Human Anatomy: Skull, Spine, and Upper Limb

Skull

• The skull comprises the bones of the head, surrounding the brain.
• Cranial bones:
  • Frontal bone (front)
  • Parietal bone (top)
  • Occipital bone (back)
  • Temporal bone (beside the ear)
  • Sphenoid bone (anterior to the temporal bone)
  • Ethmoid bone (midline, posterior to the nose, inferior to frontal)
• Facial bones:
  • Nasal bone (bridge of the nose)
  • Maxilla (connects nose, cheekbones, and upper teeth)
  • Zygomatic bones (cheekbones)
  • Mandible (jaw bone, connects to the temporal bone at the TMJ)

Spine

• The spine consists of vertebrae, numbered from top to bottom.
• Vertebral sections:
  • 7 Cervical vertebrae (C1-C7)
  • 12 Thoracic vertebrae (T1-T12)
  • 5 Lumbar vertebrae (L1-L5)
  • Sacrum
  • Coccyx
• C1 (Atlas) and C2 (Axis): Specialized vertebrae at the top of the spine.

Upper Limb

• Clavicle (collarbone): Horizontal bone between the sternum and shoulder.
• Scapula (shoulder blade): Flat, triangular bone at the back.
• Humerus: Upper arm bone.
• Glenoid fossa: Concave area on the scapula that articulates with the humerus to form the Glenohumeral joint.
• Radius and Ulna: Bones of the forearm, connecting to the humerus at the elbow and to the carpal bones at the wrist.
• Carpal bones: 8 bones of the wrist.
• Metacarpal bones: 5 bones of the palm (numbered 1-5 from thumb to pinky).
• Phalanges: Finger bones. Each finger has 3 phalanges (proximal, middle, distal); the thumb has 2.

Thorax

• Clavicle: Attaches to the sternum at the sternoclavicular joint.
• Sternum: The breastbone, made of manubrium (top), body (middle), and xiphoid process (bottom).
• Sternoclavicular joint: Connects the clavicle and the sternum.
• 12 ribs: Parallel bones, each labelled 1-12, attaching to the thoracic vertebrae.
• Costal cartilages: Connect most ribs to the sternum.
• Floating ribs: Ribs 11 and 12, not attached to the sternum.

Pelvis

• The pelvis is composed of the ilium, ischium, and pubis.
• Sacrum: Attaches to the ilium at the sacroiliac joint.
• Pubis: Bones at the front of the pelvis that fuse in the center at the pubic symphysis.
• Ischium: Inferior part of the pelvis.
• Acetabulum: Hip joint socket, formed by the junction of the ilium, ischium, and pubis.

Lower Limb

• Femur (thigh bone): Longest bone in the body. Attaches to the acetabulum of the pelvis to form the hip joint.
• Tibia and Fibula: Lower leg bones (tibia is medial; fibula is lateral) that articulate with the femur.
• Patella (kneecap): Bone at the front of the knee joint.

Ankle and Foot

• Tarsal bones: 7 bones in the ankle (Talus, Calcaneus, Cuboid, Navicular, three cuneiform bones).
• Talus: The bone articulates with the tibia and fibula at the ankle joint.
• Metatarsals: 5 bones of the foot (numbered 1-5 from big toe to little toe).
• Phalanges: Toe bones. Each toe has 3 phalanges (proximal, middle, distal), except for the big toe, which has only 2.