Osteology of the back and upper limb

Learning Objectives

1. Vertebral Column:

• Understand general and specific vertebral features.

• Recognize intervertebral discs and their relation to vertebrae.

• Explore vertebrae across regions and their functional differences.

• Identify curvatures in infants and adults.

2. Upper Limb:

• Identify upper limb bones and surface features.

Skeleton Overview

• Axial Skeleton: Central axis (skull, vertebrae, sternum, ribs, sacrum, hyoid).

• Appendicular Skeleton: Pectoral girdle, pelvic girdle, and extremities.

Vertebral Column Features

• Functions:

• Support skull/trunk, allow movement, protect spinal cord, absorb stress, and provide muscle attachment.

• Structure:

• 33 vertebrae, separated by fibrocartilage discs.

• Vertebral regions:

• Cervical (7): Neck.

• Thoracic (12): Chest.

• Lumbar (5): Lower back.

• Sacral (5 fused): Base of spine.

• Coccygeal (4 fused): Tailbone.

Vertebral Curvatures

• Normal Curvatures:

• Cervical, thoracic, lumbar, pelvic.

• Primary (present at birth): Thoracic and pelvic.

• Secondary (develop later): Cervical (from head lifting), lumbar (from walking).

• Abnormal Curvatures:

• Scoliosis: Lateral curvature, often in thoracic region.

• Kyphosis: Exaggerated thoracic curve (“hunchback”).

• Lordosis: Exaggerated lumbar curve (“swayback”).

General Vertebral Features

• Key Components:

• Body: Weight-bearing.

• Vertebral Arch: Protects spinal cord.

• Processes: Spinous and transverse for ligament/muscle attachment.

• Intervertebral Discs:

• Nucleus Pulposus: Gel-like core.

• Anulus Fibrosus: Fibrocartilage outer ring.

Regional Vertebral Features

1. Cervical (C1-C7):

• Smallest vertebrae, large vertebral foramen, transverse foramina (arteries/veins).

• C1 (Atlas): Supports head; allows nodding.

• C2 (Axis): Dens allows head rotation.

2. Thoracic (T1-T12):

• Larger than cervical, pointed spinous processes, costal facets for rib attachment.

3. Lumbar (L1-L5):

• Largest vertebrae, resistant to twisting, blunt spinous processes.

4. Sacrum:

• Fusion of five vertebrae, forms pelvic cavity wall.

5. Coccyx:

• Four fused vertebrae, provides pelvic ligament attachment.

Pectoral Girdle

• Composed of clavicle (collarbone) and scapula (shoulder blade).

• Connects upper limbs to the axial skeleton.

Bones of the Upper Limb

1. Humerus (arm):

• Articulates with scapula (proximally) and radius/ulna (distally).

2. Ulna (medial forearm):

• Trochlear notch (humerus articulation), olecranon process (elbow point).

3. Radius (lateral forearm):

• Articulates with capitulum (humerus) and carpals (wrist).

Wrist and Hand

1. Carpals (8 wrist bones):

• Two rows: Proximal (scaphoid, lunate, triquetrum, pisiform) and distal (trapezium, trapezoid, capitate, hamate).

2. Metacarpals (5 palm bones): Base, shaft, and head.

3. Phalanges (14 finger bones): Proximal, middle, distal.