Gross Anatomy Lecture 1: Intro to the Skeleton

Lecture 1: Introduction to the Skeleton

Axial Skeleton

Consists of the BONES along the axis of the body.

(i.e., skull, cranium, face, thoracic cage, ribs, sternum, etc.)

Appendicular Skeleton

Consists of the bones of the appendages (arms and legs), and the girdles (shoulder and pelvic).

(i.e. femur, patella, radius, ulna, etc.)

Structures of Bones

Articulations

Landmarks

Foramina

Articulations

Contacts with other bones

Landmarks

(Bone markings; marks)

• Are areas of muscle and ligament attachment.

Foramina

Openings for nerves and blood vessels.

How many bones the vertebral column have?

26 total

• Vertebrae: 24

• Sacrum: 1

• Coccyx: 1

How many bones do the ribs have?

24 bones

How many bones are in the middle ear?

3 bones

How many bones are in the Axial Skeleton?

80 bones

How many bones are in the appendicular skeleton?

126 bones

What is the anatomical position?

• Standing up

• Hands at the sides

• Palms facing forward

• Feet together

Anatomical Positions (laying down)

• Supine: Face up

• Prone: Face down

Process

Any projection or bump.

Ramus

An extension of a bone making an angle with the rest of the structure.

(i.e. ramus of the mandible)

Trochanter

A large, rough projection.

Tuberosity

A small, rough projection.

Tubericle

A small, ROUNDED projection.

Crest

A prominent ridge.

Line

A low ridge.

Spine

A pointed or narrow process.

Condyle

A smooth, rounded articular process.

Trochlea

A smooth, grooved articular process shaped like a pulley.

Facet

A small, flat articular surface.

Fossa

A shallow depression.

Sulcus

A narrow groove.

Foramen

A rounded passageway for blood vessels or nerves.

Canal

A duct or channel.

Meatus

A passageway through a bone.

Fissure

An elongated cleft or slit.

Sinus

A chamber within a bone, normally filled with air.

Suture

Is a synarthrotic joint located ONLY between the bones of the skull.

• Fibrous

Gomphosis

Is a synarthrosis that binds the teeth to bony sockets in the maxillae and mandible.

• Fibrous

Synchondrosis

Is a rigid, cartilaginous bridge between two articulating bones.

Synotosis

Is a totally rigid, immovable joint created when two bones fuse and the boundary between them disappears.

Syndesmosis

Where bones are connected by a ligament.

(i.e. the distal articulation the tibia and fibula.)

• Fibrous

Symphysis

Where the articulating bones are separated by a wedge or pad of fibrocartilage.

(i.e. the articulation between the two pubic bones)

• Cartilaginous

Synovial Joints

Permits a wider range of motion than other types of joints.

Typically located at the ends of long bones, such as the lower and upper limbs.

Planes of Movement (Synovial Joints)

• Monoaxial

• Biaxial

• Triaxial

Monoaxial

Movement in one plane.

(i.e. elbow, ankle)

Biaxial

Movement in two planes.

(i.e. ribs and wrist)

Triaxial

Movement in three planes.

(i.e. shoulder, hip)

Functions of the Axial Skeleton

Supports and protects organs in body cavities.

1. Attaches to muscles of the head/neck

2. Performs respiratory movements

3. Stabilizes parts of the appendicular skeleton

Vertebral Column

Part of the axial skeleton.

• Protects the spinal cord

• Supports head and body

• Thoracic cage

Vertebral Column

• Cervical (C)

• Thoracic (T)

• Lumbar (L)

• Sacral (S)

• Coccygeal (Co)

Vertebral Anatomy

Consists of:

• Vertebral body

• Vertebral arch

• Articular processes

Vertebral Body

Transfers weight along the spine.

Vertebral Arch

Posterior margin of vertebral foramen.

Articular Processes

Lateral projections between laminae and pedicles.

Intervertebral Discs

• Are pads of fibrocartilage that separate the vertebral bodies.

• Absorb shock

What is the axis of the cervical vertebrae?

C2

What is the atlas of the cervical vertebrae?

C1

Thoracic Vertebrae

T1 - T12

Where is the intervertebral foramen?

T3

Regions of Vertebrae

• Cervical = 7

• Thoracic = 12

• Lumbar = 5

Thoracic Cage

The skeleton of the chest; supports the thoracic cavity.

Rib Cage

Formed by the ribs and sternum.

What does the sternum consist of?

(also called the breastbone)

• Ribs (Costae): 12 pairs of long, curved, flat bones divided into two types:

  • True ribs (ribs 1-7)

  • False ribs (ribs 8-12); floating ribs

Pectoral Girdle

(Also called shoulder girdle);

Connects with the axial skeleton only at the manubrium.

What does the pectoral girdle consist of?

• Two scapulae: (Shoulder blades)

• Two clavicles: (Collarbones)

Scapulae

• Articulate with arm and collarbone.

• Anterior surface is called the subcapsular fossa.

Clavicles

• Originate at the manubrium (sternal end).

• Articulate at the scapulae (acromial end).

  • Lateral

The Scapulae

Body has three sides:

1. Superior Border

2. Medial Border (vertebral border)

3. Lateral Border (axillary border)

Processes of the Glenoid Cavity

• Coracoid Process: Anterior, smaller

• Acromion: Posterior, larger

  • Articulates with clavicle

  • At the acromioclavicular joint