Bones Hot List: Axial and Appendicular Skeleton Study Guide

Axial Skeleton

Cranium

The cranium is the part of the skull that encloses the brain, providing protection and structural support. It consists of several bones joined by sutures.

• Sutures: Immovable joints between skull bones.

  • Sagittal suture: Between the two parietal bones.

  • Coronal suture: Between frontal and parietal bones.

  • Squamosal suture: Between parietal and temporal bones.

  • Lamboidal suture: Between parietal and occipital bones.

• Frontal bone: Forms the forehead and part of the eye socket.

• Temporal bones: Located at the sides and base of the skull.

• Parietal bones: Form the roof and sides of the cranium.

• Occipital bone: Forms the back and base of the skull; contains the foramen magnum for spinal cord passage.

• Sphenoid bone: Forms part of the base of the skull and the sides of the orbits; includes the sella turcica (pituitary gland location).

• Ethmoid bone: Located between the eyes; forms part of the nasal cavity and orbital walls.

• Facial Bones: Include mandible, vomer, lacrimal, nasal, maxilla, and zygomatic bones.

Example: The mandible is the only movable bone of the skull, forming the lower jaw.

Vertebral Column

The vertebral column supports the body and protects the spinal cord. It is divided into regions and consists of individual vertebrae.

• Cervical vertebrae: 7 vertebrae in the neck region; C1 (atlas) and C2 (axis) allow head movement.

• Thoracic vertebrae: 12 vertebrae attached to ribs.

• Lumbar vertebrae: 5 vertebrae in the lower back.

• Sacrum: 5 fused vertebrae forming the back of the pelvis.

• Coccyx: 3-5 fused vertebrae forming the tailbone.

• Parts of a Generic Vertebra:

  • Body: Main weight-bearing portion.

  • Vertebral foramen: Opening for the spinal cord.

  • Transverse process: Lateral projections for muscle attachment.

  • Spinous process: Posterior projection for ligament and muscle attachment.

Example: The atlas (C1) supports the skull and allows nodding motion; the axis (C2) allows rotation.

Bony Thorax

The bony thorax protects vital organs in the chest and provides attachment points for muscles involved in respiration.

• Sternum: Flat bone at the center of the chest; includes the manubrium, body, and xiphoid process.

• Ribs (costa):

  • Vertebrosternal (true) ribs: First 7 pairs, attached directly to sternum.

  • Vertebrochondral (false) ribs: Next 3 pairs, attached to sternum via cartilage.

  • Vertebral (floating) ribs: Last 2 pairs, not attached to sternum.

Example: The xiphoid process is the smallest part of the sternum and serves as an attachment for abdominal muscles.

Appendicular Skeleton

Pectoral Girdle

The pectoral girdle connects the upper limb to the axial skeleton and allows for a wide range of shoulder movements.

• Clavicle: Collarbone; connects sternum to scapula.

• Scapula: Shoulder blade; includes acromion process and coracoid process.

• Glenoid fossa: Shallow cavity for articulation with the humerus.

Example: The acromion process forms the highest point of the shoulder.

Arm

The arm consists of the humerus, which articulates with the scapula at the shoulder and with the radius and ulna at the elbow.

• Humerus: Upper arm bone; includes head and epicondyles (lateral and medial).

Example: The medial epicondyle is a common site for muscle attachment.

Forearm

The forearm is composed of the radius and ulna, which allow for rotation and movement of the wrist and hand.

• Radius: Lateral bone of the forearm; includes head and ulnar notch.

• Ulna: Medial bone of the forearm; includes olecranon process (elbow) and radial notch.

Example: The olecranon process forms the bony tip of the elbow.

Carpus (Wrist) and Manus (Hand)

The wrist and hand consist of multiple small bones that allow for dexterity and fine motor movements.

• Carpus: Eight carpal bones form the wrist.

• Manus: Includes metacarpals (palm) and phalanges (fingers).

Example: The phalanges are the bones of the fingers and thumb.

Pelvic Girdle

The pelvic girdle supports the weight of the upper body and protects pelvic organs.

• Os coxae: Hip bone, formed by fusion of ilium, ischium, and pubis.

• Acetabulum: Deep socket for articulation with the femur.

Example: The acetabulum is the site of the hip joint.

Thigh, Knee Cap, and Leg

The lower limb consists of the femur (thigh), patella (knee cap), tibia and fibula (leg), and bones of the foot.

• Thigh: Femur; includes head and neck, greater and lesser trochanters, and epicondyles.

• Knee Cap: Patella; protects the knee joint.

• Leg: Tibia (medial, weight-bearing), fibula (lateral, slender); includes tuberosity, malleolus (medial and lateral).

Example: The medial malleolus is the bony prominence on the inner side of the ankle.

Foot

The foot is composed of tarsals, metatarsals, and phalanges, providing support and mobility.

• Tarsals: Seven bones including the calcaneus (heel) and talus (ankle).

• Metatarsals: Five bones forming the arch of the foot.

• Phalanges: Bones of the toes.

Example: The calcaneus is the largest tarsal bone and forms the heel.

Summary Table: Major Bones and Features

Region	Main Bones	Key Features
Axial Skeleton	Skull, Vertebral Column, Thorax	Sutures, Foramen Magnum, Sella Turcica, Sternum, Ribs
Appendicular Skeleton	Pectoral Girdle, Arm, Forearm, Hand, Pelvic Girdle, Thigh, Leg, Foot	Clavicle, Scapula, Humerus, Radius, Ulna, Carpals, Metacarpals, Phalanges, Os Coxae, Femur, Patella, Tibia, Fibula, Tarsals, Metatarsals

Additional info: This guide covers the essential bones and features of the axial and appendicular skeleton, suitable for exam preparation in Anatomy & Physiology courses.