits containing a lacrimal fossa that houses the lacrimal sac.

Palatine Bones

Facial bones forming the posterior one-third of the hard palate, posterolateral walls of the nasal cavity, and a small part of the orbits.

Vomer

A plow-shaped facial bone forming the inferior portion of the nasal septum.

Inferior Nasal Conchae

The largest of three pairs of conchae, forming part of the lateral walls of the nasal cavity.

Paranasal Sinuses

Mucosa-lined, air-filled spaces found in the frontal, sphenoid, ethmoid, and maxillary bones that lighten the skull, enhance voice resonance, and warm and humidify air.

Hyoid Bone

A U-shaped bone in the neck that does not articulate directly with any other bone; acts as a movable base for the tongue and an attachment site for muscles of swallowing and speech.

Atlas ($C_1$)

The first cervical vertebra, lacking a body and spinous process, which articulates with the occipital condyles to enable the movement for saying 'Yes'.

Axis ($C_2$)

The second cervical vertebra featuring a superior projection called the dens, which acts as a pivot for rotation to produce the 'No' head movement.

Scoliosis

An abnormal spinal curvature characterized by a lateral deviation of the spine.

Kyphosis

An exaggerated thoracic spinal curvature commonly referred to as hunchback.

Lordosis

An accentuated lumbar spinal curvature commonly referred to as swayback.

Nucleus Pulposus

The inner gelatinous core of an intervertebral disc that provides elasticity and compressibility.

Anulus Fibrosus

The outer ring of an intervertebral disc composed of collagen and fibrocartilage surrounding the nucleus pulposus.

Vertebral Foramen

The central opening formed by the body and vertebral arch; aligned together across vertebrae, they form the vertebral canal for the spinal cord.

Intervertebral Foramina

Lateral openings formed between adjacent vertebrae that serve as passageways for spinal nerves.

True Ribs (Vertebrosternal Ribs)

Rib pairs $1$ through $7$ that attach directly to the sternum via individual costal cartilages.

False Ribs

Rib pairs $8$ through $12$; pairs $8$–$10$ (vertebrochondral) attach indirectly to the sternum via the costal cartilage above, while pairs $11$–$12$ (floating) have no sternal attachment.

Floating Ribs (Vertebral Ribs)

Rib pairs $11$ and $12$ that have no anterior attachment to the sternum.

Manubrium

The superior portion of the sternum articulating with the clavicles and ribs $1$ and $2$.

Xiphoid Process

The inferior cartilaginous end of the sternum that serves as a muscle attachment site and does not fully ossify until approximately age $40$.

Pectoral Girdle

The shoulder girdle consisting of the clavicles and scapulae that attaches the upper limbs to the axial skeleton.

Clavicles

S-shaped collarbones with a medial sternal end and a lateral acromial end that anchor muscles and brace the scapulae and arms laterally.

Scapulae

Triangular flat shoulder blades situated on the dorsal rib cage surface between ribs $2$ and $7$.

Humerus

The largest and longest bone of the upper limb, articulating proximally with the glenoid cavity of the scapula and distally with the radius and ulna.

Radius

The lateral bone of the forearm whose proximal head articulates with the capitulum of the humerus and radial notch of the ulna.

Ulna

The medial bone of the forearm that forms the main portion of the elbow joint with the humerus.

Carpus

The wrist region comprising eight short carpal bones arranged in proximal and distal rows.

Pollex

Digit $1$ of the hand (the thumb), containing only two phalanges (proximal and distal).

Pelvic Girdle

The hip girdle formed by two coxal bones and the sacrum that attaches lower limbs to the axial skeleton and supports pelvic organs.

Ilium

The superior region of a coxal bone featuring an auricular surface that articulates with the sacrum at the sacroiliac joint.

Ischium

The posteroinferior region of the hip bone.

Pubis

The anterior portion of the hip bone, meeting its counterpart at the pubic symphysis joint.

Femur

The largest and strongest bone in the human body, accounting for approximately $\frac{1}{4}$ of a person's total height.

Patella

A sesamoid bone enclosed in the quadriceps tendon that protects the knee joint.

Tibia

The medial leg bone that receives body weight from the femur and transmits it to the foot.

Fibula

The lateral leg bone that does not bear weight or articulate with the femur.

Hallux

Digit $1$ of the foot (great toe), containing two phalanges.

Fontanelles

Unossified remnants of fibrous membranes connecting bones in an infant skull, easing birth and allowing rapid brain growth.

Cleft Palate

A congenital skull abnormality resulting from the incomplete medial fusion of the right and left halves of the palate.